Handbook of
General Animal
Nutrition
Udeybir Singh Chahal
B.Y.Sc. & A.H., M.Y.Sc., Ph.D.
P.S. Niranjan
B.Sc., B.V.Sc. & A.H., M.V.Sc. (Gold Medalist)
Sanjay Kumar
B.V.Sc. & A.H., M.V.Sc., Ph.D.
Department of Animal Nutrition
College of Veterinary Science & Animal Husbandry
Narendra Deva University of Agriculture & Technology
Kumarganj, Faizabad - 224 229 (U.P.), India
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Contents
PART-I
(Principles of Animal Nutrition
(including Avian Nutrition))
1
2
3
4
5
6
7
8
9
History of Animal Nutrition
The Composition and Comparison of Plants and
Animal Body
Water in Animal Nutrition
The Carbohydrates in Animal Nutrition
The Protein in Animal Nutrition
The Lipids in Animal Nutrition
The Minerals in Animal Nutrition
The Vitamins in Animal Nutrition
Feed Additives in Animal Nutrition
3
13
21
27
57
85
103
131
169
PART-II
(Evaluation of feed stuffs and feed technology)
1
2
3
4
5
6
7
Classification of Common Feeds and Fodders
181
Conservation of Green Fodder in Animal Nutrition 199
Evaluation of Energy Value of Feed in Animal
Nutrition
217
Evaluation of Protein Value of Feed in Animal
Nutrition
237
Processing Methods of Animal Feed Stuffs
251
Various Feed Processing Methods for Improving
the Nutritive Value of Inferior Quality Roughages 259
Harmful Natural Constituents and Toxic
Substances in Animal Feeds
267
Index
xi
"This page is Intentionally Left Blank"
"This page is Intentionally Left Blank"
Chapter
1
History of Animal Nutrition
Definition of Animal Nutrition:
Animal nutrition is made up of two words i.e. animal and
nutrition. Dictionary means of animal is any living thing, other
than a human being, that can feel and move or a creature with
four legs, as distinct from a bird, a reptile, a fish or an insect.
Examples are cattle, sheep, goat, horse, dogs and cat etc. In
dictionary terms, nutrition is "The series of processes by which
an organism takes in and assimilates food for promoting growth
and replacing worn or injured tissues". Therefore, nutrition
involves various chemical reactions and physiological processes,
which transform foods into body tissues and activities. It
involves the ingestion, digestion, and absorption of the various
nutrients, their transport to all body cells, and the removal of
unusable elements and waste products of metabolism So, animal
nutrition is the science of nourishment of animals.
History of Animal Nutrition:
Antoine Lavoisier (1743-1794) was the foun!1er of the
science of nutrition. He was the father of nutrition. He
established the chemical basis of nutrition and stated that life is
and thermameter
a chpmical process. He introduced the セ。ャョ」・@
int nu,."ition studies and designed a calorimeter with Laplace.
At the beginning, it was believed that nutritive value of food
resided in a single aliments. But in early nineteen century it
was proved wrong. William Prout reported that nutrient
constituent of animal body were provided by three principals
i.e. saccharine (carbohydrate), oily (lipid) and albuminous
(protein).
3
Handbook of General Animal Nutrition
In mid 19th century Chosset observed that pigeons on low
calcium diet had poor bone development. The importance of
other minerals like chlorine, magnesium, sodium, potassium and
sulphur were also known during this period.
In late 19th century Takaki observed that Beri-Beri disease
can be prevented by dietary supplementation. All the vitamins
were discovered during the period of 1910-1950.
Stephen M. Babcock (1843-1931) conducted first feeding
experiment with single plants. All the grain and forage were
from either corn or wheat plants. It stimulated the use of the
purified diet method, which resulted in discovery of vitamins.
In 20th century various vitamins, minerals, amino acids,
fatty acids and their role had been discovered. Various feeding
standards indicating the requirements of various nutrients for
various categories of livestock for different functions were
established. Various non-conventional feeds were discovered
as livestock feed. Various economical and balanced rations were
prepared for different categories of livestock. So a lot of work
has been done in 20th century. Even than, there is a great scope
for further improvement and new research in the field of animal
nutrition in 21 st century. For which a lot of research work is on
progress at various research centers and dept. of Animal
Nutrition in various College of Veterinary Sciences & Animal
Husbandry throughout the country and abroad, with a hope of
further improvement and new research in the field of animal
nutrition which will benefit the society in many ways and full
fill the objective to provide all essential nutrients in adequate
amount and in optimum proportions at least cost of feeding to
the animals.
Relationship with other branches of sciences: Animal
nutrition has a direct relationship with Physics, Chemistry,
Biochemistry, Physiology, Genetics and Breeding, Anatomy and
Histology, Biology, Mathematics and Microbiology without
which complete study of animal nutrition is impossible. So
relative study of other sciences are also necessary and helpful
for the animal nutritionists.
4
History ofAmmal Nutrition
Role of nutrition in animal production and health: The
factors responsible for efficient animal production are:
1. Genetic potentiality of animal
2. Nutritional status of animal
3. Managemental factor
Nutrition plays an important role in the animal
production and health by following ways:
1. It exploites the genetic potentiality of the animal. For
example if a cow has capacity to produce 30 litre of milk
per day (by its genetic make up) but it can not be possible
if the cattle is under fed.
2. It makes the animal production cheap and economical.
Because cost of feeding and feeds accounts for 70-80% of
total animal production cost. So it is the major means by
which production system can be made economical.
3. It also minimizes the competition between human and animal for food by introducing non-conventional feed ingredients for animal feeding.
4. It also manipulates feed ingredients for effective utilization of nutrients. In this way nutrition play an important
role in animal production and health.
Milestones in the development of Animal Nutrition:
Sr. Scientists
Contribution
No.
1.
A Lavosier (1762)
Nature
of
respiration,
calorimetery.
2.
William Prout (1834)
Nature of food
3.
Max Rubner (1908)
Energy metabolism
4.
G.]. Mulder (1838)
Gave the name protein
5.
J.B. F. Magendie (1783- Essentiality of food nitrogen
1855)
5
Handbook of General Animal Nutrition
6.
7.
Lawes and J.H. Gilbert Slaughter experiment in farm
(1855)
animals
W.O. Atwater (1892)
First human respiration
calorimeter
8.
9.
10.
11.
12.
Oscar Kellner (18511911)
H.P. Armsby (18511921)
Leonard A. Maynard
(1942)
Max Kleiber (18931976)
E.J. Underwood (1905-
Starch equivalent system of
energy evaluation
Respiration calorimeter for farm
animals
Chairman of the NRC committee
on animal nutrition
Use of the weight to the 0.75
power instead of surface area for
energy metabolism.
Mineral nutrition in livestock
1980)
13. A. Bhattacharya (1980) Study of recycling poultry waste
14.
P.J. Van Soest (1960)
15.
Henneberg and
Stohman (1861)
16. Indian Veterinary
Research Institute,
Izatnagar, (1939)
17. National Dairy
Research Institute,
Kamal (1952)
18. K.c. Sen (1954)
19.
N.D. Kehar (1950)
20.
S.K. Talapatra (1964)
as feed stuffs.
Fibre estimation in feed stuffs
Proximate analysis of feed stuffs
Various research in animal
nutrition
Various research in animal
nutrition
Nutritive value of Indian cattle
feeds and feeding of farm animals
Nutritive value of nonconventional feeds. Wet alkali
treatment to straw
Methods to estimate minerals in
feeds and fodders
6
History ofAnimal Nutrition
21. Indian Council of
Agricultural Research
1(1985)
22. K. Pradhan
Feeding standard for various
categories of livestock.
Chairman of Committee to
develop ICAR feeding standard.
Nutritient requirements for
livestock
23. NRC (National
Research Council,
USA)1942
24. ARC (Agriculture
Nutritient requirements for
Research Council, U.K. ) livestock.
1959
25. Hungate (1966)
Rumen microbiology
26. Casimir Funk (1912)
Gave term vitamine
Nutrition definitions and terms: There are various term
and definitions used in animal nutrition which are described
as:
Nutrition: Nutrition involves various chemical reactions
and physiological processes, which transform foods into body
tissues and activities.
Animal Nutrition: Science of nourishment of animals.
Nutrient: The chemical substances found in the feed
materials are necessary for the maintenance, production and
health of animals. The chief classes of nutrients include- 25
carbohydrates, 15 fatty acids, 20 amino acids, 15 essential and
10 probably essential minerals, 20 vitamins and water or any
chemical compound having specific functions in the nutritive
support of animal life.
Nutriment: Any thing that promotes growth or
development.
Nutriture: Nutritional status.
Health: Health is the state of complete physical, mental
and social well being and not merely the absence of disease or
infirmity as defined by World Health Organization.
Nutritious: Substances that promote growth and
participate in repairing tissues of the body.
7
Handbook of General Animal Nutntion
Nutritionist: A specialist in the problems of nutrition.
Nourish: To feed an animal with substance necessary for
life and growth.
Feed (Feed stuff): Food of animals comprising any naturally
occurring ingredient or material fed to animals for the purpose
of sustaining growth and development.
Diet: A regulated selection of a feed ingredient or mixture
of ingredients including water, which is consumed by animals
on a prescribed schedule.
Ingredients: Any of the feed items that a mixture is made
of.
Additives: An ingredient or a combination of ingredients
added to the basic feed mixture for specific purposes like to
increase feed ingestion or to alter metabolism.
Ration: A fixed amount of feed for one animal, fed for a
definite period, usually for a 24 hour period.
Balanced ration: The ration which provide an animal with
the proper amount, proportion and variety of all the required
nutrients to keep the animal in its form to perform best in respect
of production and health.
Complete ration: A single feed mixture, which has all of
the dietary essentials except water for a given class of livestock.
Purified diet: A mixture of the known essential dietary
nutrients in a pure form that is fed to experimental animals in
nutrition studies.
Fortify: Nutritionally, to add one or more nutrients to a
feed.
Limiting amino acid: The essential amino acid of protein
that shows the greatest percentage deficit in comparison with
the amino acids contained in the same quantity of another
protein selected as standard.
Bran: The pericarp or seed coat of grain removed during
processing.
8
HIstory ofAnimal Nutrition
Groat: Grain from which hulls have been removed.
Zein: A protein of low biological value present in maize,
deficient in lysine and tryptophane amino acid.
Fodder: Aerial parts with ears, with husks or heads.
Stover: Thick solid stem and aerial parts without ears,
husks or heads while harvesting maize, jowar commonly the
earheads is removed and the remaining dried portion can be
classed as stovers i.e. jowar and maize stover.
Hull: Outer covering of beans, peas, cotton seeds.
Husk: Dry outer covering of grains i.e. rice husk, gram
husk.
Shells: Hard outer covering of nuts e.g. groundnut shell.
Corn cobs: After removal of corn grains.
Hay: Hay is the product obtained by drying in the sun or
in the shade, tender stemmed leafy plant material in such a
way that they contain not more than 12-14 percent moisture.
Straw: Straw is the by-product of any cereal, millet or
legume crop left over after harvesting, threshing and removal
of the grains or pulses.
Bagasse: It is the fibrous material left over in the sugar
factories after extraction of all the juice from sugar cane.
Gluten: When flour is washed to remove the starch, a
tough viscid, nitrogenous substance remains. This is known as
gluten.
Germ: It is the embryo of any seed.
Meal: Feed ingredients of which the particle size is larger
than flour.
Shorts: A by-product of flour milling consisting of a
mixture of small particles of bran and germ, the aleurone layer
and coarse fibre.
Malt sprouts: The radical of the embryo of the grain
9
Handbook of General Animal Nutrition
removed from sprouted and steamed whole grain. These are
obtained as by-products of liquor processing.
Red dog: By product of milling spring wheat consists
primarily of the aleurone with small amounts of flour and fine
bran particles.
Alkaloids: Alkaloid constitu tes a large number of the active
principles of plants and all possess a powerful physiological
action.
Anatoxin: A toxin rendered harmless by heat or chemical
means but capable of stimulating the formation of antibodies.
Antizymotic: An agent, which inhibits fermentation.
Avitaminosis: A condition produced by a deficiency or
lack of a vitamin in the food.
D-value: It is percentage of digestible organic matter in
the dry matter of the feed. It describes the digestibility of animal
feed.
In vitro: Literally "in glass" pertaining to biological
experiments performed in test tubes or other laboratory vessels.
In vivo: Within the living organisms pertaining to the
laboratory testing of agents within living organisms.
Effluent: Liquid waste from an abattoir or slurry.
Gavage: Feeding an animal by means of a stomach tube.
Feed Conversion efficiency (FCE): The gain in weight in
Kg or lb, produced by one Kg or one lb of feed. It is reciprocal
of the feed conversion ratio.
Feed conversion ratio (FCR): The amount of feed in Kg or
lb necessary to produce one Kg or one lb of weight gain.
Calorie: A unit of measurement used for calculating the
amount of energy produced by various foods. It is the amount
of heat needed to raise the temperature of I gram of water by
IOC (14.50C-15.50C).
Proteins: These are complex nitrogenous organic chemical
10
History ofAnimal Nutrition
compounds specially made up of C,H, 0, S and a large but fairly
constant amount of nitrogen.
Mineral or Ash or inorganic element: A substance is ashed
to the extent that there is no black particle left, the remaining
portion is called mineral or ash.
Non-protein Nitrogenous compounds (NPN): Certain
substances that do not contain protein but are rich in nitrogen
content e.g. Urea, amides and ammonium salt.
ForagejRoughage: Poor quality feeds containing lesser
amount of total digestible nutrients (TDN) or more than 35
percent cell wall constituents and more than 18 percent of crude
fibre (CF).
Concentrate: It contains little amount (less than 18 percent)
of crude fibre and more than 60 percent total digestible nutrient.
Probiotics: Probiotics are viable defined microorganisms
in sufficient numbers, which alter the microflora of the host
intestine and by that exert beneficial health effects on the host.
Silo: A semi-air tight structure designed for use in
production and storage of silage.
Q.1 Fill in the blanks:
1. A French chemist - - - - - is known as father of sciences
of nutrition.
2. ICAR feeding standard was developed in - - - - - year under the chairman ship of - - - - - - - - - - .
3. S.K. Talapatra developed methods to estimate - - - - in feeds and fodder.
4. IVRI Izatnagar was established in year- - - - - - - -.
5. NDRI Kamal was established in - - - - - - year.
6. Proximate analysis of feed stuffs was given by - - - - - - - and-----.
7. The term protein was derived by - - - - - - - - - -
11
Handbook of General Animal Nutrition
William Prout (1834) explained the - - - - - - - - - .
Study of recycling poultry waste as a feed stuff is given
by-------.
10. NRC, started publication of Nutrient requirement for live.:
stock in year- -whereas ARC start it in - - - - - - -
8.
9.
11. Biological experiments performed in test tube is called 12. An agent which inhibits fermentation is known as - - 13. Embryo of any seed is called - - - - - - - - where as
hard outer covering of nuts is called - - - - - - - 14. A fixed amount of feed for an animal fed for a 24 hour
period is called - - - - .
15. A protein of low biological value present in Zea maize is
referred as - - - - - - .
16. - - - - - - - - (1843-1931) conducted first feeding experiment with single plant.
Q.2 Write short notes on the following :
1. Mention the contribution of five scientists in the field of
animal nutrition.
2. Name the three national institutes involved in research
activities attires in the field of animal nutrition.
3. Mention the name of five books of animal nutrition with
their author or authors including three Indian authors'
books.
4. How nutrition play important role in animal production
and health. ?
5.
Mention any five researches, which proved to be a milestone in the field of animal nutrition.
12
Chapter
2
The Composition and
Comparison of Plants and
Animal Body
The chemical composition of plant and animal represents
all the physical" and chemical basis of protoplasm of the living
processes, which occur in it. The animal body derives all the
nutrients for its physiological functions from the digestion of
plant and plant products with limited amount of animal origin
feeds such as fish meal and milk. 50 a brief consideration of the
chemical composition of the animal in relation to the composition
of its food is useful to give a general picture of the nutritional
process. We must know the chemical composition of farm
animals to understand their nutrient requirement and
composition of plants because they furnish most of the food for
livestock.
Chemical composition of plants and animals: Plants and
animals tissues are made up of similar type of chemical
substances but their relative amounts are variable. Plants are
analysed by proximate method of analysis given by Henneberg
and 5tohmann (1861). Whereas, animal body was first analysed
by Lawes and Gilbert (1858) by slanghter experiments. Most of
the nutrients present in plants and animals are arranged in to
six groups, which are water, protein, carbohydrate, fat, mineral
and vitamin. Plants and their by-products show much larger
differences in the chemical composition than the animals.
Plants synthesize complex materials from simple substances
such as carbondioxide, water, nitrates and other mineral salts
from the soil and energy trapped from the sun by the process
13
Handbook ofGeneral Animal Nutrition
of photosynthesis. The greater parts of the energy trapped as a
chemical energy within the plant itself and the animals use this
energy. Thus, plants store and animals dissipate energy. The
approximate chemical compositions of some plants, animals and
their by-products have been given in Table 2.1.
Table 2.1 Approximate percent chemical composition of some
plants, animals and their by-products
Water Crude Fat Carbohydrates Ash
Iprotein
Greenplants
Berseem
Cowpea
Maize
Pasture grass (Young
leafy)
Cereal grains
Wheat
Groundnut
Plant by- product
Wheat straw
Paddy straw
Wheat bran
Rice bran
Animal
New born calf
Dairy cow
Sheep
Pig
Hen
Animal by-product
Blood
Muscles
Milk
90.0
80.0
75.0
84.0
2.0
2.50
2.0
3.60
0.3
0.5
0.6
1.0
6.3
15.0
21.0
10.0
1.4
2.0
1.4
2.4
13.0
6.0
12.0
27.0
2.0
45.0
71.2
20.0
1.7
2.0
10.0
10.0
10.0
10.0
3.5
3.5
10.0
10.0
1.5
1.5
3.0
15.0
76.5
70.5
70.0
55.0
8.5
14.5
7.0
10.0
74.0
57.0
74.0
60.0
57.0
19.0
17.0
16.0
13.0
21.0
3.0
21.6
5.0
24.0
19.0
-
4.0
5.0
4.4
3.0
3.0
82.0
72.0
87.0
16.4
21.4
3.5
0.6
4.5
4.0
0.1
0.6
4.7
0.7
1.5
0.8
-
Basis of expressing the chemical composition: The chemical
composition of the feed stuffs can be expressed in two ways-
14
The Composition and Comparison of Plants and Animal Body
1.
2.
On fresh basis (as such basis): On as such basis means
expressing the chemical composition of the feed as is fed
to the animals. The advantage of this expression is that it
helps in computation of ration.
On dry matter basis: Chemical composition of feed stuffs
is expressed on dry matter basis. The advantage of dry
matter basis is that various feed stuffs can be compared
among themselves by bringing at same standard unit of
measurements. The average chemical composition in round
figures of the common Indian feed stuffs is given in Table2.2.
Table 2.2 : Chemical composition of some common feed stuffs
Feed stuffs
DM CP
EE CF NFE Ash Ca P
Straw (Dry matter basis)
Wheat straw
90
3
1
38
46
12
Paddy straw
90
3
1
32
49
15 0.33 0.07
Ragi straw
90
3
1
36
52
8
Gram straw
90
6
0.5 45 35.5
13
0.3 0.1
-
-
1.0 0.08
Oil cakes (Dry matter basis)
Mustard cake
90.0 36.0 1.0 10.0 33.0 10.0 0.9 1.0
Til cake
90.0 45.0
0.0 5.0 29.0 11.0
-
-
Groundnut cake
90.0 52.0 8.0 7.0 27.5 5.5
-
-
Cotton seed cake
90.0 23.0 9.0 24.0 37.0 7.0
-
-
Brans (Dry matter basis)
Rice bran
90.0 12.0 5.0 13 45.0 15.0 0.08 1.5
15
Handbook of General Animal Nutrition
Wheat bran
90.0 13.0 2.5 13 64.5
7.0 0.10 1.0
Grains (Dry matter basis)
Gram
90.0 9.50 3.5 9.5 63.5
3.5 0.30 0.40
Maize
90.0 12.0 4.0 2.0 80.0
2.0 0.04 0.35
Barley
90.0 13.0 5.0 13 64.0
5.0 0.10 0.35
Hays (Dry matter basis)
Indigenous grasses
85.0 5.0 1.0 50 47.0 12.0 0.3 0.20
Pasture grasses (dub 85.0 10.0 1.5 30 48.5 10.0 0.35 0.25
etc.)
Leguminous hay
85.0 15.0 2.0 30 41.0 12.0 1.5 0.25
Non -leguminous fodder (on wet basis)
Napier
25.0 2.0
0.5 10
12
1.35 0.06 0.05
Maize
25.0 2.0
0.6
8
13
1.40 0.07 0.05
Jowar
75.0 1.5 1.0
9
12
1.50 0.09 0.03
Oat
25.0 3.0 0.8
6
14
1.00 0.10 0.08
Leguminous fodder (on wet basis or as such basis)
Berseem
15
0.5
0.5
4
4.5
3
.30 0.05
Lucerne
25
1.0 1.0
7
9
3.5
.40 0.07
Comparison of plants and animal body composition:
Though the plants and animal bodies are made up of same
constituents but their proportion is variable. So there are a lot
of differences in animal and plant composition. In animals the
major structural material is protein and minerals in the ratio of
4:1 on moisture and fat free basis which remain almost constant.
16
The Composition and Comparison oiPlants and Animal Bodlj
Whereas plants are made up of carbohydrates like cellulose,
hemicellulose, pectin and lignin. Other differences are tabulated
as:
S.No.
1.
2.
3.
Parameters
Major constituent
Major organic
constituent
Structural
component
4.
Reserve material
5.
Carbohydrates
amount
Minerals amount
6.
7.
Variation in
composition
Animal
Water
Protein
Plants
Water
Carbohydrates
Protein and
mineral
Carbohydrates
(Cellulose,
Hemicellulose etcl
Carbohydrates (Starch)
Fat
(Glycogen)
Less
Generally
constant to
species
Less
More
Wide variation
Wide
Factors affecting chemical composition of plants: The
chemical composition of plants depends very much upon their
growth. The following factors affect the plant composition:
1. Plant factor: There is a marked difference in the chemical
composition between the different varieties of the same
species of forage because of different genetic material.
2. Agro-climatic condition: When a forage plant is exposed
to variable agro-climatic conditions it shows variable
growth performance, which directly reflects the chemical
composition. The factors like atmospheric temperature and
humidity affect the chemical composition of plants.
3. Cultivation practices: The cultivated forages, under the
same agro-climatic conditions perform in different ways
depending on the cultivation practices. The seed rate, seed
treatment, time of sowing, method of sowing, manure and
fertilizer, irrigation, weeds and disease control measures
not only influence the growth and yield of the forages but
also chemical composition.
17
Handbook of General Animal Nutrition
4.
5.
Stage of growth: There is a relationship between the stage
of growth of the plants and its chemical composition. The
content of crude protein, soluble ash, phosphorus and potash is higher just before flowering and goes down at bloom
and seed formation stage whereas, crude fibre and dry
matter content increase as the plant matures. Ether extract
goes down with the progressive maturity of the plant.
Processing and preservation practices: The changes in
chemical composition of plants are very much influenced
by method of processing and preservation. Different
processing methods may change particle size, particle shape,
nutrient contents and also composition of plant materials.
Biochemical basis of soil, plant and animal: The plant
synthesized their feed from CO2 and H 20 in the presence of
sunlight and chlorophyll in the form of carbohydrates, which is
structural as well as storage component of plants. They absorb
minerals (Inorganic component) as well as water from soil and
precede various biochemical reactions in plant body. Many
factors like applicati0n of manures and fertilizers, irrigation,
stage of growth, frequency of cutting, type of variety and strain
and soil composition affect the chemical composition of the plant.
As the composition of soil changes, it also affects composition
of plants.
Similarly, animals utilize the plants and plant by products
as their food. So composition of plants and soil also reflected
into animal body composition. When plants and animals died,
they are mixed into soil as a decaying organic material or as
inorganic material when these are burnt. Animals also nourished
the soil by their faeces, urine and other excretion and wasteproducts. Similarly plants dropped their dried leaf and fruits
on the soil. So plant and animals affect the chemical composition
of soil and the soil also have the same function. So there is a
close inter-relationship between plants, animals and soil. And
they are closely interrelated with each other. This indicates the
biochemical basis of soil, plant and animals.
18
The Composition and Comparison of Plants and Animal Body
Q.1. Fill in the blanks:
1. A major constituent of animal and plant body is - - - -.
2.
Structural component of animal body is
Where as plants are made up of _ _ __
3.
is the main structural components of plants
where as
is storage component of plants.
There is a
variation in plant composition, whereas
_ _ _ Variation in animal body composition.
Reserve material in animal body is _ _ __
4.
5.
6.
and
Proximate's analysis of plants was given _____ and
7.
Animal body was analysed by slaughter experiment technique by
and _ _ _ _ _ __
8.
On a fat and moisture free basis animal body contain _ _
percent protein and
percent minerals.
9. On advancing age of maturity in plants - - - - - - - content increases.
10. Most of the straw has - - - - - percent moisture content.
11. Groundnut cake has - - - - - - % CP and - - - - % EE.
12. Plants synthesize complex materiaJs from simple substances
in the presence of sun light by the process of - - - - - Q.2. Write short notes on following.
1.
Factor affecting chemical composition of plants.
2.
3.
Importance of plants composition in animal nutrition.
Importance of animal body composition in animal nutrition.
4.
5.
Comparison of plants and animal body composition.
Inter-relationship between plant, animal and soil composition.
19
"This page is Intentionally Left Blank"
Chapter
3
Water in Animal Nutrition
Among the nutrients indispensable (essential) for life, water
ranks second only to oxygen in importance. Doubtless, water
is the most important dietary essential nutrient. Loss of about
1j5th of body water is fatal.
Water, which is composed of hydrogen and oxygen in
the ratio of 2:1 is not only the largest single constituent of nearly
all living plants or animal tissues but it also performs
exceedingly important function. It is organic macronutrient. The
water content in the plant decreases with the progressive
maturity. The growing plants usually have 70 to 80 percent of
water and seeds that have been thoroughly cured generally
have at least 8-10 percent of water. Water content in animal
body may differ due to age and nutritional status of animal.
The animal body may contain 50 to 95 percent water. In
case of cattle water content is approximately 95 percent for the
embryo, 75 to 80 percent at birth, 68 to 72 percent at five month
and 50 to 60 percent in the mature animals. Whereas blood
contains 90-92 percent, muscle contains 72-78 percent bones
contain about 45 percent and enamel of teeth which is hardest
tissue of body contains 5 percent water.
Functions of Water:
1. Water is an essential constituent of the animal body.
2. It is an essential part of foodstuff. It makes the food soft
and palatable.
3.
4.
It helps in regulating body temperature.
It helps in absorption and transportation of nutrients to
different parts of the body.
21
Handbook of General Animal Nutrition
5.
It is an essential constituent of almost all the juices and
secretion of the body.
6. It helps in the excretion of waste product in the form of
urine, faeces and perspiration from the animal body.
7. It acts as a solvent of many constituents of body nutrients.
All the biochemical and physiological reactions take place
in liquid medium.
8. It provides shape to the body cells and essential for cell
nutrition. The metabolic water produced inside the body
help in transportation of nutrients inside the body cells.
9. During the period of hibernation, metabolic water keeps
the animal alive.
10. It helps in maintaining the acid-base balance of the body.
11. It helps in hearing by the ears and visions by the eye.
12. It acts as a cushion for tissue cells and nervous system and
protects the various vital organs against shocks and injuries.
Sources of Water:
1. Drinking water: It is consumed by the animals from the
out side source.
2. Feed: Moisture content of all the feeds supplies the water
requirement of the animal.
3. Metabolic / Oxidation water: It is the water, which is produced due to metabolism of nutrients. It meets 100 percent of water requirement in hibernating animals and embryo, 5-10 percent in domestic animals and 16-26 percent
in desert animals. A 100 g of each fat, carbohydrate and
protein metabolism produce 107, 60 and 40g metabolic
water, respectively.
4. Bound water: The water, which is combined with the constituents of protoplasm by either physical or chemical
means. It can not separated easily from protoplasm by
freezing at low temperature or by evaporation at high temperature or under dry conditions. Bound water is of special interest in connection with the ability of plants and
22
Water in Animal Nutrition
animals to resist at low temperature and drought condition.
Daily average water requirements of domestic animals:
Cattle
30-40 kg
Milking Cattle
30-40 kg + 1.8 kg per kg milk
Buffalo
40-50 kg
Horse
30-40 kg
Sheep, Goat and Pig
4-10 kg
Poultry
200-400 g
Rabbit
300 g
Guinea pig
30 g
Rat
6-10 g
Factors affecting water requirement:
1. Environment: Increased environmental temperature and
humidity enhanced the water requirement in comparison
to cold environment because of increased evaporative
losses in hot and humid environment.
2. Dietary factor: High fibrous diet like dry roughages increases water requirement than less fibrous diet. Salt and
uric acid excretion requires more water. So intake of salt
and protein whose end product is uric acid increases the
water requirement. If succulent feed is given to animals
than dietary water requirement is reduced. So a 3-4 kg
water per kg OMI is required for most of the animals ャゥォセ@
cattle, buffalo, horse and pig etc. whereas sheep requires
2 kg/kg OMI and poultry requires 2-3 kg/kg OMI. Young
animals have higher water needs per unit of body size as
compare to large animals.
3. Animal factor: Age, stage of growth, level of production,
activity, health condition and pregnancy has a direct effect
on water requirement. Other factors are salinity and sulfate
content of water, temperature of water, frequency and
periodicity of watering, social or behavioral interactions
23
Handbook of General Animal Nutrition
of animals with environment, and other quality factors such
as pH and toxic substances affect water requirement and
intake. Birds require less water as compared to mammals
because uric acid is the end product of protein metabolism
in birds as urea in mammals.
Water metabolism: It includes absorption, homeostasis
and excretion.
1. Absorption: Absorption takes place from all the parts of
G.LT. mainly large intestine. Organs of the digestive tract
absorb most of the water ingested by an animal. A number
of factors like osmotic relations inside the small intestine
and nature of the carbohydrate component of the feed
determine the extent to which absorption actually occurs.
Water is most readily absorbed when it is taken alone as
beverage, or when taken with food that after digestion
forms a solution with osmotic pressure lower than that of
blood plasma.
2. Homeostasis: It is the maintenance of uniformity and stability of water. Water balance is affected by total intake of
water and losses arising from urine, faeces, milk, saliva,
sweating and vaporization from respiratory tissues. It is
maintained by two mechanisms.
(1) Anti diuretic hormone
DeprivatIOn of water
Haemo lncentration
1
Increased plasma osmoconcentration
Drying
ッセ@
Osmoreceptors in mouth
get activated & StimulatIOn in
certain cell of hypothalamus
and cerebral ventricles
iョBGセdh@
1 セLイ・G[ッョ@
by Pltult.')' gl.nd
kidney
Increased reabsorption of water
and decreased unne volume.
!
Stimulation for thirst - -•• Oral sensation for drinking water.
24
Water in Animal Nutrition
(2) Salt- appetite aldosterone mechanism: Sodium chloride
salt is an important for water retention. If NaCl decreased,
water content is also decreased. Decreased Na+ stimulate
renin synthesis which synthesize Angiotensinogen which
convert angiotensin-I into angiotensin-II. Angiotensin-II
promotes synthesis of aldosterone, which will act on kidney, and increased Na+ reabsorption, which reflects in increased water absorption and retention, and homeostasis
of water, is maintained.
3. Excretion: Water if excreted from body by evaporation
through skin, perspiration through expired air, and
through faeces, urine, milk, tear and saliva. Amount lost
via various routes are affected by amount of milk produced, ambient temperature, humidity, physical activity
of the animal, respiration rate, water consumption and
dietary factor.
Symptoms of deprivation of water: Anorexia, discomfort
and inco-ordination in movement, decreased blood pressure
and cardiac output, increased respiration rate, shrivelled skin,
increased body temperature, delirium and death if deficiency
of water continue.
Toxic elements in water: Universal solvent property of
water sometime creates problems. Water can dissolve unwanted
material. Such water should not be used for drinking purpose.
Amount of total dissolved solids (TDS) is a measure of the
usefulness of water for animals. A level of less than 3,000 mg/
litre TDS can be tolerated by the animals but higher amount is
harmful to animals.
Q.1. Fill in the blanks:
1. . ............... is the hardest tissue of body which contain- - - - % water.
2. 100 g fats metabolism produce- - - - --- - g metabolic
water whereas 100 g carbohydrates and 100 g proteins
metabolism produce - - - - - - - - and - - - - - - - g metabolic water, respectively.
,
25
Handbook of General Animal Nutrition
3.
Loss of about - - - - - - - - - - part of body water is
fatal.
4. Metabolic water meets out - - - - - - - - % requirement in hibernating animals and - - - - - - - - - - - - % in desert animals.
5. Poultry requires - - - - - - - - - - - kg water per kg
DM!.
6. Milking animals require - - - - - - - - - - kg water
per kg milk produced.
7. High fibrous diet - - - - - - - - - - - - - - water
requirement.
8. Water content in animal body may differ due to - - - - - - - - - - - - and - - - - - - - - - - of animal.
9.
- - - - % TDS (total dissolved solid) in drinking water
is tolerable by animals.
10. Birds require- - - - - - - - water compared to mammals.
11. Young animals have - - - - - - - - - water needs per
unit of body size than mature animals.
12. Angiotensin-II promotes synthesis of - - - - - - - - 13. Water homeostasis is controlled by two hormones viz. - - - - - - - - and - --------14. - - - - - - -kg water per kg DMI is required for most
of the animals.
15. Bones and enamel of teeth contains - - - - - - and - - - - percent water, respectively.
Q.2.
1.
2.
3.
4.
5.
6.
Write short notes on the following :
Important function of water.
Homeostasis of water in body.
Deficiency symptoms of water.
Factor affecting water requirements of body.
Differentiate between bound water and metabolic water.
Toxic elements in water.
26
Chapter
4
The Carbohydrates in
Animal Nutrition
Definition of carbohydrates: Carbohydrates may be
defined as polyhydroxy aldehyde, ketones or acids and their
derivatives or compounds that yield these derivatives on
hydrolysis. The carbohydrates are neutral chemical compounds
containing the element carbon, hydrogen and oxygen, with the
last two elements present in the same proportion as in water
mostly, but not at alL One of the example of carbohydrate where
such ratio is not found in the sugar deoxyribose (CsHIOOJ which
is a constituent of DNA. Whereas acetic acid (c;H40 2) and lactic
acid (C 3H 60 3 ) can be represented as hydrates of carbon but are
not carbohydrates. The carbohydrates serve as both structural
and reserve material in the plant. The animal body contains
less than 1 percent carbohydrate, which are present in blood,
muscles and liver. The carbohydrate present in animal body is
also known as animal starch or glycogen.
Based upon their digestibility and solubility, the
carbohydrates can be divided into two groups.
(a) Soluble carbohydrates: They are called nitrogen free extract
(NFE) and include simple sugar, starch and hemicellulose,
which are easily digestible in the body.
(b) Insoluble carbohydrates: They include hard fibrous substance like crude fibre, cellulose and lignin. They are less
digestible by non-ruminants and easily digested in ruminants by rumen microflora and microfauna.
27
Handbook of General Animal Nutrition
Functions of Carbohydrates:
1. Carbohydrates serve as a major source of energy in animal body.
2. They are essential components of production, temperature
control and proper functioning of the different parts of
the animal body.
3. They are essential components of milk as lactose.
4. They are stored as glycogen, excess of carbohydrates in
the diet is converted into fat and stored in the fat depot.
These are reserve energy materials of the body in liver
and muscles of animals and starch in plants.
5. Carbohydrates are helpful in absorption of calcium and
phosphorus in younger animals.
6. They help the secretion of digestive juices in gastrointestinal
tract.
7. They provide suitable environment for the growth of
rumen bacteria and protozoa.
8. They help in peristaltic movement of food.
9. They maintain the glucose level of plasma.
10. They are also component of several important bio-chemical compounds such as nucleic acids, coenzymes and blood
group substance.
11. They playa key role in the metabolism of amino acids and
fatty acids.
Classification of Carbohydrates: The carbohydrates are
usually divided in to two major groups:
I. Sugars: The term sugar is generally restricted to those
carbohydrates, which contain less than ten monosaccharide
residues. Sugars are divided into two groups.
28
The Carbohydrates In Animal Nutrition
Sugar
Oligosaccharide
Mono ccharide
1
I
.J
Tnose
Tetroses
1
Glyceraldehyde
Dihydroacetone
1
I
I
Heptoses
Hexoses
Pentoses
L=,l
1
Arabinose
Xylose
Xylulose
Ribose
Ribulose
1
Sedoheptulose
Glucose
Galactose
Mannose
Fructose
(i) Monosaccharides: The simplest sugars are the
monosaccharides and they can not be hydrolysed into smaller
units under reasonably mild conditions. They are divided into
sub-groups depending upon the number of carbon atoms
present in the molecules e.g. Triose (C;H60 3), Tetroses (C4H 60 4 ),
Pentoses (CSH100S) and Hexoses (C 6H 120J The formula for the
four common hexoses has been given below:
cセo@
CHO
CHO
CH20H
HcicH
H\OH
t=O
HOCH
HOCH
HOCH
hセ@
HCOH
HcfoH
HOCH
HCOH
HtOH
HboH
HCOH
HboH
CH20H
(H20H
CH20H
CH20H
(D-Glucose)
(D-Mannose)
(D-Galactose) (D-Fructose)
hセ@
/
/
I
I
/
/
/
/
Sugar containing an aldehyde (CHO) group, are classed
as aldose. e.g. glucose, mannose and galactose. Whereas sugars
containing a ketone group are classed as ketoses e.g., fructose.
29
Handbook of General Animal Nutrition
Presence of active aldehyde and ketone group in
monosaccharide act as reducing sugar substances. They can be
oxidized to produce number of acids like gluconic acid, glucaric
acid and glucoronic acid. The reducing properties of these sugars
are usually demonstrated by their ability to reduce certain metal
ions such as copper or silver in alkaline solution.
Pentoses: Pentoses have the general formula CSH100S. The
most important member of this group are the aldoses,
L-arabinose, D-xylose and D-ribose,and the ketoses, D-xylulose
and D-ribulose.
L-Arabinose: Occurs in pentosans as arabans. It is a
component of hemicellulose and gum and present in silage.
D-xylose: Also occurs in pentosans in the forms of xylans.
These compounds form the main chain in grass hemicellulose
and xylose along with arabinose produce in considerable
quantities when herbage is hydrolysed with normal sulphuric
acid.
D-Ribose: It is present in all living cells as a constituent of
ribonucleic acid (RNA) and it is also a component of several
vitamins and coenzymes.
Hexoses: Glucose and fructose are the most important
naturally occurring hexose sugar, while mannose and galactose
occur in plants in a polymerized form as mannans and galcutans.
D-Glucose: This sugar occurs in plants, fruits, honey, blood
and other body fluid. Glucose is the major component of many
oligosaccharide, polysaccharide and glucosides. In the pure
state, glucose is a white crystalline and soluble in water.
Fructose or fruit sugar: It occurs free in green leaves, fruit
and honey. It also occurs in disaccharides-sucrose and in
fructosans. It differs from other sugars in being laevo-rotatory
and also known as fruit sugar.
Mannose: It occurs in polymerized form as mannan. It does
not occur free in nature.
Galactose: It is a constituent of disaccharide lactose, which
30
The Carbohydrates In Animal Nutrition
occurs in milk and is also a component of gum, mucilages,
pigments etc. It does not exist free in nature as Mannose.
Heptoses: Sedoheptulose is an important example of a
monosaccharide containing seven carbon atoms. This heptose
occurs as the phosphate, as an intermediate in the pentose
phosphate metabolic pathways.
(ii) Oligosaccharides: The oligosaccharide (Oligo=few)
includes all sugars other than the monosaccharides. The
monosaccharides linked together with a elimination of water
at each linkage and-produces di, tri, tetra or polysaccharide
containing 2,3,4 and large number of simple sugar molecules,
respectively.
Oligosaccbarides
l I
+
+
Disaccharide
TrifCharide
Tetrasaccharide
Sucrose
Lactose
Maltose
Cellobiose
Raffinose
Kestose
Stachyose
!
1
Disaccharides: The most frequently occurring
oligosaccharides in nature are disaccharides, which on
hydrolysis yield two moles of simple sugar. Disaccharides
consist of two molecules of hexose sugars combine together
with loss of one molecules of water.
RcVセP@
セ@
C12H 220 n +H 20
The most important disaccharides are sucrose, lactose,
maltose and cellobiose.
Sucrose, cane sugar, beet sugar or sacchrose: It is the
familiar sugar of domestic use, widely distributed in nature
and occurs in most of the plants. Sucrose is easily hydrolysed
by the enzyme sucrase or by dilute acids and gives one molecule
of a-D glucose and one molecule of P-D- fructose.
31
Handbook of General Animal Nutntion
Lactose or milk sugar: It occurs in milk only as a product
of mammary gland. Cow's milk contains 4.6 to 4.8 percent
lactose. It is not as soluble as sucrose and is less sweet, imparting
only a faint sweet taste to milk. On hydrolysis it produces one
molecule of glucose and one molecule of galactose.
Maltose or malt sugar: It is produced during the hydrolysis
of starch and glycogen by dilute acids or enzymes or during
the germination of barley by the action of the enzyme amylase.
The barley after germination and drying is known as malt and
is used in the manufacture of beer and scotch malt whisky.
Maltose is water-soluble but it is not as sweet as sucrose. On
hydrolysis it yields two molecules of glucose.
Cellobiose: Cellobiose does not exist naturally as a free
sugar, but is the basic repeating unit of cellulose. It is less soluble
and less sweet.
Trisaccharides: The unions of three molecules of hexose
sugars form trisaccharides.
3C6f\2 0 6
MZNセ@
SgH320 16 + Rセo@
Raffinose distributed widely in plants. On hydrolysis this
sugar produces glucose, fructose and galactose. It is a nonreducing sugar.
Tetrasaccharides: Tetrasaccharides are produce by the
union of four hexose residues.
4C6 H 120
6 ""'"
'=:",
°
C24H 42
21
+ Sセッ@
Stachyose is an example of tetrasaccharide, which is a nonreducing sugar, and hydrolysed to two molecules of galactose,
one molecule of glucose and one molecule of fructose.
II. Non-sugars: They are tasteless, insoluble, amorphous
compounds with a high molecular weight. They are divided
into two sub groups.
(1) Homopolysaccharides: They are classified according to
the kind of sugar, which produce on hydrolysis. For example, glucans are condensation polymer of glucose,
32
The Carbohydrates in Animal Nutrition
fructans of fructose and xylans of xylose. This group of
polysaccharides are a polymers of monosaccharides derivatives, such as sugar acid (eg., galacturonans) and sugar
amines (e.g. glucosaminans).
(2) Heteropolysaccharides: They are mixed polysaccharides,
which on hydrolysis yield mixtures of monosaccharides
and derived products.
NonrSugar
Complex
pOlylaccharide
!
HOmrt!ysaCCharide
HeTo!ysacLde
Arabinans
Xylans
Glucans
Fructans
Galactans
Mannans
Pectic substances
Hemicelluloses
Exudate gums
Hyaluronic acid
」。イ「ッィセ、エ・@
1
Glycolipids
G Iycoproteins
Homopolysaccharides:
Starch: The reserve materials of most plants consist
primarily of starch. When this is hydrolyzed with acids or
enzymes, it is changed into dextrin, maltose and finally into
glucose. In food this exists as a straight chain of glucose units
called amylose, mixed with a branched chain structure called
amylopectin. The quantity of amylose can be estimated in starch
by a characteristic reaction with iodine, amylose produces a
deep blue colour while amylopectin solution produce a blue
violet or purple colour.
Amylose + Iodine - -----. Deep blue colour
Amylopectin + Iodine -
----. Blue violet or purple colour
Amylose is composed of linear molecules in which the D-glucose residues are linked between carbon atom 1 of one
molecule and carbon atom 4 of the adjacent molecule where as,
amylopectin has a bush-like structure containing primarily -1,4
33
Handbook of General Animal Nutrition
linkages but the molecule also contains side chains in which
carbon atoms 6 of glucose residues is linked with carbon atom
1 of the other glucose.
Starch granules are insoluble in cold water, but when the
suspension water is heated the granules swell and eventually
the granule sacs rupture and a gelatinous is formed.
1.
2.
3.
Amylose
a- 1,4 linkage between
glucose unit
Amylopectin
a- 1,4 linkage in straight
chain and a-l,6linkage in
branched chain are
Ipresent.
Only straight chains is there Straight as well as
branched chains are
present.
Iodine test gives deep blue Iodine test gives blue violet
colour
orJ?ur£1e colour
Glycogen:.The small amount of carbohydrate reserve in
the liver and muscles in the form of glycogen, which is also
called Animal starch". They form colloidal solutions, which
are dextra-rotatory. Glycogen is the main carbohydrate storage
productin the animal body and plays an essential role in energy
metabolism.
II
Dextrins: These are intermediate products of the hydrolsis
of starch and glycogen:
Starch
} _ _ _ _ _ _•
• Dextrin
_
maltose--.glucose
Glycogen
Dextrins are soluble in water and produce gum like
solutions. The higher members of these transitional products
produce a red colour with iodine, while the lower members do
not give a colour. The presence of dextrin gives characteristics
flavour to bread crust, toast and partly charred cereal foods.
Cellulose: It is glucan and is the most abundant plant
constituent, farming the fundamental structures of the plant
34
The Carbohydrates in Animal Nutrition
cell walls by farming chemical linkages with hemicellulose and
lignin. Cellulose molecule contains between 1600 to 2700 15-Dglucose units. Cellulose is more resistant to chemical agents than
the other glucosans. On hydrolysis with strong acid glucose is
produced. Enzyme produced by germinating seeds, fungi and
bacteria attack cellulose and produce cellubiose, whic!: is acted
upon by enzyme cellubiase and produces glucose. It is fermented
in the rumen by the microbial enzymes and produces volatile
fatty acids like acetic acid, propionic acid and butyric acid.
Frutosans: It occurs as reserve material in roots, stems,
leaves and seeds of a variety of plants. Fructans are hydrolysed
to D-fructose and of D-Glucose. Inulin is the known
polysaccharides belong to this group.
Galactans and Mannans: These are polysaccharides, which
occur in cell wall of plants. It is a component of palm seeds,
clovers and Lucerne.
Pectin: The term pectic substance is used to refer to a group
of plant polysaccharides in which D-galacturonic acid is the main
constituent in which some of the free carboxyl groups are
esterified with methyl alcohol and others are combined with
calcium or magnesium ions. D-galactose and L-arabinose are
also present as additional components. Pectic substances are
found in peel of citrus fruit, sugar beet pulp. Pectinic acid posses
gelling properties and are used in Jam making.
Chitin: It is a major constituent of the exoskeleton of insects
and crustacea. It is the only known example of a
homopolysaccharide containing glucosamine being a linear
polymer of acetyl-D-glucosamine. Next to cellulose, it is
probably the most abundant polysaccharide in nature.
Heteropolysaccharide:
Hemicellulose: The hemicellulose is a group of substances,
including araban, xylan and certain hexosans and polyuronides,
which are much less resistant to chemical agents than cellulose.
It is insoluble in boiling water but soluble in dilute alkali and
hydrolyzed by dilute acids to simple sugar and uronic acid such
as glucuronic and galacturonic acid.
35
Handbook of General Animal Nutrition
Gum arabic: It is a useful plant gum and produced from
the wound in the plant, although they may arise as natural
exudates from bark and leaves. Acacia gum has long been
familiar substance; in hydrolysis it yields arabinose, rhamnose
and glucuronic acid.
Mucilages: Mucilages are found in few plants and seeds.
Linseed mucilage produces arabinose, galactose, rhamnose and
galacturonic acid on hydrolysis.
Agar: It is sulphated polysaccharides. They are found as
constituents of seaweeds and in mammalian tissues. It is used
as a gel-farming agent in microbial studies. Agar is a mixture of
at least two polysaccharides containing sulphate ester of
galactose, glucuronic acid and other compounds.
Hyaluronic acid: It is grouped under amino
polysaccharides. It is present in the skin, synovial fluid and
umblical cord. Solutions of this acid are viscous and play an
important role in the lubrication of joints. HyalurOnic acid is
composed of alternating units ofD-glucuronic acid and N-acetylD-glucosamine. Chondroitin is chemically similar to hyaluronic
acid but contain galactosamine in place of glucosamine. It is a
major component of cartilage, tendons and bones.
Heparin: It is an anticoagulant, which occur in blood, liver
and lung. On hydrolysis heparin yields glucuronic acid,
glucosamine and sulphuric acid.
ゥセ、ァ・ウエ「ャ@
Lignin: The woody parts of plants contain a complex
substance called lignin. Lignin is a high molecular
weight amorphous polymer containing carbon, hydrogen and
oxygen. Lignin is not a carbohydrate but because of its
association with carbohydrate it is usually discussed along with
carbohydrates. There is a strong chemical bonds existing
between lignin and many plant polysaccharides like cellulose.
Lignin is resistant to strong acids and microbial action in the
rumen. It is considered to be indigestible by the animals and is
responsible for poor digestion of wheat straw and paddy straw.
Carbohydrate digestion in the rumen: The major portion
36
The Carbohydrates in Animal Nutrition
of the ruminants diet consist of cellulose, hemicellulose and
other carbohydrates which can not be hydrolyzed by the
enzymes secreted by the animals in the digestive tract but broken
down by enzymes secreted by rumen microorganisms with the
production of volatile fatty acids and gases. The bacteria, which
help in carbohydrate digestion, are as follows:
1.
2.
3.
4.
Substrate
Species
Cellulose digester
1.
2.
3.
4.
5.
6.
7.
Starch digester
1.
2.
3.
4.
5.
6.
7.
8.
Hemicellulose
1.
2.
digester
3.
4.
5.
Sugar
fermenting 1.
Bacteriodes succinogenes
ButtJrivibrio fibrisolvens
Clostridium lochheadii
Clostridium longisporum
Cillobacterium cellulosolvens
Acetigenic rod
Ruminococci sp.
Clostridium lochheadii
Bacteriodes succinogelles
Butyrivibrio fibrisolvens
Streptococcus bovis
Bacteriodes amylophilus
Bacteriodes ruminocola
Succinimonas amylolytica
Selenomonas nlminantium
Eubacterium sp.
Bacteriodes ruminicola
Bacteriodes amylogelles
Ruminococcus flavefaciens
Ruminococcus alblls
Lactobacilli sp.
bacteria
5.
Methanogenic
Methanobacterium nlminantium
bacteria
6.
Proteolytic bacteria
All bacteria related to carbohydrate
fermentation.
7.
Lipolytic bacteria
Anaerovibrio Lipolytica
37
Handbook of General Animal Nutrition
The soluble carbohydrates are rapidly fermented, starches
are less rapidly fermented, whereas, the structural
carbohydrates like cellulose and hemicellulose are slowly
fermented. All carbohydrates are converted into pyruvic acid
as shown below.
cefUlose
Ce!obiose
1
Glucose - 1- phosphate
@セ
Fruct!"", uL al_ pento=< 1
Gluc",,- -pho,!,h,,",
Poetin, Homi<eIlUlr
6 - pho'!'hak
Fructose - 1,6 - diphosphate
1
Pento," ,
/
Pyruvic acid
ャセ@s
Maltor [",malt""
Glucose _
Socro.,
lッLセイオ」エN@
!
Frur'
!
Pyruvic acid +- Fructose-6 Phosphate
Glucose-6 _
Phosphate
The bacteria and protozoa mainly responsible for
fermentation in the digestive tract are mainly strict anaerobes
although, there may be a small number of facultative anaerobes.
The normal concentration of bacteria in rumen liquor is 1011
bacteria per ml. and protozoa are 1()6 per ml of rumen content.
38
The Carbohydrates in Animal Nutrition
Volatile fatty acid production in rumen: The feeds, which
is ingested by the animals broken down to volatile fatty acids
like acetic, propionic and butyric acids via pyruvic acid. Higher
fatty acids like valeric and isovaleric acid etc. are also formed
in smaller amounts. With normal diets the predominant acid is
acetic acid followed by propionic acid and butyric acid. Volatile
fatty acids represent in the following proportions.
1. Acetic acid
60-70 percent
2. Propionic acid
15-20 percent
3. Butyric acid
10-15 percent
4. Valeric and isovaleric acid
present in traces.
On an exclusive roughage diet the production of acetic acid
is highest. As the concentrates in the diet are increased, the
production of acetic acid reduces and that of propionic acid
increases. Lactic acid is also formed as an intermediate product
but is fermented to acetic and propionic acid. Mature fibrous
forage give rise to VFA mixture with high proportion of Acetic
acid (about 70%). Less mature forage tend to give a lower acetic
acid and higher proportion of propionic acid. On concentrate
feeding diet the acetic acid predominates if the rumen ciliate
protozoa survive. The proportion of fatty acids production is
changed under following condition:
1. High ratio of concentrates in the ration.
2. Fine ground forages,
3. Lack of physical fibrousness.
4. Green fodder low in fibre and high in soluble carbohydrates.
5. Pelleted concentrates.
6. Heated concentrates.
7. High starch diet.
This will bring relatively high ratio of propionic acid to
acetic acid. The conversion of pyruate into different volatile
fatty acids is shown below.
39
Handbook of General Animal Nutrition
イセG@
Pyruvic acid
Fonnate
Acetyl phosphate
TYI1\
co,t 1
MIDonyl CoA--+loto=lYI CoA
Methane
(3-Hydroxy butyryl CoA
H,
Acetate
CrotonJcoA
1
1
Butyryl CoA
Butyrate
Pyruvate
セ@
Lactate
1
Oxaloacetate
1
L.ctyl CoA
Mr"
A"YL CoA
Fum.",l<
Pro+YI CoA _ _ _ _
セsucュyi@
Propionate
..1 ,
r
CoA
Motht malonyl CoA
1
Oxaloacetate
Pyruvic Acid Metabolism
40
The Carbohydrates in Animal Nutrition
Gas production in the rumen: With the fermentation of
carbohydrates by the bacteria, gases are also produced. Carbon
dioxide and methane at present as are principal gases. The rate
of gas production in the rumen is most rapid immediately after
a meal and in the cow may exceed 30 Htres/hour. The typical
composition of rumen gas is given below:
1. Carbon dioxide
40 percent
2. Methane
30-40 percent
3. Hydrogen
5 percent
4. Oxygen and nitrogen
(small amount ingested
from air).
Carbon dioxide is produced partly as a by-product of
carbohydrate fermentation and partly by the reaction of organic
acid with bicarbonate of carbon dioxide by the methanogenic
bacteria. Hydrogen, formate and succinate are hydrogen donors
for this reaction. The quantity of methane gas formed depends
upon the type of food eaten. About 4.5 g of methane is formed
for every 100 g of carbohydrates fermented (digested) and the
ruminant loss about 7 percent of its food energy as methane.
Most of the gases in the rumen is lost by eructation. Under
metabolic disorders the gas is trapped in the rumen and the
animal is unable to remove the gases and a condition known as
bloat occurs.
Absorption of volatile fatty acid: Most of the volatile fatty
acids are absorbed directly from the rumen, reticulum and
omasum. Small amount may pass to abomasum and small
intestine from where they are absorbed. Portion of these volatile
fatty acids are used by bacteria and protozoa to synthesize their
own polysaccharides or use as a carbon skeleton for the synthesis
of their body protein.
Carbohydrates metabolism in ruminants: In ruminants
considerable amounts of volatile fatty acids (Acetic, propionic
and butyric acids) are produced from the carbohydrate
breakdown in the rumen. The acids then pass across the rumen
wall, where a little amountis converted to lactate and remaining
41
Handbook ofGeneral Animal Nutrition
is metabolized in the liver. The net gain of ATP per mole of
acetic acid, propionic acid and butyric acids are 10, 17 and 25,
respectively.
Metabolism of volatile fatty acid:
1. Acetic acid Metabolism: It is the major volatile fatty
acid present in blood and absorbed as such. It is utilized for
energy and is also a precursor of fatty acid (Short chain fatty
acid of milk fat). It is never converted to glucose.
HSCoA
::/\2
TCA Cycle
Acetyl coa⦅M|KセGPR@
+ H20
Rセ@
-12ATP
So a net 10 ATP are produced per mole of acetic acid.
2. Propionic acid Metabolism: Propionic acid, which is
produced in rumen, is carried out to the liver where it is changed
into glucose as shown below:
Propionic acid
AMP?
1
Coenzyme A
Propionyl eOA
ATP
ADP/
1
Biotin
Methyl ralonyl eOA
Succiny'l eOA
Matte
+
oxalotcetate
Phophoenol pyruvate
Glu!ose
42
The Carbohydrates in Animal Nutrition
Mole ATP
The energy balance sheet is as :-
+
2 moles propionate to 2 moles succinyl COA
2 moles succinyl COA to 2 moles malate
6
6
2 moles malate to 2 moles phosphoenol pyruvate 6
2
2 moles phosphoenolpyruvate to 1 mole glucose -
8
1 mole glucose to C(h & H20
38
----50
Net gain ATP per mole 50 ;16
16
= 17
So 17 moles of ATP are produced per mole of propionic
acid.
3. Butyric acid Metabolism: It is absorbed as aceto acetic
acid and b - hydroxy butyric acid in its passage across the ruminal
and omasal walls. It is ketogenic in nature and utilized for
synthesis of long chain fatty acid of milk fat. It is metabolised
as:
Butyric acid
B - Hydroxy butyrate
l-IATP
Aceto acetic acid
2 AcllCOA
1-24ATP
CO2 & H 20
So 25 ATP are produced per mole of butyric acid.
43
Handbook of General Animal Nutritzon
Digestion of carbohydrates in non-ruminants:
1. Digestion in the mouth: Here food, mixed with the
saliva, which contains the enzyme ptyalin (a-amylase). This
enzyme hydrolyzes starch into the maltose and isomaltose. But
the food remain in the mouth for a short time and about 3 to 5
percent of the starch hydrolyzed into maltose.
The amylase enzyme hydrolzyes the a-I, 4- glucosidic
bond in polysaccharide. When amylose, which contain a-1,4glucosidic bond is attacked by a-amylase, random cleavages of
these bonds give rise to a mixture of glucose and maltose.
Amylopectin, on the other hand contains in addition to a-1, 4D-glucosidic bond, a number of branched a-I, 6-D-glucosidic
bonds which are not attacked by a-amylase and the product
includes a mixture of branched and unbranched oligosaccharides
(dextrin) in which 1, 6-D-glucosidic bonds are abundant.
2. Digestion of carbohydrates in the stomach: The action
of a-amylase enzyme of saliva continues for about 30 to 50
minutes after the food has entered the stomach, that is, until
the content of the fundus are mixed with the stomach secretions.
Then the acid of the gastric secretion blocks the activity of the
salivary amylase. The acid of the stomach juice can hydrolysed
starch and disaccharides to a slight extent.
3. Digestion of carbohydrates in intestine: Pancreatic
secretions contain large quantities of a-amylase which is capable
of splitting starch into maltose and isomaltose in intestine. In
general, the starch is almost totally converted into maltose and
isomaltose before they have passed beyond the Jejunum. The
epithelial cells of the small intestine contain the four enzymes
VIZ.
1.
2.
3.
4.
Lactase, which split lactose into glucose and galactose.
Sucrase, which split sucrose into glucose and fructose.
Maltase, which split maltose into two molecules of glucose.
Isomaltase, which split isomaltose into two molecules of
glucose.
44
The Carbohydrates in Animal Nutrition
Thus the final products of carbohydrate digestion that
are absorbed into the blood are all monosaccharides. The
enzyme hydrolyses starches into glucose and other
carbohydrates into final products as shown below.
Starches
Salivary L-amylase
Pancreatic L-amylase
Maltose + Isomaltose
Sucrose
Lactose
l
Maltase
Lactase
Isomaltase
(Intestine)
(Intestine)
Sucrase
1
(Intestine)
Galactose .....1-------•• Glucose .....- - - -... Fructose
Table: Digestive Juices and their function
Secretion
Principal
Function
(gland)
components
Saliva
Water, Mucous Salts Soften and lubrication of food. Provide
neutral medium for action of salivary
(Salivary
gland)
amylase and help to preserve teeth
against acid formed by bacteria.
Salivary amylase
Act on starch and split into dextrin
and maltose.
Gastric juice Water, Mucous
Further soften of food. Prevent gastric
(Gastric
juice from damaging the stomach wall.
gland)
Hydrochloric acid Stop the action of salivary amylase
and allow pepsin to work and kills
microorganisms.
Pepsin (Secreted as Protein moieties of the food are
a pepsinogen)
hydrolysed into proteases, peptone
and polypeptides and curdle of milk
in adults when rennin enzymes are
absent.
Rennin
Milk casein is converted into curds
such as paracassinate, which is easily
attached by other protein digesting
enzyme.
45
Handbook ofGeneral Animal Nutrition
Bile juice Water
Waste materials excreted with faeces or
(Liver)
absorbed and re-excreted later.
Bile pigment, bile Alkaline therefore, neutralize acidity of
salt
chyme and stop action of pepsin but
allow action of intestinal enzymesemulsify fat.
Pancreatic Water,
alkaline Help to increase alkalinity in intestine and
salt
Prancreatic combined with fatty acid to form soap
juice
(pancreas) lipase Pancreatic splits fats into fatty acids and glycorol.
amylase Trypsin Splits certain proteins, proteases and
peptone into shorter polypeptide chains
Chymotrypsin
and liberate some amino acid.
carboxypoly
ipeptidase
Intestinal Water Mucus
Protect intestinal mucosa. Activates
juice
trypsinogen forming trypsin, trypsin then
(Duodenal
activate chymotryI'Sin.
gland & Enterokinase
Split amino acid.
Goblet
Peptidases
Split maltose into glucose.
cells)
Carboxypeptidase Split sucrose into glucose and fructose.
Amino peptidase Split Lactose into glucose and Galactose.
Dipeptidase,
Maltase Sucrase,
Lactase
Absorption of carbohydrate in non-ruminants: The final
product of carbohydrate digestion in non-ruminants is glucose,
galactose and fructose. Their absorption is an active process
utilizing a specific carrier protein that trans locates the molecules
across the brush border membrane of small intestine. This is
energy dependent process and also required Na+ and K+ ions.
The rate of absorption of monosaccharides is also different.
Galactose is fastest absorbed than glucose, fructose, mannose
and slowest pentose sugar.
Factors affecting digestion of carbohydrates in nonruminants:
1. Particle size: If particle size is reduced, than digestibility
will be increased because of increase in surface area for
digestion. Grinding broken down the cell wall so that cell
contents come in contact with digestive enzymes.
2. Form of starch: Soluble starch is more digestible than insoluble form i.e. amylose is more digestible than amylopectin.
46
The Carbohydrates in Animal Nutrition
3.
4.
5.
Processing: It improves the digestibility of starch by breaking down the cell wall. Cooked starch is more digestible
than uncooked.
Fibre content: If fibre content is increased more than a
level, it reduces the digestibility of carbohydrates.
Enzyme Inhibitors: Presence of enzyme inhibitors like
saponin, tannins etc. reduces the digestibility of starch.
Factors affecting fibre digestibility in ruminant:
Following factors affect the digestibility of crude fibre (cellulose
+ hemicellulose + lignin).
1. No. and type of microbes present in rumen: If number of
microbe is more, digestibility of crude fibre increase. If
cellulolytic bacteria are there, cellulose digestion is more.
2. Relative proportion of fibre component: If hemicellulose
is more, digestibility of crude fibre is more. Lignin proportion is inversely related with fibre digestibility.
3.
Protein content in diet: Increased protein level in diet
stimulates microbial growth and improves digestibility of
crude fibre.
4. Fat content in diet: Increased fat content in diet gives a
protective layer on feed particles, which depress the fibre
digestibili ty.
5. NFE: CF ratio: If NFE content is increased, then
digestibility of crude fibre is decreased. Because NFE
represents the soluble carbohydrates in feed i.e. starch
which is a more available source of energy.
6. Supplementation of green forages: It stimulates digestion
of crude fibre because they supply vitamins and some nonspecific factors required for microbial growth.
Carbohydrates metabolism: The metabolic processes in the
body are of two types. The degradation of complex
compounds to simpler materials is called catabolism. Whereas
those metabolic processes in which complex compounds are
synthesised from simpler substances are called anabolism. As a
result of the various metabolic processes; energy is made
available for mechanical and chemical work. The end products
47
Handbook of General Animal Nutrition
of carbohydrate digestion in the simple stomach animals are
glucose, galactose and fructose. Energy is produced when these
are burnt to carbon dioxide and water. The energy released
during metabolic processes in the cell is stored in the form of
high-energy bonds particularly those found in adenosine
triphosphate (ATP) and creatinephosphate (CP).
Glucose metabolism: The degradation/ synthesis of
carbohydrates in the cells is done by a number of enzymes,
which are mostly specific. The major pathway whereby glucose
is metabolized to give energy is a two-stage process.
1. Glycolysis (Anaerobic cycle, Embden-Meyerh of Paranes
pathways).
2. Tricarboxylic acid cycle (Aerobic cycle, kreb' s/ citric acid
cycle).
1.
Glycolysis. In this process glycogen, glucose,
galactose and fructose are broken down to pyruvic acid and
lactic acid in the absence of molecular oxygen. The sequence of
reactions is shown in the chart:
The ATP production in the glycolytic pathway: Two moles
ATP are used in the initial phosphorylation of steps 1 and 3 and
fructose-1-6- diphosphate so formed then break down to yield
two moles of glyceraldehyde-3 phosphate. Subsequently one
mole of ATP is produced directly at each step 6 and 9. Four
moles of ATP produced from one mole of glucose. Since two
moles of ATP are used up, the net production of ATP from
ADP is two moles per mole of glucose.
Glyceraldehyde-3 phosphate is converted to 1,3 diphosphoglyceric acid in the presence of glyceraldehyde-3phosphate dehydrogenase enzyme and reduced NAD+ is
produced and it may be oxidised via the oxidative
phosphorylation pathways, with the production of three moles
of ATP per mole of reduced coenzyme. Under aerobic
conditions, therefore, glycolysis yields eight moles of ATP per
mole of glucose.
2. Tricarboxylic acid cycle: The next stage in the
48
The Carbohydrates in Animal Nutrition
Fructose
Glucose
Galactose
jI
Hexokinas
Glucose 6 PhOSPh7as
atセdp@
'J
Glucose- 6 - Phosphate
!
Glucose phosphate isomerase
Fructose - 6 - Phosphate
6 phosphofructokinase
JI
A TP - A D P
I Hexosediphosphatase
Fructose - I, 6 - diphosphate
Dihydroxy 。」・エセ@
Phosphate
セ@
Glyceraldehyde - 3 - phosphate
/somerasl
NAD+_NADF+
Glyceraldehyde3 phosphate dehydrogenase
1,3 - Diphosphoglyceric acid
Phosphoglycerate kinase
IADP -
ATP
3 - Ph!spho glyceric acid
Phosphoglyceromutase
!
f--=
2, Phosphoglyceric acid
Enoise
H 20
Phospl1oenol pyruvate
Pyruvate kinase
ーケイuカセ@
IADP -
ATP
acid
degradation of glucose is conversion of the two pyruvic acid
molecules into two molecules of acetyl coenzyme A (Acetyl CoA) as following reaction.
2 Pyruvic acid + 2 Coenzyme A= 2 Acetyl Co-A + 2C02 + 4 H.
From this reaction it can be seen that two carbon-dioxide
molecules and four hydrogen atoms are released, while the
remainders of the pyruvic acid molecules combines with
49
Handbook ofGeneral Animal Nutrition
coenzyme-A to form two molecules of acetyl Co-A. In this
conversion, no ATP is formed, but six molecules of ATP are
formed when the four hydrogen atoms are oxidised in oxidative
phosphorylation system. So citric acid cycle (Tricarboxylic acid
cycle or kreb's cycle) is a sequence of chemical reactions in which
the acetyl portion of acetyl coenzyme-A is degraded to carbon
dioxide and hydrogen atoms. Then the hydrogen atoms are
subsequently oxidised, releasing still more energy to form ATP.
Pyruvate dehydrogenase
Pyruvate + Coenzyme A Oセ@
Acetyl- CoA
NADH (+H+)
NAD'
AcetylCoA
--!
,..--+Oxaloacetate
Citrate synthetase
Citrate
I
Aconitase
!sJcitrate
/
yAD 1isoc/trate dehydrogenase
NADH
Oxalosucclnate
!isocllrate dehydrogenase
CO, +-
a - Ketogl uterate
NAD
1
NAm/
a Ketoglutarate dehydrogenase
Succinyl COA
GTP
セ@
GDP
I
Succmate Co enzyme A synthatase
Succinate
FAD
1
Succmate dehydrogenase
FADH,/
Fumarate
!
Fumarase
Malate
NAD
1
Malate dehydrogenase
NADH,/
'--_ _ _ _ _ _ _ Oxaloacetate
50
The Carbohvdrates in Animal Nutrition
Net reaction per molecules of glucose:
2 Acetyl Co-A + 6Hp+ 2 ADP セ@
4C0 2 + 16 H + 2 CO-A + 2 ATP.
The TCA cycle involves four dehydrogenations, three of
which are NAD+ linked and one is FAD linked, resulting in 11
moles of ATP being formed from ADP. In addition one mole of
ATP arises directly with the change of succinyl coenzyme-A to
yields
succinic acid. The oxidation of each mole of pyruvate エィオセ@
15 moles of ATP. The total ATP production from the oxidation
of one mole of glucose is given below:
1
mole of glucose to 2 moles of pyruvate produces
8
Moles ATP
2
moles of pyruvate to CO2 and water produces
30
Moles ATP
Total ATP per mole of glucose
38
Now adding all the ATP molecules formed, we find a
minimum of 38 ATP molecule formed for each molecule of
glucose degraded to carbon dioxide and water. Thus, 304,000
calories of energy are stored in the form of ATP, while 686,000
calories are released during the complete oxidation of each gram
mole of glucose. This represents the overall efficiency of energy
transfer of at least 44 percent. The remaining 56 percent of the
energy become heat, which is wastage of energy.
3. Glucose metabolism by the pentose phosphate
pathway: Another pathway by which glucose is metabolized
within the body is the pentose phosphate pathway, the
phosphogluconate oxidative pathway, and the hexose phosphate
shunt. Though 95 percent or more of all the carbohydrates
utilized by the muscles are degraded to pyruvic acid by
glycolysis and then oxidized in the cells. The pentose phosphate
pathway is of considerable importance in the liver cells, adipose
tissue and the lactating mammary glands.
The steps of these pathways are shown on the following
page.
51
Handbook of General Animal Nutrition
Glucose
nadph[セZ@
イHoセィ。・@
6 - phosphogluconic acid
NADPH 2
セ@
J
-
セ@
NADP
keto - 6- Jhosphogluconic acid
jセ」ッL@
Ribulose - 5 - phosphate
Ribulose phosphate 3 epimerase
Oセ「ッウ・@
phosphate isomerase
Xylose - 5 - phosp'e + Ribose - 5 - phosphate
Jセ@
Transketolase
Sedoheptulose -7 - phosphate + Jlyceraldehyde - 3 - phosphate
JI
Transaldal""
Fructose - 6 - phosphate
+
Erythrose - 4- phosphate
The initial phosphorylation of glucose uses 1 mole of ATP
and the oxidation of hydrogen via NADP+ yields 36 ATP,
thereby leaving a net production of 35 ATP per mole of glucose.
The efficiency of free energy captured in this case is 245000/
686000 x 100 = 35 percent.
Net reaction
Glucose + 12 NADP+ + 6 セo@
""'"
'-.." 6 CO2 + 12 H + 12 NADPH
Gluconeogenesis: It is ·the process of synthesis of glucose
from the sources other than carbohydrates.
52
The Carbohydrates
In
Animal Nutrition
When the body stores of carbohydrates decrease below
normal, moderate quantities of glucose can be formed from
amino acid, glycerol portion of fat, and from propionic acid.
This process is known as gluconeogenesis. Approximately 60
percent of amino acids in the body protein can be converted
into carbohydrates.
Glycogenesis and glycogenolysis:
Glycogen synthesis from simple sugars in the body tissues
is known as glycogenesis. Glucose, galactose, fructose and
mannose are readily converted to glycogen by various stages
in which various enzyme systems are involved as shown below.
Galactose
Glucose
Fructose
Galactose - 1 - phosphate
Mannose
Fructose - 6 - phosphate
I
Giu,o", - 6 - PhOr"e セ@
Monoo", 6 - pho,ph'"
Glu,,,,, - セoBGィ@
Uridme diphosphate galactose _ _ Uridine diphosphate glucose
UDP - glucose + (glucose)n
セHgャオ」ッウ・IョK@
I
+ UDP
Similarly the process of degradation of glycogen to glucose1- phosphate in the cells is known as glycogenolysis.
Lactose synthesis: Lactose is formed by condensation of
one glucose and one galactose molecule. It is formed by the
action of the UDP - D - galactose with glucose in the presence
of the lactose synthetase.
53
Handbook of General Animal Nutrition
UDP - gaIact ose + D - gIucose Lactose synthetase) UDP + Lactose
Fat synthesis from glucose: When the carbohydrate intake
exceeds the requirement of the body for energy purposes, sugar
is transformend into fat. It involves the synthesis of two
components, fatty acid and glycerol, which combine with each
other to give fat.
Dihydroxy 。」・エッョMNセ@
gャyc・イッセ@
'IAA/
Pyruvate MLャイNセ@
Fat
Acetyl COA
CO2
Q.1. Fill in the blanks:
1. Sugars are those carbohydrates, which contain less
than
monosaccharide residues.
2. The simplest sugar is
. which cannot be hydrolysed into smaller units under mild conditions.
3. Sugars other than monosaccharides are collectively called
4.
Polysaccharides, which on hydrolysis yield mixtures of
monosaccharides and derived products, are called
5"
6.
Lactose is hydrolysed into _____ and _ _ _ __
_ _ _ _ _ is a tetra saccharide whereas _ _ _ is a tri
saccharide.
7. In amylose _ _ _ _ linkage is found benreen glucose
units.
8. Amylopectin has
linkage as well as
linkage between glucose unit.
9.
is an intermediate product of the hydrolysis of
starch and glycogen.
10. Lignin contents _ _ the digestibility of roughages.
54
The Carbohydrates in Animal Nutrition
11. Saliva contains an enzyme _ _ _-', which hydrolyse some
part of starch into
and _ _ _ _ _ _ '
12. Lactose and sucrose sugars are hydrolysed by enzyme
____ and
, respectively.
13. The final products of carbohydrate digestion in nonruminants are
and _ _ _ __
14. The absorption of galactose is ____ than glucose at
intestinal level.
15. The end products of carbohydrate digestion in ruminants
are
and _ _ _ __
16.
17.
18.
19.
20.
21.
22.
23.
24.
and
are the most commonly
gases produced in rumen during carbohydrate digestion.
is the volatile fatty acid produced in large
proportion on a normal diet in ruminants.
Glycolysis yields __________ moles of A TP under
unaerobic condition.
In glycolysis glucose is converted into _ _ _ _ __
The oxidation of one mole of pyruvic acid yields _ _ __
ATP.
Complete oxidation of one mole of glucose yields _ _ __
mole of ATP.
moles of ATP are produced from one mole of
acetic acid metabolism.
One mole of propionic acid give
moles ATP
whereas, __ moles are produced from butyric acid
metabolism.
Glycogen synthesis from simple sugars in the body is
knownas _ __
25. Degradation of glycogen to glucose is known as
26.
is an immediate source of energy in animal
body.
27. Conversion of propionate to glucose requires vitamins
_ _ _ and
55
Handbook of General Animal Nutrition
28. In the horse, the large intestine in the principal site of
_ _ _ digestion
29. Lipids in the rumen are hydrolyzed & unsaturated fatty
acids converted to saturated fatty acids by _ _ __
30. Carbohydrates, Amino acids & fatty acids are absorbed by
____ transport whereas emulsified triglycerides are
absorbed by
diffusion.
31. Two blind-ended caeca facilitates microbial digestion in
32. A process known as _ _ _ _ _ absorbs immunoglobulins
present in colostrum.
Q.2. Explain the following:
1. Classification of carbohydrates.
2. Differentiate with each other Glucose & Fructose, Lactose
& Sucrose, Starch & Glycogen, Monosaccharide & Oligosaccharide, Cellulose & Hemicellulose. Homopolysaccharide
& Heteropolysaccharide. Amylose and amylopectin, Glycogenesis & Glycogenolysis.
3. Explain the digestion and absorption of carbohydrates in
pig.
4. Explain the digestion and absorption of carbohydrates in
bullock or sheep.
5.
6.
7.
8.
9.
How the carbohydrates are metabolised in non-ruminants?
Explain the production and absorption of volatile fatty
acids in rumen.
How the volatile fatty acids are metabolised in goat?
Define the term carbohydrates. How the glucose is
metabolised by glycolytic pathway?
Glucose is helpful for lactose synthesis and fat syntheSis in
the body. Justify the statement.
56
Chapter
5
The Protein in
Animal Nutrition
Proteins are complex organic nitrogenous compounds made
up of amino acids. All proteins contain carbon, hydrogen,
oxygen, nitrogen and generally sulphur, many contains
phosphorus. Element such as iodine, iron, copper and zinc are
also occasionally present. The approximate average elementary
composition of protein is as follows:
Elements
Average
percent
Carbon
50
(51-55)
Hydrogen
7
(6.5 -7.3)
Oxygen
23
(21.5-23.5)
Nitrogen
16
(15.5-18.0)
Sulphur
0-3
(0.5-2.0)
Phosphorus
0-3
(0.0-1.5)
Most proteins contain about 16 percent nitrogen, which
means that the weight of protein nitrogen multiplied by 6.25
(100/16 = 6.25) equal the weight of protein. Suppose a feed
sample to be analysed yields 1.0 gram of nitrogen by Kjeldahl
process, then the weight of protein represented as 1.0 x 6.25 =
6.25g. Milk nitrogen is multiplied by 6.38 because milk protein
contains 15.87 percent nitrogen.
Amino acids: Proteins are hydrolysed by enzymes, acids
or alkalies into amino acids. About 20 amino acids are commonly
found as components of proteins. Amino acids have a basic
amino group and an acidic carboxyl group. So amino acids are
57
Handbook of General Animal Nutrition
amphoteric in nature and exist as dipolar ions or zwitter ions in
aqueous solution. A pH value called isoelectric point for a given
amino acid at which it is electrically neutral.
NH2
H-C-COOH
R
Classification of amino acids: Amino acids can be classified
into three groups, namely, the aliphatic, aromatic and
heterocyclic amino acids.
I.
Aliphatic Amino Acids
(a) Mono amino-mono carboxylic acids (Neutral amino
acids)
1. Glycine (amino acetic acid) It is simplest of the amino
acids.
nセN@
CH2 • COOH
2. Alanine (a-amino propionic acid)
CH3
I
NH2 CHCOOH
3.
Serine (a-amino l3-hydroxy-propionic acid)
CH2-CH- COOH
I
I
OH
4.
NH2
Threonine (a-amino l3-hydroxy butyric acid)
CH3-CH-CH-COOH
I
OH
I
NH2
58
The Protein in Animal Nutrition
5.
Valine (0.- amino-isovaleric acid)
CH3--CH--CH--COOH
I
I
CH3 NH2
6.
Leucine (a-amino isocaproic acid)
CH3--iH--CH2--fH--COOH
CH 3
7.
NH2
Isoleucine (0.- amino j3-methyl-valeric acid)
chSMセo@
I
I
CH 3 NH2
(b) Mono-amino dicarboxylic acids (Acidic amino acids)
8. Aspartic acid (0.- amino succinic acid)
CHr-COOH
I
I
CH--NH2
COOH
9.
Glutamic acid (0.- amino glutaric acid)
CHz-CH2 -COOH
I
I
CH--NH2
COOH
(c) Oi-amino mono carboxylic acids (Basic amino acids)
10. Lysine (a-cr-diamino-caproic acid)
chMRセo@
I
I
NH2
NH2
59
Handbook of General Animal Nutrition
11. Arginine (a-amino-8-guanidine-valeric acid)
nhMcRセo@
I
I
C =NH
NH2
I
NH2
12. Citrulline (8-carbamido-a-amino-valeric acid)
NH2
I
C=O
I
N -
CHz-CH2-CHz-CH-COOH
I
I
H
NH2
(d) Sulphur containing amino acids
13. Cystine (di-a-amino セMエィゥッーイョ」@
acid)
CH2
- S - S - C H2
I
I
I
I
CH-NH2
CH-NH2
COOH
COOH
14. Methionine (a-amino-y-methylthiol butyric acid)
Clfj-S- CH2
-CH2-CH-COOH
I
NH2
15. Cysteine
H。Mュゥョッセエィ@
propionic acid)
-SH
CH2
I
NH2 CH-COOH
60
The Protein in Animal Nutrition
II. Aromatic Amino 4cids
16. Phenyl alanine (a-amino-p-phenyl propionic acid)
\セ]M^@
-.,H2 -CH-COOH
NH2
17. Tyrosine (a-amino-p-hydroxy phenyl propionic acid)
hoセcRM@
-
I
NH2
III. Heterocyclic Amino Acids
18. Histidine (a-amino-p-imidazole-propionic acid)
C H - - - C - CH2 -CH- COOH
,
I
I
N
19. Proline
/
CH
I
NH
NH2
H。Mpケイッャゥ、ョ・セ「ク」@
acid)
CH2
CH 2
chセ@
CH-COOH
I
I
'"
NH
/
20. Hydroxyproline (y-hydroxy a-pyrolidine-carboxylic acid)
HO- CH ----'-----jCH 2
I
I
CH--COOH
CH2
""/
NH
21. Tryptophane
H。Mュゥョッーセ、ャ・@
61
\
propionic acid)
Handbook of General Animal Nutrition
Ochセ@
セhイMco@
HC
C
C
HC
C
CH
I
セ@
II
CH
Oセ@
II
NH
I
NH2
/
Classification of amino acids based on charge and side
chain
S.No.
1. Non polar aliphatic amino acids
Name of A.A.
Abbreviation
1.
Code
Gly
2.
Glycine
G
3.
Alanine
Ala
A
Val
4.
Valine
V
5.
Leucine
Leu
L
6.
Isoleucine
Ile
I
7.
Methionine
Met
M
2. Polar uncharged A.A.
1.
Proline
Pro
P
2.
Serine
Ser
S
3.
Threonine
Thr
T
4.
Asparagine
Asn
N
Glutamine
Q
5.
GIn
6.
Cysteine
Cys
C
3. Aromatic side chain A.A
1.
Phenyl alanine
Phe
F
2.
Tyrosin
Tyr
Y
3.
Tryptophane
Trp
W
4. Positively charged A.A.
1.
Lysine
K
Lys
2.
Arginine
Arg
R
3.
Histidine
His
H
5. Negatively charged A.A.
1.
Aspartic acid
Asp
0
2.
Glutamic acid
Glu
E
62
The Protein in Animal Nutrition
Function of proteins:
Proteins form muscles and tissues of the body; hence it is
essential for the growth and development of the body.
2. They help in maintaining theloss of body tissues and muscles.
3. They help in the formation of enzymes, hormones, antigen, antibody, digestive juices of the body and regulate
body osmotic pressure and acid-base balance.
4. They help in the repair of body cells as well as for the
production of new cells.
5. They also supply energy to the body.
6. They are essential for the formation of egg, milk protein,
wool and hairs of the animals.
7. They provide the basic cellular matrix within which the
bone mineral matter is deposited.
8. Under condition of non-digestion and no-chances for denaturation, the protein accumulates inside the cells and
produce toxicity. i.e. venoms of snakes and insects are infected by biting into the blood.
9. Endorphins (peptide) are found in brain and are involved
in the suppression of pain.
1.
Essential amino acid (indispensable amino acid): An
essential amino acid is one needed by the animal that can not
be synthesized by the animal in the amounts needed and so
must be present in the protein of the feed as such.
Non-essential amino acid (dispensable amino aicd): A
non-essential amino acid is one needed by the animals that can
be formed from other amino acids by the animals and so does
not have to be present as the particular amino acid in protein of
the feed. Those amino acids which function in animal nutrition
are usually classified on the basis of their essentially as follows:
(in rat & man)
63
Handbook of General Animal Nutrition
S.No.
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
•
Essential amino acid
Arginine
Histidine
Iso-leucine
Leucine
Lysine
*Methionine
Phenylalanine
Threonine
Tryptophan
Valine
Non-essential amino
acids
Alanine
Aspartic acid
Citrulline
Cystine
Glutamic acid
Glycine
Proline
Hydroxyproline
Serine
Tyrosine
Methionine may be replaced in part by cystine.
Chick require 10 + glycine. The pig require 9 amino acids
(other than arginine)
Non protein amino acids: There are many other amino
acids, which are never found as constituents of proteins but
which either play metabolic roles or occur as natural products.
e.g. L- Ornithine, L- Citrulline, [3- alanine (in vit. Pantothenic
acid), Creatine and g- amino butyrate (in brain). L- ornithine &
L- Citrulline occur in free state in the animal tissues and are
metabolic intermediates in the urea cycle.
CH2--CH2--CH2- -,H--COOH
NH2
L- Ornithine
Limiting amino acid: Livestock in definite proportions
requires the essential amino acids. While the proportion may
vary for different functions, it is always quite definite for any
given animal performing any given set of functions. The amino
acid which is present in a protein in the least amount in relation
to be animal's need for that particular amino acids can be used
by the animal toward meeting its essential amino acid
requiremep.t only to the extent that the so-called limiting amino
64
The Protem m Animal Nutrition
acid is present. It will be noted that lysine is the limiting essential
amino acid of corn.
Structure of proteins: The structure of proteins can be
considered under four basic headings:
1.
Primary Structure: Proteins are built up from amino
acids means of a linkage between the a-carboxyl of one amino
acid and the a -amino group of another acid. This type of linkage
is known as the peptide linkage. Large number of amino acids
can be jointed together by this means with the elimination of
one molecule of water at each linkage to produce poly peptides.
The term primary structure refers to the sequence of amino
acid along the polypeptide chains of protein.
2.
Secondary Structure: In secondary structure the
peptide chain exist in the form of a right-handed -helix. The
spiral is stabilized by hydrogen bonding between the amino
(NH) and carbonyl (CO) group of adjacent amino acids.
o
R
g
hOセr@
C/
セO@
H
セnO@
セc@
I
1\
H
o
o
H
II
c
t
3.
Tertiary structure: It describes how the chains of
the secondary structure further interact through the R-groups
of amino acid residues. These interaction causes folding and
bending of the polypeptide chain, the specific manner of the
folding giving each protein its characteristics biological activity.
The tertiary structure is stabilized by H-bonding, S-bonding
(disulphide linkage), self bridge between basic amino acid and
acidic amino acids and certain amino acids like alanine,
65
Handbook of General Animal Nutrition
phenylalanine and valine in which R-group is non-polar. If it is
coiled all non- polar amino acids come in contact to form a
hydrophobic centre.
4.
Quaternary Structure: Protein poses quaternary
structure if they contain more than one polypeptide chain. The
force that stabilized these is hydrogen bonds and electrostatics
or salt bonds formed between residues on the surface of the
polypeptide chain.
Classification of proteins: Proteins may be classified into
three main groups according to their shape, solubility and
chemical composition.
I. Fibrous Proteins: These proteins are insoluble and very
resistant to animal digestive enzymes. They are composed of
elongated, filamentous chains, which are joined together by
cross linkages. They are as follows:
1. Collagens are the main proteins of connective tissues. It
makeup about 30 percent of the total proteins in the mammalian body. Hydroxy proline is the important component of collagens.
2. Elastin is the protein found in elastic tissues such as tendon and arteries. It is rich in alanine and glycine
3. Keratins are the protein of hair, hoof, nails etc. These proteins are very rich in sulphur containing amino acid,
cystiene. Wool protein contains about 4 percent sulphur.
II. Globular Proteins: This group includes all the enzymes,
antigens and hormones that are protein.
1. Albumin is water-soluble and heat coagulable and occurs
in eggs, milk, blood and many plants.
2. Globulins are present in eggs, milk and blood and are the
main reserve protein source in seed.
3. Histones are basic protein, which occur in cell nucleus
where they are associated with DNA. They are water-soluble but not heat coagulable, and on hydrolysis yield large
quantities of histidine and lysine.
4. Protamines are basic protein of relatively low molecular
66
The Protein In Animal Nutrition
weight, which are associated with nucleic acid and are
found in large quantities in the nature, germ cells of vertebrates. Protamines are rich in arginine.
III. Conjugated Proteins: Conjugated proteins are
composed of simple protein combined with some non-protein
substances as prosthetic group.
1. Phosphoprotein is the protein' which on hydrolysis yields
phosphoric acid and amino acids. Casein of milk and phosvitin of egg yolk are the best known phosphoproteins.
2. Glycoproteins are conjugated proteins with one or more
heterosaccharides as prosthetic groups. In most of the
glycoproteins, glucosamine or galactosamine or both, in
addition galactose and mannose may be present.
Glycoproteins are components of mucous secretions which
act as lubricants in many parts of the body ego ovalbumin.
3. Lipoproteins are proteins conjugated with lipid lecithin and
cholesterol. They are the main components of cell membranes and playa basic role in lipid transport.
4. Chromoproteins contain pigment as a prosthetic group.
Exam pIes are haemoglobin, haemocyanin, cytochrome and
flavoproteins.
5. Nucleoproteins are compound of high molecular weight
and conjugated with nucleic acid.
6. Metalloproteins a large group of enzyme proteins contain
metallic elements, such as Fe, Co, Mn, Zn,' Cu, Mg, etc.
which are essential part of these proteins.
IV. Derived Proteins: This class of proteins includes those
substances formed from simple and conjugated proteins.
1. Primary derived proteins: If there is a slight change in the
proteins molecules such as metaproteins and coagulated
proteins, they are called primary derived proteins.
2. Secondary derived proteins: If there is a large change in
protein structure, they are called secondary derived proteins. They are precipitated by phosphotungstic acid. The
examples are proteoses, peptones and peptides.
67
Handbook ofGeneral Animal Nutrition
Non-protein Nitrogenous compounds: Nitrogenous
compounds, which are- not classed as proteins occur in plants
and animals called as non-protein nitrogenous compounds.
Amino acids like glutamic acid, aspartic acid, alanine, serine,
non-protein
glycine and proline forms the main parts of セ・@
nitrogenous fraction in plants, Other compounds are
nitrogenous lipids, amines, amides, purines, pyrimidines,
nitrates and alkaloids. In addition many members of the vitamin
B-complex contain nitrogen in their structure.
Nucleic acid: Nucleic acids are high molecular weight
compounds which, on hydrolysis, yield a mixture of basic
nitrogenous compound (purines and pyrimidines) a pentose
(ribose and deoxyribose) and phosphoric acid. They playa
fundamental role in living organism as a store of genetic
information and synthesis of proteins. Nucleotide containing
ribose is termed as ribonucleic acid (RNA) while those
containing deoxyribose are referred as deoxyribonucleic acids
(DNA).
Nucleosides and Nucleotides: They are carbohydrates
derivatives in which purines and pyrimidines found in nucleic
acids are linked to a sugar in a B-N-glycosyl bond. the sugar is
either D-ribose or deoxyribose in the naturallY occurring
nucleoside. If the nucleosides such as adenosine are esterified
with phosphoric acid, they form nucleotides. Naturally occurring
nucleotides are adinosine monophosphate (AMP), adinosine
diphosphate (ADP) and adinosine triphosphate (ATP).
Digestion of protein in non-ruminants: There is no
digestion of protein in the mouth because saliva has no
proteolytic enzyme. But saliva softens the food particles, which
is helpful for ingestion of protein.
Digestion of proteins in the stomach: The digestion of
protein start in the stomach by the action of peptic enzymes.
Pepsin and gastricin are the most important peptic enzymes of
the stomach. Both enzymes are most active at about pH 2 to 3,
and completely inactive at pH above 5. Gastric glands secrete
hydrochloric acid at a pH of about 0.8, but by the time it's mixed
68
The Protem in Animal NutritIOn
with the stomach contents, the pH ranges around 2-3, a high
favourable for peptic enzyme activity. These enzymes are
capable of digesting protein, collagen and nucleo proteins into
proteoses, peptones and polypeptides.
Digestion of proteins in the intestine:
1. Digestion of proteins by pancreatic secretions: When
the proteins leave the stomach they ordinarily are in the forms
of proteoses, peptones, large polypeptides and amino acids.
Immediately upon entering the duodenum the partial
breakdown products are attacked by the pancreatic enzymes
trypsin, chymotrypsin and carboxpolypeptidases. These
enzymes are capable of hydrolyzing all the partial breakdown
products of proteins to polypeptides and amino acids.
2. Digestion of polypeptides by the epithelial enzymes
of the smaIl intestine:
The epithelial cells of the intestine contain several different
enzymes for hydrolyzing the final peptide linkages of the
different dipeptides into amino acids. So the end product of
protein digestion is various amino acids.
Protein, Collagen, Nucleoprotein
Stomach
1
Pepsin, Gasbicin
Proteoses, Peptones, Polypeptides
Duodenum
1
Trypsin, Chymotrypsin,
carboxy polypeptidases
Polypeptides + Amino acids
Small intestine
1
Amino polypeptidase
Dipeptidase
Amino acid
69
Handbook of General Animal Nutrition
Digestion of protein in Ruminants: The digestion and
metabolism of proteins in ruminants are different than nonruminants. The biological success of the ruminant in utilizing
crude proteins and non-protein nitrogenous (NPN) substances
seems to be dependent upon the physiological regulation セヲ@
rumen environment as microbial habitat. As the microbes
multiply, they synthesize protein to construct their own bodies
by utilizing dietary protein and NPN substances. This microbial
protein is available to the host for subsequent digestion in the
lower part of the gut.
Food
/rotein/
UDP
セッョᄋーイャ@
DeJdable protein
Salivary gland
ーセゥ・ウ@
Amino acids
• Ammonia -
.lb·l セ@
1
LT'
(urea)
Ki'dney
MICro la protem
1
Digested in small intestine
1
Excreted in urine
Digestion and metabolism of protein and NPN compound:
Proteolysis: The proteins available to the ruminants are
digested by the process of proteolysis in the rumen and are
converted to peptides and amino acids. These are further
fermented, by deamination to carbon dioxide, ammonia and
short chain fatty acids. Ruminal proteases are mainly cell bound
but may be located on the surface of the cell where the substrate
is freely accessible to the enZymes. These proteolytic enzymes
70
The Protein in Animal Nutrition
are rather non-specific in their character, since their ability to
ferment a range of proteins is not influenced by changes in the
microflora brought about by different rations. It appears that
for the bacterial proteases to act efficiently the protein must be
in solution farm. Different proteins are proteolysed at different
,rates and rate of digestion of a particular protein is fairly
constant. The rate of proteolysis is closely related to solubility
of proteins in the water and in salt solution resembling rumen
fluid.
In spite of a strong proteolytic activity in the rumen, the
amino acid concentration in rumen fluid is low because of the
presence of microbial deaminases, the activity of which increases
with increasing protein content of the ration. The enzyme is
directly responsible for the process of deamination.
Ammonia production: The ammonia in rumen liquor is
the key intermediate in the microbial degradation and synthesis
of protein. Parts of the ammonia produced in the rumen liquor
is utilized by the rumen bacteria along with carbon moiety to
synthesize the microbial proteins, and excess of ammonia is
absorbed into the blood, carried to the liver and converted to
urea. Some of this urea may be returned to the rumen via the
saliva, and also directly through the rumen wall, but the larger
part is excreted in the urine and thus wasted out. The rumen
fluid has a pronounced urease activity so that urea entering it
is rapidly hydrolysed to ammonia and carbon dioxide.
Increased quantity of readily fermentable sugars decrease the
concentration of ammonia in the rumen thereby helping better
utilization of proteins and non-protein nitrogen.
Fate of ammonia: Rumen microbes for their rapid
multiplication utilize considerable protein and utilize ammonia
and fix it as excellent body protein composing of essential and
non-essential amino acids in presence of soluble carbohydrates,
particularly starch. The rumen microbes continuously passes to
the abomasum and small intestine, their cell proteins are then
digested by usual gastric enzymes of the abomasum and are
absorbed. as units of amino acids mostly in the region of the
small intestine. A portion of the total ammonia of the rumen is
71
Handbook of General Animal Nutrition
absorbed in to the systemic blood and converted into urea in
the liver.
Urea recycling: It is now well established that blood urea
enter back into the rumen directly by transfusion through rumen
wall and also indirectly through saliva. The process would be
of great value to animals on low nitrogen intake.
Microbial protein synthesis: Microbes in the rumen
degrade large proportion of dietary proteins and utilize some
of the degradation products for their ッセョ@
protein synthesis.
These microbes can also make use of NPN compound and can
upgrade the dietary protein of low biological values into
microbial proteins of high biological values. Therefore, it would
be advantageous to feed poor quality protein and NPN
compound to the ruminants.
Utilization of non-protein nitrogen compound:
Ruminants can utilize non-protein nitrogenous compound as a
source of protein through the microorganisms. The compound
which are commercially available are urea and biuret etc. as a
source of NPN compounds for ruminants. First evidence of NPN
compounds used in animal feed in Germany in 1879. Finger
ling et al. 1937 produced clear evidence that urea can utilized to
supply a part of protein needs for growth of ruminants. Urea is
very common and now it has been accepted that urea can replace
about 30 to 40 percent of DCP requirement.
+H20 Urease
セR@
NH 2CONH2
Urea
NH3 + CO 2
Hydrolysis
Urea is white crystalline, deliquescent solid. Pure urea has
nitrogen content 464-466 gram/ Kg (2900-2913 gram CP/Kg)
Urea entering the rumen is rapidly hydrolyzed to ammonia
and carbondioxide by bacterial urease enzyme. This ammonia
is used as a nitrogen source by the rumen microorganisms for
synthesis of microbial protein along with the carbon skeleton
corning from the carbohydrates/proteins. Efficient utilization
of ammonia for microbial protein synthesis requires the
72
The Protein in Animal Nutrition
optimum initial ammonia concentration and a readily available
source of energy for protein synthesis. Feeding practices
intended to meet these conditions include mixing urea with
other feeds which should be low in rumen degradable protein
and high in readily fermentable carbohydrates. It is important
to avoid accidental over consumption of urea since the
subsequent rapid absorption of ammonia from the rumen can
exceed the ability of the liver to re-convert it to urea, hence
causing the ammonia concentTation of peripheral blood to reach
toxic level. Optimum level of ammonia in rumen is 5-8 mg/100
ml. Ammonia concentration is increased beyond the optimum
level when diet protein is more than 13%. Urea become toxic if
the level of ammonia exceeds 80 mg/ 100 ml of rumen liquor
and 1 mg per 100 ml of blood. Whereas, 3 mg per 100 rol of
blood ammonia concentration is fatal. To avoid ammonia
toxicity, not more than 1/ 3rd of the dietary nitrogen should be
provided as urea. Urea does not provide the source of energy,
minerals and vitamins. Urea is also deficient in sulfur containing
amino acids so as a source of sulfur, 0.13 gram anhydrous
sodium sulfate is added per gram of urea.
Derivatives of urea have been used for animal feeding with
the intention of retarding the release of ammonia. Biuret is
produced by heating urea. It is colourless crystalline compound.
Biuret has nitrogen content 408 gram/Kg (2550 gram CP /Kg).
Nitrogen in biuret is not readily utilized as protein source. Biuret
is non toxic even at higher levels. Biuret is less rapidly
hydrolysed than urea but requires a period of several weeks
for rumen microbes to adapt to it. Adaptation becomes fast if
rumen liquor innoculation with rumen liquor from an adopted
rumen. However, neither biuret nor isobutylidene diurea nor
urea- starch compounds have consistently proved superior to
urea itself. Uric acid, which is present in poultry faeces, is also
used as ruminant feed.
Urea toxicity symptoms: Nervousness, muscle tremors,
difficulty in respiration, excessive salivation, bloat, tetany,
convulisons and death within 2 to 3 hours are the symptoms of
urea toxicity. The severity of symptoms depends upon the dose
73
Handbook of General Animal Nutrition
of urea intake. The drenching of glacial acetic acid cold water is
the line of treatment in urea toxicity. To avoid urea toxicity,
urea should be mixed properly in the feed and level of urea
should be 3 percent in the concentrate mixture or 1percent in
the sole ration of ruminants. Whereas BIS recommended 1
percent of urea in the concentrate mixture of ruminants.
Utilization of NPN substance by non-ruminants: Nonruminants are also able to utilize NPN compound for the
synthesis of non-essential amino acids and the optimum level is
0.3 percent of the diet. But NPN substances are of little practical
value for non-ruminants. It is ineffective for swine but used to
some extent by mature horses on low protein diet and by hen
fed diets well balanced in the essential amino acid.
Protein metabolism: Dietary proteins are digested through
the action of proteolytic enzymes to amino acids. These amino
acids are absorbed through the small intestine into the portal
blood. Major site of absorption of amino acids is proximal2.j3rd
of small intestine. Absorption is an active type in which transport
of sodium is involved. Tripeptides are absorbed more rapidly
than dipeptides, which are in turn faster than free amino acids.
There is a competition for absorption within groups of free
amino acids, viz, acidic, basic, neutral and imino acids but no
competition between groups which suggests that slightly
different mechanisms of transport exist for different chemical
configurations. They are transported to the liver and then to
the systemic blood circulation. Amino acid of the blood pool
serves as a major source for tissue protein synthesis. Excess of
amino acids, which are not required for synthesis of tissue
protein, hormones, enzymes etc. are catabolized in the liver
tissues. The catabolism of amino acid involves deamination
whereby ammonia and a-keto-acid are formed. The released
ammonia is converted into urea or may be utilized by a-keto
acid to form amino acid.
Amino acid degradation take place mainly in the liver
although, the kidney shows considerable activity, unlike
muscular tissues which is relatively inactive.
74
The Protein in Animal Nutrition
1.
Deamination: Separation of nitrogen from an amino
acid in the form of ammonia and the detachment of nonnitrogenous residue from it, is called deamination. The nitrogen
become useless during this process but the non-nitrogenous
portion serves as a source of energy to the animal body. With
the result of oxidative deamination of all the amino acids there
is formation of ammonia and the non-nitrogenous residue ketoacid.
+H 20+NAD+
Alanine-------.... Pyruvic acid + Ammonia + NADH
Alanme dehydrogenase
+ H20 +NAD+
Glutamic acid
'u-ketoglutamic acid + Ammonia + NADH
Glutamic dehydrogenase
The ammonia thus, liberated is converted to urea by the
liver and excreted through urine from the body. The nonnitrogenous portion serve, as a energy source which either
follow the pathways carbohydrate metabolism or fat
metabolism.
Non oxidative deamination: These reactions are catalyzed
by amino acid dehydratase and also require vitamin B6 •
Serine
Threonine MNセ@
セ@
Pyruvate + NH/
ex. - Ketoglutarate + NH4+
セ@ Fumaric acid + NH4+
Asparatic acid - - - -..
Transamination: In transamination the amino
3.
group of one amino acid is transferred to the a-carbon atom of
a keto acid, resulting a production of another keto acid and
amino acid. The reactions are catalysed by enzyme known as
amino transferases. The reaction for aspartic acid may be
represented as follows:
75
Handbook of General Animal Nutrition
Aspartic acid
Aspartic acid + 。Mォ・エッァャオイゥ」セL]oク@
acid + Glutamic acid.
acid
Transferases
Transaminase"
Pyruvic acid + Glutamic acid "
Alanine + a-ketoglutaric acid
In this way the pyruvic acid which is a product in the
carbohydrate metabolism is transferred to amino acid by the
process of transamination and serves in protein synthesis in
animal body.
Transmethylation: This is the process by which methyl
group is transferred from the amino acid methionine and joins
the some other compounds to form choline for the formation
of creatinine or phospholipid.
Urea formation: One of the consequences of amino acids
metabolism is the production of ammonia, which is highly toxic.
Some of this may be used in the amination of amino acids
synthesis in the body. Most is excreted from エNセ・@
body, as urea
in mammals and uric acid in birds.
The formation of urea which take place in the liver involve
two stages both of which require an energy supply in the form
of ATP. The first step is the formation of carbamoyl phosphate
from CO2 and NH3 in the presence of carbamoyl phosphate
synthetase
CO 2 + NH3 + H2 0
7"'\. Carbamoyl phosphate
2ATP
2ADP
The carbamoyl phosphate then react with ornithine to yield
citrulline, which finally converted into urea and ornithine via
kreb's urea cycle.
76
. The Protein in Animal Nutrition
Ornithine + carbamoyl phosphate
.
セヲ@
Ci
Hine
1-=:=---. AMP
Urea
II
aウー。イエセ@
ATP
Arginosuccinate
1
the
1.
2.
3.
4.
Fumarate
セ@
Utilisation of amino acids: The absorbed amino acids in
body are utilised for various functions.
For the protein synthesis
For the synthesis of essential amino acids
As a source of energy and ammonia
For a special function - various important compounds are
formed from amino acids which are very helpful in living
system.
MセI@
Histidine
Histamine
) Purine
Glycine
Aspartic acid
)
Glutamine
Purine & pyrimidine
) Pyrimidine
Lysine -------+) Camitine (responsible for transport offat)
Tryptophan
Serotonin
) Niacin and Serotonin
) 5- Hydroxytryptamine (Which is a vasoconstrictor
and Neurotransmitter)
Phenyl alanine Tyrosine
) Norepinephrine and Melanin
Serine -------+) Ethanolamine
Choline -------+) Methionine
Creatin
MセI@
Creatinine
77
Handbook of General Animal Nutrition
Protein synthesis: Proteins are synthesized from amino
acids, which become available as the end products of digestion
or as the result of synthetic processes within the body. Direct
amination may take place as in the case of a- ketoglutarate,
which yields glutamate_ The glutamate may undergo further
amination to give gluatmine and undergo transamination
reactions with various keto acids to give amino acids. Amino
acids other than glutamate may undergo such transaminations
to produce new amino acids. Thus both alanine and glycine
react with phosphohydroxypyruvate to give &erine.
Glutamate
Pyruvate
/
Glutamate
OXaIOaC?e
a-Ketoglutarate
Glutamate
1
3-70SPhOhYdroXY
1
a-Ketoglutarate
Phosphoserine
Aspartate
Alanine
ADP
Ay
pyruvate
a-ketoglutarate
1
1
Aspargine
Serine
Amino acid Synthesis from glutamate.
3- phosphohydroxypyruvte
Alanine
pyruva/
Glycine
1
\
Gl yoxal ate
Serine
The process of protein synthesis may be divided into four
stages:
1. Activation of individual amino acids
2. Initiation of peptide chain formation
3. Chain elongation
4. Chain termination.
Factor affecting protein utilization in ruminants: Various
factors affect the protein utilization in ruminants, which are
described below.
78
The Protein in Animal Nutrition
1.
2.
3.
Dietary level of protein: Protein utilization if improved
by increasing the level of protein in the diet upto the level
of requirements however, more protein supplement above
the requirement is not properly utilized.
True protein nitrogen (TPN) vs. Non-protein nitrogen
(NPN) ratio: True protein is the best source of nitrogen
which is followed by mixture of TPN + NPN and than
NPN. However, NPN utilization will depends on the degradability of dietary protein, availability of keto acid for
amino acid synthesis and minerals specially sulphur.
Degradability of protein: Protein utilization is decreased
as the degradability of protein in rumen is increased. The
optimum ratio of rumen degradable protein (RDP) and
rumen undegradable protein (RUP) in high yielding animals is 40: 60. Degradability of different feed is different.
Feed
Urea
Casein
Barley
Groundnut
Maize
Fish meal
Degradability (percent)
100
90
80
60
40
30
Fish meal is least degradable in rumen. So fish meal gives
better quality protein for ruminants. Fish meal is called
naturally protected protein because it is 70 percent
undegradable, which reach to lower GIT as such and provide
high quality protein.
4. Indigestible nitrogen content in diet: Indigestible
nitrogen present in feed is due to damage of protein. Excessive
heating leads to browning of protein in which epsilon amino
group of amino acid lysine combine with cellulose and
hemicellulose to form complex which is insoluble in acid
detergent solution. So it is called acid detergent insoluble
nitrogen (ADIN) or artifact lignin. High level of indigestible
nitrogen in diet reduces the protein utilization.
79
Handbook ofGeneral Animal Nutrition
Protein deficiency Symptoms: It includes reduced feed
intake and utilization, reduced growth rate, infertility, reduced
serum protein concentration, accumulation of fat in the liver
and carcass, reduced synthesis of certain enzymes and hormones
resulting depression of most metabolic activities which may lead
even to early death.
The classical disease of protein malnutrition of the young
is kwashiorkar. The marasmus is a calorie deficient state. The
general term for both the conditions in protein/ calorie
malnu trition (PCM) which i:; characterised by low blood protein
level, poor digestion, lethargic patient and depressed immune
system.
Amino acid deficiency: It is a condition in which the dietary
supply of one or more of the essential amino acids is less than
that required for the efficient utilization of other amino acids
and other nutrients. Diets are in general unlikely to be completely
devoid of anyone or more amino acids but may be deficient in
respect of required quantity. The amino acid, which provides
the lowest proportion of the theoretical requirement, is referred
to as the first limiting amino acids (Lysine).
Amino acid imbalance: This term is normally restricted
to circumstances where the composition of essential amino acids
in the diet results in a further poorer animal performance than
would be expected in case of amino acid deficiency where the
effect depends on the extent of limiting amino acids. Imbalance
is produced by the addition to a diet low in total protein of
either the second limiting amino acid, or more usually a group
of amino acid which doesn't include the first limiting amino
acid. The adverse effect on performance can be avoided by
supplementation with the first limiting AA.
Amino acid antagonism: Certain amino acid interferes the
metabolism of other amino acids ego Lysine in excess increases
the excretion of Arginine. Excess lysine also increases the activity
of arginase enzyme and arginine is broken down to urea and
ornithine. Antagonism differs from imbalance in that the
supplemented amino acids need not be limiting amino acid.
80
The Protein in Animal Nutrition
Secondly it refers to an excessive amount of amino acid in the
diet which affects only those amino acids belonging to members
of the structurally similar group.
Amino acid toxicity: The term amino acid toxicity is used
when the adverse effect of an amino acid in excess cannot be
over come by supplementation with other amino acids. The
effect of the inclusion of the gross amounts of an individual
amino acid with in a diet varies among amino acids. Threonine,
even in a very large amount (50g/kg of the DM of the diet) is
tolerating well and causes only a moderate depression of feed
intake and growth. Tyrosine, however when ingested in large
amounts by young growing rats gives a low protein diet, not
only depress severely feed intake and growth but caused severe
eye and paw lesions, and in great excess is lethal. Methionine is
the most toxic and in amounts exceeding 20 g / kg of the dry
matter of the diet may produce severe histopathologicalchanges.
Q.1. Fill in the blanks:
1. All proteins contain on an average about - - - - - - - - % nitrogen.
2. An amino acid, which is not synthesised by the animals in
the required amount, is called - - - - - - - - .
3. Linkage between different amino acids is called - - - -
4.
5.
6.
Sulphur containing amino acids are - - - -, - - - - and - - - - - - .
Aromatic amino acids are - - - - - - and - - - - - -
7.
8.
Neutral amino acids are - - - - - -, - - - - - - -, - - - - - - and - - - - .
Basic amino acids are - - - - - - - - and - - - - -.
Acidic amino acids are - - - - - - - - - and - - - -
9.
Heterocyclic amino acids are - - - -, - - - - - - and
81
Handbook of General Animal Nutrition
10. The non-protein group in conjugated protein is called
11. In glycoprotein the prosthetic group is - - - - - - - 12. In chromoprotein the prosthetic group is - - - - - - 13. The most commonly used non-protein nitrogenous compounds are - - - - - and - - - - - - -.
14. The pH of the stomach for efficient protein digestion
should be - - - - - .
15. The pancreatic enzymes namely - - - - -, - - - - and - - - - - attack the partial break down product of
protein in duodenum.
16. In stomach, protein is attacked by enzymes namely - - - - and - - - - - - .
17. Proteins are proteolyse into - - - - - - and - - - - in rumen.
18. Excess of ammonia produced in rumen is carried to liver
and converted into - - - - - -.
19. The optimum level of ammonia in rumen is - - - - - 20. Toxic level of ammonia in rumen liquor is - - - - - - 21. Toxic level of ammonia in blood is - - - - - - - - - .
22. - - - - - - - ammonia concentration in blood is fatal.
23. Bureau of Indian Standards (BIS) recommended - - - - urea in concentrate mixture.
24. The process of separation of nitrogen from an amino acid
in the form of ammonia is called - - - - - - - .
25. A process by which one amino acid results in the formation of another amino acid is called - - - - - - - .
26. In transamination reaction pyruric acid is converted into
- - - - -. Whereas Asparatic acid is converted into
82
The Protein in Animal Nutrition
27. The end product of protein metabolism in birds is - - 28. The two important reactions of protein metabolism are - - - and - - - .
29. Urea is - - - percent degradable in rumen whereas fish
meal degradability is - - - - - - - .
30. Acid detergent insoluble nitrogen (ADIN) is also called 31. - - - - - - - - is the first limiting amino acids.
32. The disease of protein malnutrition of the young one is 33.
34.
35.
36.
37.
38.
39.
40.
41.
42.
43.
44.
- - - - - gram anhydrous sodium sulfate is added per
gram of urea.
Urea is dificient in - - - - - - containing amino acids.
Urea has nitrogen content - - - - - gram/kg while
Biuret has - - - - gram/kg.
Urea has crude protein content - - - - - gram/kg while
Biuret has - - - - - gram /kg.
Biuretis non-toxic at - - - - levels in comparison to urea,
when added in ruminant feeds.
- - - - - - - gave clear evidence that urea can utilized
as protien source and needs for growth to ruminants.
To avoid ammonia toxicity not more than - - - - of
dietary nitrogen should be provided as urea.
Urea does not provide the source of - - - - - - -, - - - - and - - - - - .
Arginine is breakdown into - - - - - - - and - - - arginase enzyme.
- - by the action of
Rumen fluid has pronounced - - - - - - - - - activity
which rapidly hydrolyzed
urea to ammonia and carbon dioxide.
Sugar present in DNA and RNA are - - - - - - - - and - - - - - - - - - - - - - .
The basic protein present in cell nucleus and associated
with DNA is referred as - - - - - - - - - -.
83
Handbook of General Animal Nutrition
45. Positively charged amino acids are - - - - - - - - ,
- - - - - - - - - and - - - - : - - - 46. Phenyl alanine and tyrosine are - 7- - - - - - - - amino
acids while Histidine
and tryptophane are - - - - - - - - - amino acids.
Q.2. Explain the following:
1. NPN substance utilization in goat.
,
2. Digestion and absorption of pr9tein in swine.
3. Digestion and absorption of :protein and non-protein
nitrogenous compound in cattle.
4. Protein metabolism in horse.
6.
7.
8.
9.
Transamination, deamination, 'amino acid toxicity, amino
acid imbalance and antagonism, protein deficiency symptoms.
Factor affecting protein utilization in ruminants.
Urea feeding in ruminants.
Utilization of amino acids. ,
General function of protein ..
Q.3.
1.
2.
3.
4.
5.
6.
7.
Differentiate the following:
Essential amino acid and non-essential amino acids.
Dispensable amino acid and non-dispensable amino acid.
Deamination and Transamination reactions.
Acidic amino acids and Basic amino acids.
Aromatic amino acids and セャゥーィ。エ」@
amino acid.
Fibrous protein and globular protein.
Conjugated protein and derived protein.
5.
I
84
Chapter
6
The Lipids in
Animal Nutrition
Plant and animal contain a group of substances, insoluble
in water but soluble in ether, chloroform and benzene which
are referred to as lipids. They act as electron carriers in
enzymatic reactions, as component of biological membranes and
as stores of energy. Fat contains 77, 12 and 11 percent carbon,
hydrogen and oxygen, respectively. Certain compound lipids
contain nitrogen and phosphorus also. The animal body contains
17 to 26 percent fat, which is stored around the walls of the
intestine and kidney, fat depot under the skin and adipose
tissues of the body. In addition to this, in small amount it is
found in muscles and other parts of the body.
Function of fats:
The main function of fats is to supply energy to the animal
body. One gram of fat after complete oxidation produces
9.3 Kcal heat. Fats are reserved source of energy to the
animal body.
2. After hydrolysis, fats are converted into fatty acid and
glycerol, so they provide essential fatty acids (linoleic, arachidonic and linolenic) to the body.
3. It is an essential component of milk.
4. It helps in the absorption of calcium and phosphorus in
the body.
5. Certain fat soluble vitamin such as vitamin, A,D,E, and K
are absorbed in the blood in presence of fat.
6. It is an essential constituent of the body protoplasm.
1.
8S
Handbook of General Animal Nutrition
7.
Phospholipids are the essential constituent of cell wall and
play an important role in cell nutrition.
8. It helps in temperature regulation & insulation for the vital
organ, protecting them from shock.
9. It is required for the lubrication of joints.
10. Fats are important nutrient of nervous metabolism.
11. It delays the sensation' of hunger, as it requires a longer
period of time to pass through the stomach than carbohydrate and protein.
12. PolyunsaturatedF.A. particularly arachidonic acid, are the
precursor of highly active prostaglandins.
Classification of Lipids:
LIpid
I
tイャセ@
1
.1
SImple
Compound
I
n
Glycolipids
Fats
Glucohpids
Galactolipids
n
Phosphoglycerides
Lecithins
SphinolJlmyelins
Cerebrosides
Waxes
Cephalins
Steroids
Terpenes
Elcosanolds
Fatty Acids: Fatty acids are long chain organic acids having
usually from 4 to 30 carbon atoms, they have a single carboxyl
group and a long non-polar hydrocarbon tail which gives most
lipids their hydrophobic and oily or greasy nature. The chain
may be saturated (containing only single bonds) or unsaturated
(containing one or more double bonds).
Saturated Fatty Acids:
Trivial name
No.ofCatoms
2
Acetic acid
Propionic acid
3
Butyric acid
4
Systemic name
Ethanoic acid
Propionic acid
Butanoic acid
86
The LIpids in Animal Nutrition
Caproic acid
6
Caprylic acid
8
Capric acid
10
Lauric acid
12
Myristic acid
14
Palmitic acid
16
Stearic acid
18
Unsaturated Fattv Acid:
Palmitoleic
(16-C):1
acid
(i8-C): 1
Oleic acid
(18-C): 2
Linoleic acid
Linolenic acid
(18-C) : 3
Arachidonic
(20-C): 4
acid
Hexanoic acid
Octanoic acid
Decanoic acid
Dodecanoic acid
Tetra decanoic acid
Hexadecanoic acid
acta decanoic acid
9 hexa decenoic acid
9 octa decenoic acid
9,12 acta decadienoic acid
9,12,15 Octadecatrienoic acid
5,8,11,14 Icosa tetra enoic acid
Simple lipids: They are esters of fatty acid with trihydric
alcohol glycerol. The most abundant are the fats and the less
abundants are waxes.
Fats and Oils: Both have the same general structure and
chemical properties but different physical characteristics. The
melting point of the oils is such that at ordinary room
temperature they are liquid. Chemically fats are ester of fatty
acid with glycerol. In nature three fatty acid molecules combined
with one glycerol molecule with release of three molecules of
water.
CH20H
CH2·0.CO.R
I
CHOH
•
+ 3 R.COOH
I
CH2 0H
Glycerol
I
CH.O.CO.R
I
+3 H2O
CH2 O.CO.R
Triacylglycerol
fatty acid
Triglycerides differ in type according to the nature and
position of the fatty acid residues. Those with three residues of
the same fatty acid are termed simple triglycerides. When more
than one fatty acids are esterfied with glycerol then a mixed
triglycerides are formed.
87
Handbook of General Ammal Nutrition
CH2. O.CO.RJ
I
CH.O.CO.R2
I
CH 2.O.CO.R3
Where,
acids.
セL@
Rz and 1\ represent the chains of different fatty
Some of the fatty acids have one common property that
they have a terminal carboxyl group and even number of carbon
atoms, if derived from naturally occurring fat. The unsaturated
fatty acid,s contain from one to many double bonds. Their
physical properties are different from the saturated acids as
they have lower melting points and are chemically more reactive.
Essential fatty acids: Three fatty acid viz. linoleic, linolenic
and arachidonic acids are considered セッ@ be essential for farm
animals. Either one of linoleic or arachidonic acid is capable of
preventing the skin dermatitis caused by the deficiency of these
acids in the chicks, pigs, calves and goats. Ruminant taking
forages and grasses gets considerable quantities of linoleic acid.
Hydrogenation of linoleic acid in the rumen will make available
of more quantities of linolenic acid. Therefore, they are less
likely to be affected by the deficiency of these acids.
Chemical properties of the fats:
Hydrolysis: Fats are hydrolysed to glycerol and fatty acid
by the enzymes (lipases) and by alkali in the presence of water.
Such a hydrolysis is known as saponification. The fats may be
readily decomposed into glycerol and salt of the constituent
fatty acid (soap) by boiling with strong bases such as sodium
or potassium hydroxide.
Stearin + Potassium hydroxide = Potassium stearate (a soap)
+ Glycerol
Saponification number: The saponification number is
defined as the milligrams of potassium hydroxide required to
saponify 1 gram of fat. The saponification number of fat indicates
the average molecular size of fatty acids.
88
The Lipids in Animal Nutrition
Hydrogenation: The unsaturated glycerides of fat may be
hydrogenated by treatment with hydrogen in the presence of
nickel catalyst to form cooking fats. Oleic acid is hydrogenated
to stearic acid.
Halogenation: Chlorine, bromine and iodine may be added
to the double bonds of unsaturated glycerides in fats. It gives
information about the number of unsaturated bond present in
fats.
Iodine number: This is defined as the percent of iodine
absorbed by the fat or the grams of iodine absorbed by 100
grams of fat.
Acetylation: The glycerides of fats containing hydroxylated
fatty acids react with acetic anhydride and other acylating
agents to form the corresponding esters.
Acetyl number: The acetyl number is defined as the
milligram of KOH required to combine with the acetic acid
liberated by the saponification of one gram of acetylated fat.
Castor oil contain sufficient amount of hydroxylated acid to
give a high acetyl number (146-150) whereas, butter has acetyl
number of 1.9 to 8.6 indicating the presence of very small amount
of hydroxylated acid.
Acid number: It is the milligrams of KOH required to
neutralize the free fatty acids present in 1 gram of fat.
Reichert- Meissl number (R.M. Value): It is defined as
the number of me. of decinormal alkali required to neutralize
the steam volatile fatty acid from 5 g of fat.
Polenske Number: It is the number of milliliters of 0.1 N
KOH required to neutralize the insoluble fatty acids obtained
from 5 gram of fat.
Oxidation of unsaturated glycerides of fat: Oxidation of
unsaturated bonds in the glycerides of fat absorbs oxygen and
form products, which polymerize to produce insoluble hard
films. Such oils are used in the production of paints and
varnishes. The oxidation of unsaturated fatty acids takes place
at the carbon atoms adjacent to the double bond to form
89
Handbook of General Animal Nutrition
hydroperoxides. The break down of hydroperoxides yields free
radicals, which then attacked other fatty acids, and so more
free radicals are produced and the process of oxidation increases
exponentially. The products of oxidation include short chain
fatty acids, fatty acid polymers, aldehydes, ketones, epoxides
and hydrocarbons. Oxidation of saturated fatty acids results in
the development of a sweet, heavy taste and smell commonly
known as ketonic rancidity.
Rancidity of fat: When unsaturated fats or butter are
stored they become rancid. It is of two types.
Hydrolytic rancidity: It is caused by the micro-organism
in the fat in which short chain fatty acids are hydrolysed into
malodourous fatty acids. But nutritive value of fat in hydrolytic
rancidity remains same.
Oxidative rancidity: Oils containing highly unsaturated
F.A. are spontaneously oxidized into short chain F.A. (C4 to
C 10 ) and aldehydes by atmospheric oxygen at ordinary
temperature. This rancidity develops in the fat by
autooxidation. It is more common in unsaturated fatty acids.
Due to oxidation, hydroperoxides arebroken down to aldehyde
and ketone, which have offensive taste and smell. As the
structure is altered, the nutritive value of fat is reduced in this
type of rancidity. The vitamin E and hydroxyquinone are
antioxidants which are used to prevent rancidity or oxidation
of fat oxidative rancidity is observed more frequently in animal
fats than in vegetable fats. This is due to the presence of natural
antioxidants ego Tocopherol, phenols, napthols which checks
autooxidation. Synthetic anti oxidants such as Nordihdroguia
retic acid (NDGA) & Tertiary butyl hydroxy anisole (BHA) are
also used for preventing oxidative rancidity.
90
The Lipids in Animal Nutrition
Oxidative rancidity:
R -
CHz-CH=CH-CH2-R
R -
+
CH-CH=CH-CH2
-R
6o
Hydroperoxide
H
R -
yH-CH=CH-CH 2- R +OHO
0°
Free radicals
RO + O2--+ R0 20
°
R0 2 + RH --+ RO+ROOH
RO+Ro ---+ R-R
Autocatalytic oxidation of fatty acids
\\Taxes: Waxes are defined as the esters of higher fatty
acids and of higher monohydroxy alcohol. They are found in
numerous reactions in plants, animals and microorganism where
they form a protective covering and are present in oily secretion.
Beeswax: This insect wax is a complex mixture of ester,
some fatty acids, alcohols and hydroxarbons. It contains mainly
the myricyl palmitate as the ester.
Lanolin or wool fat: This material forms a protective
coating over the wool fibres and is a wax rather than fat. Lanolin
has the properties of taking up much water without dissolving,
which make it a valuable as a medium in the preparation of
ointments, cosmetics and candles.
Compound lipids:
(A) Phospholipids (Phosphatides):
These are lipids, which contain phosphorus, the latter
being present as esterified phosphoric acid. Among the many
91
Handbook of General Animal Nutrition
vital functions, regulation of plant and animal cell permeability,
participation in the transport and metabolism of synthesized
and dietary fats and role in blood coagulations are important.
CH20H
CH20COR 1
I
I
CHOH + RI COOH + R2 COOH +H 3P04 ---+ CHOCOR2
I セ@
I
CH20H
CH20-P-OH
I
イョセ@
OH
Phosphatidic acid
1. Phosphoglycerdes:
(a) Lecithins: Like fats, lecithins are ester of glycerol. Two
of the alcohol groups are esterified with fatty acid, but the third
is estrified with phosphoric acid, which is inturn esterified by
the nitrogenous base choline. A typical example would have
the formula:
OH
CH2 O.CO. Cl5 H31
I
Phosphatidic acid + CH 2CH 2 N+ (CH 3)3 Choline
I
CH.P.CO.C I7 H33
I
+
CH2.0.PO-3.CH2.CH2. N (CH3)3
The chief fatty acid present are palmitic, stearic, arachidic
and oleic. Acids below lauric are not found in the lecithins.
(b) Cephalin: Cephalin differs from the lecithins in having
ethanolamine instead of choline and is correctly termed as
phosphatidyl enthanolamine. Cephalin has the following
formula:
CH2·0.CO.R
Phosphatidic acid + OH CH 2 CH 2 NH2 Ethanolamine
I
CH.O.CO.R
I
CH 2.O.PO-3.CH2CH2' NH2
Cephalin usually contains stearic, oleic, linolenic and
arachidonic acid.
92
The Lipids in Animal Nutrition
(c) Phosphatidyl serine: They differ from lecithins in having
serine as their nitrogenous base which is phosphatidyl serine
having formula:
FH20COR
RCOOCH
1f2
@
セ
CHz-o-P-G-CH2- C-COOH
I
I
I
0-
H
(d) Plasmogens: Some phosphoglycerides contain enol form
of a long-chain aldehyde connected by ether linkage and
replacing one fatty acid found in lecthins and cephalins.
2. Phophoinositides: These compounds on hydrolysis
yield glycerol, fatty acid, inositol and phosphate. Inositol is a
vitamin. Two different types of phosphoinositides have been
described by the inositol derivatives yielded upon hydrolysis.
Monophosphoinositide found in heart, liver, soyabean and
wheat germ and diphosphoinositide found in brain.
3. Phosphosphinosides (sphingomyelins): These
com pounds are found in ョ・イカッオセ@
tissue and differ from
phospho glycerides in the nature of nitrogenous base
components and lack of glycerol. They are madeup of fatty
acids, phosphoric acid, choline and sphigosine. The general
formula of sphingomyelins is given below:
CH3 (CH2)12. CH.:CH. CHOH. CH. CH2 O.PO-3 . CH2 • CH2 . N+ (CH3)3
I
NH.CO.R
(B) Glycolipids (Glycosphigosides or cerbrosides):
The glycolipids are compounds occurring most commonly in
nerve tissues. They consist of fatty acid residue, usually of high
molecular weight, linked to the amino group of sphingosine
which is linked via its terminal alcohol group to a molecule of
93
Handbook of General Animal Nutrition
hexose sugar; this is most frequently galactose and less often
glucose.
Derived lipids: Derived lipids on hydrolysis give the
products of simple and compound lipids and additional other
compounds such as steroids, fatty aldehydes, ketones, alcohols,
essential oils and hydrocarbons.
Steroids: The steroids include such biologically important
compounds as the sterols, the bile acids, the adrenal hormones
and sex hormones. They have a common basic structural unit
of a phenanthrene nucleus linked to a cyclopentane ring. The
individual compounds differ in the number and position of their
double bonds and in the nature of the side chain at carbon atom
17.
Sterols: These have 8 to 10 carbon atoms in the side chain,
and an alcohol group at carbon atom 3. They may be classified
into:
1. The phytosterol of plant origin
2. The mycosterol of fungal origin
3. The Zoosterols of animal origin.
Cholesterol: Cholesterol is zoosterol which is quantitatively
an important constituent of the brain. It occurs in smaller
amounts in all animal cells and it can be synthesized in the body,
but, inspite of this wide distribution and apparent importance
little is known of its actual function. The thickening is due to
deposition of cholesterol inside the arterial walls.
7-Dehydrocholesterol: Which is derived from cholesterol
is an important precursor of vitamin D3, which is produced when
the sterol is exposed to ultraviolet light.
Ergosterol: It is a phytosterol widely distributed in brown
algae, bacteria and higher plants. It is important as the precursor
of ergocalciferol or vitamin D2
Bile acids: The bile acids have a five carbon side chain at
carbon 17 terminating in a carboxyl group which is bound by
an amide linkage to glycine or taurine. The bile acids are
94
The Lipids in Animal Nutrition
important in the duodenum where they aid the emulsification
of fats and the activation of lipase.
Steroid Hormones: These include male sex hormone
(androgens), and female sex hormones (oestrogen and
progesterone) as well as cortisol, aldosterone and corticosterone
which are produced by the adrenal cortex.
Essential oils: Many terpenes found in plants have strong
characteristic odours and flavours and are components of
essential oils such as lemon or camphor oil. The word essential
is used here to indicate the occurrence of the oils in essences
and not to imply that the animals require them. Among the
many important plant terpenes are the phytol moiety of
chlorophyll, the carotenoid pigments and the vitamin A, E, and
K. In animal some of the co-enzymes are terpenes.
Digestion and absorption of lipid in non-ruminants: Fat
and cholesterol are not miscible with water whereas,
phospholipids are much more miscible. Lipid digestion and
absorption イセアオゥ・@
arranging the lipid in a form that is water
miscible to cross the microvilli of the small intestine, which are
covered with aquous layer.
Peristaltic movement of stomach and duodenum made it
as a coarse emulsion. The pancreatic lipase and colipase in the
presence of bile hydrolyze the triglyceride droplets into fatty
acids and monoglycerides and reduce the lipid to a finer and
finer emulsion. 2-monoglyceride, which has a polar (glycerol)
and non-polar (fatty acid) end, is an excellent emulsifying agent.
The bile, free fatty acids and mono glyceride become oriented
into a mixed micelle containing a lipid core and a polar exterior.
Micelles are tiny particles formed by the combination of bile
salts with the free fatty acids and mono glycerides produced
during digestion.
The micelle migrates to the brush border where it is
disrupted. Most of the bile is absorbed into the mucosa and the
remaining bile in the lumen moves down the intestine and
absorbed and recirculated through the liver.
95
Handbook of General Animal Nutrition
Most of the triglycerides are absorbed upto the mid
jejunum. With in the mucosa, the fatty acids and monoglyceridp"
are resynthesized into triglycerides, combined with cholesterol
and phospholipid encased in a thin layer of protein and secreted
into the central lacteal of the villus as either chylomicron or
very low density lipoprotein (VLDL) particles. Chylomicron is
responsible for transportation of dietary fat to various tissues
in the body. The central lacteal drains into the lymph vessels
and enters the general blood circulation via the thoracic duct at
the right atrium. The hydrolysis and resynthesis of triglycerides
during the process of digestion and absorption produces similar
but not identical triglyceride molecules in the lymph. The
absorption rate is more, if dietary lipid contains
*1. Shorter chain length fatty acids
*2. More unsaturated fatty acids
*3. As triglycerides rather than free fatty acids.
Digestion and absorption of lipid in ruminants: The
ruminant diet consists of a high proportion of unsaturated fatty
acids found in galactolipids of forage and in the triglycerides
of the cereal grains. The rumen microbial population hydrolyzes
the triglyceride and galactolipid, releasing free fatty acids (FFA)
and fermented the glycerol and galactose into volatile fatty
acids. The process of hydrogenation saturates the unsaturated
fatty acids. The bacteria and protozoa are also capable of
synthesizing a number of odd chain fatty acids from propionate
and branched chain fatty acids from the carbon skeltons of the
amino acids valine, leucine and isoleucine. Lipid is present in
the form of thin layer of free fatty acids on the surface of the
feed particles in duodenum. A little triglyceride is available to
be converted to monoglyceridein duodenum and upper jejunum
because of acidic content of duodenum and upper jejunum. So
active micelle formation of the fatty acids does not occur in the
upper tract under the influence of bile salts and lecithin.
96
The Lipids in Animal Nutrition
Phospholipase
Lecithin - - -... Lysolecithin + Free ヲ。セ@
Digesta/FF A complex
acids (FFA)
1
FFA
Lecithin
Lysolecithin
--=--=----_.
Micelle
Bile Salts
----- ------- ---- -- Brush border-- -- --- -- -- -- -- -- --- -- ---- --- ----- ----- -- -I-----+Lysolecithin
Glucose
j
FFA
a-Glycerophosphate
2 moles
14---------- Fatty acyl CoA---tI
j
pィBエ「セ@
Diglyceride _ _ _ _ _ _ _ _ _.L-_+.
tイZセL[B@
Chylomicron
------------- Basement membrane
--------------------!------------------Lymph
Absorption of dietary fat in the small intestine of ruminants.
In lower three quarter of the jejunum the pancreatic
phospholipase hydrolyze lecithin into a fatty acid and
lysolecithin, which further enhances micelle formation. So
absorption of lipid takes place in lower two third of jejunum.
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Handbook of General Animal Nutrition
1,2-Dlglyceride
TriglycerIde
Lipase
•
2-Monoglycende
+
----.. +
Free fatty aCId
Free fattY acids
セmゥ」・ャL@
セ@
セ@
I-MOnOglYICende
1
Lipase
Bile Salts ____./
..........
Free fatty aCId
Short-cham
+
fatty aCIds
Glycer I
-------------------. Brush border ----------------Glucose
!
Oihydroxyacetone
phosphate
Free fat:TP Id
CoAS
{
!
AMP+PP
Fatty acyl CoA
u-GlycerophosJitate
Short and medium - c
in
fatty a ids
atセ@
AO,1
Glycerol
Phosphatidic aCId セMoャァiyc・ョ、@
1
Phospholipid
Triglyceride
!
J3-Lipoproteill
• Chylomicron
- - - - - - --- - - Basement membrane--- - -- --- - --- - - --- - - -
1-----------------
Lymph
system
Portal
blood
Digestion and absorption of triglycerides in nonruminants
Metabolism of lipids: The digestion of lipids produces
glycerol and fatty acids, which are metabolised and produce
energy.
Metabolism of glycerol: Glycerol is glycogenic in nature
and converted into dihydroxy acetone phsophate.
98
The Lipids in Animal Nutrition
CH 20H
---;r/\_.
Glycerol kinase
AT?
AD?
CH 20H
Glycerol 3-phosphate
I
Dehydrogenase
I
CHOH セcZo@
iCH,O-?
lD> Nkow
C:O-@
Glycerol
Phosphoglycerol Dihydroxy acetone phosphate
or
Glycerol 3- Phosphate
DihYdrox1<e1on, p"'ophate
fイオMGwZィセ@
G1U'T-phI'' ' ' '
Gl"",lyti, pathw.y
CO2 & H20 + 38 ATP.
Conversion of 2-mole glycerol to dihydroxyaceton
phosphate produces 6 moles of ATP and utilizes 2 mole of ATP,
whereas conversion of 2 moles of dihydroxyacetone phosphate
to one mole of glucose and glucose metabolism via glycolytic
pathway produces 38 moles of ATP. So a net
38+6-2
- 2 - = 21 moles of ATP are produced per mole of glycerol.
Metabolism of fatty acids: The fatty acid provides the major
part of the energy derived from the fat. The fatty acid is
metabolised by J3-oxidation mechanism, which shortened the
carbon chain by removing two carbon atoms at a time. The first
stage of this mechanism is the reaction of the fatty acid with
99
Handbook of General Animal Nutrition
I
coenzyme A in the presence of ATP and fatty acyl-COA and
produce acyl-COA. This occurs in the cytosol and the fatty acylCOA entered into the mitochondria as a complex with carnitine
and is there regenerated- and metabolised into acetyl-COA and
acyl-COA with two less carbon atoms than the original fatty
acid. The separation of acetyl- COA is equivalent of 5 moles of
ATP. The remaining acyl- COA undergoes the same series of
reactions and the process continues until the carbon chain has
been completely converted to acetyl-COA. This enters the TCA
cycle and is oxidised to CO2 and H 20 and gives 12 moles of
ATP. The oxidation of palmitic acid, which is a 16-C fatty acid,
is given below:
13-
oxidation:
R(CH2)n CH 2 CH 2 COO·
Fatty acid
ATP)
AMP
Acyl- CoA
<:
1
s.COA
Fatty acyl CoA ligase
H 20
R. (CH 2)n CH 2 CH 2 COS. CoA
FAD)
j
Acyl CoA dehydrogenase
FADH2
Enoyl-CoA
R. (CH 2)n CH. CH. COS. CoA
H 20 _ _
13- Hydroxyacyl-CoA
!
Enoyl CoA hydratase
R. (CH 2 )n' CHOH. CH 2 COS. CoA
NAO+
)
!f3-HYdroxyaCYI_COA dehydrogenase
NADH2
p-Ketoacyl-CoA
R.(CH2)n CH. CH 2 • COS. CoA
HS. CoA
-1
Acetyl CoA acyl transferase
R. (CH 2)n COS.CoA + CH 3 cos. CoA
Acyl-CoA
Acetyl-CoA
Oxidation of a fatty acid to acetyl CoA
100
The Lipids in Animal Nutrition
Energy production from palmitic acid:
1 Mole palmitic acid to palmitoyl-COA = - 2 ATP
1 Mole palmitoyl-COA to 8 moles acetyl- COA = + 35 ATP
8 Moles acetyl- COA to CO2 and H 20 = + 96 ATP
Net gain of ATP per mole of palmitic acid = 129. Similarly
stearic acid (18-C) produces a net gain of 146 ATP and archidic
acid (20-C) produces a net gain of 163 ATP per mole of archidic
acid.
Q.1. Fill in the blanks with appropriate words.
1. Fat contains
percent carbon.
2.
and
are essential fatty acids.
and
are simple lipids.
3.
4. When more than one fatty acids are esterifed with glycerol
then a
are formed.
5.
Fatty acids containing more than one double bonds are
called _ __
6.
Milligram of potassium hydroxide required to saponity 1
gram of fat is called _ _ __
7.
The process of hydrolysis of fats in which soaps are formed
is known as _ __
8.
Iodine number is the amount of iodine absorbed by _ _
grams of fat.
9. Acetyl number is milligram of _ _ required combining
with the acetic acid liberated by the saponification of one
gram of acetylated fat.
10.
type of rancidity affect the nutritive value of fat.
11.
type of rancidity does not affect the nutritive value
of fat.
12. The number of ml. of decinormal alkali required to neutralize the steam volatile fatty acid from 5 g of fat is called
13. Lecithin contains a nitrogenous base called _ _ __
14. Cephalin differs from the lecithin in having _ _ _ group
instead of choline.
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Handbook of General Animal Nutrition
15. Most of the triglycerides are absorbed at
in CIT.
16.
The digestion of lipid produces
and _ __
ATP.
17. Metabolism of one mole of glycerol produces
18. Fatty acids are metabolised by
process.
19. The separation of acetyl COA from fatty acids yields _ _
moles of ATP.
20. Acetyl COA produced from fatty acids in metabolised are
produce _ _ moles of ATP.
21. A net gain of _ _ moles of ATP is produced by 1 mole
palmitic acid metabolism.
22. Complete metabolism of steraric acid produces _ _ __
Moles of ATP.
23. Complete metabolism of 1 mole of arachidonic acid produces
moles of ATP.
24. Fatty acid is metabolized by - - - - - - - - - - - - which shortened two carbon atoms at a time.
25. Chylomicron is responsible for transportation of - - - - - - - - - - - - - - - to various tissues in the body.
Q.2. Explain the following:
1. Explain the digestion and absorbtion of lipids in ruminants.
2. Explain the digestion and absorption of lipids in non-ruminants.
3. How the glucerol is metabolised in the body?
4. Explain the metabolism of fatty acids by 13-oxidation
mechanism.
5.
6.
How much ATP are produced from metabolism of 1 mole
of palmitic acid, steraric acid and archidic acid each and
How?
Define the terms:
Saponification number, Iodine number, Acetyl number,
Reichert- Meissl number, Hydrolytic and oxidative rancidity in
fat, Saponification and acetylation of fats.
102
Chapter
7
The Minerals in
Animal Nutrition
The periodic system lists 104 elements. There are about
40 mineral elements that occur in measurable amount in nature
in the plants and animals tissues. Minerals are generally
classified into two categories.
1.
Macro elements (Major elements): The minerals,
which are required in relatively large amount and in most of
cases they are used in the synthesis of structural tissues. Their
concertration is expressed in term of percentage. The important
major elements are calcium, phosphorus, magnesium, sodium,
potassium, chlorine and sulphur.
2.
Micro elements (Minor elements or trace
elements): These minerals required in trace amounts and usually
function as activators or as a component of enzyme system.
The concentration of trace elements is expressed in terms of
part per million (PPM) since their concentration is very low in
the plants and body. The important trace elements are iron,
copper, iodine, cobalt, zinc, manganese, fluorine, selenium,
molybdenum, chromium, nickel, silicon, tin and vanadium and
playa functional role in animal physiology.
Essential mineral elements: These are those minerals,
which have been proved to have a metabolic role in the animal
body.
Non-essential mineral elements: Most of mineral elements
are simply component of animal tissues since they are present
in the diet and are considered to be non-essential, as they do
not play any essential metabolic role in the plant or animal body.
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Handbook of General Animal Nutrition
General Function of Minerals: The functions of minerals
in animal nutrition are inter-related. However, a few of the
general functions are given as:
1.
As a constituent of skeletal structure:
2. In regulating acid-base equilibrium.
3. They are helpful in maintaining the colloridal state of body
matter and regulating some of the physical properties of
colloidal systems like viscosity, diffusion and osmotic pressure.
4. They act as a component or an activator of enzymes and
or other biological systems.
MACRO-ELEMENTS (MAJOR ELEMENTS): All the
macrominerals are discussed here reference to their function,
metabolism, deficiency sym ptoms and sources of these minerals.
1. Calcium: Calcium and phosphorus serve as the major
structural elements of skeletal tissue, with more than 99 per
cent of the total body calcium being found in the bone and
teeth. The normal level of blood calcium inanimals ranges from
9 to 11 mg per 100 ml of serum. The cell contains negligible
amounts. From 45-50 per cent of the plasma calcium is in the
soluble, ionized form, while 40-45 per cent is bound with protein,
primarily albumin and other plasma protein. The remaining 5
per cent is complexed with non-ionized inorganic elements
depending on blood pH. The plasma of laying hens contains 30
to 40 mg calcium per 100 ml of blood.
Factors affecting the level of blood calcium:
1.
2.
3.
The absolute levels of calcium and phosphorus and the
calcium phosphorus ratio of food: A low intake of either
element over long periods of time leads to decreased blood
calcium level. A Ca: P ratio of 1:1 to 2:1 is usually recommended.
Fat content in the diet: Impaired digestion and absorption of fat causes impaired absorption of calcium because
calcium form soaps which are insoluble.
Phytic acid and oxalate: Oxalates in certain foods precipi104
TIle Minerals in Animal Nutntion
4.
S.
6.
7.
s.
9.
tate calcium in the intestine as the insoluble calcium oxalates
formed insoluble salt with calcium and makes it insoluble.
Acidity relation: Acidic medium in intestine favour calcium absorption.
Protein in the diet: Calcium salts are much more soluble
in amino acid than water. High protein level increases the
absorption of calcium.
Vitamin D in the diet: Vitamin 0 provides acidic medium
in the intestine causing more calcium absorption.
Parathyroid hormones: Parathyroid hormones regulate calcium level in the plasma.
Kidney threshold: In a normal adult any extra calcium
absorded from the kidney is readily excreted in the urine.
Sex hormone: Low level of oestrogen hormone causes poor
absorbtion of calcium.
Function of calcium: Calcium is essential for skeletal
formation, normal blood clotting, rhythmic heart action,
neuromuscular excitability, enzyme activation and permeablity
of membranes and acid base balance of body fluid and also in
curdling of milk. A number of enzymes including lipase, succinic
dehydrogenase, adenosinetriphophataseand certain proteolytic
enzymes are activated by calcium.
Absorption of calcium: The main site of calcium absorption
is the small intestine specially the proximal portion of the
duodenum. The percentage of absorption of calcium decreases
with age, high F intakes, and high ca intakes or low vitamin 0
intakes. The major route of excretion for calcium is through
faeces.
Requirement of calcium
Lactating cows
Sheep
Goat
Poultry
(% of dry matter infeed
0.43-0.60%
0.21-0.52%
0.21-0.52%
0.80-1.20%
105
Handbook of General A nimal Nutrition
Deficiency symptoms:
1. Ricket: This symptoms occure in young growing animals.
The symptoms of rickets are misshapen bones, enlargement of joints, lameness and stiffiness. This condition is
called Ricketic rosary. Calcification of normal bone does
not take place.
2. Osteomalacia: In the adult animals, calcium deficiency
results in osteomalacia. In osteomalacia the bones become
weak, porous and soft. Continuous mobilization of calcium
from the bones for the higher demand with a low intake is
responsible for this condition.
3. Osteoporosis: This is characterized by a decreased bone
mass. It is due to bone resorption being greater than bone
formation. It is prominent in aging, and related to gonadal
hormone deficiency.
4. Milk fever (parturient paresis; calcium tetany): Shortly
after parturition, high yielding cows may suffer from milk
fever. The serum calcium goes down with the result that
there are muscular spasms and in extreme cases paralysis.
There may be breeding difficulties in pregnant animals and
the calves born may be dead or very weak.
5. In laying hens deficiency of calcium results in improper
development of the egg-shell which is either not fully
formed or easily breakable. The deficiency causes soft
bones and beak, curved legs and low egg production.
Source of calcium: Milk and green leafy crops, especially
legumes, are good sources of calcium; cereals and roots are
poor sources. Animal by product containing bone, fish meal,
meat cum bone meal are rich source of calcium. Dicalcium
phosphate, calcium carbonate and calcium phosphate are also
good source of calcium.
106
The Minerals in Animal Nutrition
Calcium content of feed stuff:
% Calcium
0.09
0.04
0.05
0.16
0.36
0.91
1.00
0.19
27.3
23.1
33.8
38.0
1.42
0.37
Feed stuff
Barley
Maize
Wheat
Wheat bran
Sovabean meal
Cow milk
Spinach
Eggs
Bone meal
Dicalcium phosphate
Lime stone
C5Vster shell
Legume forages
Grasses
2. Phosphorous: Major portion of phosphorus in the animal
body is distributed in the bones. The content of inorganic
phosphorus in the blood is 4 to 9 mg per 100 ml depending
upon the species and age. Maintenance of inorganic phosphorus
level in the blood is also governed by the same factors, which
promote calcium and phosphorus assimilation. Whole blood
contains about 35-40 mg phosphorus per 100 ml.
Functions of Phosphorus:
Phosphorus plays an important role in the formation of
bones and teeth along with calcium. The amount of phosphorus present in these structure in about 80 per cent of
the total.
1.
2.
3.
4.
It maintained the normal level of blood calcium and its
proper activity.
It plays active role for the formation of phospholipid in
the cells, nucleic acid, coenzyme, phosphoprotein and phospholipid.
It plays a vital role or in energy metabolism in the formation of sugar phosphate like adenosine di-phosphate (ADP)
and triphosphates (ATP).
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Handbook of General Animal Nutrition
Deficiency symptoms:
1. Rickets: Deficiency of phosphorus causes ricket along with
calcium imbalance in young animals.
2. Osteomalacia: The element causes osteomalacia in adult
with deficiency of calcium.
3. Pica (Depraved appetite): Phosphorus deficiency causes a
specific symptom in cattle called pica. The affected animals have abnormal appetites and chew woods, bone, rags
and other foreign materials. The animals become very
weak, if not treated, they may die due to weakness or due
to secondary infections, which occur from eating decaying bones and other materials.
4. Reproduction: Low dietary intake of phosphorus has also
been associated with poor fertility; dysfunction of ovaries
causing inhibition, depression and irregularity of oestrus.
Requirements of phosphorus ('X) of dry matter in feed):
Dairy cows
Sheep! Goat
Poultry
0.31-0.40
0.16-0.37
0.32-0.50
Sources of Phosphorus: Animal products like fish meal,
meat meal and bone meal are good sources of phosphorus.
Cereal grains, wheat bran, rice bran, rice polishing, cake etc.
are fairly good sources of phosphorus though poor source of
calcium. Leguminous fodders like berseem and lucerne are poor
sources of phosphorus. Most of the phosphorus present in the
cereals and their by-products is in the form of phytates, which
are the salt of phytic acid, a phosphoric acid derivative.
Ruminants can utilize the phytate phosphorus due to rumen
microbial activity ..
Phosphorus content of feed stuffs:
Phosphorus (°It))
0.47
0.31
0.41
Feed stuffs
Barley
Maize
Wheat
108
The Minerals In Animal Nutntion
1.32
0.75
0.55
0.71
0.83
13.0
18.7
18.0
Wheat bran
Soyabean meal
Spinach
Cow milk
Egg
Bone meal
Dicalcium phosphate
Rock phosphate
3. Magnesium: About 70 percent of the total magnesium
is found in the skeleton, the remainder being distributed in
soft tissues and fluids. Blood serum contain 2 to 3 mg magnesium
per 100 m!. Bone contains about 1.5 percent magnesium.
Function of Magnesium:
1. Magnesium plays important role in activating various enzymes such as phosphate transferases, decarboxylases and
acyltransferases.
2. Magnesium is an activator of phosphates and takes an active
part in the carbohydrate metabolism.
3. It also plays an important role in calcium and phosphorus
metabolism for the formation of bone and teeth.
4. Magnesium also plays an important role for the
neuromuscular activity of the body.
Absorption of magnesium: The rumen and reticulum is
the major site of Mg absorption in ruminants. It is also absorbed
from large intestine. Magnesium is excreted via faeces, urine
and milk.
Requirement of magnesium
% of dry matter
Dairy cow
0.20
Sheep and goat
0.04-0.08
Deficiency symptoms:
1. Magnesium tetany in adult animals (Grass staggers,
Grass tetany): It is also referred as lactation tetany or wheat
pasture poisoning. There are other factors also which are
responsible for gross staggers like hormonal disturbances and
109
Handbook of General Animal Nutrition
faulty interrelationship of calcium, phosphorus and magnesium.
Clinical signs of tetany include appetite, increased excitability,
profuse salivation and convulsions.
2. Hypomagnesimia in young calves: This has been
reported in India when calves reared on milk diet without any
other supplement for a prolonged period.
3. Neurological symptoms in rats: In the rats lowering of
magnesium to 1.8 ppm resulted in hyper-irritability,convulsion
and death. The blood picture showed normal calcium and
phosphorus but magnesium content was reduced. In poultry
magnesium deficiency causes neurological symptoms like rats.
Sources of Magnesium: Most of the commonly fed
roughage and concentrates contain 0.1 percent. Bran, oil cakes
and leguminous fodder are rich source of magnesium while
milk and animal products are much poorer source.
Magnesium content of some feed stuffs:
Feed stuffs
Magnesium (mgllOOgm)
Egg
11
Cow milk
Spinach
Corn
Peas
Wheat
Soybean
12
97
121
140
165
210
4. Sodium: It is an alkaline salt which forms about 93
percent alkali of blood serum. It is found in body fluids and
muscles of the body. The total amount of sodium in the body is
about 0.2 percent out of which upto 0.05 percent is deposited in
bones.
Functions of Sodium:
1. Sodium salt is useful in the metabolism of water, protein,
fat and carbohydrate.
2. It controls body fluid concentration, contraction of nerve
and muscle fibres, body fluid pH, osmotic pressure and
110
The Minerals in Animal Nutrition
help in maintaining neutrality among body tissues.
Absorption ·of sodium: Absorption of sodium takes place
in rumen and upper small intestine. It is mainly excreted through
urine with small amount is also excreted through faeces and
perspira tion.
% of dry matter in feed
Requirement of sodium
Sheep and goat
Poultry
Dry cow
0.04-0.10
0.11-0.14
0.18-0.20
Deficiency symptoms:The deficiency of sodium in the
body of animals result in loss of appetite, general debility,
stoppage of growth and development, fall of body temperature,
neuromuscular disturbances and loss of milk production in
lactating animals.
Feed stuff
Maize
Oat
Wheat
Soyabean
Wheat straw
Grasses
Wheat bran
Fish meal
Sodium (%)
0.03
0.13
0.10
0.35
0.12
0.03
0.14
1.06
Sources of sodium: The chief source of sodium is sodium
cloride or common salt. Most of the feed and forages are poor
source of sodium except the herbage which grown on alkaline
soil for reclamation.
5. Potassium: Most of the potassium is found in the cells.
Excess of this salt in the body interferes with the absorption
and metabolism of magnesium.
Functions of Potassium:
1. Potassium is essential part along with sodium, chlorine and
bicarbonate ions, in the osmotic pressure regulation of the
body fluids and in the acid-base balance in the animals.
111
Handbook of General Animal Nutrition
2.
Potassium plays an important role in nerve and muscles
excitability and activates certain enzymes.
Absorption of potassium: Potassium is absorbed mainly
from the small intestine and to some extent in the large intestine.
The majority of potassium excretion is in the urine and also via
sweat and milk.
Deficiency symptoms:
1. Potassium deficiency result in slow growth, reduced feed
and water intake, lowered feed efficiency, muscular weakness, nervous disorders, stiffness, emaciation, intracellular acid isis and degeneration of vital organs.
2. High intake of potassium may interfere with the absorption and metabolism of magnesium in the animals, which
may be an important factor in the etiology of hypomagnesaemic tetany.
Sources of potassium: Outside the body potassium is
available in pasture grasses. Milk also contains potassium. Inside
the body it is found in muscles, plasma and blood cells.
6. Chlorine: It is found in skin, subcutaneous tissues and
gastric juices. Out of the total amount present in the body 80-85
percent chloride is found in inorganic form while the rest 15 to
20 percent in organic form.
Functions of Chlorine:
1. This mineral is required for the formation of hydrochloric
acid of the gastric juice.
2.
3.
4.
In the form of sodium chloride it assists in the digestion of
food.
Chlorine is associated with sodium and potassium in acid
base relationship and osmotic regulation.
It also helps in cell nutrition, growth and reproduction
among animals.
Absorption of chlorine: Chlorine is absorbed in
combination with sodium. It is mainly absorbed from the upper
small intestine. It is excreted through urine with small amount
in faeces and perspiration.
112
The Minerals in AnImal Nutrition
Deficiency symptoms:
1. A dietary deficiency of chlorine may lead to an abnormal
increase of the alkali reserve of the blood (alkalosis) caused
by an excess of bicarbonate, since inadequate levels of chlorine in the body are party compensated for by increase in
bicarbonate.
2. Deficiency of salt in diet leads to decreased appetite which
result in poor growth rate and milk production.
3. Deficiency of salt in poultry leads to feather picking and
canabalism.
Sources of chlorine: With the exception fish and meat
meals, the chlorine content of most foods is comparatively low.
The chlorine content of pasture grass varies from 3 to 25 gjkg
dry matter. The main source of this element for most animals is
common salt.
7. Sulphur: Most of the sulphur in the animal body occurs
in proteins containing the amino acids cystine, cysteine and
methionine. The two vitamins, biotin and thiamin and the
hormone, insulin, also contain sulphur.
Functions of Sulphur:
1. Sulphur is an essential element for protein and vitamin
synthesis. Wool is rich in cystine and contains about 4 percent of sulphur.
2. It combined with iron and used for the formation of
heamoglobin in red blood cells.
3.
4.
It also useful in blood clotting and endocrine function.
It also maintained intra and extra cellular fluid and acid
base balance.
Absorption of sulphur: Sulphur is absorbed in the rumen
and small intestine. It can be recycled to the rumen with
similarities to the recycling system for the urea-nitrogen system.
Deficiency symptoms:
1. Deficiency of sulphur in the body results in poor growth
and development of the body, loss of weight, weakness,
113
Handbook of General Animal Nutrition
2.
lacrimation and metabolic activities of the body are also
disturbed. Microbial protein synthesis is reduced and the
animal shows sign of protein malnutrition. There is evidence that sodium sulphate can be by used ruman microorganisms more efficiently than elemental sulphur.
In sheep its deficiency causes production of the poor quality
wool.
Sources of sulphur: All balanced rations, muscles, wings
of the birds, horns, hairs, nails, bile juice, saliva, R.B.C, nervous
system and hoof of the animals contain certain amount of
sulphur.
Sulphur content in feed stuffs:
Sulphur ('Yo)
Feed stuffs
Maize
Wheat
Soyabean
Alfalfa hay
Fish meal
Dried skim milk
0.15
0.17
0.41
0.16
0.11
0.08
TRACE ELEMENTS (MICRO ELEMENTS):Various trace
minerals are discussed here. The average trace minerals content
of various feeds and fodders are mentioned below:
Average traces mineral contents of feed stuffs:
Feed stuffs
Fe
Cu
1. Cereals and leguminous crops
a.Maize
36
5.0
l? Barley
48
6.4
c. Wheat
50
6.2
d.Soyabeans
17.0
125
2. Maize silage
196
7.0
11.0
3. Alfalfa hay
188
3.4
4. Wheat straw
120
5. Cotton seed cake 190
19.0
6. Wheat bran
90
11.0
7. Fish meal
340
7.5
8. Dried skim milk
9
0.7
Mg/kg air dry feed stuffs
Mn
Co
Zn
114
0.02
0.08
0.08
0.10
0.08
0.09
0.03
0.28
0.80
0.80
0.07
5
15
30
31
42
41
32
21
119
19
2.2
22
22
26
35
32
13.5
67
80
95
103
45
I
0.30
0.25
0.07
0.20
0.06
0.03
0.30
0.30
0.09
2.50
0.03
The Minerals in Animal Nutrition
1. Iron: The total amount of iron found in the body is 0.004
percent. Half of this amount remains in combination with R. B.c.
in the form of heme associated with red colouring matter or
haemoglobin. The remaining portion is found associated with
myoglobin, enzyme cytochrome, peroxidase, catalase and other
enzymes of the body; liver, spleen and kidney. As a respiratory
enzyme it is present in all the tissues of the body. In the form of
myoglobin, iron is found in all the muscles.
Functions of Iron:
1. As a part of respiratory pigment and heamoglobin, iron
helps in the utilization of oxygen by the blood.
2. It activates enzymes by taking part in the enzyme system
and assists in proper functioning of every organ of the
body. Iron is also a component of many enzymes including cytochromes and certain flavoprotiens. 4 ppm iron is
necessary for the formation of blood and growth of chicks.
Absorption and excretion: The amount of iron absorbed
is related to its need by the animal body. The capacity of the
body excrete the iron is very less therefore; its ,absorption is
controlled by the body's requirement. There are two hypotheses
for the control of iron absorption.
1. Mucosal Block theory: In this case iron is absorbed by the
mucosal cells of gastro-intestinal tract, when they become
physiologically saturated the iron absorption is checked.
2. The second mechanism by which iron absorption is controlled is the passage of iron from the mucosal cells to the
stream which is controlled by the oxygen tension in the
blood.
Before absorption, ferrous iron is oxidised to ferric state,
following absorption into the mucosal cells there it binds with
apoferritin, a protein, to form ferritin. At the blood stream end
of mucosal cell the ferric iron is again converted into ferrous
form and is detached from the ferrittin. In the blood stream it
is again auto-oxidized and is attached to a protein siderophilin,
in which form it is transported.
115
Handbook of General Animal Nutrition
Factors which affect iron absorption:
1. Acidic condition in the gastro-intestinal tract helps iron
absorption. Absorption ofiron is more efficient when body
stores are low.
2. Ascorbic acid in the diet also helps iron absorption.
3. High level of phosphorous and phytic acid present in the
diet reduces iron absorption.
Deficiency symptoms: The deficiency symptoms of iron
are lower weight gain, listleness, inability to withstand
circulatory strain, laboured breathing after mild exercise,
reduced appetite and decreased resistance to infection. Anaemia
in piglets is characterized by poor appetite and growth.
Breathing becomes laboured and spasmodic and this condition
is called 'thump'.
Source of Iron: Milk is poor and green forages are rich
sources of iron.
2. Copper: Copper is an integral part of cytochrome A and
cytochrome oxidase. It appears that copper functions in the
cytochrome system in the same way as iron, that is, through a
change in valency. The enzymes tyrosinase, lactase, ascarbic
acid oxidase, plasma amino oxidase, ceruloplasmin and uricase
contain copper, and their activity is dependent on this element.
Copper is present in blood plasma as a copper-protein complex,
ceruloplasmin. Copper absorption takes ーャ。」セ@
from the
abo mas urns and small intestine. Dietary phytate, high levels of
calcium carbonate, iron, zinc and molybdenum reduce
absorption and excreted through faeces. Acidity of the stomach,
intestinal secretion and the base content of the diet affect the
absorption of copper from gasto-intestinal tract. In metabolism,
copper is closely associated with molybdenum. Excess of
molybdenum in the body result in poor absorption and storage
of the copper salt. Deficiency of molybdenum causes more
absorption and storage of the copper in the body.
Functions of copper:
1. Copper acts as catalyst in the formation of heamoglobin
and provides oxygen absorption power to red blood cells.
116
The Minerals in Animal Nutrition
2.
3.
4.
As an essential part of enzymes system copper plays
important role in various metabolic activities of the body.
The element is necessary for the normal pigmentation of
hair, fur, wool and skin.
It is necessary for iron absorption from small intestine and
iron absorption from tissue stores.
Deficiency symptoms: Copper deficiency includes
anaemia, bone disorders, neonatal ataxia, depigmentation and
abnormal growth of hair and wool, impaired growth and
reproductive performance, retained placenta, heart failure,
gastro intestinal disturbances, immunosuppression and lesions
in the brain stems and spinal cord. These lesions are associated
with muscular incoordination, and occur specially in young
lambs.
Enzootic ataxia: The copper deficiency condition known
as enzootic ataxia has been known for some time in Australia.
The disorder is these associated with pasture low in copper
content (2 to 4 mg/kg DM), and can be prevented by feeding
with a copper salt.
Swayback: A similar condition which occurs in lambs
occurs in u.K. called swayback. The symptoms of swayback in
newborn lambs range from a complete inability to stand, to
various degree of in-coordination particularly of the hind limbs.
Salt sick: For many years it had been recognized in Florida
that cattle not thrive well due to copper deficiency. They lost
their appetite. They become emaciated and weak and their
blood was very low in heamoglobin. Young cattle were most
affected and often badly stunted many of the animals died from
the disease which is called salt sick.
Stringy wool (Steely wool, Falling disease, Baffing
disease): Copper plays an important role in the production of
crimp in wool. The element is present in an enzyme which is
responsible for the disulphide bridge in two adjacent cysteine
molecules. In the absence of enzyme the protein molecules of
the wool donot form this bridge and referred as stringy or
117
Handbook of General Animal Nutrition
steely wool. This disease is called falling or baffing disease.
Falling disease: The disease is characterized by sudden
death without any preliminary sign. In this fibrosis of
myocardium takes place and macrocytic hypochromic type
anaemia appears.
Coast disease (Neck ill, Lickin disease): This disease is
caused by the deficiency of copper and col>alt in diet of cattle
and sheep.
Teartness (Peat scours): Certain nutritional disease which
are prevented or cured by copper supplement, the forage
contains a normal amount of copper. However, the assimilation
of copper is apparently prevented by an excess of another
minerals. One disease is teartness, a type of sever scouring and
unthriftiness which affects cattle pastured on certain area of
England and similar conditions are noticed in New Zealand in
peat soil pasture known as peat scour.
Sources of copper: The requirements of copper are quite
difficult to determine since its absorption and utilization in the
animal are markedly affected by several mineral elements and
other dietary factors i.e. zinc, iron and molybdenum. Copper is
widely distributed in feed. Some soils are deficient in copper in
our country. Concentrates are rich sources of copper. Straws
are poor source of copper. Cattle require 50 mg of copper per
day. Moreover, requirement for sheep is 5 mg per day. Pigs
require 5 ppm of copper per kg of diet per day.
Copper-Molybdenum-sulphur interrelation:
Certain
pasture on calcareous soils in part of England and Wales have
been known to be associated with a condition in cattle described
as 'teart' characterized by unthriftiness and scouring. A similar
disorder occurs on reclaimed peat land in New Zealand, where
it is known as peat scour. Molybdenum level in teart pasture
are about 20 to 100 mg/kg DM compared to 0.5 to 3.0 mg/kg
DM in normal pasture, and teart was originally regarded as
being a molybdenosis. In the late 1930, however, it was
demonstrated that feeding with copper sulphate controlled the
scouring and hence a Molybdenum-copper relationship was
established.
118
The Minerals in Animal Nutrition
A mechanism which explains this interrelationship has
recently been suggested. Sulphide is formed by ruminal microorganism from dietary sulphate or organic sulphur compounds;
the sulphide then reacts with molybdate to form thiomolybdate
which in turn combined with copper to form an insoluble copper
thio-molybdate (eu Mo Su) thereby limiting the absorption of
dietary copper. In addition it is considered likely that if
thiomolybdate is form in excess, it may be absorbed from the
digestive tract and exert a systemic effect on copper metabolism
in the animals.
3. Iodine: Iodine is found in thyroid gland where it is
incorporated in the thyroxine, a hormone secreted by the gland.
It is also a constituent of di-iodotyrosine.
Functions of Iodine:
1. Iodine is necessary for the proper functiOning of the thyroid gland, treatment of simple goitre, control of metabolic activities and for the proper growth and development.
2. The thyroid hormone aacelerates reactions in most organs
and tissues in the body, thus increasing the basal metabolic rate, accelerating growth and increasing the oxygen
consumption of the whole organism.
Absorption of iodine: Iodine is absorbed from the
gastrointestinal tract. The rumen is the major site of absorption
whereas abomasums is the major site of endogenous secretion
or recently of circulatory iodine into the digestive tract. Iodine
is excreted through urine.
Deficiency symptoms: The deficiency of iodine results in
the development of simple goitre (enlargement of thyroid
gland). In this condition the thyroxine production is reduced
and so thyroid gland become over active and enlarged as a
compensatory growth. The thyroid being situated in the neck,
the deficiency condition in farm animals manifest itself as a
swelling of the neck, 'big neck'.
In pigs, its deficiency causes falling of hair, rough and hard
119
Handbook of General Animal Nutrition
skin, reproductive failure, retarded growth rate, poor mental
and sexual development.
Plants of Brassica family like cabbage, rape, kale and also
soybeans, linseed, peas and groundnut are rich in goitrogens
which cause the goitre even if the animals are receiving the
adequate amounts of iodine intake.
Sources of iodine: Iodine is available in fish meal, cod
liver oil and iodized salts such as sodium and potassium iodine.
4. Cobalt: Cobalt is dietary essencial for ruminants because
it is necessary for the synthesis of vitamin B12 by the
gastrointestinal microbes.
Functions of cobalt:
1. Cobalt is necessary for the growth and development of
the body as well as for the multiplication of rumen microbes
among ruminants.
2. It forms as essential part of the enzyme system and plays
an important role in the synthesis of vitamin B12 in rumen.
About 3 percent of ingested cobalt is converted into vitamin B12 in the rumen.
3. Cobalt is also involved in the synthesis of DNA and the
metabolism of amino acids.
4. As a component of vitamin B12, cobalt is involved in propionate metabolism where it acts as a cofactor.
Absorption of cobalt: Cobalt is utilized by rumen microbes
in the rumen and also absorbed in the lower portion of the
small intestine. Cobalt is mainly excreted in the faeces with small
amount in urine.
Deficiency symptoms:
1. The deficiency of cobalt is seen among animals of that
area (Australia and New Zealand) where pasture grass contain
0.04 to 0.07 ppm of cobalt. The ruminant animals suffer more as
compared to other animals. Loss of appetite, emaciation, rough
coat and paleness of skin, normocytic aneamia, retarted growth
or weight loss, weakness and reproductive failure, stumping
120
The Minerals in Animal NutritIOn
gait and finally leading to death are the main symptoms of cobalt
deficiency. In Australia and New Zealand, the deficiency of
cobalt is called coast disease, enzootic marasmus, wasting
disease, pining and vinguish etc.
In ruminants, cobalt is required by rumen microorganisms
for the synthesis of vitamin B12 . Deficiency of cobalt leads to
insufficient production ()f vitamin BI2 to satisfy the animal
requirements. These symptoms can be cured by the injection of
vitamin BI2 in the blood but the cobalt injection does improve
the condition. Small amount of vitamin B12 also synthesized in
caecum of monogatric animals but is not sufficient to meet the
requirements of poultry and pigs.
Source of cobalt: Normally the feed and fodders contain
traces of cobalt ranging from 0.1 to 0.25 ppm. Leguminous
grasses are rich source of cobalt as compared to other animals
feed. Cobalt sulphate and chloride are good source of cobalt.
Cobalt has been reported to be toxic. Ingestion of 20-25 mg
cobalt per 100 kg body weight daily may be toxic to the animals.
5. Zinc: Zinc has been found in very tissue in the animal
body. It is found in higher concentration in skin, hair and wool
than other tissue of the body. Zinc is a constituent of several
enzyme systems in the body like carbonic dehydrogenase,
pancreatic carboxypeptidase, glutamic dehydrogenase and a
number of pyridine nucleotide dehydrogenases. In addition zinc
act as a co-factors for many other enzymes.
Functions of Zinc:
1. Zinc is an important trace element for the proper growth
of body and development of hairs and keratinization of
epithelial tissues.
2. Being an essential part of insulin hormone it plays important role in the metabolism of carbohydrates. It is involved
in the nucleic acid and vitamin A metabolism and protein
synthesis.
3.
Zinc playa key role in both cell and antibody mediated
immune responses for resistant against infection and also
provide protection against liver damage caused by toxins
from the fungi.
121
Handbook of General Animal Nutrition
Absorption of zinc: The zinc absorption takes place in small
intestine. Absorption of zinc involves solubilisation of zinc,
which is higher at high acidic pH, dissociation from the source,
binding to receptors at the intestinal cell wall and transport
into the cell aided by zinc binding proteins. The rate of
absorption of zinc varies significantly between various forms
within and between organic and inorganic sources (dietary level,
amounts, chemical form of zinc). The inorganic sources have
low solubility and poor dissociation and hence often pass
through the gut into faeces without appreciable absorption. Zinc
is mainly excreted through faeces and a small proportion
through urine.
Deficiency symptoms:
1. Zinc deficiency in cattle: On the zinc deficient diet, milk
production reduced, poor fertility, loss of hair, lower feed
efficiency, loss of appetite etc.
2. Zinc deficiency in calves: Symptoms of zinc deficiency in
calves include inflammation of the nose and mouth, stiffness of the joints, swollen feet and parakeratosis.
3. Zinc deficiency in pigs: Zinc deficiency in pigs is characterized by subnormal growth, depressed appetite, poor
feed conversion efficiency and parakeratosis. The latter is
a reddeing of the skin followed by erupution that develop
in to scab. The deficiency symptoms are more common in
young one and housed pigs fed ad libitum on a dry diet.
High level of calcium in the diet aggravated the condition.
4. Zinc deficiency in chicks: Retarded growth, 'Frizzled'
feather, parakeratosis and a bone abnormality referred to
as the 'Swollen hock syndrome'.
Sources of Zinc: Brans are rich source of zinc. Feed and
fodders contain adequate amount of zinc.
6. Manganese: The amount of manganese present in the
animal body is very small, the highest concentrations occurring
in the bones, liver, kidney, pancrease and pitutary gland. Excess
amount of calcium and phosphorus in the body prevents its
absorption from the digestive tract. The mineral is excreted
122
The Minerals in Animal Nutrition
out from the body along with bile in faeces and urine.
Functions of manganese:
1. Manganese plays an important role for the bone
development and vital nutrient in the synthesis of
chondroitin sulphate which is the organic matrix of the
bone.
2.
Manganese is important trace mineral for normal growth,
reproduction, egg production and for the prevention of
perosis among poultry.
3. Manganese is important in the animal body as enzyme
activators such as phosphate transferases and
decarboxylases associated with the Kreb's cycle.
4. This trace mineral has an active role in immune functions
where it helps in detoxifying free oxygen radicals which
can cause tissue damage produced by immune cells in
response to killing bacteria.
Absorption of manganese: Manganese is one of the poorly
absorbed and retained trace minerals in livestock. High dietary
intake of calcium, phosphorous and iron reduces manganese
absorption from the small intestine. The mineral is excreted
out from the body along with bile in faeces and urine.
Deficiency symptoms:
1. Cattle: Deficiency of manganese show poor gowth, leg disorders, skeletal abnormalities, ataxia of the new born and
reproductive failures.
2.
3.
Swine: In swine deficiency of manganese results in poor
growth of bones with shortening of leg bones, enlarged
hocks, muscular weakness, increase in back fat and irregular oestrus cycle.
Poultry: In young chicks a deficiency leading to perosis in
young birds may be aggravated by high dietary intakes of
calcium and phosphorus. Manganese deficiency in breeding birds reduces hatchability and causes retraction in
chicks.
Sources of manganese: Forages are rich in manganese as
123
Handbook of General Animal Nutrition
compared to cereals. In feed it is available in maize, oat, wheat,
green fodder and brans.
7. Fluorine: The amount of fluorine in common feed stuffs
is 1 to 2 part per million. Presence of 100 ppm fluorine in the
ration on dry matter basis, and above 3 ppm in drinking water
is toxic to animals.
Functions of Fluorine: In very small amount the mineral
is essential for the growth and proper development of the bones
and teeth. It reduces the incidence of dental caries.
Deficiency symptoms: Deficiency of fluorine causes dental
caries.
Toxicity of fluorine: The major clinical signs of fluorine
toxicity are found in teeth and bone. It is slowly being deposited
in the body and produces ill effect afterward. The bone become
thick and soft with dirty colouration, teeth loss their normal
shining appearance. Finally they become soft and very weak.
They look quite bad and are unable to bear cold water.
Sometime yellow and black spots are also visible on the teeth.
It results in loss of appetite, growth and production.
S. Selenium: The presence of selenium in roughages and
concentrates is harmful to the animals. In soils it may be present
upto 40 ppm. Selenium is present in all cells of the body but
concentration is normally less than 1 ppm. Toxic concentration
in liver and kidney are normally between 5 and 10 ppm. Most
important role of selenium in livestock is prevention of liver
necrosis in rat and exudative diathesis in chicks.
Functions of Selenium:
Selenium is essential for growth, reproduction, prevention
of various diseases and protection of the integrity of
tissues. The metabolic function of selenium is closely related
with vitamin E and acts as an antioxident and required for
adequate immune response.
2. It is essential for prostaglandin synthesis and essential fatty
acid metabolism.
1.
124
The Minerals in Animal Nutrition
3.
It has a strong tendency to complex with heavy metals
and exerts a protective effect against t.'e heavy metals.
4.
Selenium is important part of an enzyme glutathione peroxidase. This enzyme destroys peroxides before they can
damage body tissues.
Selenium is also important in sulphur amino acid synthesis. Sulphur amino acids protect animals against several
diseases associated with low intakes of selenium and vitamin E. This protection is due to the antioxidant activity of
selenium.
5.
Deficiency symptoms:
1. Deficiency of selenium in the diet causes myopathies in
sheep and cattle.
2. In hens selenium deficiency reduces hatchability and egg
production. Exudative diathesis, a haemorrhagic disease
of chick and dietary liver necrosis in pigs are prevented
by either selenium or vitamin E.
3. Bilateral paleness and dystrophy of the skeletal muscle,
mottling and dystrophy of myocardium (mulberry heart
disease) are noticed in pigs. Mulberry heart disease is most
common when cereal based diets contain less than 0.05
ppm selenium.
Toxic effect: Selenium toxicity is known as 'alkali disease'
and 'blind staggers'. Which is characterized by stiffness of joints,
lameness, loss of hair from mane and tail and skin lesions on
the legs. In some parts of Haryana and Punjab, the animals suffer
with selenosis, the disease is known as Degnala.
9. Molybdenum: This mineral is available in pasture
grasses, liver, intestinal tissues and milk of the animals.
Functions of Molybdenum:
1. As a component of the enzyme xanthineoxidase, espeCially
important to poultry for uric acid formation.
2. As a constituent of nitrate reductase it also helps in the
utilization of nitrate.
125
Handbook of General Animal Nutrition
3.
It also takes parts in purine metabolism and stimulates
action of rumen microorganism.
4.
Molybdenum participates in the reaction of the enzyme
with cytochrome C and also facilitates the reduction of
cytochrome C by aldehyde oxidase.
Absorption of molybdenum: Molybdenum is absorbed
from the intestine. It is excreted through urine with a small
amount in bile and milk.
Deficiency symptoms: Deficiency symptoms under natural
condition have not been reported.
Toxic effect: In the molybdenum toxicity (molybdenosis)
in ruminants suffer from extreme diarrhoea, loss in weight and
reduced milk yields. The condition is known as teartness.
10. Chromium: Chromium has been found in
nucleoproteins isolated from beef liver and also in RNA
preparation. It may playa role in the maintenance of the
configuration of the RNA molecule. Chromium has also been
shown to catalyze the phospho-glucomutase system activates
the succinic dehydrogenase-cytochrome system. Chromium
influences metabolism of glucose, lipid and protein. Chromium
is a primary active component of glucose tolerance factor (GTF)
which makes the metabolic action of hormone insulin, more
effective in regulating energy utilization, muscle tissue
deposition, fat metabolism and serum cholesterol levels. As an
integral part of GTF, it helps in binding insulin to cell membrane
receptors sites and subsequent transport of glucose and amino
acids in side the cells.
Interaction of minerals: Minerals may interact with each
other and with other nutrients and non-nutrient factors. This
interaction is of two types:
1. Synergistic interaction: The interaction elements, which
mutually enhance their absorption in the digestive tract and
meet out the requirements of the body, are called synergistic
interaction. The synergism of essential minerals is described
as:
126
The Minerals in Animal Nutrition
•
•
•
•
•
•
•
•
•
•
•
•
Calcium is synergigm with phosphorous.
Phosphorous with calcium, sulphur, iodine, copper and
cobalt.
Sodium, chlorine and potassium with each other.
Sulphur with cobalt, magnesium and phosphorous.
Zinc with molybdenum
Manganese with copper, molybdenum, cobalt and iron.
Copper with manganese, iodine, cobalt, iron and phosphorous.
Iron with copper and manganese.
Molybdenum with manganese and zinc.
Magnesium with sulphur.
Iodine with copper, cobalt and phosphorous.
Cobalt with iodine, copper, manganese, sulphur and phosphorous.
Elements
Calcium
Phosphorous
Sulphur
Zinc
Manganese
Copper
Iodine
Molybdenum
Cobalt
Iron
Magnesium
Synergism with other minerals
P
Ca, S, Cu, I, Co
Co, Mg, P
Mo
Cu, Mo, Co, Fe
Mn, I, Co, Fe, P
CU,Co,P
I
Mn,Zn
I, Cu, Mn, S, P
CU,Mn
S
.
Antagonistic interaction: The interaction in which
2.
minerals inhibit the absorption of each other in the digestive
tract and produce opposite effects on any biochemical functions
is called antagonistic interaction. Antagonismmay be one sided
or two sided:
a. One sided antagonism: One-sided antagonism means
one mineral is antagonize the other but other can not. Potassium
127
Handbook of General Animal Nutrition
inhibits the absorption of zinc and manganese but zinc and
manganese may not.
Antagonism with other
minerals
Zn, Mn, Cu, I, Mg, Fe
Zn,Mn
I
Cu,Se
Co
I, P
Zn,P
Elements
Calcium
Sodium
Chlorine
Sulphur
Zinc
Molybdenum
Potassium
b. Two sided antagonism: In two-sided antagonism both
the mineral inhibit the function of each other. Phosphorous and
zinc inhibit the absorption of each other. Similarly, zinc and
copper antagonize with each other.
Antagonism with other
minerals
Zn, Mn, Fe, Mg
Mo, Fe, P
Mg,P
Zn,mo
CU,Zn
P
P,Mn
Elements
Phosphorous
Zinc
Manganese
Copper
Molybdenum
Iron
Magnesium
Interaction of minerals with other nutrients: Minerals are
not only interacting with each other but also interact with other
nutrients like protein, vitamins, carbohydrates, fats and feed
additives like antibiotics, alkaloids, antioxidants and glucosides
etc. Vitamin D affects the absorption of Ca, P, Mg and Zn.
Vitamin E is anteracts with trace mineral selenium. The minerals
may form new bonds with organic compounds and form
chelates. Such mineral organic complex chelates may stimulate
or inhibits the absorption of minerals.
•
Fat affects the absorption of Mg and Ca.
•
The protein level and their sources determine the degree
of utilization of P, Mg, Zn, Cu and other minerals.
128
The Minerals in Animal Nutrition
•
Excess Mo stimulates the elimination of urea nitrogen and
reduces the biosynthesis of muscle protein.
Specific deficiency of minerals:
Calcium: Ricket, Osteomalacia, Milk fever
Phosphorous: Ricket, Osteomalacia, Pica
Magnesium: Grass staggers, magnesium tetany
Iron: Anaemia, Thump
Copper: Enzootic ataxia, Sway back, Stringy wool
Iodine: Goiter
Cobalt: Coast disease, Wasting disease
Zinc: Parakeratosis in pig, Frizzled feather, Swollen hock
syndrome
Manganese: Slipped tendon/ perosis (poultry)
Flourine: Dental caries
Selenium: Mulberry heart disease, Exudative diathesis, Tying
up in horse
Toxicity:
Selenium: Alkali disease
Molybdenum: Teartness
Fluorine: Dental caries
Q.1. Fill in the blanks.
1. The Calcium deficiency symptoms are - - - - - - and
2.
3.
4.
5.
Pica is deficiency symptoms of - - - - - - -.
Milk fever is deficiency symptom of - - - - - -.
Gross staggers are deficiency symptoms of - - - - - -.
Magnesium deficiency symptoms are - - - - C - - - -
6.
7.
8.
Deficiency symptoms of sodium are - - - and - - - .
The most commonly used source of sodium is - - - - .
The deficiency symptoms of chlorine are - - - - - and
9.
10.
11.
12.
Sulphur containing vitamins are - - - - - and - - -.
A hormone which contain sulphur is - - - - - .
Iron deficiency symptom is - - - - - - - .
Enzootic ataxia is deficiency symptom of - - - - - - .
129
Handbook of General Animal Nutrition
13.
14.
15.
16.
17.
18.
Stringy wool in sheep is deficiency symptom of - - - -.
Copper deficiency symptoms are - - - and - - - - - .
Goitre is deficiency symptoms of - - - - - - -.
Iodine deficiency results in - - - - - - - .
Cobalt is a component of vitamin - - - - -.
Swollen hock joint in chicks is deficiency symptoms of -
19.
20.
21.
22.
23.
24.
25.
Manganese deficiency in poultry is - - - - - -.
Deficiency of fluorine is - - - - - - -.
Degnala disease is due to toxicity of - - - - - - - -.
Molybdenum toxicity in ruminants is known as - - - .
The selenium toxicity is also known as - - - - - - -.
Zinc shows one sided antagonism with - - - - - - - - .
Two minerals inhibits the absorption of each other is
called- - - - - - - - - - -.
26. The interaction which mutually enhances their absorption
in the digestive tract is called - - - - - - - - - - - - .
27. Frizzled feather in chicks is due to deficiency of - - -.
28. "Big neck" is deficiency symptoms of- - - - - - - -.
Q.2. Explain the following:
1. General functions of minerals.
2. Mucosal block theory.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.
Deficiency symptoms of calcium and phosphorus.
Deficiency symptoms of magnesium and potassium.
Deficiency symptoms of sodium and chlorine.
Functions and deficiency symptoms of sulphur ..
Functions of Iron.
Function and deficiency symptoms of copper.
Inter-relationship of copper-sulphur and molybdenum.
Deficiency symptoms of iodine and cobalt.
Deficiency sympotms of zinc, manganese and fluorine.
Deficiency symptoms of selenium, and molybdenum.
Inter-relationship of selenium and vitamin E.
130
Chapter
8·
The Vitamins in
Animal Nutrition
Definition of Vitamins:
Hofmeister defined vitamins as, these are substances,
which are indispensable for the growth and maintenance of the
animals, which occur both in animals and plants and are present
in only small amounts in food.
In modern sense, vitamins are the substances distinct from
major components of food required in minute quantities and
whose absence causes specific deficiency disease. Plant can
synthesize all the vitamins, which they require as a component
of various enzyme systems. Vitamins are organic substances
required by animals in very small amounts for regulating various
body processes toward normal health, growth, production and
reproduction. But this definition ignores the important part that
these chemical substances found in plants and their importance
generally in the metabolism of all living organisms.
The term vitamins was used by Funk in 1912 for an amine,
the active factor from rice polishing which are necessary for
existence of life (vital + amine). Later on the terminal "e" was
omitted, leaving vitamin. The existence of vitamin like factors
was first recognized in the orient when prisoners fed on
unpolished rice seemed to be suffering with beri-beri disease
than were non-prisoners consuming polished rice. Soon
thereafter, workers in the United States recognized a factor in
the butterfat of milk, which prevented blindness in calves.
However, the factors seemed to be different from that in rice
polishings since the milk fat factor was fat-soluble rather than
water-soluble and also did not contain nitrogen.
131
Handbook of General Animal Nutrition
There are atleast 15 vitamins, which has been accepted as
essential food factors and few others have been proposed. The
vitamins are divided into two main groups, the water-soluble
and the fat-soluble, which are differentiated as:
1.
2.
セ@
3.
4.
S.
6.
0
7.
8.
Water soluble vitamins
Parameters Fat soluble vitamins
Fat soluble
Water soluble
Solubility
Chemical Consist only of C,H, and Ring compound except
Pantothenic
acid
nature
O.
(straight chain), contains
C,H,O,N,S,P or cobalt
Vito B12 contain cobalt,
sulpher
containing
vitamins are thiamine
and biotin
Functions Vit. A, D, E, K works as in As
coenzymes
or
vision,
Calcium prosthetic groups of
absorption, maintenance enzymes except Vit. C.
of genital system and
blood clotting respectively
Synthesis Only Vit. K is synthesized Ruminant synthesized
symbiotic all Vit. B complex with
by
microorganisms Vit. D can incorporation of cobalt
be synthesized in the skin in diet. Niacin can 「セ@
upon exposure to sun light synthesized
from
Tryptophane except cat.
Vit. C except guinea pig.
human.
Absorption Absorbed from gastro- Absorbed
from
gut
intestinal tract by passive directly
diffusion
Storage
Liver
Not stored except Vit.
B12 (liver) and riboflavin
I (some extent)
Excretion Exertion in faeces via bile Excreted in urine
Toxicity
Excess
dietary
intake Relatively non toxic
causes toxicity because
they are stored in the body
Functions of vitamins:
1. Vitamins are essential for the good health and play important role in the body growth.
132
The Vitamins in Animal Nutntion
2.
Vitamin provides resistance against diseases and increases
the productivity power of animals.
3.
Vitamins are essential constituents of certain enzyme systems, regulate body metabolism and clotting of blood.
4.
Vitamins are needed during pregnancy for the development of foetus.
Vitamin A' is responsible for the proper functioning of
vision and Vitamin C keeps the gums in healthy state.
5.
I
Important vitamins in animal nutrition:
Vitamins
Chemical name
I. Fat soluble vitamins
Retinol
Vitamin Al
Vitamin A2
Dehydroretinol
Vitamin D2
Ergocalciferol
Cholecalciferol
Vitamin D3
Vitamin E
Tocopherol
Vitamin KI
Phylloquinone
Vitamin K2
Menaquinone
Vitamin K3
Menadione
II. Water soluble vitamins
Vitamin BI
Thiamin
Vitamin B2
Riboflavin
Niacin
Nicotinamide
Vitamin B6
Pyridoxine
Pantothenic acid
Pantothenic acid
Biotin
Biotine
Folacin
Folic acid
Choline
Choline
Vitamin B12
Cyanocobalamin
Vitamin C
Ascorbic acid
Vitamin A: Vitamin A was discovered in 1913 by
McCollum et al. It has been reported to occur in two different
forms, viz. vitamin Al or retinol and vitamin A2 or
dehydroxyretinol. It is an unsaturated monohydric alcohol. One
international unit of vitamin A is 0.344 Ilg of pure vitamin A
acetate, which is equivalent to 0.3 Ilg of vitamin A alcohol. One
133
Handbook of General Animal Nutrition
IV of provitamin A activity is equal in activity to 0.6 Ilg of
J3-carotene.
Chemical name: Vitamin A, known chemically as retinol,
is an unsaturated monohydric alcohol with the following
structural formula.
yH3
?H3
CH =CH - C=CH - CH=CH - C=CH -CH20H
CH3
Vitamin A (C20 H29 OH)
Vitamin A does not exist as such in plants, but is present
as precursors or pro-vitamin in the forms of certain carotenoid
which can readily be converted into vitamin A by the animal.
At least 80 provitamins are known and these included a,b and
g carotenes, cryptoxanthine, which is present in higher plants
and mycoxanthin which occur in the blue green algae.
Provitamin 13- carotene is the most widely distributed and most
active. Vitamin A contains one b -ionone ring and b - carotene
contains 2 J3-ionone rings. Carotene is converted into vitamin
A in the epithelial cell of intestine. Part of carotene is converted
into vitamin A in the liver also.
Metabolism: Conversion of J3-carotene to vitamin A takes
place in intestinal mucosa. In most of animals absorption takes
place in the form of vitamin A. Main site of vitamin A absorption
is proximal jejunum. Liver is the main storage site of vitamin A
(90 percent). In general, carotene digestibility was higher than
average during warmer months and lower than average during
winter.
Functions: Vitamin A plays following important functions.
1.
Growth: Vitamin A is responsible for the normal development of various epithelial tissues in the body. Changes
134
The Vitamins in Animal Nutrition
have been demonstrated in the salivary gland, tongue and
pharynx, respiratory tract, the genitourinary tract, eyes
and certain glands of internal secretion. The primary change
involves atrophy of the epithelium and the formation of
stratified keratinizing epithelium.
2.
Vision: Vitamin A is helpful in the transmission of light
stumuli from the eye to the brain. Each vitamin A molecule
is combined with srecific type protein called opsin to form
a visual pigment. Four such pigments have been identified
which are rhodopsin and porpyropsin, which are present
in rod and cyanopsin, which are in the cones of the retina.
The rods are concerned with vision in dim light while the
cones are concerned with bright light and colour vision.
3.
Reproduction: Vitamin A plays an important role in male
and female reproduction. Lack of vitamin A in the diet
causes atrophy of the germinal epithelium resulting in
sterlity.
4.
Skin: Lack of vitamin A in the diet causing keratosis of
the skin (dryness and roughness of skin). A keratosis
especially of the hair follicles 1S a prominent feature.
5.
Urolithiasis: A condition in which urinary calculi are
present is known as urolithiasis. Lack of vitamin A in the
diet causing keretinization of epithelial cells in genitourinary tract followed by bacterial invasion and deposition
of calcium phosphate precipitate on the site and ultimately
calculi is formed.
6.
Infection: Vitamin A has been called the anti-infective
vitamin. The vitamin does help to establish and maintain a
resistance to infection in the body, especially in tissues,
which undergoes keratinization in a deficiency of it.
7.
Bone development: Vitamin A has a role in the normal
development of bone through a control activity of
osteoclasts and osteoblasts of the epithelial cartilage.
135
Handbook of General Animal Nutntion
Animal
Beef cattle
Dairy cattle
Goat
Chicken
Sheep
Swine
Horse
Dog
Human children
Adults
Lactating
Requirement (IU/Kg feed)
2200-3800
2200-5000
5000
1500-4000
1500-2000
1400-2200
1600-2800
3300
400-700 Jlg/RE/ day
800-1000Jlg/RE/ day
1200!lg/REj day
(Retinol equivalent (RE)= 1Jlg retinol or 6Jlg l3-carotene)
Conversion of l3-carotene to vitamin A
Conversion of mg of 13- IU of vitamin A
(calculated
carotene to IV of vitamin activity
from carotene) percent
A (mg) (IU)
Standard
1 = 1667
100
cattle, 1 = 400
24
Beef
Dairy cattle
Sheep
Swine
1 = 500
30
Horse, Human 1 = 555
33.3
Poultry, Rat
1 = 1667
100
Cat, Mink
Carotene not utilized
Animal
Factors influencing Vitamin A requirement: Follwing
factors affect vitamin A requirements.
1. Genetic differences
2.
Conversion efficiency of carotene to vitamin A
3.
Variation in level, type and precursor of vit. A in feed
stuff.
4.
Destruction of vitamin A in feed through oxidation,
peroxidizing effects of rancid fats, length of storage and
catalytic effects of trace minerals.
5.
Presence of adequate bile in small intestine.
136
The VItamins in Animal Nutrition
Sources of Vitamin A: In the form of its precursor carotene,
vitamin A is found in carrot, yellow maize and green plants.
Liver, kidney, buttermilk, cod liver oil and egg yolk are also
rich in vitamin A.
Vitamin A (IU/gram)
Vitamin A source
I
400,000
Whale liver oil
4,000
Cod-liver oil
Butter
35
14
Cheese
Eggs
10
Milk
1.5
Carotene source
Alfalfa meal
Legume hay
Non Legume hay
Grains (except yellow corI!l
Carotene Hュセ@
110-300
10-60
20-30
0.20-0.44
Deficiency Symtpoms:
1. Night blindness: Diet deficient in Vitamin A causing
impaired rhodopsin formation. Which make unable to see in
dim light.
Rhodopsin
(Responsible for vision in dark)
In dark
Ill; light
+ opsin
Retina
ェヲZ]セ・ケュF。ウjイョ@
II-cis-retinol '\
(in blood)
\. Trans-retinol
Role of vitamin A in vision
137
Handbook of General Animal Nutrition
2. Xerophthalmia: Cattle with prolonged eye symptoms
leading to excessive watering, softening and cloudiness of the
cornea and development of xerophthalmia, characterized by a
drying of the conjunctiva. Constriction of the optic nerve canal
may result in blindness in calves.
3. Infertility and abortion: In breeding animals a deficiency
may lead to infertility, and in pregnant animals lead to abortion
or the production of dead, weak and blind calves. In male there
is failure of spermatogenesis.
4. Keratinization of epithelial cell: Vitamin A deficiency
causes keratinization of epithelial cell, which results in cold and
sinus trouble, diarrhea and formation of calculi in genito-urinary
tract and reproductive failure in male and female animals.
5. Disorganized bone growth and irritation of joints are
two manifestations of vitamin A deficiencies. In some cases,
there is a constriction of the opening through which the optic
and auditary nerves pass thereby resulting in blindness and /
or deafness.
Poultry: Retarded growth, weakness, ruffled plumage and
staggering gait are noticed in vitamin A deficiency. In mature
birds egg production and hatchability are reduced.
Hypervitaminosis: Excess of vitamin A causes
hypervitaminosis in the body resulting in diseases of the nervous
system, bone diseases, abnormalties and vomiting. The most
characteristic signs of hypervitaminosis are skeletal
malformations, spontaneous fracture, interanal haemorrhage,
degenrative atrophy and fatty infiltration of liver.
Vitamin-D: McCollum in 1922 discovered this vitamin as
an antirachitic factor. For nutritional purposes the two most
important vitamin Dare D2 (ergocalciferol) and D3
(Cholecalciferol). Ergocalciferol is produced from ergosterol,
which occurs in plants while cholecalciferol is derived from 7dehydrocholesterol. Ultraviolet light is the main power, which
converts provitamin into vitamin D. One LV. of vitamin D is
138
The Vitamins in Animal Nutrition
defined as the activity of 0.0251lg crystalline vitamin D3. The
sulfate derivative of vit. D present in milk is a water-soluble
form of vitamin. Vit. D3 is more stable then D2·
Metabolism:
7- Dehydrocholesterol
/
(Skin)
Cholecaciferol
(Food)
I
V.V. radiation
Cholecaliferol
!
Liver
25-Hydroxycholecalciferol
1
Kidney
I, 25-Dihydroxycholecalciferol
•
(active form ofvit. D)
Target tissues
About 50 percent of the dietary vitamin is found in the
chylomicrons leaving the digestive tract in the lymph; most of
this vitamin finds its way to the liver with the remnants of the
chylomicrons. Vitamin D synthesized in the liver diffuses into
the blood and picked up by a specific vitamin D bind protein
which transports it to the liver, although some may remain free
and be deposited in fat and muscle. Dietary vitamins D2 and D3
are absorbed through the small intestine and are transported
in the blood to the liver where they are converted into 25hydroxycholecalciferol, which is converted into active form as
1, 25- dihydroxycholecalciferol in kidney and reached to target
tissues by blood circulation. Vitamin D transported by protein
called transcalciferin or vitamin D binding protein (DBP).
Excretion of absorbed vitamin D and its metabolites occurs
primarily in faeces with the addition of bile salts.
139
Handbook of General Animal Nutrition
Functions:
1. Vitamin D plays an important role for the absorption of
calcium and phosphorus from gastrointestinal tract, which
accounts for the antirachitic properties of vitamin D.
2. It helps in the reabsorption of phosphorus from the kidney tubules.
3. Addition of vitamin D reduces oxidation of citric acid and
a high citrate concentration is found in kidney, bone and
blood but not in liver.
4. It increases the activity of the enzyme phytase in the intestine.
5. It also stimulates release of calcium rather than up take of
calcium by kidney mitochondria.
6. It stimulates incorporation of phosphorus into
phospholipids of intestinal mucosa.
7. It promotes normal development of bone, mobilization of
calcium from bone to extracellular fluid compartment and
biosynthesis of collagen.
Requirements: Animals and humans do not have a
nutritional requirement for vitamin-D. Factors, which influence
dietary vitamin D requirements are:
(i) Amount and ratio of dietary calcium and phosphorus.
(ii) Availability of phosphorus and calcium
(iii) Species
(iv) Physiological factors.
Animal
Beef cattle
Dairy cattle
Goat
Chicken
Swine
Dog
Sheep
Human
Requirement jlV/Kg feed)
275
300
1400
400
220
22 IV/Kg body weight
550 IV /100kg live weight
200-600 IV/day
140
The VitamIns in Animal Nutrition
Sources of vitamin D: As vitamin D it is present in codliver oil, kidneys, lungs, egg yolk, liver, milk, fish oil and sun
dried grasses. The vitamin is synthesized by the action of ultraviolet rays on the skin of the animals. Heating destroys the
rachitogenic activity.
Ergocalciferol (D2)
Food or Feed stuff
Alfalfa hay, sun cured
Barley straw
Corn silage
Molasses (sugar beat)
Red cloever, sun cured
Sorghum silage
IU/lOOgram
142
60
13
58
192
66
Cholecalciferol (D3)
Blue fin tuna liver oil
Cod liver oil meal
Cod liver oil
Halibut liver oil
Milk, cow whole
the
(a)
(b)
(c)
(d)
(e)
4,000,000
4,000
10,000
1,20,000
1-4
Deficiency Symptoms: Deficiency of vitamin D impairs
following functions.
Failure of calcium salt deposition in the cartilage matrix.
Failure of cartilage cells to mature, leading to their accumulation rather than destruction.
Condensation of proliferating cartilage cells.
Elongation, swelling and degeneration of proliferative
cartilage.
Abnormal pattern of invasion of cartilage by capillaries.
In young animal vitamin D deficiency results in rickets and
retarded growth. Ricket includes skeletal deformities
characterized by enlarged junction between bone and cartilages,
curvature of the bones, tendency to drag hind legs, beaded
ribs, deformed thorax and weakening of muscular tissue and
susceptibility to infection. In adult animals vitamin D deficiency
141
Handbook of General Animal Nutrition
causes osteomalacia, where there is reabsorption of bone calcium
already laid down.
In poultry a deficiency of vitamin D causes the bone and
beak to become soft and rubbery, growth is usually retarded
and the legs may become bowed, ruffled feathers. Egg
production is reduced and egg quality deteriorates.
In swine, deficiency of vitamin D causes poor growth,
stiffness, lameness and stilted gait, softness of bones, bone
deformities, unthriftiness, enlargement and erosion of joints.
Hypervitaminosis of vit 0 3 :
Increase calcium absorption--+Hyperca1cemia
、ゥ・エ。イケ⦅ウlセ@
Excessive
Vitamin 0 3
/
body セ@
セ@
Dystrophy of soft tissues
Checks cartilage
maturation
•
Calcinosis
Stunted growth
Inhibited - - - . . . HYIOPhOSPhatasemia
osteolysis
OsteonecrosIs
Atrophy of
-v
- - - _ . Osteopenia
osteoblasts
Vitamin-E (Tocopherol): In 1936 Evans and Sure
discovered it as an important factor in reproduction of rats.
After absorption from the wall of the gastrointestinal tract the
vitamin is mainly stored in the liver and to a certain extent in
various organs and tissues of the body. The vitamin can pass
through the placenta and mother's milk to its offsprings. Vitamin
E is a group name, which includes a number of closely related
active compounds. Eight naturally occurring forms of the
vitamins are known and they can be divided into two groups.
1. Four saturated vitamins that is a, b, g and d tocopherols
2. Four unsaturated vitamins thatis a, b, g and d tocotrienols,
142
The VItamins in Animal Nutrition
a-tocopherol is the most biologically active and most
widely distributed. Selenium and vitamin E are interrelated. Both are needed by animals and both have metabolic roles in the body in addition to an antioxidant effect.
Metabolism: It acts as a biological antioxidant with
glutathione peroxidase enzyme, which contains selenium. It
protects cells against oxidative damage caused by free radicals.
Free radicals are scavenged by vitamin E and glutathione
peroxidase destroys any peroxide formed before they can
damage the cell. Vitamin E is also helpful in development and
function of the immune system. Absorption of Vit.E either in
free alcohol or esters is facilitated by bile and pancreatic lipase.
Most of Vit.E is absorbed as alcohol. Tocopherol passes through
placental membranes and mammary gland. Less than 2 percent
of dietary Vit.E is transferred from feed to milk. Vit. E i& stored
through out all body tissues, with highest storage in liver. In
the plasma, the vitamin is transported in the low density
lipoprotein (LDL) fraction and concentrates in the cell
membrane. Highest concentrations are found in the adipose
tissue, other organs and tissues which contain the vitamin
include liver, heart, skeletal muscle and adrenal gland.
Functions:
1. Vitamin E acts as an antioxidant at cellular level. Thus for
an example it prevent the oxidation of unsaturated fatty
acids mostly present in all cell wall components. a-tocopherol is an excellent natural antioxidant.
2. It participates in normal tissue respiration possible by the
way of cytochrome reductase system and to protect the
lipid structure of mitochondria from oxidative destruction.
3. It aids the normal phosphorylation of creatine phosphate,
ATP-which is a high phosphate energy compound in the
body.
4. It also involved in the synthesiS of ascorbic acid, ubiquinone (Co-enzyme) and the metabolism of nucleic acid.
5. a-tocopherol exerting a unique influence on structural component of membrane phospholipid.
143
Handbook of General Animal Nu tri tion
6.
7.
8.
It stimulates the formation of prostoglandin E from ara-
chidonic acid while synthetic vito E had no effect.
Vito E inhibits platelet aggregation so help in blood clotting.
Relationship of vit E with toxic elements-
Both vitamin E and selenium provide protection against
toxicity with three groups of heavy metals.
(i) Cadmium and Mercury- Selenium is highly effective in
altering toxicities, vito E has little influence.
(ii) Silver and Arsenic- Vito E is highly effective and selenium
at higher doses.
(iii) Lead- Vito E is highly effective in altering toxicity produced
by lead.
Requirements: Vito E requirement of normal animals and
humans is approximately 30 ppm of diet. Requirement of vit E
is dependent on dietary levels of polyunsaturated fatty acids
(PUFA), antioxidants, and sulphur containing amino acids and
selenium.
Animal
Requirement (IU/Kg animal
feed)
Beef cattle
Dairy cattle
Goat
Chicken
Turkey
Sheep
Swine
Dog
Horse
Human
15-60
300
100
5-10
10-25
15-20
10-20
22
233 flgjKg body weight
8-13 mgjday
Sources: Vitamin E is widely distributed in foods. Green
fodder is good sources of a-tocophero1. Cereal grains are also
good sources. Animal products are relatively poor sources of
the vitamin. One LU. of vitamin E is defined as the specific
activity of lmg synthetic a-tocopherol acetate.
144
The Vitamms in Animal NutntlOn
Feed and Feed stuff
a-tocopherol content of
feed (ppm)
Alfalfa meal, dehydrated 17% protein
Alfalfa meal, sun cured, 13% protein
Alfalfa hay
Barley, whole
Butter
Egg
Oat
Rice bran
Wheat bran
Sorghum grain
30-120
18-60
23-102
22-42
10-33
8-12
18-24
34-87
15-20
10-16
Deficiency symptoms: The vit E deficiency symptoms in
farm animals are muscle degeneration (myopathy). Nutritional
myopathy (muscular dystrophy) in cattle affects the skeletal
muscles, which is manifested by difficulty in standing, trembling
and staggering gait. The animals are unable to rise and weakness
of the neck muscles prevents them from raising their heads,
also known as white muscle disease. Nutritional myopathy in
lambs is called stiff lamb disease (white muscle disease).
In pigs vitamin E deficiency diseases are myopathy and
cardiac disease known as mulberry heart disease (haemorrhagic
lesions within the heart that gives characteristic 'mulberry'
appearance) and hepatosis dietetica (toxic liver dystrophy). In
poultry, Vit. E defciency causes following diseases.
1. Exudative diathesis: It is characterised by edema, blackening of affected part, apathy and inappetance.
Nutritional ・ョ」ーィ。ャセュゥ@
(Crazy chick disease): It
2.
is characterised by ataxia, head retraction and cycling with
legs.
3.
Muscular dystrophy
* Vitamin E is non toxic even at higher doses.
Vitamin-K: Vitamin-K was identified in 1935 by Henrik
Dam to be an essential factor in the prevention of haemorrhagic
symptoms produced in chicks. The new fat-soluble vitamin was
145
Handbook of General Animal Nutrition
designated as vitamin K for the Danish word Koagulation.
Vitamin K is synthesized in the body of ruminants by the action
of rumen microbes. Bile juice assists in the absorption of this
vitamin from the intestine. In dogs there is microbial synthesis
in the intestine. The important naturally occurring compounds
are vitamin Kl (Phylloquinone) and vitamin K2 (Prenylmenaquinone). Vitamin K3 (Menadione) is a synthetic
compound, which is about 3.3 times as potent, biologically, as
the naturally occurring vitamin セN@
Metabolism: Like all fat-soluble vitamins, Vitamin K is
absorbed in association with dietary fats and requires the
presence of bile salts and pancreatic juice for adequate uptake
from the alimentary canal vit. K is stored in the liver. Most of
the ingested vitamin appears in the chylomicrons entering the
lymph. The synthetic form is absorbed directly in the hepatic
portal vein and carried to the liver, where it is activated and
then released along witll the naturally occuring forms of vitamin
K. These are carried in the LDL to target sites.
Functions: The vitamin K is necessary for the formation
of prothormbin, which is important intermediate of the blood
clotting process. Prothrombin must bind to calcium ions before
it can be activated as thrombin. If the supply of vitamin K is
inadequate, the prothrombin molecule is deficient in acarboxyglutamic acid, a specific amino acid responsible for
calcium binding. Thrombin converts the protein fibrinogen in
blood plasma into fibrin, which holds blood clots together.
There are four blood clotting proteins, which are dependent
on vitamin K for their synthesis.
Blood platelets
- - - - -...
セ@
Thromboplastin
セ@
Thrombokinase
Prothrombin - - - - - - -....
セ@ Thrombin
Fibrinogen
__T_h_ro;;..m. . . ;. bl..cn,--_
.·
...
セ@ Fibrin
146
The Vitamins in Animal NutritIOn
The important biochemical function has been found to be
involved in electron transport and in bacteria, oxidative
phosphorelation.
Requirements: The daily requirement for most species
varies in a range of 2-200 セァ@ vitamin K /Kg body weight. This
requirement can be altered by age, sex, strain, antivitamin K
factor, disease condition.
r・セオゥイュョエ@
Animal
Beef cattle, Dairy cattle, Horse,
Goat, Sheep
Swine
Fish
Dog
Chicken
Human
Infants
Adult
Hュfikセ@
Microbial synthesis
0.5
0.5-1.0
1.0
0.5-1.0
12llgjday
70-14O llgjday
Sources of Vitamin K: Green and leafy fodder, Lucerne,
Cabbage, soyabean, liver, fish meal and egg yolks are good
source of vitamin K.
Feed or feed
stuff
Alfalfa hay, sun
cured
Alfalfa
dehydrated
Spinach
Tomato
Barley, corn, sorghum, grains
Liver
Milk (cattle)
Milk (human),
Vit K level (ppm)
19.4
14.2
6.0
4.0
0.2
1-8
0.02
0.2
Egg
Fish meal
2.2
147
Handbook of General Animal Nutrition
Deficiency symptoms:
1. Ruminants and pigs: Under normal conditions vitamin
K deficiency have not been reported, but deficiency symptoms,
occur when spoiled sweet clover forage is fed. When sweet
clover hay undergoes spoilage with certain molds, the coumarin
is converted to dicumarol, (Dicumarol passes through the
placenta in pregnant animals and new born animals may become
affected immediately after birth) an anti-vitamin K and lowers
the prothrombin content of the blood and at the same time a
bleeding syndrome develops throughout the animal body. This
disease is called sweet clover poisoning or bleeding diseases or
haemorrhagic sweet clover disease. Prolongation the
prothrombin time in absence of liver disease indicates vitamin
K deficiency. Initial signs may be stiffness and lameness from
bleeding into the muscles and articulations. Haematomas,
epistaxis or gastrointestinal bleeding may be observed.
2. Poultry: The symptom of vitamin K deficiency in chicks
is a delayed clotting time of the blood; birds are easily injured
and may bleed to death. Chicks show anaemia, which in part
may be due to loss of blood or to the development of a
hypoplastic bone marrow.
3. Human: It is uncommon in humans because wide
distribution of vitamin K in plant and animal tissue and
microflora of gut synthesize the menaquinones. Newborn
infants may suffer because(i) Placenta is a relatively poor organ for maternal-foetal transmission of lipids.
(ii) Sterile gastrointestinal tract.
(iii) Breast and cow's milk are poor source of vitamin K.
Factors which causes vito K deficiency:
1. Increase control feeding with less pasture and alfalfa meal.
2. Feeding of solvent extrcted soyabean meal and other seed
meal and better quality fishmeal.
3. Haemorragic gastric ulcers which occurs frequently.
4. Mycotoxins and molds present in the feed.
148
The Vitamins in Animal Nutrition
5.
6.
7.
Any antimetabolites (antivitamin K) in the feed.
Use of sulfa drugs and different type of antibiotics.
Use of slatted floors which reduce the opportunity for
coprophagy.
Vitamin K toxicity: Toxic effects mainly related with
haematological and circulatory disturbances. The natural vitamin
K phylloquinone and menaquinone are non-toxic at very high
dose level. Synthetic menadione shows toxic effects at higher
level i.e. anaemia, hemoglobinuria and urobilinuria.
Water soluble vitamins: The vitamins of the B complex
and vitamin C comprise the water soluble group. Vitamin C is
the only member of the water soluble groups that is not a member
of the B familyand its functions and characteristics are different
from the B complex vitamins.
Vitamin B Complex: The vitamins included under this
group are water soluble and most of them a component of coenzymes. Ruminants are able to synthesis all the vitamin of B
group in the rumen through rumen microorganism. In preruminant calves and mono gastric animals B-complex vitamin
should be supplied in the daily ration.
Some coenzymes and enzyme prosthetic groups involving the
B vitamins:
Vitamin
Co-enzyme or prosthetic group
Thiamine
Pantothenic acid
Thiamin diphosphate (fDP),
Thiamin pyrophosphate
Flavin mononucleotide (FMN),
Flavin adenine dinucleotide
(FAD)
Nicotinamide adenine
dinucleotide and their phosphate
Nicotinamide adenine
dinucleotide phosphate (NADP)
Co-enzyme (Co A)
Folic acid
Biotin
Tetrahydrofolic acid
Biotin
Cyanocobalmin
Methyl cobalmin
Riboflavin
N icotinarnide
Pyridoxine
149
Enzymatic and other
function
Oxidative
decarbO)(ylation
Hydrogen carrier
Hydrogen carrier
Transaminases and
decarboxylases
Acyl transfer
One carbon transfer
Carbon dioxide
transfer
Isomerases and
dehydrases
Handbook of General Animal Nutrition
Thiamin (Vitamin B1 ): Thiamin is considered to be the
oldest vitamin. Deficiency of this causes beri-beri in man which
is earliest documented deficiency disorder. In 1890 Eiijkman, a
Dutch investigator, seen polynerritis in chicken that was fed
boiled polish rice. Jansen and Donath (1926) succeeded in
crystallizing vitamin B in pure form. In 1936 R.R. Williams
determined the chemical structure of thiamin. 1. U. of thiamin is
the activity of 3 セァ@ thiamine hydrochloride. Thiamin is a complex
nitrogenous base containing a pyrimidine ring joined to a
thiazole ring. Because of the presence of hydroxyl group at the
end of the side chain, thiamine can form esters. The main form
of thiamine diphosphate ester (TDP) formerly known as
thiamine pyrophosphate (TPP), although thiamine
monophosphate and thiamine triphosphate are also occure.
Metabolism: Thiamine is absorbed in duodenum.
Ruminants can also absorb free thiamin from the rumen. The
horse can also absorb from the caecum. The mechanism of
thiamin absorption is both active absorption and simple
diffusion. At high levels of intake, most absorption is passive.
Absorption may be inhibited by alcohol and by the presence of
thiaminases, which are found in some fishes. On absorption,
thiamine is phosphorylated to thiamine pyrophosphate (TPP),
especially in the liver. The major tissues which contain thiamine
are the skeletal muscle, heart, liver, kidney and brain. Thiamin
is most poorly stored of all vitamins, is mainly retained in organs
with a high metabolic activity. Absorbed thiamine is mainly
excreted through urine, faeces and sweat.
Functions: Thiamine diphosphate is a coenzyme involved
in the oxidative decarboxylation of pyruvic acid to acetyl
coenzyme A, the oxidative decarboxylation of a-ketogluterate
to succinyl coenzyme A in TCA cycle the pentose phosphate
pathway. Thiamine involved in the synthesis of the amino acid
valine in bacteria, yeast and plants.
Deficiency symptoms: Deficiency of thiamin in human
causes beri-beri disease, which is characterised by numbness of
the legs, later with pain in muscles, severe exhuastion, finally
emaciation and paralysis. The patients have difficulty in
150
The Vitamins in Animal Nutrition
breathing, there is an abnormal enlargement of the right side
of the heart and decrease in the rate of the heart beat. The most
characteristics feature of the disease is the so-called pheripheral
neuritis. This is often accompanied by contraction of the feet
and severe weakness of the wrists. The brain may be affected
under these conditions.
Thiamine deficiency in chick causes poor appetites and
consequently emaciated followed by polyneuritis, which is
characterised by nerve degeneration paralysis. On thiamin
deficient animals, there is an accumulation of pyruvic acid and
its reduction product, lactic acid, in their tissues, which leads
to muscular weakness. Ruminants since microbial synthesis
occur in the rumen of cattle, sheep and goat and in the caecum
of horses are unlikely to show thiamin deficiency. Raw fish
contains thiaminase, which destroys the activity of thiamin of
food with which the raw fish is mixed. Heat treatment or cooking
destroyed the activity of thiaminase. Microbes of gastrointestinal tract of man, pig, poultry, cat and dogs are having
thiaminase activity. Due to this reason the thiaminase deficiency
occurs.
Sources: Egg yolk, liver, heart, all living cells of the body,
milk, meat, green grasses, cereal grains and yeast are rich
sources of this vitamin.
Riboflavin (Vitamin B2): It was found in a coenzyme before
it was discovered in free form. The discovery of riboflavin goes
back to 1929 when Norris and his associates found out an
unknown vitamin as a cause of leg paralysis among chicks. In
1934 Gyorgy isolated it from B complex. Independently, Kuhn
and Karrer et al. (1935) synthesized it. ,Riboflavin consists of a
dimethyl-isoalloxazine nucleus combined with ribitoL It is
yellow, crystalline compound and soluble in water. It is stable
in heat, acid and nerutal solution but destroyed by alkali. It is
unstable to ultraviolet light.
Absorption and metabolism of Riboflavin: Riboflavin is
readily absorbed from the small intestine. In the plasma it is
carried in association with albumin, which carries both the free
151
Handbook of General Animal Nutrition
vitamin and co-enzyme forms. In the tissues, riboflavin is
converted into co-enzymes flavin mononucleotide (FMN) and
flavin adenine dinucleotide, which constitute the active groups
in a number of flavoproteins.
Functions: Riboflavin is required as part of many enzymes
essential to utilization of carbohydrate, protein and fats.
Riboflavin in the form of flavin mononucleotides (FMN) and
Flavin adenine dinucleotide (FAD) act as the prosthetic group
of several enzymes involves in biological oxidation-reduction
reaction. Both FMN and FAD act as electron and hydrogen
donors and acceptors, which allow them to play a critical role
in many oxidation-reduction reactions of metabolic pathways,
passing electron to the electron transport chain.
Deficiency symptoms: Deficiency of riboflavin in human
produces a cheilosis (severe dermatitis and fissures at the comer
of the mouth), angular stomatitis, glossitis and seborrheic
dermatitis.
Chick: Deficiency causes slow growth and develops" curled
toe paralysis" a specific symptom, caused by peripheral nerve
degeneration, in which the chicks walk on their hocks with toe
curled inwards. In breeding hen causes poor hatchability,
embroyonic abnormalities, including characteristic "clubbed
down" condition in which the down feathers continue to grow
inside the follicle, resulting in a coiled feather.
Sources: It is widely distributed throughout the plant and
animal kingdom with very rich sources in anaerobic fermenting
bacteria. Milk, liver, kidney and heart are good sources of
vitamin.
Niacin (Nicotinamide): American scientist Elvehjem and
his associates in 1937 discovered this vitamin as a cure for black
tongue disease in dogs and pellagra in human being. It is not
destroyed by heat, acid, alkali or by oxidation.
Absorption and metabolism of niacin: Thereis a rapid
absorption of dietary niacin, both by active and passive
mechanisms. Once the niacin has been converted to NAD or
NADP, it is trapped within the cells and can not diffuse out.
152
The Vitamins in Animal Nutrition
NAD and NADP act as hydrogen acceptors in oxidation
reactions forming NADH and NADPH.
Functions: Its function in the animal body as coenzyme
such as: Diphosphophyridinenucleotiede (DPN) or coenzyme I
or Nicotinamide adenine dinucleotide (NAD) and
Triphosphophyridinenucleotide (TPN) or coenzyme II or NADP
(Nicotinamide adenine dinucleotide phosphate (NADP).
The primay action of these two coenzymes is to remove
hydrogen from substrate as a part of dehydrogenase enzymes
and transfer hydrogen and/ or electrons to the next coenzyme
in the chain or to another substrate which then become reduced.
Deficiency symptoms:
Poultry: The deficiency of vitamin causes "black tongue"
characterized by inflammation of the mouth and the upper part
of the oesophagus. In chick deficiency produces enlargement
of the tibiotarsal joint, a bowing of the legs, poor feathering
and slight dermatitis.
Swine: In swine niacin deficiency is known as "pig
pellagra" the disease is characterized by poor growth, poor
hair and skin condition, occasional vomiting and diarrhoea.
Sources: Nicotinic acid can be synthesized from tryptophan
in the body tissues. Niacin is found abundantly in yeast, meat,
liver and poultry, groundnut and sunflower meal, milk,
tomatoes and varieties of leafy green vegetables. Milk and eggs
are almost deviod of the vitamin alothough they contain the
precursor tryptophan.
Pyridoxine (Vitamin-B6 ): Pyridoxine was first defined by
Gyorgy (1934) as a part of vitamin B-complex, which is
responsible for specific dermatitis in rats. The dermatitis is
characterized by scaliness around the peripheral part of the body
such as paws and mouth. The vitamin exists in three forms
(pyridoxine, pyridoxal and pyridoxamine) which are
interconvertible in the body tissues. The amine and aldehyde
derivatives are less stable than pyridoxine and are destroyed
by heat.
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Handbook of General Animal Nutrition
Absorption and metabolism of vitamin B6: The vitamin
has to be released from its phosphorylated forms prior to
absorption. Once in its free form, absorption is rapid. The liver
and muscles are the main sites for pyridoxal phosphate in the
body; once it is phosphorylated, the vitamin is trapped in the
cell. Pyridoxal is involved in many biological reactions
particularly those associated with amino acid metabolism like
decarboxylation and transamination etc.
Functions: The active compound pyridoxal phosphate plays
an essential role as a coenzyme in the reaction by which a cell
transforms nutrient amino acids into mixture of amino acids
and other nitrogenous compounds required for its own
metabolism. These reactions involve the activities of
transaminases and decarboxylases.
Requirement:
Animals
Ruminants and horse
Chicken
Rat
human
Requirements
Microbial synthesis
3.0-4.5 mg/kg
6.0mg/kg
0.3-2.8 mg/kg
Sources: Yeast, liver, milk, pulses and cereal grains are
rich sources of this vitamin. To a limited extent egg and leafy
vegetables are also a source of vitamin.
Food and food stuffs
Alfalfa sun cured
Lin seed meal
Barley grain
Wheat bran
Corn
Vitamin B6 (mglkg)
4.4
6.0
7.3
9.6
5.3-8.8
Deficiency symptoms:
Chicks: IPyridoxine deficiency causes acute convulsion,
flatter on the pen, usually start kicking, a characteristic pasture
with wings slightly spread and head resting on ground and
generally die.
154
The Vitamins in Animal Nutrition
Pigs: Deficiency of vitamin causes anorexia, roughness of
hair coat, fatty infiltration of the liver, goose step type of gait
and convulsions:
Pantothenic Acid: Williams and his associates discovered
pantothenic acid in 1933 which was derived from Greek word
"pantos" means found every where. Pantothenic acid is a
dipeptide derivative and the two components of pantothenic
acid are dihydroxydimethyl-butyric acid and the amino acid,
セM。ャョゥ・N@
Functions: Pantothenic acid is the prosthetic group of
coenzyme A, an important coenzyme involved in many
reversible acetylation reactions in carbohydrate, amino acid and
fat metabolism with synthesis of steroids. Coenzyme A may
act as an acetyl donor and acetyl acceptor. The vitamin involved
in the formation of cit-ate oxaloacetate in the T.CA. cycle.
Requirement: For growth and reproduction, the majority
of species have a dietary requirement between 5 and 15 mg/
kg. For egg production by chickens the vitamin requirement is
very low (2.2 mg/kg) compared to requirement of 10 mg/kg
for growth and reproduction.
Requirement
Animals
Microbial synthesis
Ruminants and horse
12 mg/kg
Swine
Human
4-7mg/kg
Sources: Egg yolk, kidney, liver and yeast, groundnuts,
pea skimmed milk, sweet potatoes and molasses are the good
source of this vitamin.
Food and food stuffs
Alfalfa hay, sun cured hay
Mollases, sugar cane
Barley grain
Brewer's grain
Butter milk cattle
Eggs
Fish meal
Liver
Pantothenic acid (mi}kg)
28-32
50
9
9
40
27
1
165
155
Handbook of General Animal Nutrition
Deficiency symptoms: It causes severe degeneration of
myelin sheath of nervous tissues and affects steroid hormones
of adrenal gland.
Poultry: Retarded growth, dermatitis, fatty liver condition,
severe edema and subcutaneous haemorrhage are the common
symptoms.
Swine: Deficiency symptoms are retarted growth rate and
bloody diarrhea. Goose stepping gait, a typical nerve disease
that is characterized by movement of hind leg become stiff and
jerky, exaggerated legs.
Folic Acid (Folacin): The name folic acid was proposed
by Mitchell et aI. (1941) for a compound isolated from spinach
and shown to be necessary for growth of streptococcus faecelis
R. The same pterayl glutamic acid compound was later on called
as folic acid. It contains three distinct components i.e. p-amino
benzoic acid (PABA) and pteridine nucleus.
Absorption and metabolism of folate: Most folate in the
diet is in the bound form and for optimal absorption glutamates
have to be removed to produce the monoglutamate. Most folate
is stored in the liver, which is therefore also a good dietary
source of folate. Once taken up by target cells, polyglutamates
are formed. These are trapped within the cell and are used as
co-enzyme tetrahydroforate. Polyglutamate forms are digested
via hydrolysis to pteroyl monoglutamate prior to transport
across the intestinal mucosa. The enzyme responsible for the
hydrolysis of pteroyl polyglutamate is a "a-carboxy peptidase"
known as folate conjugate. Pteroyl polyglutamate is absorbed
predominately in the duodenum and jejunum by an active
process involving sodium.
Functions: The active form of the vitamin is tetrahydrofolic
acid (FH4), Folic acid is carrier for the single carbon groups,
may be either formyl (-CHO), formate (H. COOH), or
hydroxymethyl (-CH 2 0H). These are metabolically
interconvertible in a reaction catalyzed by a NADP dependent
hydroxymethyl dehydrogenase. Folic acids are important in the
biosynthesis of purine and pyrimidines and in certain
156
The Vitamins in Animal Nutrition
methylation reactions. Folic acid is involved in the
interconversion of glycine to serine, methylation of
ethanolamine to choline and homocysteine to methionine. Folic
acid is needed to maintain immune system.
Requirement:
Requirement (mJrlkg)
Microbial synthesis
0.25-0.50
0.30
0.20
Animal
Ruminants
Chicken
Swine
dッセ@
Horse
Human
RPュセO、。カ@
40-800 J,1g/ day
Sources: Fresh leafy green vegetables, cauliflower, cereals
and extracted oilseeds meal are rich sources of folic acid.
Feed and feed stuffs
Folacin (mJrlkg)
Alfalfa meal
5.5
Brewer' s セイ。ゥョ@
7.7
c。「セ・L@
corn
0.3
Fish meal
0.2
Liver
8.4
Rice polish
0.2
Linseed meal
1.4
Deficiency symptoms: Glossitis, gastrointestinal
disturbances, diarrhoea and reduced erythropoiesis are common
deficiency symptoms. In chicks, poor growth, poor feathering,
depigmentation, anaemic appearance and perosis develops. In
pigs, macrocytic anaemia, lipopenia, megaloblastic arrest etc.
develops.
Biotin: Biotin was first described as the factor protective
against" egg white injury". Egg white contains avidine which
combined with biotin and prevent its absorption from the
intestine. Chemically, biotin is 2-keto-3, 4-imidazolido-2tetrahydro-thiophene-n-valeric acid. Rat fed large amount of
raw egg white devloped an eczema-like dermatitis, paralysis
of the hind legs, and characteristics alopecia around the eyes,
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Handbook of General Animal Nutrition
aptly termed spectacle eye. This vitamin has been known by a
variety of names including bios factor, vitamin-H, coenzyme R
and egg white injury protection factor.
Functions: Biotin serves as the prosthetic group of several
enzymes which catalyze fixation of carbon dioxide into organic
linkage. Enzymes containing biotin include acetyl coenzyme A
carboxylase, propionyl coenzyme A carboxylase and
methylmalonyl transcarboxylase. The acetyl coenzyme A
carboxylase is required for the initial stage of fatty acid synthesis.
In biological systems, it function as the coenzyme for
carboxylases, enzyme which catalyse carbon dioxide fixation
or carboxylation and also appear to be necessary for synthesis
of dicarboxylic acids. Specific biotin dependent reactions in
carbohydrate metabolism are1. Carboxylation of pyruvic acid to oxaloacetic acid
2. Conversion of ュ。ャゥセ@
acid to pyruvic acid
3. Interconversion of succinic acid and propionic acid
4. Conversion of oxalosuccinic acid to a-ketoglutaric acid
Biotin enzymes are important in protein synthesis, amino
acid deamination, purine synthesis and nucleic acid metabolism.
Requirements: Biotin is synthesized by many different
microorganisms and certain fungi.
Animal
Beef cattle, Dairy cattle, Sheep,
Goat, Horse
Cattle calf
Chicken
Swine
Human
Reguirement
Microbial synthesis
10 Ilg/Kg body weight
0.15-0.20 mg/Kg
0.15-0.20 mg/ Kg
40-200 IlPJ day
Sources: Yeast, milk, cereals and vegetables state, pea nuts
and eggs.
158
The Vitamins in Animal Nutrition
Food or Feed stuff
Alfaalfa meal dehydrated
Corn
Peanut
Soybean meal
Eggs whole
Liver, beef
Biotin level (,.w/gram)
0.33
0.05-0.20
1.63
0.18-0.50
0.25
1.00
Deficiency symptoms: Biotin deficiency is more prevalent
in swine and poultry than farm animals. Biotin deficiency could
be introduced by giving animal avidin, a protein in raw egg
white, which combined with biotin and prevent it absorption
from the intestine. The deficiency symptoms are retarded
growth and development, falling of hairs (alopecia) and
dermatitis characterized by dryness, roughness and brownish
exudates, ulceration of skin, transverse of soles and tops of
hooves. Recently it has been demonstrated that biotin deficiency
is the chief cause of fatty liver and kidney syndrome (FUG)
which is characterized by a lethargic with death. Reduced
growth rate, disturbed and broken feathering, dermatitis, leg
and weak deformities are observed in poultry.
Choline: It is discovered as an essential part of the
phospholipid lecithin. The requirement of the choline is met
through two ways (1) By ration (2) By the process of
transmethylation. Choline can be synthesized in the liver from
methionine. The chemical structure of choline is given below.
Functions:
1. Choline is a metabolic essential for building and maintaining cell structure. As a phospholipid it is a structural part
of lecithin (phosphatidylcholine ),certain plasmalogens and
the sphingomyelins.
159
Handbook of General Animal Nutrition
2.
3.
4.
It plays an essential role in fat metabolism in the liver. It
prevents abnormal accumulation of fat (fatty liver) by
promoting its transport as lecithin or by increasing the
utilization of fatty acids in the liver itself. Thus choline is
referred as lipotropic factor.
It is essential for the formation of acety1choiline, which is
important in the transmission of nerve impulses.
Choline is as a source of three labile methyl groups for
formation of methionine by the transmethylation reactions.
Deficiency symptoms: Deficiency of choline causes a
deficiency of phospholipid in tissues, which are generally
concerned with the transportation and oxidation of fatty acid
in the liver. As a consequence, fat accumulates in the liver causing
fatty liver. So choline is also concerned with the prevention of
perosis or sleeped tendon in chicks.
Sources: Natural fat is a good source of choline. Green
leafy materials, yeast, egg yolk and cereals are rich sources.
Vitamin-B 12 (Cyanocobalmin): Rickes and his associates
(1948) isolated this vitamin from the liver as pinkish crystalline
substance and name it B12 • It was also known as animal protein
(APF) and antipernicious anaemia factor (APA). In patients
suffering from pernicious anaemia the absorption of B12 from
the gastro intestinal tracts is impaired owing to the absence of
a specific glycoprotein termed the "Intrinsic factor" normally
secreted in the gastric juice. Vitamin BI2 has been isolated in
several different biologically active forms. Cyanocobalamin, the
principle form of the vitamin contains a cyanide group attached
to the central cobalt. The cyanide ion may be replaced by a
variety of anions e.g., hydroxyl (Hydroxy cobalamin) or nitrite
(nitro cobalamin. The biological actions of these derivatives
appear to be similar to that of cobalamin. Vitamin B12 was the
last vitamin to be discovered and the most potent of the vitamin.
Vitamin B12 is unique that it is synthesized in nature only by the
microorganisms.
Absorption and metabolism of vitamin B12 : Ingested
vitamin B12 has to be combined with intrinsic factor produced
160
The Vitamins in Animal Nutrition
by the stomach before it can be absorbed. Vitamin is ,absorbed
from terminal ileum leaving the intrinsic factor behind, in the
absence of intrinsic factor there is only minimal absorption of
the vitamin by passive diffusion. The metabolic role of vitamin
B12 is associated with availability of tetrahydrofolate and
metabolism of some fatty acids.
Functions:
1. There is a nutritional inter-relationship with folic acid, B12
vitamin and the metabolism of one-carbon compound.
2. Cobamide coenzyme plays an important role in the transformation of methly malonyl coenyme A to succinyl
coenzyme A in the metabolism of propionic acid in
ruminats.
3. Vitamin B12 and folic acid are required for the formation
of DNA whereas vitamin B12 alone being necessary for the
synthesis of RNA.
4. Folic acid and B12 are essential for the maturation of RB.C.
Vitamin B12 is necessary in reduction of one carbon compounds of formate and formaldehyde, it participate with
folacin in biosynthesis of labile methyl groups. Formation
of labile methyl groups is necessary for biosynthesis of
purine and pyrimidine bases.
Requirements:
Requirement
Microbial synthesis
0.34-0.68 Ilg/Kg body weight
3-9 Ilg/ Kg
5-15 Ilg/ Kg
261lg/Kg
0.5-4.0 Ilg/ day
Animal
Ruminants, Horse, Rabbit
Cattle calf
Chicken
Swine
Dog
Human
Sources: The origin of Vitamin B12 in nature appears to be
microbial synthesis. Foods of animal origin are good sources
i.e. meat, kidney, liver, milk, egg, fish, root nodules of certain
legumes contain small quantities of Vitamin B12 . It is mostly
deficient in grains and fodder crops.
161
Handbook of General Animal Nutrition
Vitamin B12 (ppm)
Food and food stuffs
Blood meal
Fish meal
Meat meal
Liver meal
Milk
50
130-160
70
540
54
Deficiency symptoms:
Human: Vitamin B12 deficiency causes pernicious anaemia.
Poultry: In poultry, poor growth, poor feathering and
kidney damage may occur. In adults hatchability goes down.
Pig: Young pig shows poor growth, show in coordination
of the hind legs. Adult pigs show dermatitis, a rough coat, and
suboptimal growth.
Ruminants: It has been shown that when the vitamin is
deficient, propionic acid can not be metabilized adequately when
sufficient cobalt is present in the diet, the sufficient amount of
vitamin B12 can be synthesized by the rumen microorganism to
meet the animal needs.
Vitamin-C (Ascorbic Acid): The name of vitamin C became
quite popular in 18th century when it was found that sailors
developed a disease called scurvy after they had been at sea
for a period of 4 to 5 months. A British Naval Surgeon Dr. Lind
in 1747 told that scurvy disease can be prevented by feeding
the juice of citrus fruits in human beings. On this basis it was
discovered as an Anti- scurvy factor. It was first isolated in
1932 by American scientist King and Hungarian scientist S.
Gyorgy. Vitamin C is chemically known as L- ascorbic acid and
has the following formula.
The vitamin is colourless, crystalline, water soluble
compound having acidic and strong reducing properties. In
some species it is synthesized from glucose, via glucuronic acid
and gulonic acid lactone; the enzyme L-gulonolactone oxidase
is required for the synthesis. Glycoascorbic acid acts as an
antimetabolite for vitamin C. This enzyme is absent in guinea
162
The Vitamins in Animal Nutrition
O=C---,
I
HO-C
I
L- Ascorbic acid
HO-C
I
I
H-C - - - '
HO-C-H
I
CH2 0H
Ascorbic acid - - +
Dehydroascorbic acid
MNセ@
Diketogulonic acid
(biologically inactive)
pig, human, bats, certain birds and fishes. Glycoascorbic acid
acts·as antimetabolites for vitamin-Co One LV. is the activity of
0.05 mg of ascorbic acid.
Absorption and metabolism: Both forms of vitamin are
readily .absorbed by active transport and passive diffusion.
Vitamin C is absorbed from the small intestine and excreted
via urine. There is particularly no storage of this vitamin and
secreted in the milk of lactating animals.
Functions:
1. Vitamin C is essential for collagen formation.
2. It aids for the conversion of folic acid to its active form
tetrahydrofolic acid.
3. Vitamin C is also involved in the hydroxylation of proline,
lysine and aniline, which are important for normal physiology of the animals.
4. It aids iron to stay in reduced state, which is very
important for the. body and have stimulatory effect on
phagocytic activity of leucocytes.
5. It participates in the synthesis of steroid hormones by the
adernal cortex.
6. It involves in the metabolism of lipids, as blood cholesterollevel appear to fall with the administration of ascorbic acid and rise due to deficiency of this vitamin.
163
Handbook of General Animal Nutrition
7.
8.
It aids for the conversion of tryptophan to serotonin.
It is an antioxidant and used in canning of certain fruits to
prevent the oxidative changes which cause darkening.
Sources: Citurs fruits and juices, lemon, tomato, green
vegetables, milk, body tissues and plasma are good sources.
Dry roughages and concentrates are deficient in ascorbic acid.
Guava and Aonla are very rich in vitamin C.
Vitamin C (mliflOO g)
Vegetables
Cauliflower raw
Peppers raw
Spinach
Corn
Potato
Fruits
Apple
Grapes
Guavas
Lemon
Limes
Orange
Straw berries
Fish
50-90
100
10-60
12
8-18
10-30
35-45
300
80
250
40-60
40-90
5-30
3-7
Deficiency symptoms: Man, monkey and guinea pig suffer
with severe deficiency of vitamin C is called scurvy. The disease
is characterized by weakness, swollen and tenderness of joints,
delayed healing of wounds, spongy haemorrhagic friable gum,
loose teeth and small haemorrhage which may appear anywhere
throughout the body, particularly near the bone and joints and
under the skin and mucous membrane due to increase fragility
of the blood capillaries. Resistance to infection is reduced.
Symptoms of oedema, emaciation and diarrhoea are also
appeared.
Unidentified vitamins: The discovery of vitamins is of
course a very great research in the field of nutrition. If all the
vitamins discovered so far are included in the ration of poultry,
even then they may lack in proper development. When these
164
The Vitamins in Animal Nutrition
birds are offered fish meal, penicillium mycelium meal, molasses,
green leaves and dried skimmed milk. They have a better
growth and development. It clearly indicates that these
substances contain certain nutrients which are still to be
identified. Hence they were called as unidentified viatmins or
growth factors. Certain factors which appear to be of some
significance in poultry nutrition are the grass factor, whey factor
and fish factor. The evidence for these has been obtained from
growth responses in feeding trials and from hatchability studies.
Hypervitaminosis: It is the name given to pathological
conditions resulting from an overdose of vitamins. In natural
conditions, it is unlikely to occur, until the synthetic vitamins
are not added in the ration. Clinical sign of hypervitaminosis A
in young chicks include loss of appetite, poor growth, diarrhoea,
encrustation around the mouth and reddening of the eyelids.
In pigs rough coat, Scaly skin, hyperirritability, haemorrhages,
periodic termors and even death. Excessive intakes of vitamin
o cause abnormally high levels of calcium and phosphorus in
the blood, which result in the deposition of calcium and
phosphorus in the blood, which result in the deposition of
calcium salts in the arteries and organs. Hypervitaminosis K
showed a depression in growth and anaemia as toxic symptoms.
Specific deficiency of vitamins:
Vit A: Night blindness, Xerophthalmia
Vit 0: Ricket, Osteomalacia
Vit E: White muscle disease (stiff lamb disease), Crazy chick
disease, Muscular dystrophy
Vit K: Sweet clover poisoning
Vit C: Scurvy
Thiamine: Beri-beri, Stargazing in poultry
Riboflavin: Curled toe paralysis
Niacin: Black tongue (poultry), Pig pellagra
Pyridoxine: Goose stepping in pig
Pantothenic acid: Goose stepping in pig, Fatty liver in poultry
Biotin: Alopecia, Fatty liver and kidney syndrome (FLKS)
Folic acid: Anaemia
Cyanocobalmin: Pernicious anaemia
165
Handbook ofGeneral Animal Nutrition
Q.1.
1.
2.
3.
4.
5.
6.
7.
Fill in the blank.
- - - gave the term vitamins
Vitamin A was discovered by - - - - - - -.
The forms of viatminA is - - - - - and - - - - - .
One International unit of vitamin A is equal to - - - -The precursor of vitamin A is - - - - - - .
Anti infective vitamin is - - - - - - .
Vitamin D as an antirachitic factor was discovered by - -
8.
The active forms of vitamin Dare - - - - and - - - -
9. The precursor of ergocalciferol is - - - - - -.
10. The precursor of cholecalciferol is - - - - - .
11. One International unit of vitamin D is equal to - - - - 12.
13.
14.
15.
16.
Vitamin D deficiency in young animals is - - - -.
In adult animals vitamin D deficiency is - - - - -.
The chemical name of vitamin E is - - - - - -.
Vitamin E was discovered by - - - - - -.
Vitamin E and - - - - - enzyme acts as biological antioxidant.
17. Stiff lamb disease is caused by - - - - -.
18. Mulberry heart disease is deficiency symptoms of - - 19. Crazy chick disease is caused by - - - - -.
20. Exudative diathesis in chicks is deficiency symptoms of 21. Vitamin K was identified by - - - - -.
22. The naturally occuring form of vitamin K is - - - - and
23. Sweet clover poisoning is deficiency symptoms of - - 24. Beri-beri disease is caused by - - - - -.
166
The Vitamins in Animal Nutrition
25.
26.
27.
28.
Peripheral polynuritis is deficiency symptoms of - - - .
Curled toe paralysis is deficiency symptoms of - - - - .
The deficiency symptom of niacin is - - - - in dog.
Niacin is prosthetic group in co-enzymes namely- - - and - - - .
29. Niacin deficiency in pig is known as - - - - - .
30. Black tenque in poultry is a deficiency symptoms of - -
31.
32.
33.
34.
35.
Niacin in body can be synthesized from - - - -.
Goose stepping in pig is deficiency symptoms of - - - .
The active form of vitamin folic acid is - - - - - .
Perosis in poultry is deficiency symptoms of - - - - - .
Biotin is a prosthetic group in enzymes namely - - - and
36. Deficiency symptoms of biotin is - - - - - .
37. Choline is an essential part of phospholipid knownas - 38.
39.
40.
41.
Deficiency symptoms of choline is - - - --The deficiency symptom of cyanocobalamin is - - - - .
The chemical name of vitamin C is - - - - - - .
The deficiency symptom of vitamin C is - - - -.
Q.2. Explain the following:
1.
2.
3.
4.
5.
6.
7.
8.
Differentiate the fat soluble and water soluble vitamins
Define the vitamin.
Role of vitamin A in eye - vision.
Metabolism of vitamin D.
Deficiency symptoms of vitamin E.
Role of vitamin K in blood clotting
Deficiency symptoms and source of vitamin C.
Explain the deficiency symptoms of riboflavin and thiamin
167
Handbook of General Animal Nutrition
9.
10.
11.
12.
13.
14.
Explain the functions and deficiency symptoms of niacin
and pyridoxine.
Deficiency symptoms of pantothenic acid and folic acid.
Functions and deficiency symptoms of biotin and choline.
Functions and deficiency symptoms of cyanocobolamin.
Write a note on unidentified factor and Hypervitaminosis.
Construct tables to compare common features (i.e. functions, sources, sign of deficiency etc.) of the following pairs
of vitamins:
(a) Riboflavin and niacin
(b) Vitamin B12 and folate
(c) Vitamin C and Vitamin E
(d) Vitamin D and Vitamin A
168
Chapter
9
Feed Additives in
Animal Nutrition
Definition of feed additives: Feed additive is an ingredient
or combination of ingredients added to the basic feed mix or
parts thereof to fulfill the specific need or any chemical
incorporated in an animal feed for the purpose of improving
rate of gain, feed efficiency or prevention and control of disease.
These are used in microquantities and require careful handling
and mixing. A feed additive is need not be a drug. Feed
additives are of two types.
1. Nutrient feed additives like minerals and vitamin
supplements
2. Non-nutrient feed additives like antibiotics, antioxidants,
coccidiostat and feed preservatives etc.
Feed additives increase feed quality and feed palatability
and improve the animal performance as feed additives are
mixed with feeds in non therapeutic quantities for the purpose
of promoting animal growth, lowering feed consumption and
protecting the animal against all sorts of harmful environmental
stresses. Addition of antioxidants to diet produces grades of
meat in which the fat does not rancidify or does so more slowly.
So the use of additives also makes end products more
homogenous and of better quality. Low levels of additives,
mainly of antibiotics or other growth promoters and related
compounds in animal feed contribute to increase production of
animal protein for human consumption so decrease the cost of
animal products. Non-nutrient feed additives not classified
under nutrients, but are considered as feed supplements.
169
Handbook of General Animal Nutrition
1. Antibiotic feed supplement: Antibiotic are a group of
soluble organic substances produced from microorganism,
which in small concentration have the capacity of inhibiting the
growth of other microorganism, and even of destroying them.
They have the properties of inhibiting at low concentrations
for growth, activity or multiplication of other microorganism.
Mode of action of antibiotic:
1. Antibiotic spares protein, amino acid..and vitamins.
2. They act by increasing the absorption of B- complex vitamin in gastro- intestinal tract.
3. They increase the absorptive capacity of the intestine.
4. Suppressing or destoying organisms,which produced subclinical infections and compete with the host for supplies
of nutrients.
5. Stimulating the growth of microorganism, which synthesizes essential nutrients.
6. Antibiotic alters intestinal bacteria so that less urease is
produced and thus less ammonia is formed. As ammonia
is harmful and suppresses growth in non-ruminants.
Antibiotics in pig feeding: The good effect of feeding the
antibiotic feed supplement is observed with animals given all
vegetable protein diets than those receiving animal protein
supplements. The increase in growth rate may between 10-20
percent and reducing the feed intake by about 2.5 percent.
Highest the nutritive value of ration, the less would be the
improvementin growth rate on antibiotic feeding. The antibiotic
improves the efficiency of feed utilization to the extent of 5-8
percent. A mixture of two or more antibiotic is no more effective
than the single effective antibiotic. The greatest beneficial effect
of antibiotic feeding is observed during the early growth period
between weaning and 50 Kg body weight, there after the effect
diminishes with age. If the antibiotics are stopped in the ration
of pigs after 50 Kg body weight, the initial advantage in the
improvement of growth rate is last. Therefore, it is
recommended to feed the antibiotics till the pigs reach the
market weight. Runty pigs give better response with antibiotic
170
Feed Additives in Animal Nutrition
feeding. The optimum level for most antibiotics in the diet is
within the range 5-15 mg per kg and there is no advantage in
exceeding these low levels.
Antibiotics used as feed additives for growth promotion:
Animal dose
and Poultry
Swine
Beef
Poultry
Chlorteracycline
Swine
Beef
Poultry
Dynafac
Swine
Beef
Sheep
Growing chicks
Erythromycin
Beef
Poultry
Swine
{mgflb. feed)
2-25
5-25
17-35 mg/day
5-25
5-25
25-70 mg/ day
45-90
200 mg/d
200mg/d
300-400 mg! d
2.3g.
37.0 mg/d
3.5-5.0
75.0
Oleandomycin
Oxyretracycline
Broiler and Turkey
Poultry
Swine
Beef
Sheep
0.5-1.0
2.5
12.25
25.75
5-10
Pencillin
Poultry
Swine
Poultry
Swine
Poultry
Swine
1.2-25mg/d
5.25
11-22
11-33
2-25
5-25
Products
Bacitracin
derivatives
Roxarsone
Tyrosin
Source. Animal nutrition growth by Hafez and Dyer (1969).
Antibiotics in Poultry feeding: Pencillin is more effective
than other antibiotics especially to young and growing chicks.
It increases the growth rate and this effect is most marked upto
one month of age. As with pigs, the effect diminishes with age.
171
Handbook of General Animal Nutrition
The highest effect is upto 6 weeks of age. In the laying birds
the egg production is also improved. About 5 g of procaine
pencillin per ton of ration for poultry is needed; but to control
diseases, a higher level of 50 gm or more/ton for feed is used.
Use of a combination of antibiotics has been no more effective
than that of single effective antibiotic. In layer, egg production
has not been increased by adding antibiotics to a ration which
is nutritionally complete. But, if hens are fed on only vegetables
product ration, an antibiotic vitamin B12 feed supplement may
increase both egg production and hatchability.
Antibiotic in ruminant feeding: The addition of antibiotics
supplement in calf rations has increased the growth rate of dairy
calves specially when there had been much trouble from disease
in the herd. It has reduced the incidence of scours and other
infectious disease. Most of the growth improvement occurs
before up to 8-10 weeks of age at the rate of 30 mg of Auromycin
or Terramycin per calf daily. As far as adult animals are
concerned, the results are conflicting. It has been assumed that
the inclusion of antibiotics in the diet could be harmful by
suppressing the activity of cellulotytic organisms and thus
impairing cellulose digestion and other rumen microorganisms
are also depressed. So feeding antibiotics after 12 weeks of age
has not beneficial effect on the animals. Following points should
be kept in mind while using antibiotics for animal feeding.
1. Antibiotics should be used only for:
a. Growing and fattening pigs
b. Growing chicks and turkey
c.
Growing calves upto the age of 10-12 weeks.
2. Antibiotics should not be used in the feed of ruminant
animals breeding pigs and breeding and laying poultry
stock.
3. While adding antibiotics at the recommended level, care
should be taken that they are thoroughly and evenly mixed
with the feed.
4. For the best result, antibiotics should be used with
properly balanced feeds.
172
Feed Additives in Ammal Nutrition
5.
Antibiotics are not a substitute for good management and
healthy living condition or for properly balanced ration.
Antibiotics feeding hazards in animals: There has been a
serious concern about the indiscriminate use of antibiotics as
feed supplement in the animals. The meat from these animals
contains the residue of the antibiotics and constant use by the
human being could present a hazard to human health because
of the potential development of enteric bacteria.
2. Hormones: Some of the hormones used as a growth
promoting agents in livestock such as estrogens. androgens,
progesterone, growth hormones, thyroxin and thyroproteins.
Iodinated casein is a commercial product which has given
variable response. This compound has been given response for
a shorter period in the lactating animals. Long term feeding
gave discouraging results.
The growth promoting hormones are grouped into two
on the basis of their effects on the body.
1. Anabolic: ( Somatotropin, thyroxin and androgens)
2. Catabolic (estrogen and glucocorticoids)
1. Anabolic agents: The hormones of the anabolic class by
nature exert their effect on both skeleton and protein
metabolism. Somatotrapin stimulates growth. of endochondral
bones and epiphysis of long bones while in protein metabolism
it aids nitrogen and overall protein synthesis. Thyroxin also
stimulates growth of long bones as well as protein synthesis.
Testosterone at low dose increases the epiphyseal diameter,
promotes muscles growth by angmenting nitrogen retention.
2. Catabolic agent: The hormone belonging to catabolic
group similarly exert their on both skeleton and protein
metabolism. Estrogen inhibits skeletal growth although in
ruminants it increases nitrogen retention. Gluco corticoids
decrease growth of epiphysis and also aid in degrading protein
and amino acids and there by inhibit protein synthesis in
extrahepatic tissues.
173
Handbook of General Animal Nutrition
Effect of hormones on milk production: It is an established
fact that milk production in the cow will increase following the
feeding of thyroprotein or thyroxine. The most effective daily
dose appears to be about 15 g/ cow in case of thyroprotein and
100mg/ cow daily for thyroxine. The addition of hormones in
the diet of cows has increase milk production from 15 to 20%
above control animals, if concomitant increase in energy intake
was maintained. If additional feed is not given then the response
is either very poor or nill.
Effect of hormone on growth: Synthetic oestrogenic
hormones like stilbesterol are being used in many countries as
growth promoters. Studies with fattening lambs have shown
that feeding 2-5 mg of stilbesterol daily increase the average
daily gain about 20 percent and reduced the feed Intake per
unit of gain. These substances either be given at the rate of 10
mg/ day in beef cattle or can be implanted under the skin in the
form of pellets in a single dose of 75 g and 10 mg in sheep.
Synthetic estrogens should never be given to female animals;
otherwise there will be derangement of the breeding behaviour.
Some workers have reported increased rate of gain improved
feed efficiency as a results of feeding thyroprotein or thyroxin
to growing pigs from the time of weaning to market weight.
Harmful effect of hormone feeding:
1. There are certain side effects in the animals fed on synthetic hormones, such as (a) restlessness (b) milk secretion
from rudimentary teats etc.
2. The most serious danger is to the human being ariSing
from the residues of synthetics estrogen in the meat which
have carcinogenic properties.
3. Feeding of thyroprotein in dairy animals causes general
excitability and injuries in the body.
Optimal amount of oral dose or implantation of various
hormonal compounds as reported by the National Research
Council Committee are given below.
174
Feed Additives in Animal Nutrition
Hormones and their doses for livestock:
Products
Diethylstilbestrol
Thyroprotein
Diethylstilbestero
I + testosterone
Thiouracil
Animals
Cattle
Sheep
Cattle
Poultry
Cattle
Doses
10mg/d
2mg/d
24to36mg
12 to15mg
24mg+ 120mg
Method of use
In feed mash
In feed mash
Subcutaneous
Subcutaneous
Subcutaneous
0.2 percent of In feed mash
Swine and
diet
poultry
Iodinated casein Lactating cow 200mh/kg diet In feed mash
(thyroprotein) Lactating cow 25-5 mg/ kg diet In feed mash
3. Probiotics: The term probiotic means 'for life'. These
are live cultures of non-pathogenic viable organisms which are
administered orally. Probiotics are coined by Parker in 1974 as
an organisms and substances which contribute to intestinal
microbial balance. Fuller in 1989 defined probiotics as live
microbial feed supplements which beneficially affect the host
animal by improving its intestinal microbial balance. Probiotics
are available in pastes, powder and liquid form or directly fed
feed additives. The term pronutrient may also be used for
probiotic. Most commonly used microorganisms, as probiotics
are Lactobacillus acidophillus, Lactobacillus fermentum, Lactobacillus
lactis, Aspergillus oryzae, Streptococcus foecium, Saccharomyces
cerevisiae etc. Live yeast culture, Direct fed microbials (DFM)
and curds are examples of probiotics.
Characteristics of a good probiotics:
1. It should not be toxic or pathogeruc to the host.
2. It should have a positive effect on the host.
3. It should be posses high survival rate and multiply faster
in the digestive tract. The adhesive capability to micro
organisms must be firm and faster.
4. It should be cheap and economical.
5. Feeding of probiotics to animals should be easy, safe and
simple.
175
Handbook of General Animal Nutrition
4. Prebiotics: Prebiotics are non-digestible feed ingredients
that beneficially affect the host by selectively stimulating the
growth and or activity of one or limited number of bacteria in
the colon that can improve the host health. Galacto
oligosaccharides, fructooligosaccharides and lactose derivatives
have been used in poultry and other non-ruminants.
Oligosaccharides may directly inhibit the growth of certain
intestinal pathogenic species by increasing the concentration of
lactic acid which will decrease the pH in the lower gut Microbes
are able to attach themselves to the mucosa through recognition
of oligosaccharide binding sites on the wall. Dietary
oligosaccharides attract microbes away from the intestinal
binding sites and therefore, reducing colonization of pathogens.
Chicken treated with caeca (Bailey et al., 1991) and the reduction
was attributed to shift in the intestinal gut microflora. More
over, certain oligosaccharides like a-l,2- gluco oligosaccharides
substrate for beneficial Bifidobacterium sp. at lower tract which
favoured their colonization and prevent colonization of harmful
bacteria.
5. Arsenicals: It was reported that organic arsenals had
growth promoting properties similar to those of antibiotics
when added to the diet of chicks. In addition to their use as
growth stimulants, these have been used at low levels to help
protect feeds from microbial destruction and to prevent and
control poultry diseases. Arsanilic acid, sodium arsanilate are
compounds used.
6. Tranquilizers: A number of tranquilizing drugs have
been usually used to combat stress due to heat or other
environmental factors. Certain tranquilizers such as natural
alkaloid of Rauwolfia, reserpine, hydroxyzine, chloropromazine
have been shown in certain trails to improve daily live weight
gain to livestock. The compounds act by reducing hypertension
and nervousness specially in summer or under any stress
condition.
7. Copper sulphate: At 0.1 percent level of the diet in
fattening pigs, improve the rate of gain and feed conversion
efficiency between weaning and bacon weight. Sheep are
176
Feed Additives in Animal Nutrition
particularly susceptible to copper poisoning, and there are
several instances of death through sheep eating copper fortified
pigmeals.
8. Anthelmentics, coccidiostat and antifungal:
Anthelmentics are the deworming drugs and used periodically
in the feed or water to prevent parasitic infestation, specially
of round warm. Out of many commercial products, 2,2
dichlorovinyl dimethyl phosphate, has both anthelmintics and
separate growth stimulatory effect in cattle. Coccidiostat are
routinely used in the diets of the poultry to prevent the most
devastating type of disease the coccidiosis. Antifungals are
natural or synthetic substances which inhibit the growth of
fungi.
9. Pigmenters and flavoring agents: Pigmenters are usually
carotenoid sources added to feed to improve pigmentation of
broilers and egg yolk. Some time some flavouring substances
are also used as feed additives to improve the palatability of
certain feed stuffs.
10. Antioxidants: Fats are subject to oxidation with
development of rancidity, which reduces palatability, and may
cause some digestive and nutritional problems. Antioxidants
are added for the stabilization of fats and fat soluble vitamins
and also to prevent the destruction of vitamin by oxidation.
Vitamin E is a good antioxidant of vitamin A, carotene and
fats. The antioxidants which are recommended to prevent
rancidity of fat are DPPD (Diphenyl-para-phenylene-diamine),
BHA (Butylated hydroxy anisole), BHT (Butylated hydroxy
toluene) and ethoxwuin.
Q1. Fill in the blanks.
1. Antibiotic feed additives are recommended in animals like
- - - and - - .
2.
- - - - and - - - - are most commonly used antibiotics
feed additives.
3.
In ruminants antibiotics feed additives are used at a age
upto - - - - .
177
Handbook of General Animal Nutrition
4.
- - - and - - - - are catabolic hormones used as feed
additives.
5.
- - - - and - - - - are anabolic hormones used as feed
additives.
6. Feeding of hormone- - - - - the milk production.
7.
- - - - and - - - - are the side effects of hormones
feed additives.
8.
- - - - and - - - - are hormones used as feed additives.
9. - - - - and - - - - - are bacteria used as probiotics.
10. The term probiotics are coined by - - - - - - -.
11. Examples of probiotics are - - - - and - - - - - -.
12. Copper sulphate is used as feed additive in pig at a rate of
Q.2.
1.
2.
3.
4.
S.
Explain the following.
Antibiotics feeding in non-ruminants.
Probiotics as a feed additive.
Mode of action of antibiotics as feed additives.
Harmful effect of antibiotic feeding.
Harmful effect of hormone feeding
6.
Pigmenters and flavouring agents as feed additives.
178
"This page is Intentionally Left Blank"
Chapter
1
Classification of Common
Feeds and Fodders
The animals are dependent on plants for the supply of their
consum.:: forage, straws, concentrates and
food material. tャBセケ@
their byproducts for various body functions. These feed stuffs
can be grouped as roughages and concentrates on the basis of
bulkiness and chemical composition (Table 1).
1. Roughages: These are the feed stuffs which contain more
than 18% crude fibre and less than 60% TDN and more than
35% cell wall on dry matter basis. These are further subdivided
into following ways.
A. On the basis of nutrient density:
1. Maintenance type roughages: They have 3-5 percent DCP
and fed to animals as a maintenance ration. Examples are
green maize, sorghum and oat etc.
2. Non-maintenance type roughages: They have below 3%
DCP and can not provide maintenance ration to animals
when fed alone. Examples are straw, stover and kadbi etc.
3. Productive type roughages: They provide production
ration to the animals and have 3-5 percent DCP. Examples
are berseem, lucerne and cowpea etc.
B. On the basis of the season of cultivation:
1. Kharif roughage: These are grown during the period of
June to October. Examples are cowpea, guar, rice, bean,
bajra, jowar, maize and teosinte etc.
2. Rabi crops: These are grown from October to March month
of the year. Examples are berseem, lucerne, mentha, sarson,
oat, barley etc.
181
Handbook of General Animal Nutrition
Table 1: Classification of feeds and fodders
----...
セ@
Hays
lS-34%CF
40-60%TON
Considerable carotene
{
セ[Z・イョL@
berseem, etc.)
> 10.5%CP,>
0.90/oCa
Non leguminous
(sorghum, dub etc.)
6-105% CP <O.9%Ca
Ory
>SO%O{
Roughages
>IS%CF
<60% TON
Low quality roughages (Straws hke wheat, nee,
>2S%CF- many >34%CF oat,jowar, barley)
<52% TON - several < 40"10 TON
<6% CP, little carotene, if any
セヲL⦅@
Succulent [
\
Legummous (Berseem,
Lucerne, cowpea,
clusterbean, !,>Teell
pea>IO%CP
Pasture
Tree leaves
Silage (2545% and
OM,Mediumm
Carotene) Root
(9-30% OM <3% CF)
non-leguminous
(Fodders of jowar,
maize, bajra, oat etc.
grasses of sudan,
napier, gumea etc.)
Feeding
St fTs
Energy -
« IS%CP)
I-___..セヲ[Z。エ・ウ@
1
>60%TON
Grain and seeds (Maize, barley, sorghum etc.)
Mill by products (Wheat bran, rice bran, chunis
of dais) Roots (Turnip, potato, tapioca etc.)
Molasses
Ammal origin _ _
Mostly >47% CP
>1%Ca
> 1.5 % P
Animal by products
(Blood meal, meat
scraps, driedwho\e and
skimmed milk), Marine
byproducts, Bone meal,
Feather meal
Plant origin セ@
Defatted (cakes and
Protem
(> IS% CP)(
mッウエャケ\TWEcpセュ・。IQe@
L.-_ _....
<1%Ca
Oil seeds
<1.5% P
> 17% EE
Brewer's grain and yeast
<2.5% CF
Mineral supplements (Ca, P, Cu, Mn, Fe, Co etc.)
Vitamin supplements (water and fat soluble)
Additives (antibiotics. hormones, probioticsetc.)
182
Classification of Common Feeds and Fodders
3.
Zaid roughages: These are grown in summer season from
April to June. Examples are cow pea, guar, maize, bajra
etc.
C. On the basis of legumes:
1. Leguminous roughage: These are roughages having dicotyledons seed and rich in protein i.e. berseem, lucerne,
cowpea etc.
2. Non-leguminous roughage: The roughages having
monocotyledon seeds are called non-:eguminous roughages
i.e. bajra, maize, oat, barley etc.
Stage of l'lant Growth: Stage of Maturity is an important
factor that influences the nutritive value of forages, silages. In
perennial fodders the actual growing time of plant is used as
stage of maturity.
Early vegetative: Stage at which the plant is vegetative
i.
and before the stem elongates.
ii. Late vegetative: Stage at which stems are beginning to
elongate just before blooming, first bud to first {lower.
iii. Early bloom: Stage between initiation of bloom and stage
in which 1/10 of the plants are in bloom.
iv. Mid-bloom: 1/10 to 2/3 of the plants are in bloom.
v. Late-bloom: Stage in which blossoms begin to dry and fall
and seeds begin to form.
vi. Milk Stage: Seeds well formed, soft & immature.
vii. Dough stage: Seeds with dough like consistency.
viii. Mature: Stage at which plant is harvested for seeds.
ix. Past ripe: Stage that follows maturity.
Non Leguminous fodder:
Maize (Zea mays): This crop is very much popular among
the farmers due to it's dual use for grains as well as fodder.
Maize forage is more nutritious at milk stage. It is nonleguminous kharif crop. It is a maintenance type fodder having
8-10 per cent protein.
183
Handbook of General Animal Nutrition
Jowar/Sorghum (Sorghum vulgart): It is also nonleguminous kharif crop grown under irrigated and non-irrigated
conditions. For feeding of livestock it should be harvested at
50% flowering stage of growth. Green jowar contains 0.5 %
OCP, 16% TON, 0.13% calcium and 0.03% phosphorus.
Bajra or Pearl Millet (Pennesetum typhoids): It is grown
as a grain crop. But when grown for fodder crop, it is harvested
before flowering stage for feeding the animals. It contains 13 %
TON and 0.9% DCP.
Teosinte or Mak Chari: It is an inter-genetic cross between
maize and chari and grown in those areas which are suitable
for maize and chari. It contains 6.0% OCP and 55% TON on dry
matter basis.
Oats (Avena sativa): This is a non-leguminous crop of the
rabi season. It is the best crop for haymaking. It is a maintenance
type fodder having 7-9 percent CP and 55% TON.
Leguminous fodder:
Berseem (Trifolium alexandrium): Berseem is one of the
most important cultivated forage crops of India. Kashni is the
weed crop grown along with berseem. It is grown in rabi season.
It contains 15% CP and 60 % TON. But excessive intake of
berseem may leads to bloat condition.
Senji (Melilotus parviflora): It is also an important
leguminous rabi crop. It contains 2.5% OCP and 13% TON on
fresh basis.
Lucerne (Medicago sativa): This is a productive type fodder
which can support growth as well as milk production when fed
alone. It contains 12-15 % CP and 55-60% TON.
Lobia or Cow pea (Vigna sinensis): It is one of the most
important fodder crops of irrigated land for the summer season.
It contains on an average 15% CP and 30% crude fibre on dry
matter basis.
Grasses: These are the self grown as well as cultivated
plants which are used for grazing animals as well as stall- fed
184
Classification of Common Feeds and Fodders
animals. Grasses are available in most of the season of the year.
Most commonly cultivated grasses are Pusa giant Napier grass,
guinea grass, sudan grass and para grass whereas dub grass
and many other grasses as a weed in cultivated crops are selfgrown grasses. The grasses have a. wide range of nutritive value
because of different species, varieties and stage of cutting etc.
On an average grasses contain 3-20 percent crude protein, 2040 percent crude fibre which is inversely related to the protein
content, and less than 4 percent lipid. The moisture content is
high (75-85 per cent) in early stage of growth and reduces
towards maturity. Soluble carbohydrates of pastures contain
fructan, glucose, fructose, sucrose and raffinose whereas
cellulose and hemicellulose are cell wall components which
increase with maturity.
Tree leaves: Tree leaves feeding is a common practice in
many parts of India especially for sheep, goat and camel. There
is wide variation in nutritive value of tree leaves which ranges
up to 20 percent crude protein, 25 percent crude fibre, 5-10
percent ether extract, 10 percent ash material and 40 percent
nitrogen free extract. Tree leaves are rich source of calcium and
poor source of phosphorus. So these have unbalanced Ca: P
ratio. Most of the tree leaves contain tannic acid, which is a
toxic factor for animals and reduces the availability of protein
so digestibility of protein is reduced. Mimosine is another toxic
factor present in tree leaves. Tree leaves are fed as grazing the
animals or by makirLg a tree leaf mixture, which is also used as
a protein, supplement especially in ruminants. Subabul, pakar,
gular, pipal, neem, bargad and casuarina leaves are most
commonly used for animal feeding.
Roots and Tubers: The roots include carrots, turnips and
sugar beet. The sugar beet is grown primarily for its sugar
content and is normally not given to animals as such. However,
the two by-products from the sugar extraction industry, sugar
beet pulp and molasses are important and nutritionally valuable
animals foods. The main tubers are potatoes, tapioca or cassava
and sweet potato grown extensively in India.
Roots: The root contains high moisture (75-95 per cent)
185
Handbook of General Animal Nutrition
and low crude fibre (4-13%). The organic matter of roots consists
mainly of sugars (50-75%) and is of high digestibility (80-90%).
Roots are generally low in crude protein although like most
other crops these components can be influenced by the
application of nitrogenous fertilizers.
Carrots (Daucus carota): Carrots are not given on a large
scale for feeding to farm animals. This crop is mainly grown
for human consumption as vegetable, halwa and salad. Even
then carrot is a valuable feed for all classes of animal being
particularly for horses. Carrot has a dry matter content of about
11-13 per cent and ME value of 12.8 MJ/kg of dry matter. The
carrot is a rich source of carotene.
Turnips: Turnip is grown as vegetable crops in India. This
can be grown in a variety of soil, including alkaline soil. The
root can be fed to animals but in practice it is not common feed
for livestock in India. There are two types of trunips that are
grown, the yellow fleshed cultivars which have high dry matter
content than the white fleshed cultivars. It contains 9.0 percent
dry matter, 92.2 percent organic matter, 1.2 percent crude
protein, 1.1 percent crude fibre and 72.0 percent digestible
organic matter.
Sugar beet: Most sugar beet is grown for commercial sugar
production, though it is sometime given to animals, especially
cow and pigs. Because of its hardness the beet should be pulped
or chopped before feeding. It contains 22-25 percent dry matter,
4-6 percent crude protein, 4-6 percent crude fibre, 65-75 percent
sugar. Digestible organic matter is about 85-90 percent whereas
digestibility of crude protein is about 35-40 percent. After
extraction of the sugar of the sugar beet factory, two valuable
by-prod ucts are obtained which are given to farm animals. These
are sugar beet pulp and molasses.
Sugar beet pulp: After extraction of the sugar from sugar
beet the residue is called sugar beet pulp. The water content of
this product is 80-85 percent. The sugar beet pulp mainly consists
of cell wall polysaccharides and consequently the crude fibre
content is relatively high. The crude protein and phosphorus
186
Classification of Common Feeds and Fodders
content is low. Beet pulp is extensively used as a feed for dairy
cows and is also given to fattening cattle and sheep. It is not
suitable for pig and poultry because of high crude fibre content
in it. It contains 18 percent dry matter,
96 percent organic
matter, 10.6 percent crude protein, 20.6 percent crude fibre and
84 percent digestible organic matter.
Beet molasses: After separation of sugar from the water
extract, a thick black liquid remains known as molasses. The
product has 70-75 percent dry matter. It contains about 90-95
percent organic matter and 2-4 percent crude protein. Most of
the crude protein presents in the forms of non-protein nitrogen
compounds, including the amine, betaine, which is responsible
for the fishy aroma associated with the extraction processes.
Molasses is used, generally at a level of 5-10 per cent of the
ration, in the manufacture of feed mash and pellets. The
molasses not only improves the palatability of the product but
also acts as a binding agent. Since molasses is a rich and
relatively cheap source of soluble sugar and it is some times
used as an additive in silage making.
Tubers: Tuber differs from root crops in containing either
starch or fructans instead of sucrose as the main storage
carbohydrates. They have higher dry matter and lower crude
fibre contents and are more suitable than roots for feeding to
pigs and poultry. The main tubers are potato, tapioca and sweet
potato.
Tapioca or Cassava (Manihot esculenta): Tapioca is a tuber
crop grown in Kerala and parts of Tamilnadu. In Kerala about
0.6 million tonnes of leaves are available at the time of harvest.
Cassava is a tropical shrubby perennial plant, which produces
tuber at the base of the stem. The chemical composition of these
tubers varies with maturity, cultivars and growing conditions.
Cassava tubers are used for the production of tapioca starch
(Sabudana) for human consumption, although the tuber is also
given to cattIe, pig and poultry. It contains 35-40 percent dry
matter, 90-98 percent organic matter, 3.4 percent crude protein
and 4.3 percent crude fibre.
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Handbook of General Animal Nutrition
The p' 'lnts and tubers contain certain degree of poison since
they contain varying proportion of two cyanogenic glucosides
(Linamarin and lotaustralin), which readily break down to give
hydrocyanic acid. In all cases care must be taken to use the
tuber and plant. It should be used after boiling, grating or
squeezing or grinding to a powder and then pressing.
Experiments have been carried out for utilizing tapioca
waste as an ingredient of cattle and pig ration. It contains 2
percent DCP and 64 percent TDN on dry matter basis for
ruminants. Growth and lactation studies in cattle with tapioca
waste, replacing the entire maize protein in concentrate mixture,
have shown that it can be used as one of the ingredient of the
concentrate mixture.
Potatoes (Solanum tuberosum): It differs from the root
crops, in that the main component is starch and not sucrose.
The starch contents of the dry them particularly suitable for
pigs and poultry. The crude fibre content is about 3-4 percent.
The crude protein of the dry matter is approximately 9-10
percent, about half of this being in the form of non-protein
nitrogenous compounds. The protein of uncooked potatoes is
poorly digested.
Potatoes are a poor source of minerals, except of the
abundant element potassium, the calcium content being
particularly low. The phosphorus content is higher since this
element is an integral part of the potato starch molecules, but
some 20 percent of it is in the form of phytates.
Sweet potatoes (Ipomoea batata): The sweet potato is a
very important tropical plant whose tubers are widely grown
for human consumption and as a commercial source of starch.
The tubers are of similar nutritional value to ordinary potatoes
although much higher dry matter and lower crude protein
content. It contains 32 percent dry matter, 96-97 percent organic
matter, 3.9 percent crude protein and 32.8 percent crude fibre.
Concentrates: Concentrate contains little amount of crude
fibre and more than 60% TDN. Concentrates constitute essential
part of ration. This is well known fact that roughages alone can
188
Classification of Common Feeds and Fodders
not supply all the essential nutrients to the producing, growing
and working animals. They include oil seed cakes, cereal grains
and their byproducts.
Cereal Grains: The cereal grains are high in starch and
low in fibre. They are rich in TDN and net energy. The digestible
crude protein ranges between 7-10 percent and TDN from 7080 percent. Starch occurs in the endosperm of the grain in the
form of granule. The cereals are all deficient in calcium
containing less than 19/kg DM. The phosphorus content is higher
being 3-5g/kg DM. The cereal grains are deficient in vitamin
D. Calves, pigs and poultry depend upon cereal grains for their
main source of energy.
Barley (Hordeum sativum): Barley being the second main
rabi crop of India. It contains 7-8 percent DCP and 75-80 percent
TDN, 0.07 percent Ca and 0.28 percent P. Barley is deficient in
vitamin A, D and riboflavin but rich in niacin content.
Maize (Zea mays): Maize contains 7 percent DCP and 80
percent TDN. The yellow maize contains enough amount of
carotene, hence good for feeding of livestock and poultry birds.
Protein content varies from 8-12 percent. It is deficient in lysine
and methionine. Maize contains about 730 gm starch/Kg DM,
is very low in fibre and has a high metabolised energy value.
Gram: Gram contains 12 to 16 percent DCP and 78 percent
TDN. Animals have great liking for this grain and so, used for
preparing the concentrate mi?'ture for feeding the livestock.
Jowar: Whole grains are usually fed to chickens. It contains
7 percent DCP and 74 percent TDN and high percentage of
leucine. Due to high content of leucine, too much feeding of
jowar may result in development of niacin deficiency symptoms
- a disease called pellagra.
Bajra: Bajra contain crude protein ranges from 10-12 percent
and TDN from 70-75 percent. It can be used in place of maize in
swine and poultry feeding.
Oat (Avena sativa): The oat has always a favourite cereal
for ruminant animals and horses but has been less popular in
189
Handbook of General Animal Nutrition
pig and poultry feeding because of its comparatively high fibre
content and low energy value. The crude protein content which
ranges from 70-150 g/kg DM. Oat contains 7-9 percent DCP
and 70-72 percent TDN. It contains 0.12 percent Ca and 0.33
percent P. It is more palatable and nutritious as compared to
other cereal grains.
Wheat: Depending upon variety, the crude protein range
from 8-14%. It is good source of energy but is seldom used for
livestock feeding in the country. It contains 12-14 percent crude
protein and 85 percent TDN Poultry are less susceptible,
although wheat with high gluten content should not be given
since a doughy mass may accumulate in the crop.
Rice: Rice (Oryza sativa) is main cereal crop of eastern and
southern Asia. It is good source of energy but is seldom used
for livestock feeding. It's byproduct rice polish contain 12-14
percent crude protein and about 12 percent of oil. Rice threshed,
has a thick fibrous husk or hull like Oat, the state is known as
rough rice. The hull is easily removed to leave product known
as brown rice. Rough rice may be used as a food for ruminant
and horse but brown rice is preferable for pigs. The hulls are
high in fibre content and can contain upto 210 g/kg DM of silica.
Oil seed cakes: These are the by-products left after the
extraction of oil from oil seeds. In India oil cakes are prepared
by two methods e.g.
(1) Machine made (expeller pressed) (2) Ghani pressed.
Ghani pressed cake is more nutritious as compared to
expeller pressed and is widely used by farmer in village for
feeding their animals. Special care is needed in preserving these
feeds because they are more susceptible to fermentation action
and mould growth. According to the method of processing,
the cakes can be Classified as:
1. Ghani pressed Cake- Contain 10-12 percent ether extract.
2. Expeller prEssed cake- It contain 6-8 per cent ether extract.
3. Solvent extracted cake- It contain less than 1 percent ether
extract. So also called deoiled cake. But this type of cake
190
Classification of Common Feeds and Fodders
contains more percentage of crude protein than other cakes.
Cotton seed Cakes: In cotton growing area it is main source
of protein to livestock. It contains 38-40 percent crude protein
and is very much used for feeding of milch cattle. Cake contains
18 percent DCP, 72 percent TDN, 0.11 percent Ca and 0.53
percent P. The cake contains more than 0.065 percent gossypol
and deficient in lysine and not fit for feeding to swine, poultry
and calves. When upper covering of seed is removed (dehulling)
and pressed to form cake than known as decortica ted cake which
is rich in crude protein and low in crude fibre than
undecorticated cake.
Linseed cake: It contains about26 percent DCP, 72 percent
TDN, 0.49 percent Calcium and 0.89 percent P. Linseed cake is
very much used for feeding of horse and young calves. It is
good for pregnant animals. It is good source of protein for
cattle, buffalo, sheep and swine but is not good source of protein
in poultry ration. Immature linseed contains a small amount of
cyanogenetic glycoside, linamarin and linase enzyme which
hydrolysed it into hydrogen cyanide which is very toxic to
animals. Normal processing conditions destroy the linase and
then cake is safe for feeding. Linseed meal has a protective
action against selenium poisoning.
Ground nut cake: It contains 40-50 percent crude protein,
70-75 percent TDN 0.08 percent calcium and 0.23 percent
phosphorus. It is an important source of protein for livestock
feeding. The content of oil is variable according to process of
extraction of oil. It contains 10-12 percent in ghani pressed, 6-8
percent in expeller pressed and 0.5-0.7 percent fat in solvent
extracted cake. Groundnut cake is fed to cattle, buffalo, sheep,
goat, poultry and swine. It is liable to contain a toxic factor
known as aflatoxin (B](most toxic), B2, G1 and G 2) which is
produced by the fungus Aspergillus fIavus particularly during
warm rainy season. It may also be rancid particularly during
rainy season. Therefore it should not be stored for more than 6
weeks.
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Handbook of General Animal Nutrition
Til cake: It contains enough amounts of calcium,
phosphorus, & protein and can be kept preserve for longer
period. It contains about 38-40 percent DCP and 75-78 percent
TDN. The hulls of sesame seeds contain oxalates and it is
essential that meals should be completely decorticated in order
to avoid toxicities.
Mustard cake: Widely used cake in India. It is very much
used in village for feeding the working buffalo. It contains 3437 percent crude protein, 27 percent DCP, 65-70 percent TDN,
0.29 percent Ca and 0.39 percent P. In case of poultry and pig it
is not a good source of protein. About 10-15 percent of it can be
incorporated in poultry and swine ration. It contains
glucosinolate which on hydrolysis release goiterogenic substance
such as thiocynate and isothiocynate which produce goitre.
Goiterogenic compound present in mustard cake reduces the
growth rate in poultry and swine.
Coconut cake: In coconut growing area, cake is used for
feeding the animals. It contains about 7-10 percent DCP (21
percent crude protein), 8 percent fat, 12 percent crude fibre
and 8 percent ash.
Rice bran cake: It is very good feed for feeding the
livestock. When it is mixed with some other substances has
better nutritive value as cattle feed.
Soyabean cake: Soyabean contains from 160-210 g/kg of
oil and are generally solvent extracted. It is generally one of
the best sources of protein available to animals. It is poor source
of vitamin-B and these must be provided either as a supplement
or in the form of an animal protein. If no supplementation sow
may produce weak litter and older pigs show in co-ordination
and failure to walk.
Neem cake: Neem seed contains about 40-45 percent oil.
It contains about 13 percent protein of which about 50-60 percent
digestible. It is not palatable. It can be incorporated upto the
level of 25 to 30 percent in concentrate mixture.
Rubber seed cake: It is available in fairly large quantities
in area where rubber plantations are available. Maximum
192
Classification of Common Feeds and Fodders
availability is in Kerala state. It contains 16.6 percent DCP, 78.8
percent TDN for pig where as for cattle it contains 18.6 percent
DCP and 54 percent TDN.
Agro-industrial by-products: Various agro-industrials byproducts are used as animal feed. These are further divided as:
A- Concentrate By-product:
Wheat bran: It is product obtained after wheat flour is
removed from the husk. It is widely used as concentrate mixture
for dairy animals. It contains 10 percent DCP, 65 percent TDN,
0.07 percent Ca and 0.35 percent P. In concentrate mixture for
growing young calves wheat bran may be incorporated upto
50 percent of total grain mixture.
.
Rice bran: It is mostly used for horses. Feeding of rice
bran alone may result in colic pain due to formation of ball
inside the intestine. It contains 7 percent DCP, 65 percent TDN,
0.06 percent calcium and 1.12 percent phosphorus. It is also used
for cattle, buffaloes, sheep, swine and poultry feeding.
Rice polish: Rice polish contains about 3 percent fibre, 12
percent fat and 12-14 percent protein. It is excellent source of
energy and rich in vitamin B- complex.
Husk or chunies: It is obtained as a by- product during
process of pulse making. It contains enough of nutrients and is
used for feeding the animal along with the concentrate mixture.
Maize gluten feed: It is obtained after removal of most of
starch and germ from maize. Maize gluten meal generally
contains 45-48 percent protein.
B-Animal By-product:
Fish meal: Fish meal is produced by cooking fish, and
pressing the cooked mass to remove most of the oils and water.
It is highly nuh"itious feed obtained from fish body. It contains
about 10 percent moisture, 55 percent protein, 6.9 percent fat
and 25 percent mineral salt particularly 5.4 percent Ca and 3.4
percent P. It contains vitamin A, D and richest source of vitamin
B12 • Sterilized fish meal should be used for feeding animals.
193
Handbook of General Animal Nutrition
Blood meal: Major slaughter house by-product which
contains over 80 percent crude protein, but poor in Ca and P.
Blood meal is incorporated only in poultry ration in this country.
Meat meal: This is obtained by boiling and drying the meat
obtained from dead animals which is subjected to fine powder.
It contains almost all the nutrients found in meat and is rich
source of animal protein.
Feathers Meal: Poultry feathers are not digested by single
stomach animals. When feathers are processed under low
pressures (130°C, 21/2 hours) or under high pressures (145°C, 30
min) and dried at about 600C This product is extremely high in
protein but deficient in several essential amino acids. It is used
primarily in ration of swine and poultry.
Bone Meal: Bone meal is rich in calcium, phosphorus &
low in protein. It is used primarily in rations of swine & poultry.
Sugarcane plant by-products:
Sugarcane by-products are also used as animal feeds which
are tabulated as below:
Sugarcane plant
A
Sugarcane tops
Green
ヲッ、セ|ゥi。ァ・@
Sugarcane stems
ウオNaoimGセ@
Sugarcane
ェセ・@
/\
Dry fodder
Bogasses+Molasses + Urea
Feed resources availability: Feed resources are broadly
classifieds in to three major categories viz. crop residue,
concentrates and green fodder. Over the last two decades the
total feed resources has increased by 37 percent while the crop
residue, concentrate and green fodder have increased by 52, 76
194
ClassIfication of Common Feeds and Fodders
and 2 percent, respectively so efficient management of feed
resources would be ? vital component in the livestock sector.
The growth in feed resources availability especially the
concentrate and green fodder have not been commensurate with
the increase in the demand of these resources by the livestock.
Dry matter availability at national level (million tonnes)
Feed
Years
Required % Deficit
resources
1985-86 1995-96 2004-05 2004-05
11
Crop residue
240.7
305.1
365.8
412
Concentrate
19.6
30.2
34.5
47
28
124.3
Green fodder
124.3
126.6
193
35
Total
384.6
459.6
526.9
652
19
Q.1. Fill in the blanks.
1.
Kharif roughages are - - - - - - - and - - - - - - -
2.
The examples of Rabi 」イセーウ@
3.
Examples of maintenance type roughages are - - - - - - - - and - - - - - - which contain - - - - - - - - percent DCP.
- - - - - - - - and - - - - - - - - are productive
type roughages which contain - - - - - - - - - - %
DCP.
The roughages which can not provide maintenance ration
when fed alone are called - - - -:..- - - - - - - .
The examples of non-maintenance type roughages are - - - - - - - - - and ------whichcontain-- - - - percent DCP.
Crops grown from April to June are called - - - - - -
4.
5.
6.
7.
8.
9.
are - - - - - - - - - - and
- - - - - - - - and - - - - - - are leguminous crops.
- - - - - - - - and - - - - - - - non-leguminous
crop.
195
Handbook of General Animal Nutrition
10. Maize is - - - - - - - - - type of fodder.
11. Jowar is - - - - - - and - - - - - - type of fodder.
12. Bajra is - - - - - - - type of fodder.
13. Teosinte (Mak Chari) is an intergenetic cross between - - - - and - - - .
14. Oat is - - - - - - - type uf crop of the rabi season.
15. Berseem fodder contains - - - - - percent CP and - - - - - - percent TON on dry matter basis.
16. Most commonly cultivated grasses are - - - - - -, - - - - - - and - - - - .
17. Tree leaves of - - - - - , - - - - - - and - - - - - are most commonly used as ruminant feed.
18. - - - - - - - , - - - - - and - - - are the main tubers
used as animal feed.
19. - - - - -, - - - - - - - and - - - - - are the main
roots used as animal feed.
20. After extraction of the sugar from sugar beet, the residue
is called- - - - - .
21. Two valuable by-products from sugar beet factory are - - - and - - - - .
22. Roughages contain - - - - percent TON and - - - - percent CF.
23. The by-product left after the extraction of oil from oil seeds
is called - - - - .
24. Solvent extracted cakes contain - - - - - percent ether
extract.
25. The toxic factor present in cotton seed cake is - - - - 26. When upper covering of cotton seed is removed to form
cake, than - - - - cake is formed.
27. Decorticated cotton seed cake contains - - - - - - crude
fibre than under corticated cakes.
28. - - - - - is the toxic factor of linseed cake.
29. Ground nut cake contains the toxic factor known as - -
1%
Classification of Common Feeds and Fodders
30. The toxic factor of til seed cake is - - - - - - - - - -.
31. Mustard seed cake contains - - - - - - - - - - as a
toxic factor.
32. When husks are removed from wheat flour, the product is
called - - - - -.
33. - - - - - - - is a byproduct during process of pulse
making.
34. After removal of starch and germ from maize, we obtain
35. Bone meal is rich source of - - - - - - - - - - and 36. Feather meal is rich in protein content and used primarily
for feeding of - - - - - - and - - - - - - - - - 37. Linseed meal has a protective action against - - - - - - - - poisoning.
38. The - - - - - - - content in potato is higher because it
is associated with starch.
39. The main tubers used in livestock feeding are - - - - - - - - -, - - - - - - - - and - - - - - - - - -.
40. The common antinutritional factors present in tree leaves
are - - - - - - -, - - - - - - - and - - - - - - Q.2. Explain the following:
1. Classify the roughages on the basis of nutrient density and
season of cultivation.
2.
3.
4.
5.
6.
Differentiate between roots and tubers and their importance as animal feed.
Importance of grasses and tree leaves in animal nutrition.
Define and classify the cakes.
Mention the various toxic factors present in different cakes.
Tabulate the classification of various feeds and fodder of
animal nutrition.
197
"This page is Intentionally Left Blank"
Chapter
2
Conservation of Green Fodder
in Animal Nutrition
Feeding of green and succulent fodder is of great
importance to farm animals. Butthe availability of green fodder
is limited to a particular season only. During the lean months
of May, June, October and November, green fodders are not
available for feeding to the livestock. In India, during Kharif
season plenty of greens are available but they are not properly
utilized by the farmers due to lack of sufficient knowledge of
fodder conservation. When conventional feedstuffs are not
available to animal for feeding, use of unconventional (i.e. not
commonly used for feeding of livestock but used during fodder
scarcity period) feeds is being done to maintain the animals
and their production. The importance of conservation of fodders
is as follows•
To store surplus fodder during harvesting season.
•
To provide good quality fodder during the lean months
of the year.
•
To maintain the production of animal even during lean
period.
So to feed green fodders during lean periods they can be
conserved in the form of hay and silage.
Hay making:
Definition of hay: A forage plant when preserved through
reducing the moisture contentto the level at which plant tissues
are dead or dormant is termed as hay.
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Handbook of General AnImal Nutrition
Advantage of Hay Making:
The hay provides the nutritious feed to the livestock during the lean season when there is scarcity of green fodder.
2. The good quality legume hay may reduce the cost of production by replacing certain amount of concentrate in the
ration.
3. The fodders can be harvested at the stage when there is
maximum accumulation of nutrients in the plant.
4. The ration of the animals can be balanced with the help of
good quality hay.
1.
Crops for Hay Making: The legumes crops are preferred
for hay making which have soft, thin and pliable stem. Berseem,
lucerne, oat, cowpea, soyabean, anjan and sudan grasses are
suitable crops for hay making. Some self-grown grasses during
mansoon are also used for this purpose.
Method of Hay Making: The fodder or grasses used in
hay making processed to reduce the moisture level below 15
percent. The various methods of hay making are described as:
1. Jungle hay: The reserve forests, community forests and
pastures are full of perennial grasses and legume mixtures. These
are multicut in nature, so, even after several cuttings there is a
lot of surplus fodder left behind unharvested in the field till
the end of rainy season. The forage mixtures are then harvested
and preserved for the feeding of livestock during lean season.
These dried out forages are usually termed as jungle hay.
Although the method through which the jungle hay is prepared,
the forages mixture losses its nutritive value due to low protein
and poor digestibility.
2. Sun Drying: The harvested forages can be processed
using different ways to reduce the moisture content to a safe.
level for preservation. The forage mixtures after harvesting are
dried in the field condition with frequent turning of the material.
The forages are sometime pooled together to form a poola.
These poolas are then kept vertically in the field in the shape of
a cone. Sometime the fodder crops after harvesting is spread
over in the layer on the barbed wire fencing or boundary wall
200
Conservation of Green Fodder in Animal Nutrition
of the farm or tripod or pyramid which is made of three wooden
or iron pieces with an average height 2.5 to 3 meters. It is tilted
once or twice before storages for proper curing.
3. Barn drying: The hay can be prepared while storing the
forage mixture in a barn. The barn, which is generally used for
this purpose have false floor or a system to facilitate the air
blowing from ground surface with the help of draft blowers.
The air which is blown may be heated or unheated. This type
of process is not in practice in the Indian sub-continent.
Advantages of Barn drying:
1. The forages may be baled before drying, thus reducing
the cost of transportation to the drying site.
2. The drying time is reduced.
3. The loss of nutrients which occur due to rain is avoided as
the process is performed in a barn.
4. The loss of leaves is less to that of field curing.
Disadvantages:
1. The drying is not uniform as the layer facing the blower
dries rapidly than that of the opposite layer.
2. The cost of drying is high.
3. The process is not suitable under the high humidity conditions.
4.
The turning is not possible for uniform drying.
4. Dehydration of forages: The nutrient loss is high due to
handling and plant enzyme activity. The process involves forced
hot air ciruclation for rapid drying of the forages. Differed types
of drier like low temperature drier, high temperature drier and
solar drier are used for dehydration of forages.
Advantages:
1. The forages are dried at a fast rate.
2. The loss due to plant enzyme is minimised.
3. The loss of plant parts mainly leaves is low due to lesser
handling during the process.
201
Handbook a/General Animal Nutrition
4.
Bales of forage can also be dried.
Disadvantages:
1. High cost involved during establishment and maintenance
of dehydration plant.
2. High cost of processing if sufficient amount of forages are
not available for dehydration to run the plant continuously.
3. The operation skill is required.
Losses during hay making: The main aim of hay making
is to reduce the moisture content of the herbage to a safe level
(about 15%) and to retain its nutritional characteristics during
the process. Various factors are responsible for the loss of
nutritional characteristics of the forage to a variable degree
given below.
1. Physical losses: The leaves of forage plants are rich in
proteins and also more palatable to the animals than that of the
stem usually get separated from the plant during the process of
drying. The physical losses are variable depending on the
handling and processing of hay making.
2. Chemical losses: The fresh forage plant contains various
chemical constituents apart from the water. The loss of water is
desirable during the process of hay making while the loss of
other components which may reduce nutritional value is
undesirable. The losses of chemical constituents which are
brought about by plant enzymes, respiration activity and
processing method are difficult to measure in field conditions.
1. The enzymes act on soluble carbohydrates and convert
them into carbon dioxide and water.
2. The plant proteases start working immediately after the
harvesting and are responsible for the loss of nitrogenous
fraction.
3. The vitamins A, D and E are mostly affected by drying
process. The carotenes, a precursor of vitamin A is unstable in light and air.
4. A considerable loss of carotenes occurs from the action of
lipoxidase.
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Conservation of Green Fodder in Animal Nutrition
3. Loss of nutritive value: The loss of nutrients is variable
in various processes. The chemical constituents of nutritional
importance like carbohydrates, nitrogenous substances and
vitamins etc. are known to reduce during the process of hay
making.
Characteristic of Good hays:
1. It should have a typical aroma of the forage from which it
has been prepared. Moisture content should not exceed
15-20 percent.
2. It should be free from foreign material like dust, moulds
and undesirable weeds.
3. It should possess reasonable green colour, which gives a
rough idea of carotene content.
4. It should maintain leafiness of original fodder. The loss of
leaves during the process will produce a poor quality
product.
5. It should be palatable to animals. The poorly prepared hay
generally is not readily accepted by the animals.
6. Leguminous hay contain 9-15% DCP and 50-60% TDN
while gram hay contain contain 2-4% DCP and 45-50%
TDN.
Storage of Hay: The forage dried by above methods should
contain moisture upto 15 percent. Under drying may result in
the development of fermentation and formation of poor quality
hay. There is loss of leaves, green colouring matter, and certain
nutrient like carbohydrates and vitamins by fermentation,
leaching and shattering etc. during the process of storage of
hay. These losses can be prevented by storage of hay. The hay
is generally stored in the different forms like loose hay, chopped
hay, baled hay, and pelle ted hay.
Silage making:
Definition of silage: Silage is the green material produced
by controlled fermentation of the green fodder crop retaining
the high moisture content and maintaining anaerobic conditions,
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Handbook of General Animal Nutrition
allowing lactobacilli or other similar species to proliferate and
produce lactic acid and restricting the growth of spore forming
anaerobes and clostridia which produce amines, ammonia and
carbondioxide. The process of silage making is called as ensiling.
The invention of the baler and plastic wrapping has made it
much advantage of the benefits of silage as a supplementary
feed for livestock. The high protein green leaf is maintained
with only about 20 percent of the nutrients lost in the silage
making process. Upto 30 percent of the original nutrients can
be lost if silage is made poorly.
Wastelage: It may be defined as a material obtained after
ensiling of waste material (animal organic waste) in a suitable
combination with forages and additives, under anaerobic
conditions, through fermentation by lactic acid producing
bacteria.
Advantages of Ensiling:
1. Silage can be prepared from green fodder when the
weather does not permit for hay making.
2. Surplus green fodder abundantly available in rainy season can be preserved as silage for feeding during lean season.
3. Silage can be prepared from plants having thick and solid
stems that are generally not very suitable for hay making
like jowar and maize. Crop should be rich in sugars and
starch.
4. Weeds can also be utilized along with main fodder crops
for silage making. Silage making destroyed majority of
weed seeds.
5. It is highly palatable. Silage from cereal fodder, contains
about 2-4% DCP and 50-63% TDN.
6. The organic acid produced in the silage are similar to those
normally produced in the digestive tract of the ruminants
and therefore are used in the same manner.
7.
There is lesser loss of carotenes in silage making than that
of hay making.
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Conservation of Green Fodder in Animal Nutrition
Fear of loss due to spontaneous fire sometime experienced
in hay making is not there.
9. Green fodder can be stored for a very long period by
silage making.
10. The inclusion of raw organic wastes (poultry litter, pig
waste etc.) is possible in ruminant diet through ensiling it
with forages.
8.
Disadvantages of Ensiling:
1. Transportation of silage is difficult.
2. Permanent structures for preparing silage are required.
3. Wastage during silage making may be high due to affluents
losses.
4. Poorly prepared silages are not accepted by animals.
Suitable Crops for Silage Making: The suitable crops for
silage making are forages which contain adequate amount of
fermentable carbohydrates like maize, jowar, bajra, etc. So nonleguminous crops are more suitable than leguminous crops.
However, leguminous fodder can also be used for silage making
even they contain less amount of carbohydrates. For that
molasses or minerals should be sprinkled over them or mixed
with non-leguminous fodder at the time of silage making. The
crop for silage making should be harvested at flowering stage
as they contain maximum amount of nutrients at that time. The
crop should be harvested in the morning after the dew has
dried off and should be spread over the field, till noon under
the sun rays so that some moisture may be dried up. In the
afternoon the crop is collected in bundles.
Silo: The specialized device or containers used for the
preparation of silage are called silo. The silos are trench silo,
silo tower and silo pit may be rectangular or cylindrical. Based
on materials used in construction silo can be made up of brick,
cement, stainless steel and kachcha sand. Kachcha silo is
prepared by digging a pit or trench in the ground. The sides
and floor of silo are generally plastered with a mixture or cow
dung and clay (1:1) for making the wall and floor smooth.
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Handbook of General Animal NutritIOn
Site selection of silo:
1. Site should be easily approachable from field as well as
dairy farm.
2. The area should not be low lying, because such type of
areas are prone to water logging.
3. The chaffing shed should be adjacent to the site.
Characteristics of Silos: For the preparation of good silage,
the silo should have air tight walls without any cracks to avoid
entry of rain water which, otherwise spoil the silage. The walls
of silo should be smooth and strong without comers. The depth
of the silo depends upon the water table in the soil. It should
always be above the water table. Similarly, the height of silo
will depend upon the machinery available for filling the tower
silos. In our country since filling is done by manual labour
normally silos are not more than 2-3 m above ground level.
Filling of Silos: Silos can be filled with long fodder as
well as with chopped fodder. Chopping is helpful for better
packing to minimize the loss of nutrients and chaffed fodder
filling and removal of silage is easier.
After chaffing and ensuring that dry matter is around 35
percent the silo is filled with the fodder. The fodder should be
evenly distributed throughout the pit. The trampling should
be done properly either with men or bullock cart or tractor
depending upon the size of pit. At the top, the fodder should
be filled in 1.5 m higher than the ground level. From all sides it
should be covered with long paddy straw or poor quality
grasses and then covered with wet mud and bhusha to seal the
materials so that air and water cannot go inside the packed
material. The layer of straw/grasses may be between 4-5
inches. The silage would be prepared in 4-6 weeks after
covering.
Process of Ensiling: The process of ensiling begins with
the cutting of crops. The respiration activity continues till the
silo is closed and acidic conditions are achieved in the silo. The
whole process may be divided into four different phases:
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Conservation of Green Fodder in Animal Nutrition
Phase I: The phase I immediately start after sealing the
tightly filled silo. The plant cells continue to respire till the
trapped oxygen is exhausted so length of phase I depends upon
the amount of oxygen present in the silo. The carbondioxide
produced make the silo anaerobic. Thus, favours the growth of
anaerobic bacteria.
Phase II: At the initial stage clostridia and coliform bacteria
are active, causing degradation of protein and amino acid and
production of amine and acetic acid. Lactic acid producing
bacteria are also increased.
Phase III: The lactic acid producing bacteria dominate
which increased lactic acid content and reduced pH of ensiled
material. The presence of readily available carbohydrate
enhanced the growth of such types of desired bacterial
population.
Phase IV: This phase is quite variable and dependent on
phase III. If pH is reduced to around 4.0 the silage is stable and
no further degradation occur. If sufficient acid is not produced
to bring down the pH around 4.0 the microbial activity still
continues. The degradation of lactic acid to butyric acid starts
which spoils the smell and acceptability of silage, through the
action of clostridia. High moisture .contents favour this
undesirable fermentation.
Reaction inside the silo pit (Changes during ensilage):
The ensiling is a very complicated process and many changes
occur during ensiling. The loss of dry matter, carbohydrate,
proteins and pigment occur invariable during fermentation
process of silage making. The changes may be biological or
chemical in nature and their intensity depend upon the physical
and chemical characteristics of ensiled material, compactness
of filling and moisture content of ensiled material.
1. Microbiological changes: At initial stage, the aerobic
type microbes dominate. The activity of aerobic micro-organisms
gradually ceased with the development of anaerobic condition.
These are then replaced by fast multiplying anaerobic bacteria
such as Escherchia, Klebsiella, Bacillus, Clostridium, Streptococcus,
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Handbook of General Animal Nutrition
Leuconostoc, Lactobacillus and Pediococcus. Being facultative
anaerobes, yeasts present in the silo contents also proliferate in
the silage. Growth of micro-organism in ensiling materials are
influenced by moisture content of forages, soluble
carbohydrates, mechanical processes and additives added to
the ensiled materials.
2. Chemical changes in ensiling:
Changes in carbohydrates: Monosaccharides (glucose and
fructose) and disaccharides (sucrose) are the dominating water
soluble carbohydrates in forages. Oligosaccharides other than
sucrose are present in low quantity. The components which are
utilized maximum during the processof ensiling are the soluble
carbohydrates as polysaccharide and oligosaccharides present
in green forage which are hydrolyzed asCellulose
Glucose
l3-glucosidase
endo-l3-glucanase
Hemicellulose
Starch
xylanase, arabinase
_ _ _.=am:::..:..Ly..:::las=e_ _ _ _ _ _Nセ@
Sucrose
invertase
Xylose+ Arabinose
Glucose
Glucose + Fructose
The chemical changes take place by plant enzyme in initial
stage then microbial fermentation take place.
(a)
Plant enzymes: The plant cells remains active and
respire till the oxygen of silo is lost. They utilize soluble
carbohydrates and convert them into carbondioxide and water.
C6H I2 0 6 + 6 O2
)
6 H20 + 6 CO2 + 673 K cal
(b)
Microbial degradation of carbohydrate: The
carbohydrates glucose, fructose, xylose and arabinose, are
degraded by lactic acid producing bacteria. The degradation
208
ConservatIOn of Green Fodder in Animal Nutrition
of various carbohydrates take place by homo lactic and
heterolactic fermentation and produce various fermentative
products such as lactic acid, acetic acid, mannitol and
carbondioxide. The number of lactic acid producing bacteria is
usually low in fresh forage and most of these bacteria are
heterofermentative. Heterofermentative lactic acid bacteria
produce less organic acid than homofermentative and some of
energy is lost in the form of carbon dioxide which is responsible
for the loss of energy of the forages during the ensiling process.
This loss can be minimized by using a inoculum of a
homofermentative lactic acid producing bacteria in the premix
before filling in the silo.
The degradation products of homo lactic and heterolactic
fermentation of hexoses and pentoses are given below:
S.No. Substrate
1.
2.
3.
4.
5.
6.
Type
of End products.
fermentation
Glucose + ADP (1 Homolactic Lactic acid + 2 ATP (2
mole)
fermentation mole)
Fructose + 2 ADP Homolactic Lactic acid + 2 ATP (2
fermentation mole)
:(2 mole)
Glucose + ADP (1 Homolactic Lactic acid + Ethanol +
mole)
fermentation CO2 + ATP (1 mole)
Fructose + 2 ADP Heterolactic Lactic acid (1 mole) +
+ H20 (3 mole)
fermentation Mannitol
(2
mole)
+Acetic acid (1 mole) +
CO2 +2ATP
Arabinose + 2 Homo and
Lactic acid (1 mole) +
ADP (1 mole)
heterolactic Acetic acid (1 mole) + 2
fermentation ATP
Xylose + 2 ADP (1 Homo and
Lactic acid (1 mole) +
mole)
heterolactic Acetic acid (1 mole) + 2
fermentation ATP
Microbial degradation of organic ,acids: Forages generally
contain proportionally higher quantities of citric acid and malic
acid, which are degraded both by homo and heterolactic
bacteria. Degradation products of organic acid by homo and
heterolactic fermentation are lactic acid, acetic acid, formic acid,
ethanol and 2, 3 butanediol.
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Handbook of General Animal Nutrition
Homo and hetero
Citnc a c i d - - - - - + . Acetic acid + formic acid + butyric acid + ethanol + CO, + lactic acid
Lactic fermentation
Homo and hetero
Malic acid
- - - - - - Lactic acid + acetic acid + formic acid + ethanol + CO,
Lactic fermentation
Chemical changes in nitrogenous compound:
The degradation of nitrogenous compounds during
ensiling is caused by plant enzymes and microbes of aerobic or
anaerobic nature.
1. Plant enzymes: The changes in the nitrogenous fraction
and degradation of protein to non-protein nitrogen (NPN) is
carried out by plant enzymes. The activity of plant enzyme is
dependent on moisture content of forage and pH of ensiled
material. The plant proteolytic activity is high during high
moisture level in forages. The leaf proteases are more active in
a pH range of 5.0 to 6.0. Apart from the hydrolysis of proteins
further breakdown of amino acid is also possible. Below pH
4.3, the proteolytic activity of plant enzymes is ceased. A slow
rate of wilting associated with slow decline in pH may cause
extensive loss of proteinous fractions of ensiled forages by
proteolytic activity.
2. Microbial degradation of nitrogenous compound:
Proteins are broken down into amino acids by microbial
degradation in well preserved silage. There are many different
types of microbes like lactobacilli, pediococcus, sterptococ.cus
and clostridium etc. which are present in the content of silo.
The degradation of nitrogenous source is variable depending
on the nature of bacteria, rate of pH decline and nature of crops
etc.
In badly preserved silage the amino acid are further broken
down to produce various amines like tryptamine, phenylethlamine and histamine. The principal products of putrification
are betaine, adenine and pentamethylene diamine.
Pigments: The colour of the forages usually changes on
210
ConsenJation of Green Fodder In Animal Nutrition
ensiling. The light brown colour or golden yellow colour is
caused by the action of organic acid on chlorophyll. The
phacophytin is the resultant of this reaction.
Flavour and aroma: A well prepared silage with lactic acid
fermentation has its characteristics flavour and aroma. It has
been observed that even off flavour and aroma of pig waste
can be converted to pleasant fruity smell after ensiling with
forage and molasses.
Losses during ensilage: The losses of nutrient during
ensiling include all type of losses arising from processes involved
from harvesting of forage in the field to finishing product
(silage). These losses which occur during the process of silage
are discussed below:
1.
Field losses: The losses occur after the harvesting
of crop till it is filled in the silo are considered field losses.
These losses may be due to shattering of leaves and other
nutritious plant parts after harvesting the forage. Apart from
the handling, the loss of dry matter may be due to tissue
respiration and activity of plant enzymes during the process of
wilting.
2.
Aerobic fermentation: During the process of filling
the silo pit, the air pocket, are usually left in side pit. The air
present in silo causing aerobic fermentation of carbohydrates ..
The extent of losses due to aerobic fermentation processes is
directly and positively related with the amount of air present
in the silo.
3.
Anaerobic fermentation losses: The losses of dry
matter due to anaerobic fermentation processes may be of water
soluble carbohydrates, proteins, and organic acids. The intensity
however, depends on the nature of microorganism dominating
of forage and the rate of decline in pH. The losses of dry matter
due to anaerobic fermentation may range to 2-10 percent of
heavily wilted forage samples.
4.
Effluent losses: As effluent production in the silo
is responsible for a considerable loss of nutrients, when forage
of high moisture content (more than 70 percent) is ensiled. The
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Handbook of General Animal NutritIOn
loss of dry matter recorded upto 10-80 percent when formic
acid used as a preservative for lush green forage. The effluent
production is influenced by following factors:
(a) Moisture content of ensiled forage
(b) Degree of compactness
(c) Pre-treatment of ensiled forage
(d) Preservative used
(e) Nature of crops
(f) Fermentation processes
The effluent production is directly and positively related
with the moisture content of forages. This correlation is true
with the forages having more than 70 percent moisture. In the
forage with less than 70 percent moisture level the effluent
production is negligible. The legumes are mostly harvested at
succulent stage, so care should be taken to avoid the loss due
to effluent production through mixing it either with dry fodder
or low moisture forages.
Procedure for preparation of good silage: To get a good
silage one should take care at every stage of ensiling. A few
precautions required to be taken are given below:
1. Harvesting of crop: The ensiling does not add nutrients to
the forage but it preserves the nutrients of the herbage.
The necessary precaution should be taken to select a suitable stage of forage for harvesting maximum nutrients.
The boot of half bloom stage is suitable in single cat forage while multicut crops can be harvested at 55-60 days
after sowing for first cut and after 25-30 days for subsequent cuttings.
2. Wilting of crop to 30-40 percent dry matter: The loss of
dry matter is more due to effluent production which is
associated with high moisture content of ensiled material,
so the wilting of crop to reduce moisture content to 60-65
per cent is desirable.
3. Chaffing of forages: Chaffed forages can be compressed
to a greater extent and it exposes more plant surface area
for faster microbial growth and lactic acid production.
212
ConservatIon of Green Fodder In Animal Nutrition
4.
5.
6.
7.
S.
Mixing of legume and non-legume crops: The legumes
are rich sources of protein with low level of carbohydrates
whereas non-legumes are poor in protein and rich sources
of carbohydrates. When both are mixed together, they can
be turned into good quality silage.
Mixing of additives: There are many types of additives
being used in ensilage. These may be stimulators or
inhibitors of microbial activities in silage. These are a
follows:
(a) Inorganic chemicals. Calcium carbonate, magnesium
carbonate, ammonium sulphate, sodium sulphate, zinc
sulphate, copper sulphate, ferrous sulphate, manganese sulphate, sodium chloride, sodium nitrites, calcium phosphate, calcium silicate and phosphoric acid.
(b) Organic chemicals. Acetic acid, citric acid, benzoic acid,
formic acid, lactic acid, propionic acid, formaldehyde,
ethyl alcohol, propylene glycol, lactate, sodium
gluconate, ethyl acetate, ethyl butyrate, ethyl diamine
dihydro iodide and urea etc.
(c) Feed stuffs. Used as silage additives are wheat bran,
crushed maize, starch, dextrose, molasses, whey and
yeast etc.
(d) Fermentation products and micro-organisms. A few
enzymes like malt diastase and extract of fungi and
several species of micro-organisms like lactobacilus
acidophil us, torulopsis sp., Bacillus subtilis etc. have
been used for enhanced silage production.
Filling of silo: The well compressed packing of silage will
help the creation of anaerobic condition earliest causing
the production of good silage.
Sealing of silo: The air-tight sealing is necessary to avoid
the entrance of air in the silo.
Removal of silage: After a period of 4-6 weeks the silage
is ready for feeding to the livestock. After the removal of
silage, the open end of the silo should be covered in such
a manner that the contact from the air is minimum.
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Handbook of General Animal Nutrition
Special Methods of Silage Making: Excellent silage can
be produced from legumes and other grasses when ground
grain or other concentrates are added to the green fodder. This
is a practice in U.s.A. It is not at all practised in our country.
A.LV. method: This method is named after the name of
its originator A.I. Virtanen. In the A. LV. method, a mixture of
sulphuric acid and hydrochloric acid is added to the forage to
bring the pH below 4.0. The resultant mixture is preserved for
a sufficiently long period. Cattle are able to consume the silage
without any detrimental effect. This method of silage making
is not at all practised in our country.
Artificial drying of grasses: In some agriculturally
advanced countries leguminous forage are dehydrated. The
forage is first chaffed and is passed through the drier, where it
is exposed to hot air. Dehydration preserve the nutritive value
of the fodders better than the field cured hay but it is very
costly and is not at all practised in our country on commercial
scale. Artificially dried berseem, Lucerne etc. can be used as a
protein supplement in pigs and poultry rations also.
Extraction of ャ・セ@
protein concentrates: The proteins are
present in the cell content of the forages. The whole processes
involve following steps and the quantity and quality of leaf
protein concentrate$ depends on the processing.
1. Selection of crops: Succulent and juicy forage with high
levels of protein is usually preferred for the extraction of
leaf protein. The legumes like berseem, lucerne and cowpea
etc. can be good source of leaf protein. Immature young
crops of wheat and oats are also harvested for the extraction of leaf protein concentrates.
2. Harvesting of crops: The protein and water contents of
plants diminish with the increasing age of plant. Protein
and water content are the main responsible factors affecting the yield of the leaf proteins. With the maturity the
carbohydrates content of the cell wall increases which adversely affect the extraction of plant proteins. The early
harvesting is, therefore, required for extract the maximum
cell content.
214
Conservation of Green Fodder in Animal NutntlOn
3.
4.
Extraction of crop: The juice from the forages may be extracted by different methods depending upon the several
factors like extracting efficiency of the method, capacity
of the extraction, type of the crop etc. commonly used
sugarcane juice extractors may be used for this purpose.
Processing of juice: The juice extracted from plants contains
many chemical constituents other than proteins. Separation
of protein from other undesirable plant constituents
involves many steps and the quality of plant protein is
affected by the processing steps. Various types of leaf
protein concentrates has been developed for human
consumption but their acceptability is poor because due to
slightly bitter taste, strong grassy flavour and green colour.
This can be easily used in the diet of pigs, poultry and
other animals replacing costlier and scarce sources of
conventional proteins. The cost of leaf protein preparation
for the feeding of animals can be reduced by eliminating a
few steps of processing like removal of colour and smell
etc.
Haylage: It is a low moisture silage (40-45% moisture)
made from grass or legume that is wilted to 40-45 percent
moisture content before ensiling.
Q.1. Fill in the blanks.
1. Green fodders are conserved by the process of - - - and - - - - .
2. Best crop for hay making is - - - - - - - .
3. The hay to be stored should contain - - - - - percent
moisture.
4. The suitable crops for hay making should be harvested at
- - - - - stage.
5. The vitamins - - - - - -and - - - - - - are most
affected by drying process during hay making.
6. The best hay should contain - - - - percent dry matter.
7. There is less loss of - - - - - - - in silage making than
that of hay making.
8. The best crop for silage making is - - - - - - - -.
215
Handbook of General Animal Nutrition
9. The container used for silage making is - - - - - - -.
10. For silage making the dry matter content of crop should
be - - - - - percent.
11. - - - - - - - - - , - - - - --and - - - - ---are
the anaerobic microbes which proliferate in the silage.
12. The pH value of good silage is - - - - - - - .
13. The soluble carbohydrates are degraded into - - - - and
14. - - - - - - - - - and - - - - - - type of fermentation will take place during microbial degradation of carbohydrates in silage making.
15. A good silage has - - - - odour and - - - - - - - colour.
16. On fermentation, glucose breaks down into - - - - - and - - - - - - - - - .
17. Growth of the microorganisms in ensiling materials is inand - - - - - - - - - fluenced by - - - - - - 18. Green fodder can be stored for a longer period by - - - - - - - - - - making.
19. Kachcha silo is prepared by - - - - - - - - - - - - - - - - in the ground.
Explain the following.
Advantage of hay making.
Losses occur during the process of hay making.
Define the term "hay". What are the suitable crops for hay
making?
4. Characteristics of good silage.
5. What are the advantages of silage making over hay making?
6. What is a silo? Explain the type of silo and characteristics
of silo.
7. Explain the various process of ensiling.
8. Explain the changes occur during ensiling.
9. What are the losses occur during ensiling?
10. Explain the procedure for preparation of good silage.
Q.2.
1.
2.
3.
216
Chapter
3
Evaluation of Energy Value of
Feed in Animal Nutrition
Definition of energy: Energy is defined as the capacity to
do work. As we know, heat is measured in some units known
as calories which may be defined as follows:
1. Calorie (Cal): The amount of energy as heat required to
raise the temperature of 1 gram of water to 1 °C (precisely
from 14.5°C to 15.5°C). One cal is equal to 4.184 Joule.
2. Kilocalorie (K cal): The amount of energy as heat required
to raise the temperature of 1 kg of water to 1°C (from
14.5°C to 15.5°C). Kilocalorie is equivalent to 1000 calories.
3. Megacaloria (M cal): Equivalent to 1000 kilocalories or
1000,000 calories, formerly referred to as a thermo
4. British thermal unit (BTU): The amount of energy as heat
required to raise the temperature of 1 pound of water to
1°F. It is equal to 252 calories.
5. Joule 0): The International Union of Nutritional Sciences
and the nomenclature committee of the International Union of Physiological Sciences have suggested the Joule (J)
as the unit of energy for use in nutritional, metabolism
and physiological studies.
The Joule is defined as 1 newton metre, and 1 J = 0.24 caL
kilo joule (KJ) and mega joule (MJ), are also explained similarly.
The simplest method for measuring the value of any feed
is to determine the amount of digestible nutrients that is
supplied to the animals. For expressing the energy value of feeds
and requirements of animals, following systems are used.
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Handbook of General Animal Nutrition
1.
2.
3.
4.
5.
6.
7.
Total digestible nutrients (TDN)
Starch equivalent (SE)
Gross energy (GE)
Digestible energy (DE)
Metabolizable energy (ME)
Net energy (NE)
Scandinavian feed unit.
1. Total digestible nutrients (TDN): TDN is simply a figure
which indicates the relative energy value of a feed to an animal.
It is ordinarily expressed in pounds or kilogram's or in percent
(pound or kg of TDN per 100 pound or kg of feed). It is arrived
at by adding together the following:
TDN percent = Percent digestible crude protein + Percent
digestible crude fibre + Percent digestible nitrogen- free extract
+ Percent digestible ether extract x 2.25
% TDN = % DCP + % DCF + % DNFE + % DEE x 2.25.
Fat on oxidation provides 2.25 time more energy as
compared to carbohydrates, hence the figure is multiple by
2.25.The protein in this equation has been included because of
the fact that excess of protein eaten by the animals serve as a
source of energy to the body.
Limitation of the TON System:
1. It over estimates the value of roughages because more
energy spent in chewing of such feeds remains unaccounted.
2. Only the loss in faeces is accounted.
3. If feeds are high in fat content will some time exceed 100
in percentage of TDN.
Factors affecting the TON value of a feed:
1. The percentage of the dry matter. The more water
present in feed, the less there is of other nutrients, and lowers
the TDN value.
218
EvaluatIOn of Energy Value of Feed in Ammal NutritIOn
The digestibility of the dry matter. Unless the dry
2.
matter of a feed is digestible, it can have no TDN value. Only
digestible dry matter can contribute TDN. Lignin has a high
energy value but it can not be digested by the animals so has
no digestible energy or TDN values.
The amount of mineral matter in the digestible
3.
dry matter. Mineral contribute no energy to the animal though
mineral compounds are digestible but have no TDN value. The
more mineral matter a feed contains, other things being equals,
the lower will be its TDN values.
The amount of fat in the digestible dry matter.
4.
Fat contributes 2.25 times as much as energy per unit of weight
as do carbohydrates and protein. The feeds high in digestible
fat some time TDN value exceed 100%. In fact, a pure fat which
had a coefficient of digestibility of 100 percent would
theoretically have a TDN value of 225% (100 x 2.25 = 225).
Thus we find that the digestibility data obtained from the
simple digestion trial is of a very limited application, but the
animals shall have to feed on the basis of some standard. The
Morrison feedi11-g standard is based on the total digestible
nutrients, obtained from carefully conducted digestion trials.
2. The starch equivalent: Kellner, measured the values of
feeds for productive purposes in terms of strach values, instead
of net energy values stated in therms. In this system 1 pound of
digestible starch is taken as the net energy unit. Suppose the
starch equivalent of wheat bran is 45 kg it means that 100 kg of
the wheat bran can produce as much animal fat as 45 kg of pure
starch when fed in addition to maintenance ration or in other
words 100 kg of wheat bran contain as much net or productive
energy as 45 kg of the starch. The starch equivalent can be
calculated as:
SE =
Weight of fat stored per unit of food
x 100
Weight of fat stored per unit weight of starch
Kellner added pure carbohydrate, protein and fat to a basal
maintenance ration to determine the relative amounts of these
219
Handbook of General Animal Nutrition
pure digestible nutrients required to produce a unit of body fat
using the nitrogen-carbon balance method.
One kg of digestible proteins produces 235 grams of fat
One kg of digestible starch and cellulose produces 248
grams of fat.
One kg of digestible cane sugar produces 188 grams of fat.
One kg of digestible fat produces 474 to 598 grams of fat.
Taking starch as the unit, the fat producing power of
protein, fat and carbohydrate was then calculated as follows:
One part digestible protein
=
One part of digestible fat
474 to 598 1 .91 to 2.41 (SE)
248 248
=
235 = 0.95 (SE)
248
One part of digestible starch = 248 = 1.00 (SE)
248
Kellner conceived that the ether extract from oil cake
(which is more or less pure oil) and the same extract from a
green plant could not have the equal fat producing capacity or
SE value and suggested the following multiplication factors to
be used in the calculation of SE.
Factor
One part of digestible fat from coarse fodders
like green or dry roughage (straws, hays, silage
and green grasses)
1.91
One part of digestible fat from brans and other
grains or grain products
2.12
One part of digestible fat from oilseed, oilcakes
and other animal products
2.41
220
Evaluation of Energy Value of Feed in Animal Nutrition
Body fat in calories
Calculated
Observed
values
value
186.90
191.40
186.80
182.80
170.50
173.90
179.80
179.50
98.90
20.10
103.60
62.80
111.10
74.70
122.80
77.10
81.10
118.30
100 grams feed
(On dry matter basis)
Cotton seed meal
Linseed cake
Palm-kernel
Groundnut meal
Wheat straw
Oat straw
Barley straw
Meadow hay
Clover hay
Kellner also compared the observed and calculated value.
The observed and the calculated values agreed remarkably well
in cakes and meals but differ with coarse feed stuffs like straws
and hays. He realized that there should be some difference
between the efficiency of utilization of a straw and oil cakes.
The descripancy was explained on the basis of the crude fibre
content of the feeds. Kellner conceived that more fibrous was
the food, the greater was the expenditure of energy in chewing,
mastication, digestion etc. In fact he demonstrate that if the
fodder was chopped and fed, for every gram of crude fibre
eaten, the expenditure of energy was 0.70 calorie, whereas,
when fed unchopped, energy spent was 1.36 calories for the
same fodder. This means that chopping itself reduces the
expenditure of energy by half. He finally suggested the use of
the following factors for the calculation of starch equivalent.
Type of fodder
Percentage of crude
fibre to be multiplied by
the factor
1. Dry roughages !Straw, hayetcl
0.58
2. Dry roughages finely chopped
0.29
3. Green fodder (Percentage of fibre on wet basis)
4.0
0.29
5.0
0.31
6.0
0.34
7.0
0.36
221
Handbook of General Animal Nutrition
8.0
9.0
10.0
11.0
12.0
13.0
14.0
15.0
16.0 or more
0.38
0.40
0.43
0.45
0.48
0.50
0.53
0.55
0.58
It was observed that when dry straw such as wheat or
paddy are chopped, the expenditure of energy in chewing and
mastication is almost similar to that of a green roughage
containing only 4 per cent of crude fibre.
Examples for the calculation of SE:
1.
Concentrates such as linseed cake:
Nutrients
Crude protein
Ether extract
Nitrogen-free extract
Crude fibre
% digestible nutrients Factor
24.0
9.0
29.0
5.0
0.95
2.40
1.00
1.00
Total
SE
22.80
21.60
29.00
5.00
78.50
In case of concentrates like oilseed cake, no deduction for
fibre is needed. The digestible nutrients are only multiplied by
a value number. Such value number mostly range between 95
and 100 in the case of oil cakes. The value number of linseed
cake is 97.0. Therefore, the SE value is 78.40 x 0.97 kg per 100
kg of materials.
2. Green fodder such as berseem:
Nutrients
Crude protein
Ether extract
Total carbohydrates
% digestible Nutrients
2.0
0.5
9.0
Content of crude fibre on wet basis = 6.0 %
Therefore, deduct 6 x 0.34 = 2.04
222
Factor
0.95
1.91
1.00
Total
SE
1.90
1.00
9.00
11.90
11.90
- 2.04
--9.86
Evaluation of Energl{ Value of Feed In Animal NutntlOn
Hence 100 kg of green berseem contain 9.86 kg of SE. It
indicates that SE of green fodder is much less than oil cake.
3. Dry roughage such as hay :
% digestible
Nutrients
Factor
SE
Crude protein
4.0
0.95
3.80
Ether extract
1.0
1.91
1.90
Crude fibre
28.0
1.00
28.00
Nitrogen-free extract
13.0
1.00
13.00
Nutrients
Total SE calculated
46.70
Deduct crude fibre 28.0 x 0.58 = 16.20
16.20
Corrected
SE
30.50
Total calculated SE
46.70
Deduct crude fibre 28.0 x 0.29 if the hay is chopped
8.10
Corrected SE
38.60
Therefore, 100 kg of the hay contains 30.5 kg SE and 38.6
kg SE (if the hay is chopped).
3. Gross energy: Gross energy is the total heat of
combustion of a material as determined with a bomb calorimeter
and expressed as megajoule/kg dry matter. Some typical gross
energy values are shown in table. The gross energy value of a
feed has no relationship to the feeds digestible, metabolizable
or net energy values, except that the latter can never exceeded
the GE. Certain products such as coal, mineral oil and lignin
have 'high gross energy values but, because of their
indigestibility have no energy value to the animal. Roughages
have high gross energy values comparable to those of
concentrates, but the two differ greatly in digestible,
metabolizable and net energy values.
223
Handbook of General Animal Nutrition
Gross energy values
MJlKgDM
15.60
1. Food constituents
Glucose
17.70
Strach
Cellulose
17.50
Casein
24.50
Butter fat
38.50
Fat (from oil seeds)
39.00
2. Fermentation products
Acetic acid
14.60
Propionic acid
20.80
Butyric acid
24.90
Methane
55.00
23.60
3. Animal tissue
Muscle
Fat
39.30
Maize
18.50
4. Feeds
19.60
Oat grain
18.50
Oat straw
21.40
Linseed oil meal
18.90
Grass hay
24.90
Milk (4% Fat)
Constituents
4. Digestible energy (DE): This is that portion of the gross
energy of a feed which does not appear in the faeces. It includes
metabolizable energy as well as the energy of the urine and
methane. Considerable quantity of heat of the digested food is
eliminated in the faeces. The apparent digestible energy of the
food is the gross energy of the feed less the energy contained
in faeces.
5. Metabolizable energy (ME): It is that portion of gross
energy not appearing in the faeces, urine and gases of
fermentation (Principally methane). It is digestible energy minus
the energy of the urine and methane. It is comparable to the
energy of TDN minus the energy of the fermentation gases.
Metabolizable energy = Gross energy - (energy lost in
faeces + energy lost in combustible gases + energy lost in urine).
224
Evaluation of Energy Value of Feed in Animal Nutrition
Normally about 8 percent of the gross energy intake is
lost through the methane production. Metabolizable energy can
also be calculated from the digestible energy by multiplying
with 0.82 which means that about 18 percent of the energy is
lost through urine and methane. In poultry, metabolizable
energy is measured more easily than digestible energy because
the faeces and urine are voided together.
Swift and coworkers gave the following equation for
calculation of methane production.
Methane production in sheep
=
E = 2.41 X + 9.80
Methane production in cattle
=
E = 4.012 X + 17.68
Where,
E = methane in gram
X = digestible carbohydrates in 100 grams
Methane contains 13.34 k cal of energy per gram.
1.
2.
Factors affecting the MetabolizableEnergy values of foods:
Species of animals: The metabolizable energy of feeding
stuffs varies according to the species to which it is being
fed. In the ruminants about 8-10 per cent losses of energy
are in the methane production while in the non-ruminants
there are no such losses. Therefore, the ME values are
higher in non-ruminants than ruminants. This gap is more
in the feeding stuffs rich in the crude fibre.
Composition of feed: Chemical composition of the feed
also affect the ME values of food. If the crude protein
present in the food is unbalanced then the majority of the
amino acids will be deaminated and greater proportion of
nitrogen will be excreted as urea. One gram of urea excreted will be equivalent to 23.00 KJ of energy. Therefore,
generally the ME values are frequently corrected to zero
nitrogen balance. For ruminant a factor of 31.17 KJ per
gram of nitrogen has been used; for poultry the factor is
34.39 KJ per gram. The crude fibre level also affect the ME
value of feed.
225
Handbook of General Animal Nutrition
3.
4.
Processing of food: Processing of food also affect the ME
values since it affects the losses of nutrients in faeces and
methane production.
Level of feeding: The level at which feed is being fed affect
the ME value of the feed. At high level of feed intake ME
values are reduced.
6. Net energy (NE): This is that portion of metabolizable energy
which may be used by the animals for work, growth,
fattening, foetal development, milk production, and/ or
heat production. It differs from metabolizable energy that
net energy does not include the heat of fermentation and
nutrient metabolism or the heat increment. The fate of the
gross energy of food is summarised as:
Gross energy
I
I
Digestible energy
Faecal energy
I
Losses in urine
Metabolizable energy
I
and methane
1
Net energy
Lossess in heat
increment
I
I.
Used for mamtenance
(Basal
rretabolism),
regulation of body
temperature
Used
for
production
(Tissue growth, milk.
work)
Heat increment of metabolizable energy and net energy
used in maintenance is summarized as total heat production of
the animal. The heat increment is also known as specific dynamic
effect of food. This heat is useful only for keeping an animal
warm during very cold weather. At other times the energy
226
Evaluation of Energy Value of Feed in Animal Nutrition
represented by this heat is not only a complete loss but also
may actually interfere with production by causing the animals
to be too warm.
7. Scandinavian feed unit system: In this system one
pound of barley grain is taken as the standard. The feed unit
value for any other feed is the amnunt of that feed which is
estimated to have the same productive value as 1.00 pound of
barley. For example, the feed unit values of soybean oil meal
for dairy cows are 0.85 pound and the value for corn grain is
0.95 pound. This means 0.85 lb. of soybean oil meal or 0.95 Ib
of corn is equal to 11bs of barley in feeding value. In this system
feeds that are rated below barley in value per pound are given
higher numerical values than 1.0. The feed unit value of wheat
bran is given 1.25 Ibs. This means that it will take 1.25 Ibs of
wheat bran to equal 1 Ibs of barley in value for dairy cows.
This system has the merit of comparing the values of feed on
the basis of actual result when applied in practice. Consequently
any specific value that the feed may possess in addition to its
protein and energy values receives proper recognition.
Methods for measuring the heat production and energy
retention: There are two ways by which heat production can
be measured for determining the net energy values of the
feeding stuffs.
1. Direct calorimetry: In which heat production is measured
directly; this combines the feature of both respiration chamber and calorimeter.
2. Indirect calorimetry: In this method net energy is determined by indirect means where only exchange of gases is
recorded that means only respiration chamber is needed.
Direct calorimetry: This apparatus was used by Atwater
in 1892 for the human beings. After that Armsby built an
apparatus for energy metabolism studies for the farm animals.
In this apparatus there is a provision for recording the intake
of feed, water and oxygen and the outgo of faeces, urine,
gaseous excretion and heat loss from the body. The heat is lost
from the body through conduction, radiation, convection and
227
Handbook of General Animal Nutrition
evaporation of water from skin and expired gases through lungs.
The animal calorimeter is basically an air tight and insulated
chamber. Evaporative losses of heat are measured by recording
the volume of air drawn through the chamber and its moisture
content on entry and exit are used for calculation of heat loss.
The heat loss through conduction, radiation and convection
of the animal is measured by the rise in temperature of the cold
water flowing in various pipes suspended in the chamber from
ceiling. The rate of flow of water and differences in the
temperature at the entry and exist are used for the calculation
of heat loss.
2000
c
;] 1500
i!...
e=
c.
..
::
';; 1000
8 ........... .......... . .............. _......... ............ D
500 A
o
. .............. ... ... ... ........ . .....
500
E
1000
1500
2000
ME intake (MJ/day)
Determination of heat increment:
The heat increment of the feed is determined by feeding
two levels of feed intake. The difference in the two levels would
give the heat production due to the increase in feed intake. In
this case assumption is made that heat production due to basal
metabolism would remain the same at both the levels. The
increase in heat production at higher intake is due to the
additional feed given to the animal. In given example a particular
228
Evaluation of Energy Value of Feed in Animal Nutrition
feed was fed to an animal in respiration calorimeter at two
levels of metabolizable energy namely 1000 and 2000 MJ. There
was an increase in heat production 500 MJ. The heat increment
with an increase of 1000 MJ of ME would be:
CD
x 100
BD
500
x 100 = 50 percent
1000
= --
A is the basal metabolism and Band C represent heat
production at metabolizable energy intakes of 1000 and 2000
MJ, respectively. For the sake of simplicity the relation between
heat production and metabolizable energy intake is shown here
as being linear, i.e. ABC is a straight line.
Animal calorimeters are expensive to build and the earlier
types required much labour to operate them. Because of this
most animal calorimetry today is carried out by the indirect
methods.
Indirect calorimetry: Measurement of heat production by
direct calorimetry is costly so, most of the measurements for
heat production, are done by indirect method. The heat loss in
indirect calorimetry is measured by carbon-nitrogen balance
or through gaseous exchange method.
1. Carbon-nitrogen balance method. Carbon and nitrogen
enter the body only in the food. Carbon leaves the body through
faeces, urine, methane and carbon dioxide and nitrogen leaves
the body through faeces and urine only. Therefore, the balance
trial must be carried outin a respiration chamber. The procedure
for calculating energy retention and heat loss from carbon
nitrogen balance data is illustrated by considering an animal in
which storage of both fat and protein is taking place. In such an
animal intakes of carbon and nitrogen will be greater than the
quantity excreted and the animal is said to be a positive balance
with respect of these elements. The quantity of protein stored
is calculated by multiplying the nitrogen balance by factor 6.25.
Protein also contains 51.2 percent (g CII00 g), and the amount
of carbon stored as protein can therefore, be computed. The
remaining carbon is stored as fat, which contains 74.6 percent.
229
Handbook of General Animal Nutrition
Fat storage is therefore, calculated by dividing the carbon
balance, less that stored as protein by 0.746. The energy present
in the protein and fat stored is then calculated by using average
calorific values for body tissue. These values for cattle and sheep
are 3.93 MJ/I00 g for fat and 2.36 MJ/I00 g of protein.
Calculation of the energy retention and heat production of a
sheep from carbon nitrogen balance is given below as.
Nutrient
Carbon (g)
684.5
279.3
33.6
20.3
278.0
73.3
Intake
Excretion in faeces
Excretion in urine
Excretion as methane
Excretion as carbon dioxide
Balance
Intake of metabolizable
energy
Protein and fat storage
(2.30 x 6.25)
Protein stored
Carbon stored as protein
(14.4 x 0.512)
Carbon stored as fat
(73.3 - 7.4)
Fat stored
(65.9 + 0.746)
Energy retention and heat production
(14.4 x 23.6)
Energy stored as protein
Energy stored as fat
(88.3 x 39.3)
Total energy retention
(0.34 + 3.47)
Heat production
(13.95 - 3.81)
Nitrogen
Energy
(g)
(MJ)
41.67
13.96
25.41
28.41
11.47
1.50
1.49
2.30
13.95
14.4g
7.4g
65.9g
88.3g
O.34M]
3.47MJ
3.81M]
10.14M]
Calculation of energy retention and heat production by
carbon-nitrogen balance in sheep:
2. Respiratory exchange of gases method: These methods
take into account the oxygen consumption, carbon dioxide
production and urinary nitrogen to calculate the non-protein
RQ.
The respiratory quotient (RQ) is the ratio between the
volume of carbon dioxide produced and the volume of oxygen
used by the animals.
230
EvaluatlOn of Energy Value of Feed in Animal Nutrition
RQ
=
Volume of carbon dioxide produced
Volume of oxygen used
When carbohydrates are being oxidised in the body for
energy purposes the R.Q. is 1 and has been shown by the
following equation:
C6 H120 6 + 6 CO2
6 CO 2 + 6 Hp + 2.82 MJ.
)
When fats (tripalmitin) are being oxidised in the body for
energy purposes the R.Q. is 0.7 and has been shown by following
equation:
C 3 Hs (C 1sH 31 COO):I + 72.5
51 CO 2 + 49 Hp + 32.04MJ.
PRセ@
The heat of combustion of protein varies according to the
amino acid proportion but averages 22.2 KJ / g proteins. The
quantity of protein catabolized can be estimated from the output
of nitrogen in the urine, 0.16 g of urinary nitrogen being excreted
for each gram of protein. For each gram of protein oxidised,
0.77 litre of carbon dioxide is produced and 0.96 litre of oxygen
used, giving an RQ of 0.8. In an experiment the following results
were obtained:
Oxygen consumed
392.0 litres
Carbon dioxide produced
Nitrogen excreted in urine
310.7 litres
14.8 g
Heat from protein metabolism
Protein oxidised
(14.8 x 6.25)
=
92.5g
Heat produced
(92.5 x 18.0)
=
1665 KJ
Oxygen used
(92.5 x 0.96)
=
88.8 litre
Carbon dioxide
(92.5 x 0.77)
=
71.2 litre
Heat from fat and carbohydrate metabolism
Oxygen used
Carbon dioxide produced
Non-protein RQ
(392.0 - 88.8)
=
303.2 litre
(310.7 - 71.2)
=
239.5 litre
0.79
231
Handbook of General Animal Nutrition
Thermal equivalent of oxygen when RQ is 0.79 = 20.00 KJ/litre
Heat produced
(303.2 x 20.0) = 6064 KJ
Total heat produced
(1665 + 6064) = 7729 KJ
For measuring the respiratory exchange in the farm animals
two types of respiration chambers have been used.
1. Open circuit respiration chamber,
2. Close circuit respiration chamber.
In both the cases the chamber is air-tight where there is an
arrangement for feeding, watering, and milk(ng of the animals.
There is arrangement for collection of faeces and urine also.
Brouwer equation: This equation is used for calculation
of heat production (H.P.) in Kilojoule.
H.P = 16.18 V02 + 5.16 VC02 - 5.90 N - 2.42 CH4
Where
V02 = Oxygen consumed (litres)
VC02 = Carbon dioxide produced (Htres)
N = Urinary nitrogen excreted (gram)
CH4 = Methane production (litres)
For Poultry, the N-coefficient is 1.20 (instead of 5.90) as
poultry excrete nitrogen in the more oxidized form of uric acid
rather than as urea.
Physiological Fuel Values of Atwater: In human nutrition,
Atwater calculated the calorific values of the nutrients which
were available for transformation in the body. The following
digestibility figures were taken for the nutrients.
Carbohydra tes
98%
Fats
95%
Proteins
92%
The calorific values of the nutrient were then multiplied
by these coefficients to get the physiological fuel values. In the
case of protein 5.23 MJ is substrated per g of protein in order to
232
Evaluation of Energy Value of Feed in Animal Nutrition
account for the energy lost in the urine as urea. The physiological
fuel values were calculated as follows:
1.0 gram of carbohydrates = 17.46 x 0.98
1 gram of fat
=
39.33 x 0.95
=
=
16.27 MJ
37.36 MJ
1 gram of protein = 23.64 - 5.25 x 0.92
=
16.00 MJ
The factor 5.22 MJ is too low to estimate the urine loss in
case of herbivore because of excretion of large amount of
hippuric acid instead of urea. Physiological fuel values are not
applicable in case of ruminants because the digestibility of
nutrient is low in ruminant than non-ruminants. Physiological
fuel values are similar to metabolizable energy.
Q.1. Fill in the blanks.
1. The percentTDN = - - - - - --+ - - - - - - + - ---+ - - - - - - 2. Only the losses in - - - is accounted in TDN system.
3. The percent ether extract content is multiplied by a factor
- - - - in TDN system.
4. The term starch equivalent is given by - - - - - - - .
5. In starch equivalent system - - - - - is taken as the net
energy unit.
6. One Kg of digestible protein produces - - - - - g of fat.
7.
8.
One Kg of digestible starch produces - - - - - - g of
fat when fed above the maintenance requirement.
The starch equivalent for one part digestible protein is -
9.
The starch equivalent for one part digestible fat is - - -
10. The percentage of crude fibre to multiplied by the factor
- - - - - to calculate corrected SE for dry roughages.
11. One Joule is equal to - - - - - - - calorie.
12. The joule is defined as - - - - - - - - - - - - .
13. Digestible energy is that portion of the gr')ss energy of a
feed which does not appear in the - - - - - - - - - .
233
Handbook of General Animal Nutrition
14. Digestible energy includes - - - - - - - - and - - 15. In Scandinavian Feed unit - - - - is taken as standard.
16. - - - - - - - - - built an apparatus for energy metabolism studies for farm animals.
17. The respiratory quotient (RQ) is the ratio - - - - - - 18.
19.
20.
21.
22.
23.
24.
25.
When carbohydrates are being oxidized in the body for
energy purposes the RQ value is - - - - - -, whereas
for fat and protein it is -------and - - - - - - ,
respectively.
Physiological fuel value is a product of calorific value to
its-----.
Digestible nutrient namely - - - - - - is not added to
calculate the TDN value.
- - - - - - - is used by animal to meet its maintenance
requirement and to form new body tissues or products.
For an animal species, losses of energy in urine and methane are relatively constant and are about - - - - - percent of D.E.
Gross energy (MJ jKg DM) of carbohydrate, protein, fat
and average foods are ............... , - - - - - - -, - - - - - - - and - - - - - - respectively.
The original source of energy is ................. .
In brouwer equation, H.P.=- - - - - - - - - - - - -
26. Direct calorimetry involves the feature of both - - - - - - - and - - - - - - - -.
27. Indirect calorimetry needed only - - - - - because only
- - - - - - - is recorded.
28. Portion of ME used for work, growth セョ、@
milk production is called - - - - - --.
29. ME is measured easily than DE in poultry because - - - - - - - - and - - - - - - - are voided together.
234
Evaluation of Energy Value of Feed in Animal Nutrztion
Q.2.
1.
2.
3.
4.
5.
6.
7.
8.
9.
Explain the following.
How will you calculate TDN value and SE value of a feed?
Define the term energy, calorie and joule.
Explain the partitioning of food energy into its components.
Explain the direct calorimetery.
Explain the carbon- nitrogen balance method and Respiratory Quotient method for energy production.
Explain the gross energy, digestible energy, metabolizable
energy, not energy, heat of increment and physiological
fuel value.
Why digestible protein is also added to calculate TDN value
inspite the protein is not a source of energy in normal condition?
Explain the factors affecting the TDN value and
metabolisable energy value of a feed.
Explain associative effect of feed.
235
"This page is Intentionally Left Blank"
Chapter
4
Evaluation of Protein Value of
Feed in Animal Nutrition
It has long been known that all animals must receive in
their food at least a certain minimum amount of protein. For
simple stomach animals, the quality or kind of protein is fully
as important as the amount. Fortunately, ruminant has much
more simple requirement for protein than non-ruminants. This
is because the rumen micro-organisms are able to use very
simple nitrogen compounds as a protein source. This microbial
protein is used by the ruminants. Different approaches to the
evaluation of protein sources are therefore necessary for
ruminant and non-ruminant animals.
Crude Protein (CP): Crude protein in the feed stuffs is
estimated by determining the nitrogen content of feed and
multiplying it by a factor 6.25. Two assumptions are made in
calculating the protein content from the nitrogen: firstly, that
all the nitrogen of the food is present as protein and secondly
that all food protein contains 16g N/100g. The nitrogen content
of the food is then expressed in term of crude protein (CP)
calculated as follows.
CP (g/100g) = g nitrogen /100g x 100/16 Or more commonly
CP (g/100g) = g nitrogen /100g x 6.25
Both above assumptions are unsound. Different food
proteins have different nitrogen contents, and therefore
different factors should be used in the conversion of nitrogen
for individual food. The nitrogen content of a number of common
proteins together with appropriate nitrogen conversion factor
is shown as:
237
Handbook of General A11lmal Nutrition
Food protein
Cotton seed
Soyabean
Barely
Oat
Wheat
Maize
Egg
Meat
Milk
Nitrogen (gIlOOg)
Conversion factor
18.87
17.51
17.15
17.15
17.15
16.00
16.00
16.00
15.68
5.30
5.71
5.83
5.83
5.83
6.25
6.25
6.25
6.38
True Protein (TP): The term true protein is used to denote
the protein only. It can be separated from non-protein nitrogen
by precipitation with cupric hydroxide or by heat coagulation.
The protein is then filtered and residue subjected to nitrogen
estimation by Kjeldahl method. The protein is determined by
multiplied the factor 6.25.
Digestible Crude Protein (DCP): When the crude protein
content of the feed stuffs is multiplied by its digestibility
coefficient, it gives the digestible crude protein. It is the most
common way of expressing the protein values and requirement
of the ruminants on most of the countries. In India, DCP is
taken as the measure for expressing the protein values of feeds
for ruminants. Digestible crude protein figures are not entirely
satisfactory assessments of protein, because the efficiency with
which the absorbed protein is used differs considerably from
one source to another.
Protein Equivalent (PE): In some of the European countries
protein equivalent is used instead of DCP. In protein equivalent
non-protein nitrogen fraction is given half the nutritive of the
true protein and is calculated as follows:
PE= %DCP+ % DTP
2
So PE is the arithmetic mean of the percentage of DCP and
DTP.
Protein Quality (PQ): In ruminants protein quality is not
given much of the importance since all the essential amino acids
238
Evaluation of Protem Value of Feed in Animal Nutrition
are synthesized in the rumen by the synthesis of microbial
proteins. However, digestible crude protein value for nonruminant animal is not adequate to express the protein value. It
is important to know how much of the absorbed protein is used
by the animal body. This utilization will be different with the
various protein sources as it is dependent upon the amino acid
composition of the protein.
Evaluation of protein value of feed in non-ruminants:
Protein Efficiency Ratio (PER): The protein efficiency ratio
normally uses growth of the rat as a measure of the nutritive
value of dietary protein. It is defined as the weight gain per
unit weight of protein eaten, and may be calculated by the
following formula.
.
..
.
Gain in body weight (g)
Protem effiCiency ratlO = MセGB
Protein consumed (g)
The PER values will vary with different protein sources as
the composition of protein varies with regard to essential amino
acids. For the optimum rate of growth, various level of protein
would be required depending upon the quality. On this basis
comparison between different sources of protein can be made.
It is simplest method for evaluating protein quality.
Net Protein Retention (NPR) : A modification of PER
method, where the weight gain of the experimental group is
compared with a group on a protein free diet, give the net protein
retention which is calculated as follows:
Weight gain of test protein group fed - Weight loss of
_ _ _ _ _ __
NPR = _ _ _ _ _ョ⦅ッMBーイエ・ゥ]ァオGセ、@
Weight of protein consumed
The NPR method is claim to give more accurate results
than the PER method.
Gross Protein Value (GPV): The body weight gain of chicks
receiving a basal diet containing 8.0 g CP /100g are compared
with those of chicks receiving the basal diet plus 3g/100 g of
239
Handbook of General Animal Nutrition
test protein, and of others receiving the basal diet plus 3 g 1100
g of casein. The extra live weight gain per unit of supplementary
test protein, stated as a proportion of the extra live weight gain
per unit of supplementary casein, is the gross protein value of
the test protein.
Groups
Chicks
Basal diet
Supplementary diet
8
8.0g CPII OOgram
8
8.0g CP/I 00 gram
3.0g CPII 00 gram of
3.0g CP/I 00 gram
casein
test protem
!
Measured body weight
gam
where W B is gram increased weight gainl gram of test
protein and W A is gram increase weight gainl g casein.
Protein Replacement Value (PRV): It is based on the
nitrogen balance. This value measures the level at which the
protein under test gives the same balance as an equal amount
of standard protein. To evaluate the protein replacement value,
two nitrogen balance studies are conducted; one for the
standard protein likes egg or milk and another for the protein
under test. The following equation is used for calculation of
PRY.
A-B
PRV=--N intake
Where A = Nitrogen balance for standard protein in mg
per basaLK cal,
B = N balance for protein under test in mg per basal K cal.
The PRY measures the efficiency of utilizatirn of the protein
given to the animal. Other methods measure the utilization of
digested and absorbed protein.
240
Evaluation of Protein Value of Feed in Animal Nutrition
Biological Value (BV) of Proteins: It is defined as the
proportion of nitrogen absorbed which is retained by the
animals for maintenance and/ or growth or proportion of
digested protein that is not excreted in urine. A balance trial is
conducted in which nitrogen intake and urinary and faecal
excretions of nitrogen are measured, and the results are used
to calculate the biological value as follows.
BV = N intake - (Faecal N + Urinary N) X 100
N intake - faecal N
Part of the nitrogen in faeces, ,the metabolic faecal nitrogen,
is not derived directly from the)' feed. Urinary nitrogen also
contains a proportion of nitrogen, known as the endogenous
urinary nitrogen, which is not directly derived from feed. The
existence of nitrogen fractions in both faeces and urine whose
excretion is independent of feed nitrogen is most conveniently
demonstrated by the fact that some nitrogen is excreted when
the animal is given a nitrogen free diet. It is obvious that their
exclusion from the faecal and urinary fractions in the formula
given above will give more precise estimate of biological value
by Thomas- Mitchell formula.
BV = N intake - (Faecal N-MFN) - (urinary N-EUN)
N intake - (Faecal N-MFN)
where, MFN = Metabolic faecal nitrogen
EUN = endogenous urinary nitrogen.
The biological values of some of the proteins source have
been given below:
Food
BV
Milk
Whole egg
Fish meal
Wheat
Maize
Soya bean meal
Cotton seed meal
Linseed meal
Barley
Peas
95
94
74-89
67
49-61
63-76
63
61
57-71
62-65
241
Handbook of General Animal Nutrition
The biological values are dependent on the amino acid
composition. If all the essential amino acid present in right
amount and proportion than BV will be higher since the protein
will be utilized for body tissues rather than being diverted for
energy supply. In the latter case the amino acid will be
deaminated and there will be more excretion of urea. Animal
proteins have higher BV since the essential amino acids present
in them are very near to the proportion in which they are needed
by the body. Deficiency or excess of anyone of the amino acids
lowers the biological value.
Biological value of individual protein has a limited scope
in practical feeding since no single protein is fed. Mixture of
protein will have different biological value as it would not be a
simple mean because one protein deficient in one amino acid
may be supplemented by the addition of other. The biological
values are also dependent on the level at which protein is being
fed. It is maximum at maintenance level. For determining the
B.V. the protein under test must be fed adequately as per
requirement. Excess protein will reduce the BV. Adequate
amount of energy must also be present in the diet otherwise
protein would be used for energy purpose which would reduce
the biological value of test protein.
Nitrogen balance: It evaluate protein quality in ruminants
and non ruminants.
Nitrogen balance index: It is same as biological value.
NBI = Nitrogen balance (B) - Nitrogen balance when N-intake is zero (Bo)
Nitrogen absorbed
Net Protein Utilization (NPU): The usefulness of a protein
to an animal will depend upon its digestibility as well as its
biological value. The product of these two values is the
proportion of the nitrogen intake which is retained, and is
termed as the net protein utilization. It is based on comparison
of body nitrogen content resulting from a test protein with that
resulting over the same period on a nitrogen free diet.
242
Evaluation of Protem Value of Feed in Animal Nutritio1l
NPU
Body N. Content with test protein - Body N content with N free diet
N intake
Or
NPU = Retained Nitrogen X 100
Nitrogen intake
Net Protein Values (NPV): The product of the NPU and
the percent crude protein is the net protein value (NPV) of the
food, and is a measure of the protein actually available for
metabolism by the animals.
Chemical score: Chemical score was given by Block &
Mitchell (1946). There are methods in which protein quality is
estimated without conducting the animal experimentation. The
protein quality is dependent upon the amount and proportion
of essential amino acids present in the protein. The value would
be lower if one or more essential amino acids are deficient. The
biological value of egg protein is higher since essential amino
acids are present in right amount and proportion. In the chemical
score method the content of each essential amino acids of a
protein is determined and expressed as the percentage of
standard and the lowest percentage is taken as the score. For
example, in wheat protein lysine is the first limiting amino acid.
The content of it is 7.2 and 2.7 percent in egg and wheat protein,
respectively.
Amino Acids
Egg (%)
Wheat Protein (%)
Lysine
7.2
2.7
Isoleucine
8.0
3.6
Methionine
4.1
2.5
The chemical score for wheat protein is
2.7 x 100 = 37.0
7.2
These values compare with the biological values for protein
in rat, pig and human being but not in poultry. It is because
243
Handbook of General Animal Nutrition
there are other amino acids which are deficient in the protein
and are taken into account.
The Essential Amino Acids Index (EAAI): It was given
by B.L. Oser (1951). In this case all the ten essential amino acids
are considered. It is defined as the geometric mean of the egg
ratio's of these acids to the food amino acids and may be
calculated as follows:
EAAI
セ@
n
J Mセ
X
セZM
X --;: X
Mセ@
X -----
-i:---
Where a, b ..... J = concentrations g/100 gram of the essential
amino acids in the food protein.
ae, be ... ' ... , Je = concentration of same amino acid in egg
protein,
and n= the number of amino acids.
It has the advantage that all the essential amino acids are
considered but proteins having different amino acids
composition may have the same index.
Both the chemical score and the essential amino acid index
are based upon gross amino acid composition. A more logical
approach would be to use figure for the amino acids available
to the animal.
Measures of Protein Quality in Practical Feeding of Pig
and Poultry: The difficulties in assessing the value of proteins
in the diet will now be apparent from the variety of methods
that have been proposed, all of which have considerable
limitations. A crude protein figure is useful, because the
degradability of the proteins in foods commonly given to pig
and poultry is fairly constant. More recently DCP has been used.
In practice pigs and poultry diets are based largely on
cereals and assessment of the protein value of foods for such
244
Evaluation of Protein Value of Feed in Animal Nutrition
animals is then a question of measuring their ability to
supplement the amino acid deficiencies of the cereals. To gross
protein value is probably the most commonly used biological
method for evaluating proteins.
Protein Quality for Ruminants: The significance of protein
quality in ruminants is very limited since all the essential amino
acids are synthesized by the micro-organism. The poor quality
protein are improved in BV whereas, high quality proteins are
degraded. The BV of microbial protein is about 70 but the overall
BV of the food protein is very much less because of the
production of ammonia in the rumen. Therefore, BV in the
ruminants has little application.
For higher production, protein quality in ruminant is also
getting importance. It has now being established that the
microbial protein synthesized in the rumen are deficient in
sulphur containing amino acid for higher production and
specially for wool production in sheep in which cystine is present
to the extent of 11 percent in the protein. Good quality protein
should be protected from rumen degradation so that better
amino acid mixture is available in the blood pool of the animals.
The protection of protein is being done by physical means (heat
treatment) or by chemical means of treating the protein with
formaldehyde and tannic acid. Several alternative systems for
evaluating the protein values in ruminants have been proposed.
1. Metabolisable protein: Metabolisable protein is that part
of the dietary protein which is absorbed by the host animal
and is available for use at tissue level. It consists partly of dietary
true protein which has escaped degradation in the rumen but
has been broken down to amino acid which are subsequently
absorbed from the small intestine. Microbial protein synthesized
in the rumen, similarly contributes to metabolisable protein.
This system is used in the United State of America. Calculation
of metabolisable protein schematically is given as:
245
Handbook of General Animal Nutrition
Dietary (CP 1000 g)
True protein
NPN
Degraded to NH3
セGMiZ]@
- - - - - - - - - - - - 850
t--""'-----
degradation
/ \
Converted to
MIcrobial N
1
Excreted
Protein
In
urine
340
metabolism
Microbial NPN
M icrobial70f
true protein
I Excreted in faeces I 40
MセNZ[@
560
Escapes ruminal
Plasma urea pool
110
450g
750g
300g
Metabolisable protein
Dietary ongin
Microbial origin
Calculation of metabolisable protein of diet.
2. Rumen degradable and undegradable protein: In this
system of protein allowances, proposed by the Agricultural
Research Council (ARC) for the United Kingdom and based on
rumen degradable protein, i.e. that available to the
microorganism, and undegradable protein which escapes
degradation in the rumen but which undergoes digestion and
absorption in the lower gut, and utilisation at tissue level.
The proportion of protein escaping breakdown in the
rumen may be estimated in vivo by measuring dietary nitrogen
intake, and non ammonia nitrogen and microbial nitrogen
passing the duodenum. Degradability of nitrogen is then
expressed as:
246
Evaluation of Protein Value of Feed In Animal NutritIOn
'l'
1 Non-ammonia duodenal N-Microbial N
Degra d a b llty =
Dietary N intake
The duodenal nitrogen fraction contains microbial Nand
endogenous N. Microbial - N in duodenal -N is usually
identified by means of marker substances such as diamino
pimelic acid (DAPA), Amino ethyl phosphoric acid (AEPA),
RNA, 355, 32p and 15N levelled amino acid.
The formula for calculating de grad ability given above
ignores the fact that duodenal nitrogen contains a significant
fraction which is of endogenous origin. It would be more
accurate if degradability was calculated as follows.
'lo
1 Non-ammonia duodenal N-(Microbial N-Endogenous N)
D egra d a b1 Ity = - - - - - - - - : - - - - ' : - : - - : - - - - - - - - " ' - - - - ' Dietary N intake
The endogenous N fractions constitute about 50 to 200 g/
kg of duodenal nitrogen but are difficult to quantifyo
A method of estimating protein degradation in the rumen
by incubation of the food in synthetic fibre bag suspended in
the rumen has been proposed. The degradability figure is
calculated as the difference between the nitrogen initially present
in the bag and that present after incubation, stated as a
proportion of the initial nitrogen.
OlO
nitrogen - Nitrogen after incubation
D egra d a b1 Ity = _--"'--_ _-"0-_ _ _ _ __
Initial nitrogen
The technique is subject to several source of error like
sample size, bag size and porosity of the bag materials which
must be controlled if reproducible results are to be obtained.
Q.1. Fill in the blanks:
1. The nitrogen content of a feed is multiplied by a factor - - - - - - to calculate the protein content of that feed.
2. The conversion factor for milk nitrogen to convert it into
protein content is - - - - - - .
3. Cotton seed protein contains - - - - - - percent nitrogen. So conversion factor for it - - - - - - - .
247
Handbook of General Animal Nutrition
4.
5.
6.
7.
B.
9.
10.
11.
12.
13.
14.
15.
16.
17.
lB.
Protein equivalent is the - - - - - - - mean of the percentage of DCP and DTP.
Protein efficiency ratio is the weight gain per unit of - Net protein retention is a modification of - - - - - - method.
Gross protein value calculation requires a basal diet containing - - - - - - - percent protein.
Biological value is the proportion of - - - - - - which
is retained by the animals.
The biological value of milk protein is - - - - - - - - .
The product of biological value of a protein to its
digestibility Coefficient is called.
- - - - - - - and - - - - - - are the methods in
which protein quality is estimated without conducting the
animal experimentation.
In essential amino acid index method, - - - - - - amino acids are considered.
The essential amino acid index is defined as ·the - - - - - amino acids.
The proportion of dietary protein which escapes degradation in the rumen is called - - - - - - - - .
Two assumptions for estimating protein content are, all
nitrogen of food present in - - - - - - - and food protein contains - - - - - - - - N/kg.
Animal protein has higher - - - value than plant protein.
Biological value is dependent primarily upon - - - - -.
Ideal protein is used for evaluating proteins for - - - -
19.
For poultry, evaluation of protein source is based on - - - -, - - - - and - - - amino acids.
20. - - - - - - , - - - - - and - - - - - are used as
growth response for protein in experimental animals
especially monogastric animals.
248
EvaluatIOn of Protein Value of Feed in Animal Nutrition
21.
- - - - - - and - - - - - - - are based on the proportion of main limiting amino acid of the protein.
22. The geometric mean of egg ratio's of these acids to the
food amino acids is
called as - - - - - - -.
23. Egg and wheat protein contains - - and - - - percent
lysine content,
respectively.
24. The product of NPU and percent CP is - - - - - - - 25. Gross protein value is defined as - - - - - - - - - - 26. The full form of DAPA and AEPA is - - - - - - - - ----and - - - - - - - - - - - .
27. The duodenal nitrogen contains - - - - - - - - - and
28. Mixture of protein has - - - - - - - - - - - - biological value.
Q.2. Explain the following.
Crude protein, True Protein, Non- Protein Nitrogen,
Digestible crude protein, Protein equivalent, protein Efficiency
ratio, Net protein retention, Gross protein value, Protein
replacement value, Biological value, Net protein utilization, Net
protein value, chemical score, Essential amino acid index,
Metabolisable protein, Rumen degradable and undegradable
protein.
249
"This page is Intentionally Left Blank"
Chapter
5
Processing Methods of
Animal Feed Stuffs
Animal Feed technology: It deals with processing of feeds,
fodders and preparation of formula feeds for which the
knowledge of nutritional requirements of various livestock and
poultry, quality control of feed ingredients, feed plant
management and storage of feed ingredients and feeds are
essential. It may also be defined as the application of physical,
chemical, biocheminl, biological, physiochemical and
engineering methods to increase the nutrient utilization of feeds
and fodders in animal system for the development of livestock
and poultry and feed industry.
Objective of feed processing:
To make the feed more palatable.
2. To detoxify or remove undesirable ingredients
3. To make the storage easy and safe.
1.
4.
5.
6.
To increase nutrient content and nutrient availability.
To change the particle size or density of feed.
To make the animal production more economical.
Roughage processing methods: All these methods are
broadly divided into two groups i.e. Dry processing method
and wet processing method based on the addition or deduction
of water content of roughages. These methods are further
classified based on thermal treatment.
1. Cold processing method: It includes cracking/ dry rolling, grinding, crimping, crumbling, extrusion, water soaking, reconstitution and decortication.
251
Handbook of General Animal Nutrition
2.
Hot processing method: It includes steam rolling, steam
flaking, pressure cooking, exploding, gelatinization, popping, pelleting, roasting and micronizing.
A.
Dry processing methods: ·In these methods water
content is reduced to a desired level. It includes baling, field
chopped, grinding, pelleting, cubing and dehydration.
1. Baling: The forage is cut and dried in the field condition.
Dried forage is then baled or bundled. By this method we
make storage and handling of forage easy and convenient.
2. Chopping: It is also known as chaffing. The forages are
chopped into small pieces as fine or coarse particles. Chopping avoids the selective feeding thus wastage of plant
material is reduced. The machine used for the intended
purpose is called chaff cutter. Chopping facilitates easy
handling due to increased bulk density and also improves
digestion due to exposure of relatively large surface area
of roughages for microbial digestion.
3. Grinding: It is a process of particle size reduction. Grinding of roughages improves the feed consumption and
growth rate but reduces the digestibility of crude fibre
due to faster rate of feed particles in gastro intestinal tract
due to smaller particle size. But due to large cost, grinding of roughages is not economical.
4. Pelleting: The ground roughages are pelleted and fed to
animals. It improves the consumption of poor quality
roughages. A complete feed is made by pelleting poor
quality roughage with 30 per cent concentrates. The size
of pellets is 12 I 64" to 48/64" and has a density of 40 lbl
eft whereas long hay roughages have density equal to 5
lb/eft.
5. Dehydration: It is a process of reduction of moisture content in a dehydrator using a temp. 600-1500oP for a short
time period of 3-5 minutes. The dehydrated forage retains
a lot of dry matter and protein and there is no loss of
leaves, but carotene content is reduced due to dehydration.
252
Processing Methods of Animal Feed Stuffs
6.
Cub bing: It is a process of cub making. It increases the
density of roughages upto 30 lb/ cft. The good quality hay
is sprayed with water to increase the moisture content upto
14 per cent and broken down rather than to ground the
roughage so that there is minimum of fine particles in the
cube.
Wet processing method: It includes soaking and
B.
green chopping. Soaking is a process of mixing or spraying water
on roughages so that stems become soft and mixing of
concentrates with roughage is uniform which improves the feed
intake and digestibility of roughages. When green roughages
are chaffed, there is no need of soaking and fed as such or
mixed with dry roughage or concentrate mixture.
Processing of grains: Processing methods for grain are
broadly divided into two groups as:
A.
Wet processing methods. It includes soaking, steam
rolling, flaking, pressure cooking, exploding, pelleting and
reconstitution, extrusion, gelatinization.
B.
Dry processing methods: It includes grinding, dry
rolling, popping, micronizing, extruding and roasting,
decorticating / dehulling, crimping and crumbling.
1. Soaking: Grains are soaked in water for 6 to 24 hours.
The soaking softens the grains, which swells during the
process and thus a palatable product is made. Soaked grains
are easily mixed with roughages and wastage is reduced.
Some time when soaked cakes of mustard and neem seed
are filtered, help to remove the toxic factors present in
cakes.
2. Reconstitution: It is similar to soaking water is added to
mature dry grain to raise the moisture content to 25 to 30
percent and stored the wet grain in an oxygen limiting
silo for 14 to 21 days prior to feeding. It also increases the
solubility of the grain protein.
3. Steam rolling: The grain is subjected to live steam for different periods of time depending upon the pressure used
253
Handbook of General Animal Nutrition
4.
5.
6.
7.
prior to rolling. At atmospheric pressure, 100°C temperature and 16-20 per cent moisture containing grain is steamed
for 8 to 20 minutes whereas at a pressure of 20 to 60 psi
preconditioning, grain having a temperature of 121 to 150°C
and 18-25 percent moisture is steamed for a period of 1 to
2 minutes only. This only softens the grains without any
significant change in starch granules. The only advantage
of steam rolling over dry rolling is the production of large
particles with little fines.
Steam flaking: Steam treatment is given for 15 to 30 min.
due to which moisture content in the grains rises to 18-20
per cent. After rolling of such grains, flakes are produced.
This process ruptures the starch granules and improves
physical texture, nutrient utilization and performance of
the animals in most of the cases.
Pressure cooking and flaking: In this process the grains
are first cooked under steam pressure, cooled to room temperature and then rolled. The product is more or less similar to steam flaked grains but the processing is much expensive. Grains are cooked with live steam at 50 psi for
1.5 min in air tight pressure chambers, which achieved a
temperature of 300oP. When flakes are made, this temperature is reduced to 2000P and moisture content up to 20
percent by passing them through cooling and drying tower.
Extrusion: A process of cooking in which feeds are also
expanded by the application of adequate pressure is known
as extrusion. The main purpose of extrusion is the gelatinization of starch in grains or complete feeds. It is also
used for the incorporation of urea in starchy feeds and for
the control of pathogenic microorganisms in the feeds of
animal source.
Exploding: The process of swelling of steam treated grains
under high pressure and sudden expose to atmospheric
pressure or the grains are treated withhigh pressure steam
(250 psi) for 20 seconds followed by sudden decrease to
atmospheric pressure is known as exploding. It is done in
steel vessel fitted with valve for injecting steam to raise
254
Processing Methods of Animal Feed Stuffs
8.
9.
pressure inside the grain containing vessel to 250 psi for
about 20 sec. After that outlet is opened through which
treated grains escape in the shape of expanded grains with
the husk removed. This happens due to entry of large
amount of moisture in the kernels due to high pressure.
Pelleting: The process of densification of a ground grain
or composite feed with or without the application of stearn
or moisture is known as pelleting. The ground feed material
is forced to pass through the holes of specific size by a
mechanical process. The machine used for the purpose is
called pelleting machine. The purpose of pelleting is to
change dusty and unpalatable feed material into more
palatable, easy to handle large particles by application of
optimum amount of heat, moisture and pressure. The
normal size of pellets is 3.9 mm to 19 mm with cylindrical
shape.
Gelatinization: The complete disintegration of starch
granules of a grain brought about by the combined
application of moisture, heat and pressure is known as
gelatinization. It improves the digestion of feed by
increasing water absorption ability and rate of action of
amylase on soluble carbohydrates (starches).
Dry processing methods:
1. Cracking or dry rolling: It is the disintegration of kernels
2.
3.
4.
into particles with the application of pressure by moving
rollers. It is done by a combination of breaking and crushing of the grains. The physical properties of dry rolled or
cracked grain would be very similar to that of grains
coarsely ground in a hammer mill.
Crimping: The process of rolling of feed ingredients with
the use of corrugated rollers is called crimping. The process
may include conditioning and cooling of the processed feed.
Crumbles: The feed of granular particle size produced from
the grinding of pelleted feeds is called crumbles.
Popping/puffing: It is produced by the action of dry heat
(370-425°C) for 15-30 seconds causing a sudden expansion
255
Handbook of General Animal Nutrition
5.
6.
7.
of the grain which rupture the endosperm and this results.
in rupture of starch granules and makes the starch more
available to the animals. About 3 percent moisture of grain
is lost during heat treatment. Popping reduces the density
of grains and increases palatability and digestibility of
starch. Popped grains are also a good carrier for molasses.
Micronizing: The popping of grains with the application
of infra red heat energy having wavelength of 3x108 to
3x1011 cycles/second is called micronizing.
Roasting: The treatment of grains with direct flame is
called roasting. It causes expansion in volume due to heating and generally increases digestibility. Roasting of whole
soyabeans inactivates enzymes or inhibitory factors which
improves the nutritive value for poultry.
Grinding: The process of reduction of feeds into particles
with the application of pressure and shearing. It is a prerequisite for mixing, pelleting or extrusion. It is simplest
and least expensive method which is accomplished with
the help of hand stone mill, hammer mill and roller mills.
The size distribution of grains depends on the shape, size
and hardness of the kernel.
Advantages of grinding:
1. It is prerequisite for mixing, pelleting or extrusion.
2.
It increases the surface area of grains which is reflected as
improve feed utilization, digestibility and performance of
animals.
3.
It avoids selective feeding of grains and reduces the scope
of shorting out less palatable feeds by the animals from
the compounded mash.
4.
Grinding increases compactness and reduces space requirement for storage.
Q.1. Fill in the blanks.
1. Chopping is also known as - - - - - - - .
2. In grinding the particle size of grain is - - - - - - - - .
256
Processing Methods of Ammal Feed Stuffs
3.
4.
5.
6.
7.
8.
The density in pelleted feed is - - - - - - - - - .
Dehydration is a process of reduction of moisture content
in a dehydrator using a temp. - - - - - - - for - - - - - - minutes.
Cubbing increases the density of roughages upto - - In soaking grain are soaked in water for - - - - - - hours.
In reconstitution the moisture content of grain is raised
upto - - - - - - .
The wet grains are stored in an oxygen limiting silo for 14
to 21 days prior to animal feeding in a process called - -
9.
In steam flaking steam treatment is given for -:- - - - - - minutes due to which moisture content in the grains
rises upto - - - - - - percent.
10. A process of cooking in which feeds are also expanded by
the application of adequate pressure is known as - - - 11. The process of swelling of steam treated grains under pressure caused by the release to atmosphere is known as - 12. The normal size of pellets is - - - - - - - .
13. The complete disintegration of starch granules of a grain
brought about by the combined application of moisture,
heat and pressure is known as - - - .
14. The process of rolling of feed ingredients with the use of
corrugated rollers is called - - - - - - - .
15. The feed of granular particle size produced from the grinding of pelleted feeds is called - - - - - - - - .
16. The popping of grains with the application of infra red
heat energy is called - - - ..:.. - -.
17. The treatment of grains with direct flame is called - - -
'257
Handbook of General Ammal Nutrition
18. The process of reduction of feeds into particles with the
application of pressure and shearing is called - - - - 19. Roasting of whole soybean inactivates enzymes which imeroves the nutritive
value for - - - - - - - - - 20. The size distribution of grains depends on - - - and - - - - - - - - .
21. _About - - - - - percent moisture of grains
ing heat treatments.
22. The normal size of pellets is - - - - - to - cylindrical shape.
23. Popping, micronizing and grinding are - - - - - - methods.
Q.2.
1.
2.
3.
4.
5.
6.
7.
- - - -is lost dur- - - with
- - - - -
Explain the lollowing.
Dry processing methods for roughages.
Wet processing methods for roughages.
Wet processing methods for grains.
Dry processing methods for grains.
Objective of feed processing.
Define these terms: Baling, Chppping, Grinding, Pelleting,
Dehydration, Cubbing, Soaking, Reconstitution, Steam
rolling, Steam flaking, Pressure cooking, Extrusion, Exploding, Gelatinization, Cracking or dry rolling, Crimping,
Crumbles, Popping, Micronizing, Roasting,
Advantage of grinding and pelleting.
258
Chapter
6
Various Feed Processing
Methods for Improving the
Nutritive Value of Inferior
Quality Roughages
Feed accounts for 60-70 percent of total cost of livestock
production. Inferior quality roughages are dry fibrous crop
residues available for the feeding of livestock like wheat straw,
paddy straw, finger millet straw and barley straw and stover
(kadbi) of sorghum, pearl millet and maize etc. These straw
and stovers are now considered as conventional dry roughages
for the feeding of farm animals in India. Several nonconventional dry roughages are also used for the feeding of
animals, which are sugar cane trash, baggase and fallen tree
leaves etc. But due to low voluntary intake, low digestibility,
low crude protein, essential minerals and vitamins content and
presence of certain antinutritional factors like lignin, silica,
oxalates and tannins make their utilization inefficient even by
the ruminant animals. The situations manifest itself as poor
animal performance, low growth rate, reduced fertility, high
mortality and incidence of disease and parasitism. So there is a
need for quality improvement of dry fibrous crop residues and
other similar roughages. Various methods for improving the
nutritive value of poor quality roughages are classified asPhysical Treatment: Soaking, chopping, Grinding Pelleting,
Wafering, Steam treatment and Irradiation.
Chemical treatment: Alkali treahnent, Ammonia treatment,
Acid treatment etc.
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Handbook of General Animal Nutrition
Biological treatment: Enzyme, rot fungi, mushroom and
yeasts.
A. Physical treatment:
1. Supplementation with deficient nutrients source:
Various nutrients are added by their enriched source to
compensate the deficiency of that particular nutrient in poor
quality straw. Addition of urea,molasses, green fodder, legume
straw, ensiling straw with top feeds minerals and vitamins
supplements are helpful to improve the nutritive value of poor
quality straw for animals.
Molasses: Molasses is the by product of sugar industry. It
contains about 45-50 percent sugar. Molasses has been mainly
used in animal feeding at 5-10 percent level. These levels were
mostly used as1. Carrier for urea impregnation of poor quality roughages.
2. As binder for commercial pelleted feeds for the convenients
and economic feeding of livestock ego uromoL
3. As sweetener for increasing voluntary intake of compounded feed.
Now present time urea molasses mineral blocks (UMMB)
are also used as supplements in animal feeding. At Ludhiana,
Uromol compound was prepared by heating urea and molasses
in the ratio of 9:1 (w/w) at 110°C.
2. Irradiation - Improvement of digestibility of wheat
straw by high voltage X-rays has been found to be due to the
breaking of the cellulose and hemicellulose bonds, resulting in
formation of oligosaccharides. This can be utilized by rumen
organisms. Forage lignin resists the X-rays. Upon irradiation
ergosterol, a plant sterol yields calciferol, commonly known as
vito D 3 • This method involves high cost and technology.
B. Chemical treatments:
The aim of chemical treatment is to breakdown the
lignocellulose complex and the swelling of cell walls facilitates
the easy access of rumen microbial enzymes to the cellulose
260
Various Feed Processing Methods
and hemicellulose fraction of the feeding material. Various
chemical treatments are explained as:
Acid treatment: The acid treatment changes the chemical
composition to a certain extent without any alteration in the
nutrient utilization. Various organic and inorganic acids may
be used. But it is cost effective process and have low practical
utility.
Treatment with oxidizing agents: Various oxidising agents
like alkaline hydrogen peroxide, ozone, sulphur oxide, sodium
sulphite and bleaching powder are effectively used to nutritional
improvement of poor quality roughages. But due to high cost
of treatment and lack of suitable technology for large scale
treatment are the main limiting factors for this treatment.
Alkali treatment: Various alkalies like sodium hydroxide,
lime, caustic soda, sodium bicarbonate and ammonia are used
to improve the nutritive value of poor quality roughages which
are explained below.
I. Sodium hydroxide treatment:
Wet treatment: The roughages are chopped and treated
with 1.5 percent (WIV) NaOH solution for at least 4 hours. The
treated straw was drained and washed with a large quantity
of water to remove all the NaOH solution.
Dry treatment: In this treatment chaffed dry fodder is first
spread on clean hard floor or thick plastic sheet. Solution of
NaOH (3-4%) is sprinkled and mixed with fodder. 4 to 6 kg of
NaOH dissolved in 200 Htres of water is adequate to wet 100
kg fodder. This makes the fodder moist and has pleasant odour
and improved nutritive value. But care should be taken to
protect the skin from NaOH which is corrosive in nature. But
cost of NaOH solution increase the cost of treatment, which is
not economical in general, conditions. During the First World
War (1914-18) a product "fodder cellulose" was produced in
Germany by treating straw with NaOH under high pressure
and high temperature.
2. Treatment with lime: Since calcium oxide and calcium
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Handbook of General Animal Nutrition
hydroxide are weak alkali, higher amount is required for longer
duration for straw treatment. It is safe, economical and easily
available chemicals than sodium hydroxide.
3. Ammonia treatment: Ammonia is also used to improve
the nutritive value of straw. It serves as an alkali to potential
rate and extent of digestion of straw and as a source of nitrogen
for rumen microbes. In this treatment stacks of straw were
wrapped with polyethylene cover and injected with 3%
ammonia. Aqueous ammonia (20-35 %) is also used for straw
treatment.
4. Urea ammoniation treatment: It is the most convenient
method of chemical treatment to straw. Urea is easily available
and well known to farmers. In this method weighted chaffed
straw is spread on the polythene sheet in a layer of 45-50 cm 3
kg urea is dissolved in 40 litres of water for 100 kg straw. The
urea solution is sprayed over the straw, mixed uniformly and
then stacked air tight and left for 3 weeks. After that stack is
opened and straw is ready for animal feeding after overnight
aeration of straw.
In order to reduce the loss of nitrogen during treatment
of roughages tier system method is applied in which alternate
layers of 3 per cent followed by 2 per cent urea treated roughages
are stacked. The excess ammonia in higher concentration layer
diffuses to the lower concentration layer and results in
considerable saving of urea and ammonia. Sometime a top layer
of about 20-30 cm. thickness acidified with mild solution of
commercial sulphuric acid may be used. This layer absorbs large
proportion of unutilized ammonia.
Conditions for urea treatment: For the better results, some
conditions are to be maintained so that urea hydrolysis should
be complete which are as:
Moisture level: 35-40 litres of water for 100 kg roughages
is sufficient for ureolysis.
Temperature: The optimum temperature for urease activity
in soil is 3CJlC. Ammoniation is increased at higher temperature.
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Various Feed Processing Methods
Level of urea: Optimum level of urea should be used for
better utilization as well as to avoid toxicity of urea. 4-5 percent
urea (V IV) solution may be used. Urease enzyme is a natural
contaminant of straw. Urea was extensively hydrolysed by this
enzyme. But addition of an urease source reduces the treatment
time. 50yabean powder (8.5%) is an urease source.
5. Treatment with animal urine: Animal urine an
unconventional NPN source abundantly available is also used
to improve the nutritive value of poor quality roughages.
Precautions for chemical treatments:
(i) Mixing of the chemicals should be thorough and uniform.
(ii) Chemicals should be handled carefully as these are corrosive in nature.
(iii) Ammonia is an explosive in nature so fire should not be
ignited near the stock or during the injection of ammonia
gas.
(iv) Ammoniated fodders should be properly aerated before
feeding to the animals.
(v) Animals should be adapted to chemical treated roughages
by feeding low concentrated chemical treated roughages
initially.
C. Biological treatment Biological treatments involves the
living organisms specially microbes (Fungi) to improve the
nutritive value of poor quality roughages. In this treatment poor
quality straws are treated with aerobic fungi namely white rot
fungi such as Sporotrichum sp., Lenzitis sp., Coprinus sp. Trichusus
spiralis, Pacilomyces fusisporus etc. Pure culture of fungus strain
are raised on suitable medium and then incubated with straw
at varying moisture level for different periods, which will
improve the nutritive value of straw.
Most microorganisms have some effect on crop residues
and other fibrous materials and metabolise lignin, cellulose and
other fibrous components. They should have the ability to break
down the ligno-cellulose complex and degradation of lignin and
cellulose with their enzyme secretion. 50 that digestibility of
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Handbook of General Animal Nutrition
these cell wall components may improve. The ideal
microorganisms for biological treatment should have strong
lignin metabolism with low or no affinity. towards cellulose and
hemicelluloses. The biological methods of straw treatment which
involves the use of microorganisms capable of degrading lignin
by producing extra cellular" Phenol oxidase" the enzyme which
are probable involves in the process of lignin degradation and
thus rendering cellulose and hemicellulose fraction free. A high
activity cellulase is required for ・ョコケュ。セ」@
hydrolysis of cellulose.
Lignin - - - - - . . . . . cellulose + Hemicellulose
!
!
Cellulase (enzymatic hydrolysis)
Free hexoses and pentoses subunits
Single cell protein (SCP)
Free hexoses and pentoses subunits are used for single
cell protein. Best results of Biological treatment are obtained
when the roughage incubated with fungal spore for the period
of at least 30 days. But care should be taken that these microbes
should not produce toxins, easy to handle and cost effective.
Thus, these methods have great appeal as an alternative to the
use of expensive chemical and physical methods to produce
economic ruminant feeds.
Q.1. Fill in the blanks.
1. Feed is the major input in livestock farming which accounts
for ........... percent of total cost of production.
2. Optimum level of molasses is ............ which is used in
animal feeding.
3. Full form of UMMB .......... used in animal feeding.
4. In forage ............. resist the X-rays.
5. . ........... and ............ are required for longer duration
for straw treatment.
6.
Animal urine is an unconventional ............. source.
264
Various Feed Processing Methods
7.
8.
9.
10.
11.
12.
13.
14.
15.
16.
17.
18.
The optimum level of urea .............. % (v Iv) solution is
used for bette r utilization of poor quality roughages.
. ............. is an explosive in nature so fire should not be
ignited near the stock.
Main fungi involved in biological treatment of roughages
are ............ , ............ and ............. .
The fungi secrete an enzyme ......... which degraded the
lignin.
The phenol oxidase enzyme degrades the lignin into ..... .
fraction free.
Free hexoses and pentoses subunits are used in ........ .
Best result of biological treatment of roughages is obtained
when it is incubated for a period of ............... with fungal spore.
- - - - - - - enzyme is a natural contaminants of straw.
During First World War "fodder cellulose" was produced
in Germany by treating - - - - - - - with - - - - under high pressure and temperature.
Molasses is used in commercial pelleted feed as - - - -.
Uromol is prepared by heating urea and molasses in the
ratio of - - - - - (w/w) at 110° C.
Some common examples of poor quality roughages are ------, ---
--------, ------
- - - and - - - - - - - - .
Q.2. Explain the following.
1. Various feed processing methods for improving the nutritive value of roughage .
. 2. Why lignin is degraded in roughages when it is treated
with fungal spores.
3.
Short notes ona. Physical treatment of roughage.
b. Chemical treatment of roughage.
c. Biological treatment of roughage.
d. Single cell protein
265
"This page is Intentionally Left Blank"
Chapter
7
Harmful Natural Constituents
and Toxic Substances in
Animal Feeds
A toxicant is a substance, which under practical
circumstances can impair some aspect of animal metabolism and
produce adverse biological or economical effects in animal
production. This is a broad definition, but encompasses those
aspects that are relevant in livestock production. Virtually
everything is toxic, if given in large enough dose. Thus, the
term "toxicant" refers only to those substances which might
normally be encountered at toxic levels. Other terms used
synonymously with toxicant are "poison" and "toxin".
Anti-nutritionalfactors may be defined as those substances
in the diet which by themselves or their metabolic products
arising in the system interfere with the feed utilization, reduced
production or affects the health of the animals. Toxicants can
be classified based on their chemical properties and their effect
on utilization of nutrients.
1. According to their chemical properties:
1. Alkaloids
Pyrrolizidine and piperidine
alkaloids.
2. Glycosides
Saponins, cyanogens,
Glucosinolates.
3. Proteins
Protease inhibitors and
Haemagglutinins.
4. Metal binding
Substance or inorganic toxicants.
5. Phenols
Gossypol and Tannins.
6. Mycotoxins
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Handbook of General Animal Nutrition
2. Effect on nutrient utilization
1. Substances affecting protein utilization are protease
inhibitor, haemagglutinin, saponin and polyphenolic
components.
2. Substances reducing solubility or interfering with the
utilization of minerals are phytic acid, oxalic acid, gossypol
and glucosinolates.
3. Substances affecting carbohydrates digestion are amylase
inhibitors, phenolic compounds and flatulence factors.
4. Substances increasing the vitamins requirements.
1. Alkaloids: Alkaloids are basic substances that contain
nitrogen in heterocyclic ring. They are widely distributed in
the plants; it has been estimated that 15-20% of all vascular
plants contain alkaloids. Most alkaloids are derived from amino
acids in their synthesis by plants. Amino acids are
decarboxylated to amines and theamines are converted to
aldehydes by amine oxidase. Condensation of the aldehyde and
amine groups then yields the heterocyclic ring. Various alkaloids
with their sources are tabulated below
Alkaloids with their sources
Atropine
Deadly nightshade
Cocaine
Leaves of Coca plant
Coniine
Hemlock
Morphine
Dried latex of opium poppy
Nicotine
Tobacco
Quinine
Cinchona bark
Solanine
Unripe potatoes
Strychnine
Seeds of nux vomica
Pyrrolizidine alkaloids (PA) contain the pyrrolizidine
nucleus. The structure of serecionine and heliotrine are
representative of toxic principle in livestock nutrition. The PAs
are biosynthesized from amino acids such as ornithine. Most of
the P A containing plants used in livestock feeding are in the
genera Senecio, Crotaliaria, Heliotropium and Echium. The
268
Harmful Natural Constituents and Toxic Substances in Animal Feeds
principle pathology is irreversible liver cirrhosis with
pronounced fibrosis and biliary hyperplacia. Mortality is related
to impair liver function. The most important piperidine alkaloids
in animal production are coniine and related alkaloids found in
Conium maculatum (poison hemlock). These alkaloids affect the
central nervous system and are also teratogens. An example of
pyridine is nicotine in Nicotiana spp. (cultivation and wild
tobacco).
Indoles are the derivatives of the amino acid tryptophane
Examples are the ergot alkaloids such as perloline. The
quinolizidine nucleus consists of two six-membered rings.
Lupines contain these alkaloids which cause acute poisoning in
sheep and teratogenic effect in calves (crooked calf disease).
Tryptamine alkaloids are found in Phalaris tuberosa, a forage
grass grown in Australia. Phalaris poisoning results in acute
neurological sign and chronic muscular incordination. A tropine,
found in Datura spp. (Jimson weed), is at:l example of a tropane
alkaloid. It has pronounced effect on the central nervous system.
2. Glyeosides: Glycosides are ethers containing a
carbohydrate moiety and a non-carbohydrate moiety (aglycone)
joined with an ether bond. They are usually bitter substances.
Often the aglycone is released by enzymatic action when the
plant tissue is damaged, as by wilting, freezing and mastication.
They are classified on the basis of aglycone.
(a) Cyanogens: Cyanogens are glycosides of a sugar or
sugars (usually glucose) and cyanide containing aglycone. They
can be hydrolysed by enzymatic action with the release of
hydrogen cyanide which is a potent toxin. The major cyanogens
of importance in animal nutrition are the following.
(i) Amygdalin (laetrile): This glycoside found in Rosaceae,
such as chokecherries, wild cherries. Mountain mahogany
and the kernels of almonds, apricots, peaches and apples.
Prunasin is also found in these plants; it has the same structure as amgydalin except it has one glucose rather than
two attached to the aglycone.
(ii) Dhurrin: This occurs in sorghum species such as grain sorghum, forage sorghum (sudan grass) and Johanson grass.
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Handbook of General Animal Nutrition
(iii) Linamarin: This compound is found in white-clover, flax
(Lin seed), cassava and Lima beans.
Hydrogen cyanide is formed when the glucosides are
hydrolyzed by plant enzymes (f3-glucosidase and
hydroxynitrilelyase).
Mode of action HeN: HeN is readily absorbed and enters
in tissue cells. It affects the electron transport system at two
sites by affecting the cytochrome oxidase.
(i) Cytochrome-b is reduced to lesser extent in the presence
of cyanide.
(ii) The electron transfer from cytochrome-a to water is
completly inhibited, ATP formation ceases and the tissues
suffer energy deprivation and death follows rapidly.
In subacute conditions oxygen is not taken up by the
tissue because blood does not transfer the oxygen. So that
arterial blood remains like venous blood. In acute condition
when the quantity eaten is more it paralyses the medula
oblongata in brain where respiration receptors are located,
therefore, respiration stops and leading to death.
Sign of HeN toxicity: Sign of cyanide poisoning are
dyspnoea (difficult breathing), excitement, gasping, paralysis,
staggering, convulsion, coma and death. Cyanide is readily
detoxified. Liver, kidney and thyroid tissue contain an enzyme
rhodanase which catalyzes conversion of cyanide to thiocyanate,
which is excreted in the urine. Ammonia and nitrite inhalation
is also useful during mild toxicity.
(b) Glucosinilates: Glucosinolates are glycosides of セMdᆳ
thioglucose with an aglycone that yields an isothiocyanate, nitrile
or thiocyanate or similar structure upon hydrolysis. Most of
the glucosinolate containing crucifers that are important in
human or animal nutrition are in the genus Brassica includes
cabbage, broccoli, rapeseed, mustard and turnips.
The glucosinolates are hydrolysed by an enzyme system
(glucosinolase or thiglucosidase). The enzyme is found in plant
and is released when the plant material is crushed. It is also
270
Harmful Natural Constituents and Toxic Substances in Animal Feeds
produced by the rumen microorganisms. The major effect of
the hydrolysis products of glucosinolates is inhibition of the
function of thyroid gland and results in goitre. The thyroid
produces hormone known as thyroxine that are important in
regulating the rate of cellular metabolism.
Sign of glucosinolate toxicity: Goiter in humans has been
observed. Poultry and swine fed raw rapeseed meal exhibited
enlarge thyroid, growth depression, perosis, low egg
production, off flavours in egg and liver damage.
Treatment:
1. Feeding of iodinized salt reduces the incidence in man and
animals.
2. Heat treatment of rapeseed reduces the glucosinolate.
3. Thyroxine therapy may be useful for curing the disease.
(c) Coumarin: Sweet clover poisoning, sweet clover
(Melilotus albus and Melilotus officinalis) contains a glycoside
called melilotoside,an ether of glucose and coumarin. Coumarin
is metabolised to produce dicoumarol. Dicoumarol is an
inhibitor of vitamin K and induces a vitamin K deficiency セ@ hich
is characterized by susceptibility to haemorrhage.
Sweet clover poisoning occurs almost exclusively in cattle.
The predominant sign is haermorrhage. Internal haermorrhage
results in bovine subcutaneous swellings caused by pooling of
blood. The mucous membranes are pale, and the animal
becomes weaker and dies without struggle. Sweet clover
poisoning can be treated with injections of vitamin K and whole
blood transfusion.
(d) Saponins: Saponins are glycosides widely distributed
among plants like chick-pea, soyabean, alfalfa and common
beans. Saponins are characterized by a bitter taste and foaming
properties and involved in bloat in ruminants. Saponins have
industrial and commercial applications, including use in soft
drinks, shampoo, soap and the synthesis of steriod hormones.
Pasture species that causes livestock problems because of
their phytoestrogen content includes subclover, red clover and
271
Handbook of General Animal Nutrition
alfalfa. The estrogens in clovers are usually isoflavones, while
alfalfa contains coumestans. Due to the action of micro-organism
in rumen of sheep and cattle the isoflavones are converted into
equol and phenolic acid.
Physioloigical effects of phytoestrogens: After sheep have
grazed estrogenic for several years the fertility of the flock
becomes depressed. The condition of permanent infertility is
known as clover disease. The main cause of infertility is a failure
of fertilization associated with poor sperm penetration to
oviduct. The cervical mucous has an altered consistency which
impairs sperm storage in the cervix. In ewes affected by clover
disease, the cervix shows structural and functional changes. In
sheep uterine prolaps, interference in sperm transportation in
female, abnormal ova transport and uterine cyst have been
noted.
Mechanism of action
Some results indicated that normal hormonal interrelationship is interefered resulting in failure of endogenous
estrogens.
2. Pituitary seems to be achieving site because the pituitary
basophils in ewes given coumestan diet is enlarged causing inhibition of gonadotropin releasing factor from the
pituitary.
3. The depression in ovulation rate with coumestanediet also
appears to be in some way related to FSH.
4. Folicular abnormalities in ovary have also been noticed in
ewes given red clover.
1.
3. Proteins and amino acids:
(i) Trypsin (protease) inhibitors: A wide variety of plants .
contain protein fraction which inhibit protein digestion in the
digestive tract of animal. The trypsin inhibitors of soya beans
are the best known and most widely studied. Other plant
containing trypsin inhibitors include most types of beans,
potatoes, rye, triticale, barley and alfalfa. Protease inhibitior is
probably a better term, since other enzymes such as
272
Harmful Natural Constituents and Toxic Substances in Animal Feeds
chymotrypsin are also affected.
Nutritional significance of trypsin inhibitor: Soyabean
is the major protein supplement used in swine and poultry diets.
It must be heat treated to destory· trypsin inhibitors. The mode
of action of trypsin inhibitors is not entirely clear. In
nonruminant includes poor growth, reduced feed intake, a
reduction in protein digestibility, pancreatic hypertrophy and
a deficiency if sulphur containing amino acids. Trypsin inhibitors
are readily destroyed by treatment of plant material with heat.
Over 95% of the activity is destroyed in 15 min. at 100°e.
(ii) Hemagglutinins (lectins): Hemagglutinins
(Phytohemagglutinins, lectins) cause the clumping or agglutination
of red blood cells in vitro. They were first isolated from castor
beans, which contain a potent lectin called ricin. Lectins are
proteins that have a high affinity for certain sugar molecules.
Probably their biological effects are due to their affinity for
sugars.
Lectins are found in soyabean and other field beans such
as kidney, pinto and navy bean. Haemagglutinincauses various
adverse effects, including reduced growth, diarrhoea, decreased
nutrients absorption and increased incidence of bacterial
infection. The major effects seem to be on the intestinal mucosa.
In addition, there is evidence that lectins impair the immune
system. Lectins are destroyed by moist heat. They are resistant
to dry heat.
(iii) Bloat- producing proteins: Bloat is a distension of
the rumen as a result of the inability of the animal to eructate
gases produced in normal processes to rumen fermentation.
The principle gases are carbondioxide and methane and these
gases are trapped in the form of stable foam. The eructation
mechanism is inhibited by the presence of foam at the base of
the oesphagus; eructation of foam would result in it getting in
to the lungs. Bloatproducing plants, primarily legumes, contain
substances which causes the production of a stable foam in the
rumen. The most important bloating species in temperate
regions are alfalfa (Medicago sativa), red clover (Trifolium pratense)
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Handbook of General Animal Nutrition
and white clover (T. repens). Tropical legumes are not bloat
producers. In addition, animal factors as well as rumen microbes
are also involved in bloat condition. The use of antifoaming
agents such as poloxalene (Bloat Guard) and vegetable oil in
legume pastures has vastly reduced the bloat problems.
(iv) Mimosine: Subabul (Leucaena leucocephala), commonly
referred to as leucaena, is a tropical legume with great potential
as a protein source for livestock. It is vigorous, rapidly growing,
drought tolerant, palatable, high yielding crop and its leaves
contain 25-30% crude protein. These potential attributes are
presently limited by the occurrence of the toxic amino acid
mimosine in leucaena. Mimosine is structurally very similar to
tyrosine and in rumen it is metabolized to 3,4
dihydroxypyridine (DHP). DHP is a goitrogen, impairing the
incorporation of iodine in to iodinated compounds in the thyroid
gland.
In non- ruminant mimosine causes poor growth, alopecia
and eye cataracts. Ruminant animals may show various
symptoms such as poor growth, loss of hair, swollen and rough
coronets above the hooves, lameness, mouth and oesophageal
serum thyroxine level and goiter developed.
lesions, 、セーイ・ウ@
(v) Lathyrogens: Lathyrism is a crimpling disease in humans
caused by the consumption of seeds of Lathyrus spp., principally
L. sativus (chick pea). Lathyrism is of two types: neurolathyrism
and osteolathyrism.
Osteolathyrism: This is the principal form of lathyrism that
affects livestock. Consumption of seeds of L. odoratus, L. silvestris
and L. hiscsutus. The lathyrogen in lathyrus odoratus and related
species is p- amino propionitrile (BAPN), an amino acid
derivative. BAPN causes skeletal deformity and rupture due
to defective synthesis of cartilage and connective tissue.
Malformations of long bones are caused by irregular hyperplastic
cartilage formed in the epiphysis. Arotic rupture due to the
formation of arotic aneurysm, is due to defective collagen and
elastin synthesis.
274
Harmful Natural Constituents and Toxic Substances in Animal Feeds
Neurolathyrism: Neurolathyrismis a paralysis of legs due
to nerve damage in the spinal cord caused by neurotoxins in L.
sativus, L.latifolius and L. cevcera. The principalneurolathyrogen
is f3-N- oxalye- L-a.-f3- diamino propionic acid (ODAPP).
4. Metal-binding substances and inorganic toxicants:
A. Oxalates: Oxalates of certain foods precipipate calcium
in the gastrointestinal tract as insoluble calcium oxalate. Paddy
straw and Pusa gaint Napier grass and some other green fodder
and tree leaves are rich in oxalate. Oxalate containing feed
causing a calcium deficiency in cattle resulting poor milk
production and growth. Poultry are also affected. Animal
response to oxalate poisoning varies with species of animals
and plants.
B. Phytic acid: It is an ester formed by combination of the
six alcoholic groups of inositol of with six molecules of
hexaphosphoric acid. Seeds of cereals, dried legumes, oil seeds
and nuts are rich in phytic acid. It depresses the utilization of
several mineral elements such as phosphorus, calcium,
magnesium, Iron and zinc etc. by forming the insoluble
compounds, which are excreted in the faeces. Supplementation
of enzyme phytase in poultry makes the phosphorus available
for birds.
C. Minerals as toxicants: Though minerals are very
essential for maintenance and growth for all animal species but
their excess amount in diet may produce harmful effects. The
selenium, molybdenum, fluorine, sulphur are few minerals
which have significant toxic effect in animal production and
health. Common salt, phosphorus and some other trace minerals
have also adverse effect if consumed in excess amount.
5. Phenols:
(i) Gossypol: It is found in cotton seed. It is available in
free form as a well bound form as gossypol-protein complex.
Whole cotton seed contains 1.09-1.53 percent of gossypol. Heat
treatment of Cotton seed meal decreases the gossypol content.
The physiological effects of free gossypol are reduced appetite,
275
Handbook of General Animal Nutrition
loss of body wt., reduced heamoglobin content, cardiac
irregularities, accumulation of fluid in body cavities and depress
liver function. It is more toxic to non-ruminants than ruminants
because in rumen gossypol combines with soluble protein. This
complex is resistant to enzymatic break down. Gossypol also
combines with Iron and lysine. So ferrous sulphate
supplementation reduces the toxic effect of gossypol.
(ii) Tannin: It is a high molecular wt. polyphenolic
substance widely distributed in nature. It is of two types i.e.
hydrolysable tannins which can be readily hydrolysed by water,
acids, bases or enzymes and yield gallotannins and ellagitannins.
Condensed tannins are flavonoids- polymers of flavonol.
Sorghum, salseed meal, mustard oil cake and lucerne meal
contain sufficient amount of tannin.
Tannins are astringent in nature. They bind with protein
and reduces its availability to animals. They depress cellulase
activity and thus digestion of crude fibre reduces. Most of the
tannins are present in seed coat. So decortication of seeds will
decrease the tannin content Other physical methods like soaking
and cooking reduce the tannin content. Addition of tannin
complexing agents like polyethylene glycol (PEG) and polyvinyl
proldone (PVP) prevent formation of protein-tannin complex
as well as break the already formed complex thus liberating
protein.
6. Mycotoxins: Aflatoxins are a group of closely related
toxic substances produced by the fungi, Aspergillus flavus and
Aspergillus parasiticus, mostly in improperly stored feedstuffs
such as cereal grains and oil meals. Although other fungi such
as Penicillium spp, Rhizopus spp, Muco spp. and Streptomyces spp.
are capable of producing aflatoxins, but their toxicity to livestock
production has not been established. The name " aflatoxin"
derives from- Aspergillus (a-), flavus (-fla-) and toxin. A. flavus
and A. parasiticus produce four major toxins: Bt' B2, G1 and G2 •
These were named according to their fluorescence properties
under shortwave ultraviolet light on thin-layer chromatography.
BI and B2 fluoresce blue, whereas G 1 and G 2 fluoresce green.
Fourteen other aflatoxins are known but most of these are
276
Harmful Natural Constituents and TOXIC Substances in Animal Feeds
metabolites, formed endogenously in animals administered one
or more of the four major aflatoxins. Metabolites of toxicological
significance includes, aflatoxin Bj -2,3 oxide (AFB j -2,2 oxide),
aflatoxin セ@
HafセI[@
aflatoxicol and aflatoxin B2 (ABF2J
Aflatoxins were first discovered as toxic factors when
heavy mortality occurrred amongst turkeys, ducklings and
patridges in early 1960 in England. The cause was known to be
mycotoxins in mouldy groundnut meal that was imported from
Brazil to England for the use as protein supplement in animal
diets.
Aflatoxin-producing strains of Aspergillus are the
constituents of microflora of air and the soil throughout the
world. When environmental conditions are favourable, then
colonization and mould growth can easily be occur on the
substrate (feed or seed). Strain variations, nature of substrate
and environmental conditions (temperature, moisture, aeration)
influence the aflatoxin production with respect to their type
and their individual concentrations. The relative humidity
surrounding the substrate was the most improtant factor for
the growth of Aspergillus flavus. Optimum temperature for
alfatoxin production by A. fIavus has been shown to be 25°C for
aflatoxin Bj and 30°C for G 1• A. fIavus is primarily a seedcolonizing mould and is usually referred to as a storage mould.
Three major feedstuffs with high potential for invasion by
Aspergillus spp. during growth, harvest, transportation or
storage are corn, cotton seed and groundnut (Peanut).
Effects of aflatoxin on productivity of animals:
Acute intoxication: Acute intoxication poisoning of farm
animal is less likely to occur than chronic aflatoxicosis. The
principle target organ in all species is the liver. Numerous liver
functions are affected and the cumulative impact can be fatal to
animals. Hepatocytes undergo progressive changes such as
infilteration with lipids eventually ending in necrosis. These
toxic effects are believed to be result of widespread and nonspecific in interactions between AFB j or its metabolites and
various cell proteins. Interaction with key enzymes can disrupt
277
Handbook of General Animal Nutrition
basic metabolic processes in the cell such as carbohydrates or
lipid metabolism, and protein synthesis. Modification of
permeability characteristics of hepatocytes or subcellular
organelles, primarily the mitochondria, contributes to the
necrosis. As the liver losses its functionality, other effects appear
such as derangement of blood clotting mechanism
(coagulopathy), icterus uaundice), and reduction of essential
serum proteins, which are synthesized in the liver.
In young swine, which are highly susceptible to acute
poisoning, early hepatocytic changes occur within 6 hr. after
exposure. Haemorrhages and cell necrosis occur by 9-12 hours,
elevated serum glutamicoxalo-acetate transaminase (SGOT) at
12-14 hr, and death followed within 24-34 hr. In general, these
same biological changes occur in all acutely intoxicated species.
However, the susceptibility among different species is highly
variable. Rabbits and ducks are highly sensitive to aflatoxins,
whereas, sheep and rat are less sensitive.
Chronic intoxication: Chronic poisoning or aflatoxicosis
can result when low levels of toxin are ingested over a prolonged
period. In general, affected livestock exhibit decreased growth
rate, lowered productivity (meat and eggs) and immuno
suppression. Carcinogenicity has also been observed and studies
in several species. Liver damage is also prevalent in chronic
aflatoxicosis in all species. At necropsy, the liver is usually pale
to yellow, and the gall bladder may be enlarged. Histological
changes include cellular accumulation of lipids, fibrosis and
extensive bile duct proliferation.
Swine: Feed containing 0.4 ppm or greater of AFBl fed
from weaning to market weight can adversely affect the health
of pigs. Among the midest affects are decreased fet:;d efficiency
and poor rate of gain. More severe effects include acute hepatitis,
systemic hemorrhage and nephrosis. The extent of pathological
abnormality observed in the liver and kidney was closely related
to the AFB1 levei in the diet. In a swine reproduction experiment,
no adverse effects were detected in piglet produced from sows
fed 450 ppm aflatoxin. Moreover, piglets are more sensitive
than older pigs. However, stunted growth has been observed
278
Harmful Natural Constituents and Toxic Substances in Animal Feeds
in piglet that nursed on sows fed contaminated feed since AFM1,
a toxic metabolite of AFBl is transferred into milk. Clear damage
to liver, changes in blood and loss of appetite were observed in
many pigs with 2 or 4 mg aflatoxin per day per animal.
Poultry: Avian species are quite variable insensitivity to
chronic aflatoxicosis. Turkey, poultry and ducklings are the
most sensitive, i.e. a dietary level of 0.25 ppm impair their
growth. A level of 0.5 ppm in chickens is required to reduce
growth rate and a level of 1.25 ppm or more in chicks diet
resulted in increased liver lipids. A level of 2.5 ppm and above
reduced the final weight of chicks significantly. Dietary
concentrations of aflatoxin greater than 2 ppm can significantly
diminish egg production in layers and production decreased to
50% with 10 ppm and 0% at 20 ppm. Chicken were protected
again at the growth inhibiting effects of 5 ppm dietary aflatoxin
when the protein in the diet was increased from 20 per cent to
30 per cent. Rickets were observed in broiler chicks fed aflatoxin
containing diet and showing that aflatoxins impair the
availability of bile salts in the gut, resulting in decreased
absorption of fat soluble vitamins. Decreased bone strength in
broilers fed aflatoxins was attributed to inadequate
mineralization of bone.
Ruminants: In chronic intoxication the growing calves
displayed loss of appetite and reduced growth rate while milk
yield was reduced in cows. This resulted in wider feed: gain
ratio. However, there was no loss of appetite. Calves are more
sensitive than adult cattle. A dose level of about 0.2 mg/kg
body causes reduced rate of gain and impaired blood
coagulation in calves. Early metabolic indications of aflatoxicosis
in calves are poor feed utilization and a rapid rise in serum
alkaline phosphatase (APT) activity. Feeding of aflatoxin
contaiminated cotton seed meal to young beef cattle showed
reduction in growth rate and feed efficiency and gross evidence
of liver damage at 0.7 and 1.0 ppm levels while no abnormalities
were seen with 0.1 and 0.30 ppm levels. Cows fed daily doses
of 13 mg aflatoxin either as pure B1 or as crude mixture for 7
days showed fluctuation in feed intake and milk production.
279
Handbook of General Animal Nutrition
There was a significant decrease in milk production of cows
receiving crude mixture. Antireproductive effects of aflatoxins
in ruminants include decreased fertility in sheep and abortion
and birth of underweight calves in cattle.
Food adulterants: Food adulterants are generally mixed
along with the concentrate mixture, especially when it is mash
or pellet form. Individual ingredients are sometimes also found
adulterated with various types od adulterants, which are not
only poor in nutritive value but are also harmful to the animals.
The costly feeds are generally adulterated. The fish meal is
adulterated with sand, urea and salt. The grains are adulterated
with water. Several adulterants are added in various bulks like
rice husk, saw dust, ground nut shells, brick powder and small
pieces of stones. The quality control of feed is regulated by the
legislation laid down by the Bureau of Indian Standards (BIS),
New Delhi. The adulterants, which are commonly mixed with
foodre:
1. Sweet potato, potato and hydrogenated vegetable oils
(margarine, vanaspati etc.) mixed with ghee.
2. Water and starch are mixed with milk and milk products.
3. Argimone oil mixed with mustard oil.
4. Coloured saw dust mixed with turmeric powder and tea
leaves.
5. Foils of aluminium used in place of silver foil to wrap betel
and sweets.
6. Besan of khesari (Lathyrus odoratus) mixed the besan of gram
and others.
7. Sacchrin in sweets.
The adulterants may be harmless or harmful, which may
cause bad effect on health. So the laboratory must be equipped
with the facilities to detect the presence of adulterants in feed.
0.1. Fill in the blanks
1.
- - - - - - - - and - - - - - - which are toxic to animals.
280
are the alkaloids
Hamlful Natural Constituents and Toxic Substances in Animal Feeds
2.
3.
4.
Hydrolysis of cyanogens produce - - - - which is a potent toxin.
- - - - - cyanogen is found in sudan grass.
Cyanide is converted into thiocyanate by enzyme - - -
6.
Glucosinolates inhibit the function of - - - - - - - gland.
Glucosinolates are l,.ydrolysed by enzyme - - - - - -
7.
Glucosinolates toxicity produced symptoms like - - - -
8.
Sweet clovers (Melilotus albus) contain a toxic glycoside
known as - - - .
The toxicity symptoms of sweet clover poisoning are - -
5.
9.
10. The sweet clover poisoning can be treated by injection of
vitamin - - - - .
11. Saponins are glycosides found in plants like - - - - - and - - - - - - - .
12. Trypsin inhibitors are found in plants like - - - - - - and - - - - - - - .
13. - - - - - -treatment destroys the trypsin inhibitors.
14. Hemagglutinins cause the - - - - - - of red blood cells.
15. The toxic amino acid mimosineis found in plants - - - 16. Lathyrism is a crimpling disease produced by comsumption
of - - - - seeds.
17. - - - - -and- - - - - - crops are rich in oxalate content.
18. - - - - - - -percipitatecalcium in gastrointestinal tract
as calcium oxalate.
19. Phytic acid is found in plants like - - - - - - - - and-
281
Handbook of General Animal Nutrition
- - - - - - - - - depresses the utilization of many
minerals specially phosphorus.
21. - - - - - - - - - - a n d - - - - - - - - are the phenol derivatives which are present in many plants as toxic
substances.
22. The toxic substance present in cotton seed is - - - - - 20.
23. Tannin a toxic substance found in - - - - - - - and 24. Tannins reduce the availability of - - - - - - - by forming complex with it.
25. - - - - , - - - - - , - - - - - - and - - - - are the
four major toxins produced by fungi.
26. The most potent mycotoxin is - - - - - - - - .
27. - - - - - - -and - - - - - - - are the fungal species
producing aflatoxins.
28. The quality control of feed is regulated by the legislation
laid down by the - -- - - - - - - - - - - - - -.
29. When low levels of toxin are ingested over a prolonged
period results into - - - - - - - .
30. - - - - - - - - and - - - - - - - are highly sensitive
- - and - - - - to aflatoxins where as - - - -- - - - - are less sensitive.
Q.2. Explain the following:
1. Define the toxin substance. How the naturally occuring
toxic substances are classified?
2. Explain the naturally occuring alkaloids and Glycosides in
plants which are toxic to animals.
3. Mention the various toxic substances which influence the
protein utilization by animals.
4. Write a note on metal binding substance and inorganic
toxicants.
5. Effect of mycotoxins in animal production.
6. Gossypol and Tannin as harmful natural constituents of
plants.
282
Index
Berseem
Bile acids
Blood meal
Bone Meal
Bound water
British thermal unit
Brouwer equation
A
Absorption
24
89
Acetyl number
Acetylation
89
Acid number
89
Agar
36
Agro-climatic condition
17
Aliphatic Amino Acids
58
Alkaloids
10,268
Amino acid deficiency
80
Amino acid imbalance
80
Amino acid toxicity
81
Ammonia production
71
Amygdalin
269
Anabolic agents
173
Animal Body
13
Animal By-product
193
Animal fa,ctor
23
Animal Feed technology
251
Animal Nutrition
3
Anthelmentics
177
Anti diuretic hormone
24
Antioxidants
177
Aromatic Amino Acids
61
Arsenicals
176
Ascorbic Acid1
62
C
Calcium
Calorie
Carbohydrate
Carbohydrates metabolism
Carrots
Cassava
Catabolic agent
Cellobiose
Cellulose
Cephalin
Cereal Grains
Chitin
Chlorine
Cholesterol
Choline
Chopping
Chromium
Cobalt
Coconut cake
Cold processing method
Comparison of Plants
Compound lipids
Conjugated Proteins
Copper
Copper sulphate
Cotton seed Cakes
B
Bagasse
Bajra
Balanced ration
Baling
Barley
Beet molasses
184
94
194
194
22
217
232
9
184, 189
8
252
189
187
317
104
217
27
47
186
187
173
32
34
92
189
35
112
94
159
252
126
120
192
251
13
91
67
116
176
191
Handbook of General Animal Nutrition
271
184
237
253
17
160
269
Coumarin
Cowpea
Crude Protein
Cubbing
Cultivation practices
Cyanocobalmin
Cyanogens
D
252
67
34
269
23
224
31
22
Dehydration
Derived Proteins
Dextrins
Dhurrin
Dietary factor
Digestible energy
Disaccharides
Drinking water
E
G
Galactose
Globular Proteins
Glucose metabolism
Glucosinilates
Gluten
Glycogen
Glycogenesis
Glycolysis
Glycosides
Gossypol
Gram
Green Fodder
Green fodder
Grinding
Gross Protein Value
Ground nut cake
30
66
48
270
9
34
53
48
269
275
189
199
222
252
239
191
Ii
Ensiling
205
Environment
23
Ergosterol
94
Essential fatty acids
88
Essential mineral elements 103
Essential oils
95
F
Fatty Acids
Feathers Meal
Feed
Feed Additives
Feed Conversion efficiency
Feed conversion ratio
Fibrous Proteins
Fish meal
Fluorine
Fodder
Folic Acid
Frutosans
86
194
22
169
10
10
66
193
124
9
156
35
284
Halogenation
89
Hay
9
Hay making
199
Haylage
215
Hemicellulose
35
Heparin
36
Heptoses
31
Heterocyclic Amino Acids 61
Heteropolysaccharide
33,35
Hexoses
30
Homeostasis
24
Homopolysaccharides 32,33
Hormones
173
Hot processing method
252
Husk
9,193
Hyaluronic acid
36
Hydrogenation
89
Hypervitaminosis
165
Index
I
Iodine
Iodine number
Iron
Irradiation
119
89
115
260
J
Joule
Jowar
Jungle hay
217
189
200
K
Kharif roughage
181
L
Lathyrogens
Lecithins
Leguminous fodder
Lignin
Limiting amino acid
Linamarin
Linseed cake
Lipids
Lobia
Lucerne
274
92
184
36
8
270
191
85
184
184
M
103
Macro elements
Magnesium
109
Maize
183, 189
Maize gluten feed
193
Mannose
30
Meat meal
194
Metabolizable energy
224
Micro elements
103
Milk fever
106
Mimosine
274
Minerals
103
Molasses
260
285
125
29
192
276
Molybdenum
Monosaccharides
Mustard cake
Mycotoxins
N
Neemcake
Net Protein Retention
Net Protein Utilization
Night blindness
Non Leguminous fodder
N on-essential mineral
elements
Nucleic acid
Nucleosides
Nucleotides·
Nutrient
Nutriment
192
239
242
137
183
103
68
68
68
7
7
0
Oat
Oil seed cakes1
Oligosaccharides
Osteolathyrism
Osteomalacia
Osteoporosis
Oxalates
Oxidation water
Oxidative rancidity
184,189
90
31
274
106
106
275
22
90
p
Pantothenic Acid
Pearl Millet
Pectin
Pelleting
Pentoses
Phenols
Phophoinositides
Phosphatidyl serine
Phosphoglycerdes
155
184
35
252
30
275
93
93
92
Handbook of General Ammal Nutrition
Phospholipids
91
Phosphorous
107
93
Phosphosphinosides
Phytic acid
275
177
Pigmenters
210
Pigments
Plant enzymes
208
Plant factor
17
Plasmogens
93
Polenske Number
89
Potassium
111
Potatoes
188
Prebiotics
176
11, 175
Probiotics
Protein
57
Protein deficiency Symptoms 80
238
Protein Equivalent
Protein metabolism
74
Protein Quality
238
Protein Replacement Value 240
Protein synthesis
78
Protein Value
237
70
Proteolysis
Pyridoxine
153
R
Rabi crops
Red dog
Reichert- Meissl number
Riboflavin
Rice
Rice bran
Rice bran cake
Rice polish
Ricket
Role of nutrition
Roughages
181
10
89
151
190
193
192
193
106
5
181
S
Saponins
271
286
Saturated Fatty Acids
Selenium
Senji
Silo
Soaking
Sodium
Sodium hydroxide
treatment
Sorghum
Soyabeancake
Starch
Steam flaking
Steam rolling
Steroid Hormones
Steroids
Sterols
Sugar beet
Sulphur
Sweet potatoes
86
124
184
11,205
253
110
261
184
192
33
254
253
95
94
94
186
113
188
T
Tannin
Tapioca
Teosinte
Tetrasaccharides
Til cake
Tocopherol
Toxic elements in water
Toxic Substances
Tranquilizers
Transmethylation
Tree leaves
Tricarboxylic acid cycle
Tubers
Turnips
276
187
184
32
192
142
25
267
176
76
185
48
187
186
U
Urea formation
Urea recycling
Urea toxicity symptoms
76
72
73
Index
V
Vitamin A
Vitamin B Complex
Vitamin-C
Vitamin-D
Vitamin-E
Vitamin-K
133
149
162
138
142
145
W
Wastelage
204
287
Water
Water metabolism
Water soluble vitamins
Wet processing method
Wheat
Wheat bran
21
24
149
253
190
193
Z
Zaid roughages
Zinc
183
121