ANIMAL NUTRITION
DEFINITION OF TERMS
Nutrition is the study of various physical and chemical processes that
transform food elements to body elements and the influence of
various feed additives to various processes in the body. It involves
the ingestion, digestion and absorption of various nutrients, their
transport to all body cells, its metabolism and the removal of
unusable nutrients and waste products and metabolism.
The series of processes by which an organism takes in and
assimilates food for promoting growth and replacing worn-out or
injured tissues.
Encompasses several fields of discipline like biochemistry,
chemistry, physiology, endocrinology, microbiology, genetics.
Food/Feed Term given to any materials that embraces naturally in both plants
and animals including its by-products prepared from them.
Example: corn, rice bran, fish meal, soybean meal, etc.
Feedstuff Term given to any materials both natural in origin and synthetically
prepared that when properly used have nutritional value in the diet.
Example: Corn, DL – Methionine, Feed supplements, some
vitamins premixes, etc.
Prepared by: JE PEPITO-May '09
Nutrients are substances or elements found in the feeds that are very necessary
to support normal life processes of the animals. These are the
carbohydrates, fats, protein, minerals, vitamins and water.
Any feed constituent, or a group of feed constituents of the same
general chemical composition that aids in the support of life.
May include synthetically produced vitamins, chemically produced
inorganic salts or biogenically synthesized amino acids.
Ration the food given to the animals with balance of all nutrients needed by
the animals within 24 hours requirement/food allowance.
Diet it is the kind of food given to animals regardless whether balance or
unbalance of nutrient requirements needed by the animals.
Digestion is the process of breaking down of food particles through mechanical,
enzymatic and/or microbial process in the preparation for nutrient
absorption.
Absorption is the transport of all digested nutrients to all parts of the body tissues
and cells.
Transfer of substance from gastro-intestinal tract (GIT) to the
circulatory (blood, or lymph) system.
Prepared by: JE PEPITO-May '09
Metabolism is the next process of nutrient utilization in the body after it is
digested and absorbed in the cells. It is the sum total of all
physical and chemical changes occurring in the body where
nutrients are metabolized into energy in the form of ATP, carbon
dioxide and water (metabolic water)
Combination of anabolic (reactions that build and maintain the
body through energy formation) and catabolic (reaction
that release energy by the breaking down of substances)
reactions occurring in the body with the liberation of
energy).
Metabolic water is the water produced from the nutrients (carbohydrates, fats and
protein) when metabolized in the cells.
Enzymes A complex protein produced in living cells that causes changes in
other substances within the body without being changed itself
(organic catalysts).
Acid Detergent This value represents the fiber portion of the forage that is left
Fiber after treatment with detergent in acid conditions. Its value
essentially is the indigestible and poorly digestible portions of
the plant and can thus be used to estimate digestibility of the
forage when fed.
Prepared by: JE PEPITO-May '09
Neutral Detergent This value represents the fiber portion of the forage that is left when
Fiber treated with a neutral detergent. Its value is essentially the
digestible and indigestible portions of the cell wall. Neutral
detergent fiber is inversely related to dry matter intake. This
means that as the NDF in forages increases, animals will be able
to consume less of the forage.
Crude fat A measure of the total fat in the forage.
Lignin is an indigestible non-carbohydrate component in forage. It
increases in forages as they mature.
Non-Fiber This value approximates the carbohydrates that can be rapidly
Carbohydrate fermented in the rumen and usually represents pectins, starches,
and sugars.
Crude Protein The total protein in a feed ingredient estimated from the total
nitrogen measured. CP = %N * 6.25
True Protein That protein which is composed of only amino acids
Non-Protein- Compounds which are not true protein in nature but contain N and
Nitrogen can be converted to protein by bacterial action (i.e. urea)
Digestible Protein That portion of the crude protein which is the animal can digest;
represented by the difference what is present in the feed and what
is appear in the feces.
Prepared by: JE PEPITO-May '09
Available Protein Protein that is not damaged or bound and is available for use by the
animal
Unavailable Protein that is unavailable to the animal. Heat damaged protein that
Protein is found in this fraction
Neutral Detergent This is protein that is contained within the neutral detergent fiber of
Crude Protein the forage. Typically this fraction contains the slowly digested
protein and the bound or unavailable protein.
Soluble Protein This protein is completely soluble (dissolves) in the rumen and is
rapidly converted to ammonia.
Degradable The portion of the protein that is degraded in the rumen
Protein
Total Digestible This is a measure of the total digestible energy in the forage.
Nutrients
Prepared by: JE PEPITO-May '09
GROSS CHEMICAL COMPOSITION OF PLANT AND ANIMAL TISSUES
Nutrient Plant Animal
Carbohydrates Very high – 75 % Zero-negligible
Comparison of Fats Low 3-10 % pseudo fats High 20 % true fats
plant and animal Protein Low – High 3-45% High 20-75%
in terms of Minerals Low – 0.5% High 4%
nutrients: Vitamins High High
Water High 60% High 60 %
Feeds contain nutrients (water, energy, protein, minerals and vitamins) that are
used to meet the requirements (maintenance, growth, production, reproduction and
health) of animals. Feeds also contain substances that have no nutritive value.
Some compounds have complex structures that are indigestible and may interfere
with the digestion of some nutrients (i.e. tannins, lignins). Thus, feed composition
and routine analysis is presented below.
Prepared by: JE PEPITO-May '09
Feed
composition
and routine
laboratory
analysis
Prepared by: JE PEPITO-May '09
Nitrogen Free Extract (NFE) = 100 – [(%water + %Crude Protein + % Crude Fiber +
% Crude Fat + % Crude Fiber)]
Total Digestible Nutrient (TDN) = % COD * % Crude Protein
+ % COD * (% Crude Fat * 2.25)
+ % COD * % Crude Fiber
+ % COD * % NFE
∑ TDN
Coefficient of Digestibility (COD) or Apparent digestibility
% Nutrient in the Feeds [intake] - % Nutrient in Feces
= ----------------------------------------------------------------------- * 100
% Nutrient in the Feeds [intake]
Prepared by: JE PEPITO-May '09
Factors affecting digestibility:
a. age of animals
b. disease and/or parasites
c. feed source and composition of diet
d. level of feed intake
e. rate of passage through GIT (Rapid – lack of time for complete digestive action
and absorption; Slow – may be excessive subject to wasteful fermentation;
highly influenced by particle size and degree of feedstuff preparation)
f. nutrient excess or deficiency – cause poorer of absorption and utilization of
other nutrients
g. digestibility of a mixture or physical form of a feed
h. Temperature
Classes of Nutrients:
Water and Energy
Prepared by: JE PEPITO-May '09
