Chapter 1 The animal and its food

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Transcript Chapter 1 The animal and its food

Chapter 1-3
Concepts of Nutrition
• The food components capable of being utilized
by animals are described as nutrients. That
supports normal reproduction, growth, lactation
or maintenance.
• The six classes of nutrient: water, protein
( amino acids ) , carbohydrate, lipids,
vitamins and inorganic elements.
• Nutrient support cellular need for water,
fuel, structural constituents , metabolic
regulation.
• Food: an edible material that provides
nutrients.
• Feed: a food but is more applied to animal
food than to human food.
• Foodstuff (Feedstuff ): any material made
into food or feed.
• Diet: is a mixture of feedstuff used to
supply nutrient to an animal.
• Ration: is a daily supply of feed.
1.1 Water
• 75-80% in newborn animals, 50% in
mature fat animals
Table 1.1 Composition of some plant and animal products
expressed on a fresh basis and a dry matter basis
1.1 Water
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The water content of food is variable
60g/Kg in concentrate to 900 g/Kg in
some root crops. Because of this great
variation in water content, the
composition of foods is often expressed
on a dry matter basis.(table 1.1).
1.2 Dry matter (DM) and its
components
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Organic material
Different carbohydrate in animal and
plant cell wall
Cell wall of plant consist of carbohydrate
material (cellulose), the wall of animal
cells are lipid and protein.
1.2 Dry matter (DM) and its
components
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The lipid content
Protein component
Organic acid occur in animal and plant
Inorganic material
Vitamin
Other inorganic: calcium and phosphorus
are major components of animal.
Chapter 3 Common Methods of Analysis
for Nutrients and Feedstuff
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Sampling for analysis
small amount of material that give the
best reasonable estimate of the total
batch.
Ex.: protein determination, 2g
beef carcass, 9-10-11 rib cut give a
accurate estimate of the total carcass for
fat, protein water and ash.
Analytical methods
1. chemical method: use various chemical
procedures that are specific for a given
element or compound. It can’t answer the
availability of nutrients from feeds
2. biological method: tell the amount of a
nutrient that animal uses from feeds. Chick
and rat often use this.
3. microbiological method: determine how
much of a given amino acid or vitamin is
available in a given product or mixture.It
may not be applicable to animals.
• Proximate analysis is developed in
Germany well over a century ago.
• It has many faults.
• Forage analysis by the detergent extration
methods of Van Soest(1982).
Proximate analysis of foods
(Composition of food)
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Moisture
Ash
Crude protein (CP)
Ether extract (EE)
Carbohydrate
Crude fibre (CF)
Nitrogen-free extractives (NFE)
Moisture
• The loss in weight that result from drying a
known weight of food to constant weight at
100℃.
Ash
• The loss in weight of the food at 550℃
until all carbon has been removed. The
residue is the ash and is taken to
represent the inorganic constituents of the
food.
Crude protein (CP)
• Calculated from the nitrogen content of the
food(16%), determined by a modification
of a technique originally devised by
Kjeldahl method. Nitrogen x 6.25=protein
Ether extract (EE)
• Determined by subjecting the food to a
continuous extraction with petroleum ether
for a defined period. The residue, after
evaporation of the solvent, is the ether
extract.
Crude fibre (CF)
• Determined by subjecting the residue food
from ether extraction to successive
treatments with boiling acid and alkali of
defined concentration; the organic residue
is the crude fiber.
Nitrogen-free extractives (NFE)
• When the sum of the amounts of moisture, ash,
crude protein, ether extract and crude fibre, the
difference is designated the nitrogen-free
extractives.
• NFE is made up primarily of readily available
carbohydrates, such as the sugers and starches,
it may also contain some hemicellulose and
lignin in the forage.
Measurement of protein in foods for ruminants
Fig 1.1 Proposed model for characterization of foods for ruminants. Cornell
net carbohydrate and protein system, The neutral and acid detergent
extraction of Van Soest.
Table 1.2 Classification of forage fractions using the detergent methods
of Van Soest.
Fibre
• NDF (neutral detergent fiber)
• The residure after extraction with boiling
neutral detergent , consist mainly of lignin,
cellulose and hemicellulose .
• ADF(acid detergent fiber)
• The residure after extraction with boiling
acid detergent , consist mainly of lignin,
cellulose .
Dietary fibre
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Defined as lignin plus those
polysaccharides that cannot be digested
by monogastric endogenous enzymes.
• NSC (Non-structural carbohydrate )
• The fraction obtained by subtracting the
sum of the amounts (g/kg) of CP, EE, ash
and NDF from 1000
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NSP(non starch polysaccharide)
Represent the components of cell walls.
Modern analytical methods
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Starch and sugars
Minerals: Atomic Absorption
Spectrophotometry
Amino acid
Fatty acid: Gas-liquid chromatography
Energy : bomb calorimetry