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DIFFERENT METHOD OF NUTRIENT
DIGESTIBILITY IN ANIMALS
SUBMITTED BY
ASAD ULLAH BABER
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DIFFERENT METHOD OF NUTRIENT DIGESTIBILITY IN ANIMALS
Digestibility
The word digestibility as used in animal nutrition has limited
meaning. It denotes only the
percentage of the feed which is digested or otherwise retained
in the body.
Through this we can measure the chemical composition of o feed
and energy given by him.
Following method are use to determine the nutrient
digestibility.
IN VIVO DTERMINATION METHOD Total collection method Difference
method Marker method
Total collection method
The accurate feeding of weighed amount of individual feed or
thoroughly mixed ration and the
collection of excreta without loss are important to the conduct
of digestion experiments.
Certain equipment are use in this method.
A metabolic crate is actually a stall or box large enough for
the set on legs from 50 cm to 1 m
high. It is also planned as to permit the qualitative collection
of feces and urine under it or in
the lower part of it. The feces collected daily should be
weighed, thoroughly mixed, recorded
and taken one-tenth aliquot.
Procedure
y Add 10 ml toluene or a crystal of thymol to sample to inhibit
bacterial action.y Otherwise freeze the samples.y Keep the daily
aliquots in sealed jars or plastic bags in the refrigerator, each
days
collection being added to the previous ones.
y Keep the permanent numbers on the storage containers to
correspond with the animalnumbers.
y 5-14 days is collection periodFormula
% dry matter digestibility
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Difference method
Digestibility, when feedstuff is fed in combination with one or
more than one feedstuffs. It is
generally used to evaluate tha energy and protein supplements
which are not routine feed
ingredient in a diet.
Digestibility of such feedstuffs can be calculated by
determining the digestibility of mixed diet
containing the feedstuff of interest if digestibility of other
feed ingredient is determined
previously.
It is assume that the digestibility of mixed diet is equal to
the summation of the proportion s of
the diet supplied by the digestibility of that ingredient if it
were fed alone .
Formula
100
Marker method
This method is time consuming and this method require more
expenses other than two
method.
In this method, in addition to the chemical analysis of usual
proximate nutrients, the contents
in feed and feces of an indigestible reference substance is
determined.
The substance may be a natural constituent of the feed (internal
indicator) or it may be added
to the feed or administered orally to the animal (external
indicator).
The digestibility is calculated from the relation between the
nutrients the indicator substance in
the feed and in the feces. This method has been called a
qualitative method, although this
name is not strictly accurate.
By chemical analysis of a suitable feed sample, the ratio of the
concentration of the inert
substance to that of any nutrient in the feed can also be
established.
A similar ratio can be determined in the feces and the
digestibility can then be calculated
without weighing either the feed consumed or the feces produced.
If the percentage of
nutrient is known and the %age of the indicator substance is
also determined in the feed and
feces, the digestibility of that nutrient can be found by means
of the following formula:
)
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For indicators which in any experiment are consistently found to
be recovered incompletely in
the feces, such as is sometimes true of chromic oxide and lignin
especially, the factor for %age
recovery may be substituted for 100 in the previous equation.
Therefore, the new equation
would read as follows:
There are some situation where Marker can be used.
A. Feed intake is known but total feces cannot be collected
)
B. Neither feed intake nor fecal output is known and measure of
feed intake is desired
REFRENCES
ANIMAL NUTRITION
BY P MCDONALD, CA MORGAN
ANIMAL NUTRITION
BY Aron A. Bondi, David Drori
The influences of digestion on animal heat processes
By Edward Tyson Reichert
