773.5 | 60.0 | 6.9 | 362.8 | 2.5 | 1895
Milk | 2000.0 | 63.0 | 92.6 | 100.0 | 14.0 | 1585
| | ------- + ------- + -------+-------+---------
Total | 38.2 | 123.0 | 99.5 | 462.8 | 16.5 | 3480
Feces | | 9.9 | 7.0 | 11.3 | 10.1 | 194
| | ------- + ------- + -------+-------+---------
Total amount | | 113.1 | 92.5 | 451.5 | 6.4 | 3286
digested | | | | | |
Per cent digested | | | | | |
or coefficients | | | | | |
of digestibility| | 92.0 | 93.0 | 97.5 | 38.8 | 94.4
| | | | | |
Available energy | | -- | -- | -- | -- | 90.0
=============================================================================

In this experiment 92 per cent of the crude protein, 93 per cent of the
ether extract, and 97.5 per cent of the carbohydrates of the bread and
milk ration were digested and absorbed by the body. In calculating the
available energy, correction is made for the unoxidized residue, as urea
and allied forms. It is estimated that for each gram of protein in the
ration there was an indigestible residue yielding 1.25 calories.

226. Available Nutrients.--A food may contain a comparatively large
amount of a compound, and yet, on account of its low digestibility, fail
to supply much of it to the body in an available form. Hence it is that
the value of a food is dependent not alone on its composition, but also
on its digestibility. The digestible or available nutrients of a food
are determined by multiplying the per cent of each nutrient which the
food contains by its digestion coefficient. For example, a sample of
wheat flour contains 12 per cent protein, 88 per cent of which is
digestible, making 10.56 per cent of available or digestible protein (12
x 0.88-10.56). Graham flour made from similar wheat contains 13 per cent
total protein, and only 75 per cent of the protein is digestible, making
9.75 per cent available (13 x 0.75 = 9.75). Thus one food may contain a
larger total but a smaller available amount of a nutrient than another.

227. Available Energy.--The available energy of a food or a ration is
expre