16 BULLETIN 751, tJ. S. DEPARTMENT OF AGRICULTURE. 
Summary of digestion experiments witTi wheat bran in a simple mixed diet., 
Experiment No. 
Subject. 
Digestibility of entire ration. 
Esti- 
mated 
digesti- 
bility 
of pro- 
tein of 
bran 
alone. 
Esti- 
mated 
digesti- 
bility 
of carbo- 
hydrate 
of bran 
alone. 
Protein. 
Fat. 
Carbo- 
hydrate. 
Ash. 
409 
D. G..G 
A. J. H 
Per cent. 
30.8 
( 'i.o 
46.8 
27.4 
55.4 
41.8 
37.3 
Per cent. 
93.6 
88.8 
92.8 
93.2 
94.7 
95.7 
91.4 
94.5 
Per cent. 
79.9 
78. 8 
84.8 
87.6 
78.8 
88.7 
83.8 
87.3 
Per cent. 
65.2 
50.6 
60.9 
62.6 
61.7 
71.3 
62.9 
65.0 
Per cent. 
13.4 
( 2 ) 
( 35. 6 
16.7 
49.7 
31.1 
21.6 
Per cent. 
45.4 
45.8 
59.4 
60.3 
41.5 
72.1 
58.4 
60.7 
410 
411 
R. L. S 
O.E.S 
D. G. G.-._.._. 
A. J. H 
412 
436 
437 
438 
439 
R. L. S 
0. E. S 
35. S 
C3.1 
82.8 
62.5 
28.0 
55.5 
1 Negative result, fecal protein exceeding that of diet. 
2 Negative result, fecal protein exceeding that of bran eaten. Not included in average. 
On an average the food consumed by the subjects furnished 24 
grams of protein, 103 grams of fat, and 237 grams of carbohydrate 
daily, with an average energy value of approximately 1,970 calories. 
Although the subjects ate, in round numbers, 400 grams of the bran 
bread daily, the total amount of protein supplied per day was small. 
However, it was desirable that bran should furnish the major portion 
of the protein, and so, as was the case in the experiments with finely 
ground bran, no attempt was made to increase the protein intake by 
increasing the amount of potato consumed with the coarse bran bread. 
The coefficients of digestibility of the diet as a whole were 35.8 per - 
cent for protein, 93.1 per cent for fat, and 82.8 per cent for carbohy- 
drate. These values are, of course, lower than those which have been 
reported for an average mixed diet, 1 namely, 92 per cent for protein, 
95 per cent for fat, and 97 per cent for carbohydrate. 
It is of interest to compare the coefficients of digestibility of the fat 
of the diet, 93.1 per cent (practically all obtained from lard used in 
preparing the bread and butter eaten with the bread and potato), 
with the coefficient of digestibility, 97 per cent, found for both lard 
and butter in experiments previously reported. 2 
In experiment No. 410 a negative value was obtained for the diges- 
tibility of protein, the amount excreted in the feces exceeding the 
amount supplied by the diet. In experiments Xos. 409, 411, and 436 
the coefficients of digestibility were decidedly lower than in the re- 
maining tests. Excluding these low values the coefficient of digesti- 
bility of protein becomes 45.3 per cent. The average digestibility of 
the carbohydrate of the coarse bran, 55.5 per cent, closely approxi- 
mates the value 56.6 per cent obtained in the tests with finely ground 
bran. 
3 Connecticut Storrs Sta. Rpt. 1901. p. 245. 
a U. S. Dept. Agr. Bui. 310 (1915), pi. 21. 
