180 
Journal of Agricultural Research 
Vol. XXVIII, No. 2 
Eighty days after the 50-gram body weight had been attained, the weight of 
the six male rats fed peanut meal ranged from 255 to 284 gm. with 273 gm. as 
an average. On the fortieth day the range for the four female rats was 147 to 
174 gm., with an average of 157 gm. 
The range of weights for the six males receiving the ether-extracted cottonseed 
kernel diet was 245 to 282 gm., with an average of 259 gm. on the eightieth day. 
The different butter fat quantities fed made no apparent difference in these few 
experiments. Therefore the growth curves have been arranged together. The 
maximum range and average body weight are only slightly below those for the 
males on the peanut meal diet, and appear to be within the limits of experimental 
error when so few experiments are used. The growth curve of the single female 
rat does not differ greatly from the rate of growth of the female rats on the peanut 
meal diet. It is 10 gm. below the lowest weight on the peanut diet. The bulki¬ 
ness of the ether-extracted cottonseed kernel diet probably accounts for the 
very slightly smaller average daily intake of this diet (not shown on the charts), 
in which case, other things being equal, a slightly less rapid growth was to be 
expected. According to the literature, the utilization of cottonseed protein in 
animal feeding is not as complete as the utilization of protein in many other 
kinds of feed. However, it has been shown in the Protein Investigation Labora- 
Fig. 3.—Effect on young rats of diet containing 0.225 per cent gossypol. Figure at left of curve indicates 
the weight at the beginning of the experiment; figure above the curve, the laboratory number of the 
animal. Because of short duration of experiments chart has been drawn on a scale twice that used in 
preceding and succe eding charts 
tory of the Bureau of Chemistry that isolated cottonseed protein is as well di¬ 
gested in vitro as casein and arachin, the protein of the peanut (5 ). 
The conclusion to be drawn from these experiments is that for the purpose of 
this study there was no significant difference in the rate of growth of rats fed 
the peanut meal diet and those fed the ether-extracted cottonseed kernel diet. 
CONTROL DIET CONTAINING ADDED GOSSYPOL 
That the diet was totally adequate has been shown. The growth curves 
in figure 3 show that young rats used in these tests failed to grow and eventually 
died on a diet containing 0.225 per cent of gossypol. On a diet containing 0.18 
per cent two rats died rather soon, while two lived for some time (fig. 4). Re¬ 
covery to some extent was begun when the diet was changed to the control food. 
From these few tests it is impossible to say with certainty that the subsequent 
decline on the control diet was connected with the previous gossypol feeding. 
From other experiments, however, it would seem that after the removal of gos¬ 
sypol from the diet, animals do not always recover their full health or normal 
growth rate. It is not certain in any of these tests that some of the results may 
not have been due to loss of appetite. 
The rates of growth of rats upon diets containing 0.045, 0.0675, 0.09, and 0.135 
per cent of gossypol are given in figures 5 to 9. 
