186 
Journal of Agricultural Research 
Vol. XXVIII, No. 2 
REPRODUCTION, STUNTING, AND SENSITIVITY DUE TO AGE, TEM¬ 
PERATURE, AND APPETITE 
Grown rats, some of which had been raised on control diets, as well as some 
which had been raised on diets containing a small quantity of cottonseed kernels 
or gossypol, were fed the more toxic concentrations of cottonseed kernels or 
gossypol. The results of these tests vary somewhat and are not sufficient in 
number to warrant detailed consideration. Nevertheless, they show that the 
older rats were less sensitive than the younger ones. Perhaps this is due to the 
relatively small food requirements of the larger rats. In consequence, they 
would ingest less gossypol in proportion to their body weight than the smaller 
rats. Perhaps the loss of appetite, a symptom of gossypol intoxication, was a 
factor, for inanition is more serious for a young rat than for an old one. 
Several litters of young were reared on a diet containing 0.0675 per cent of 
gossypol. There appeared, however, to be an undue proportion of breeding 
failures. With 0.135 per cent in the diet no litters were born, although breeding 
was attempted. 
Post-mortem examination of several undersized rats revealed nothing abnormal 
except when a decided loss in body weight had occurred. The tail and body 
lengths and the weight of undersized rats which had not lost body fat agreed with 
those reported by Donaldson (4). The weights of the heart and liver were also 
within the normal limits for rats of their size. This touches upon a practical 
problem in nutrition as yet unsolved—the criterion by which stunting of a mild 
type and without evidence of malnutrition or disease is to be determined. Thus 
a possibility to be considered is that the feeding of certain quantities of cotton¬ 
seed products containing gossypol under some conditions, while apparently com¬ 
patible with perfect health, may produce undersized animals. 
Temperature affects the resistance of animals to gossypol. In the winter and 
cool spring weather when the laboratory was not well heated at night young 
rats and grown mice succumbed to concentrations of gossypol which otherwise 
would have survived. This was also true of young rats fed diets containing 
raw cottonseed kernels. No mice were tried on this diet. These observations 
agree with the observation made on cottonseed meal, namely, that cold increases 
the sensitivity of the animals to it. In the authors 7 feeding experiments it did 
not appear that the cause of the increased toxicity was the increased consumption 
of food which caused an increase of gossypol intake per kilo of body weight of the 
animal. Presumably the deaths must be placed under the vague caption 
“exposure. ” 
Gossypol and raw cottonseed kernels markedly affect the appetite, although 
the effect is not regular. It appears that one gets the normal weight variation 
plus a variation due to the effect of gossypol on the appetite. This is shown in 
some groups of animals in which the difference between the better and the poorer 
growths is greater in the case of animals fed gossypol or cottonseed than in those 
on the control diet. 
The extent of growth followed the appetite or food intake. Comparisons, 
however, were made only when approximately the same concentrations of gossypol 
or comparable quantities of cottonseed kernels are involved and for the same 
sex. The food intake diagrams are not presented. 
