Sept. 2 ,1918 
Comparative Toxicity of Cottonseed Products 
449 
AN EXPERIMENT WITH COMMERCIAL COLD-PRESSED MEAL 
Experiments with rats and rabbits revealed the fact that cold-pressed 
meals were not so markedly toxic as certain hot-pressed meals made 
from very dry seed and insufficiently cooked. It was thought desirable 
to ascertain how a cold-pressed meal would affect pigs. 
Two pigs in pens were fed for 30 days on a cold-pressed meal and 
corn meal (1: 2). The pigs were fed as much as they would readily eat. 
They consumed relatively much more meal than was eaten during the 
previous experiments with hot-pressed meal, and maintained good 
appetites throughout. No safe conclusion may be drawn, but it was 
evident that these animals were less affected in this short period than 
the pigs on diets 1 and 2 of the previous experiments in a similar period. 
The fact that by far the greater part of the gossypol of the raw seed is 
removed from cold-pressed cottonseed meal and that the remaining 
small amount may undergo oxidation, etc., while the hot meal is exposed 
to the air should prove of interest in the practical matter of avoiding 
cottonseed-meal “injury” of swine. The results of this experiment are 
given in Table XII. 
Table XII .—Effect of commercial cold-pressed cottonseed meal on the growth of pigs 
Weight. 
Average quantity of 
cottonseed meal eaten. 
Initial. 
Final. 
Gain. 
Total. 
Per day. 
Pounds. 
70 
8S 
Pounds. 
8S 
99 
Pounds. 
15 
14 
Pounds. 
32. I 
32. I 
Pounds. 
I. 07 
I. 07 
GENERAL SUMMARY AND CONCLUSIONS 
f 
Various cottonseed products, including raw cottonseed kernels, ether- 
extracted kernels, gossypol, and several meals, have been fed to rats, 
rabbits, poultry, and swine. 
Raw cottonseed kernels and the gossypol therefrom have been found 
highly toxic to all these animals. Cooking the kernels under oil-mill 
conditions causes a profound reduction in toxicity. This change is so 
great that the thoroughly cooked products show no pronounced toxic 
effect on rats and poultry in suitable diets. Thoroughly cooked meals, 
however, appear to be definitely injurious to rabbits and swine, which 
are peculiarly susceptible to cottonseed-meal “injury.” Rats and fowls 
are able to withstand much larger relative amounts of cottonseed meal 
for longer periods. In the “cold-pressing” process of making cottonseed 
meal the toxic substance passes into the oil to a great extent, thus leaving 
a meal which may be less harmful than certain hot-pressed meals. 
