Antagonism of Fresh Fat to the Toxicity of Heated and Aerated Cottonseed Oil

Abstract

The inclusion in a rat diet of 15 to 20% of refined cottonseed oil, aerated and heated to 95°C. for 200 to 300 hours, led to rapid loss of weight and death within three weeks. The condition was accompanied by diarrhea and by the occurrence of large livers, kidneys, and adrenals and small spleens and thymuses. Histologically, the only change was an occasional intestinal edema. Addition of fresh oil to the diet containing the heated and aerated oil protected the animals against the toxicity. Only growth retardation persisted. This protective effect could also be observed in paired-feeding experiments in which the paired rats received the same number of calories and equal amounts of protein and of treated oil. When fresh cottonseed oil was fed by dropper instead of being included in the diet, its protective effect was only slight. Extra feeding of 25 mg of DL-alpha-tocopherol acetate (and other fat-soluble factors) gave mild protection. Peroxides are probably not responsible for the toxic effect of the heated and aerated cottonseed oil; polymerization may be a better explanation. No definite explanation for the antagonism of fresh to treated oil can be given; the effect is probably not due to an antimetabolite relationship but could be caused by a change in the state of polymerization.