The Effect of Fat Level of the Diet on General Nutrition VII. Comparison of the Potency of Arachidonic and Linoleic Acids in Furnishing the Requirement for Essential Fatty Acids in the Rat ,

Abstract

Methyl arachidonate has been shown to have 3.5 times the biopotency of linoleic acid when fed to fat-deficient rats; the ratio of the biological activity of arachidonate to that of linoleate when these acids were fed as a mixture was found to be 6.2:1. The requirement of the male rat for linoleate was shown to exceed 100 mg daily; in confirmation of our earlier work, it has been demonstrated that the optimum level for female rats is considerably lower than that for male animals. The gain in weight noted in an 8-week assay period was greater in the rats receiving a cottonseed oil diet than in those on a fat-low regimen supplemented with as much as 100 mg of linoleic acid daily, 20 mg of methyl arachidonate per day, or mixtures of these two essential compounds. The efficiency of utilization of the calories was increased progressively with increasing dosages of essential fatty acids; however, the highest efficiencies were obtained with the 30% fat diet. Greater efficiency of utilization of the calories obtained in the males than in the females.