A Study of Sex Differences in the Composition of Rats, with Emphasis on the Lipid Component

Abstract

Male and female albino rats were raised on 3 simplified diets; the control diet contained 20% lard while the other 2, deficient in essential fatty acids, were fat-free and rich in saturated fat (hydrogenated coconut oil), respectively. The composition of these individuals in terms of total lipid, total non-lipid solids, and water content was determined in addition to the unsaturation of body fat. A sex difference in the unsaturation of fatty acids obtained from the body fat of rats raised on the 3 respective diets could not be established. Evidence was presented showing that on a high-fat diet deficient in essential fatty acids females store more fat than males, and it was adduced that the latter are more sensitive to a deficiency in essential fatty acids than the females when both derive the bulk of their calories from fat. Rats receiving a diet very high in saturated fat, but lacking essential fatty acids, are unable to effect an appreciable increase in the amount of total body lipid, but they readily exchange the dietary fatty acids with those in the tissues.