The fat composition of milk-fed rats

Abstract

The ether extract of rats fed from the time of weaning for 11 wks. on milk alone was studied in detail. The comp. of the rat fat was only slightly altered from "normal" by the milk diet. Of the 22.8% (molar) of C4, Co, C8, C10 and C12 acids present in milk fat only 1.4 mol. % (C10 and C12 acids) were stored by the rat. The somewhat larger amt. of myristic acid than is usually obtained from rat fats might be related to the quantity present in the milk fat. On a low fat diet, the rat appeared to build a body fat of roughly constant comp. This usually contained small amts. (3-6%) of myristic, stearic, hexadecenoic and octadecadienoic acids with approximately constant amts. of both palmitic (25%) and oleic (45-50%) acids. The presence of tetradecenoic acid was indicated, as was also that of decanoic, lauric, arachidic and arachidonic acids (1% or less, each). From a consideration of various data reported for rat fats, a threshold level of the saturated acids as suggested by Barbour [1934] was likely to occur at 32-35 mol. % (somewhat higher than Barbour''s original figures).