Effect of Fat in Diet on Unsaturated Fatty Acids in Phospholipid, Cholesterol Ester and Glyceride Fractions in Serum of Dogs

Abstract

The distribution of the essential fatty acids in blood serum as influenced by diet has been determined in the phospholipid, cholesterol ester and glyceride fractions for 10 healthy control and 12 fat-deficient dogs. In the diet of healthy animals, dietary fat and linoleic acid constituted 30% and 4% of the calories, respectively. In the fat-deficient group, these were 1% and 0.1%, respectively. Spectrophotometric analysis was used for determination of the 2, 3, 4, 5 and 6 double-bond fatty acids. In control animals, there were appreciable amounts of di- and tetraenoic acids present in the phospholipids and cholesterol esters with tetraenoic (arachidonic) acid predominating in the former and dienoic (linoleic) predominating in the latter fraction. There was very little tri-, penta- and hexaenoic acid in the serum of healthy dogs. In fat-deficient dogs, serum levels were low for di-, tetra- penta-and hexaenoic acids in all fractions, but were high for trienoic acid in the phospholipid and cholesterol ester fractions. Trienoic acid was the predominant unsaturated fatty acid in the phospholipids of these animals. Glycerides for both groups of dogs contained more dienoic than tri-, tetra-, penta-and hexaenoic acid. Significant differences in fat levels and distribution of the unsaturated fatty acids between male and female dogs were not demonstrated. However, young control animals showed lower levels for dienoic acid than adult animals. Young animals in the low-fat group had lower levels for di- and trienoic acids than adult dogs.