Effect of Dietary Fat and Cholesterol on the in vitro Incorporation of Acetate-14C into Hen Liver and Ovarian Lipids

Abstract

A study was made of the incorporation of acetate-1-14C into the lipid fractions of liver slices and ovarian tissues from hens fed a basal diet and diets containing either safflower oil (30%), animal fat (30%), cholesterol (1%), or cholesterol (1%) and safflower oil (29%). When safflower oil was fed, acetate, incorporation into total liver lipids decreased. The distribution of 14C (ratio of 14C in a particular fraction to the 14C in total lipids) increased in the cholesterol and phospholipid fractions, decreased in triglycerides, and remained the same in diglycerides and cholesterol esters. When animal fat was fed, the distribution of 14C increased in the cholesterol fraction and decreased in triglycerides, but total lipid synthesis was depressed further than it was when safflower oil was fed. When cholesterol was fed, acetate incorporation into liver cholesterol decreased, while incorporation into triglyceride increased slightly. When both safflower oil and cholesterol were included in the diet, synthetic control by cholesterol predominated. Regulation of the pathways of lipid biosynthesis from acetate was observed in ovarian tissue only when the diet containing both cholesterol and safflower oil was fed. The implications of these results on the synthesis of egg yolk lipids are discussed.