Conjugated Linoleic Acid and Dietary Fats Differentially Affect Hepatic ACAT Activity and LDL-Cholesterol in Postweanling Pigs Fed Low-Fat Diets

摘要

Two separate studies tested the hypothesis that plasma low-density lipoprotein cholesterol(LDL-C)can be decreased by conjugated linoleic acid(CLA)by depressing hepatic acyl-coenzyme A:cholesterol acyltransferase(ACAT)activity.In the first experiment,3 groups of 6 early-weaned piglets were fed low-fat diets containing either 1.5% CLA,1.5% corn oil or 1.5% beef tallow;fat provided 8% of the energy intake.In the second experiment,4 groups of 6 early-weaned piglets were fed high-fat diets containing either 15% beef tallow,12% beef tallow plus 3% CLA,15% corn oil,or 12% corn oil plus 3% CLA;fat provided 29% of energy intake.Cholesterol was balanced across diets in both experiments.In pigs fed the low-fat diets,all dietary fats increased LDL-C and triacylglycerols and decreased high-density lipoprotein cholesterol(HDL-C)and very low-density lipoprotein cholesterol(VLDL-C).LDL-C was the same in pigs fed low-fat tallow or low-fat CLA diets.However,ACAT activity was nearly 80% higher in pigs fed the low-fat tallow diet than in pigs fed the low-fat CLA diets.All high-fat diets increased LDL-C,HDL-C and triacylglycerols equally with no effect on VLDL-C.There were no unique fatty acid effects of the high-fat diets on ACAT activity.We conclude that supplemental fats had differential effects on hepatic ACAT activity and LDL-C,but only in pigs fed low-fat diets.