INFLUENCE OF PROPIONIC ACID ON THE CHOLESTEROL METABOLISM OF PIGS FED HYPERCHOLESTEROLEMIC DIETS

Abstract

Sixty-four crossbred pigs averaging 24 kg liveweight were used to study the effects of dietary propionic acid (PA) on plasma and tissue cholesterol concentrations of pigs fed hypercholesterolemic diets for 10 wk. Four diets, based on barley, wheat and soybean meal, consisting of a control diet and a diet containing 10% tallow, both fed with and without the addition of 5% PA were used in this study. Addition of PA to the control diet decreased feed intake (ADF) by 16%, decreased average daily gain (ADG) by 8% and improved feed conversion efficiency (FCE) by 8%. Addition of tallow to the control diet resulted in a 15% reduction in ADF, a 3% improvement in ADG and an 18% improvement in FCE. When both tallow and PA were present, ADF was depressed 26%, ADG decreased 5% and FCE improved 23%. The addition of tallow significantly increased the levels of total plasma cholesterol while the addition of PA significantly decreased the plasma cholesterol levels in comparison with the control diet and prevented the increase noted in the tallow group. Addition of PA to the control diet significantly increased the cholesterol content of backfat and significantly reduced the cholesterol content of the kidneys. Addition of PA to the tallow diet significantly reduced the cholesterol content of kidneys, but did not significantly affect the cholesterol content of backfat. It is suggested that the increased cholesterol content of backfat in pigs fed diets containing PA reflects a reduced transport of cholesterol from peripheral tissues to the liver for excretion in the bile.