Dietary raw peas (Pisum sativum L.) reduce plasma total and LDL cholesterol and hepatic esterified cholesterol in intact and ileo-rectal anastomosed pigs fed cholesterol-rich diets

Abstract

ABSTRACT Although the cholesterol-lowering effect of some dietary legumes is well established from animal and human studies, the mechanism by which they exert this effect is not completely understood. The present study was undertaken to investigate the effect of raw pea seeds on cholesterol metabolism and steroids output of intact and ileo-rectal anastomosed (IRA) pigs. Twenty-four growing pigs were divided in four groups and allocated to cholesterol-rich semi-purified casein (C) (pigs with and without IRA) and raw pea seeds (RP) diets (pigs with and without IRA). Diet-induced hypercholesterolemia was inhibited by RP diet through a significant decrease in plasma LDL-cholesterol. LDL receptors activity was significantly higher in intact RP-fed pigs. RP diet was also responsible for liver triacylglycerols and free cholesterol increases and liver esterified cholesterol reduction. RP-fed pigs higher gallbladder bile free and total cholesterol were not accompanied by significantly higher fecal and ileal digesta neutral sterols output, but increased bile acids were detected in bile and fecal and ileal digesta of these animals. Meanwhile, no differences were detected between cholesterol 7α-hydroxylase and sterol 27-hydroxylase activities. IRA effects were mainly registered on the inhibition of cholesterol and phytosterols bacterial transformation, on higher absorption of ileal digesta bile acids, and on the reduction of ileal digesta secondary to primary bile acids ratio. These results suggest that the mechanism for the hypocholesterolemic effect detected in this trial involved a modulation of liver LDL receptor levels, an increased hepatic cholesterol conversion into bile acids and increased cholesterol clearance via the intestinal route.