Effects of different fractions of the barley kernel on the hepatic lipid metabolism of chickens,

Abstract

Various physical fractions of the barley kernel were fed to one-day-old female and male chickens to determine their effect on hepatic β-hydroxy-β-methylglutaryl coenzyme A (HMG-CoA) reductase, cholesterol 7α-hydroxylase and the lipogenic enzymes, acetyl-CoA carboxylase (ACX), malic enzyme (ME), citrate-cleavage enzyme (CCE) and fatty acid synthetase (FAS) at the subcellular level. Significant inhibition (p<0.01) of cholesterol biosynthesis accompanied by significant decreases in plasma cholesterol concentrations and induction of fatty acid synthesis were found in diets based on pearled barley, barley pearlings and a high-protein barley flour (HPBF: aleurone and subaleurone layers of barley endosperm) separated from the pearlings when compared to corn. Lower weight gains in 1- to 4-week-old birds fed the high-protein barley flour were found to be the result of lower feed consumption; pair feeding of 12-week-old birds with diets based on corn and high-protein barley flour produced equal weight gains in both treatments and significant reductions in hepatic HMG-CoA reductase, plasma cholesterol and induction in several lipogenic enzymes in birds fed the high-protein barley flour. Substitutions of 5–20% high-protein barley flour for corn in a corn-based diet produced significant weight gains (p<0.01) of 10 to 20% in 2-week-old chickens, inhibited cholesterol biosynthesis by 45–65% and produced a 3-fold increase in a fatty acid synthetase. The results indicate that HPBF contains an inhibitor(s) of cholesterol biosynthesis and a growth factor(s) when compared to a corn-based diet.