The effect of a combined dietary treatment with cholesterol and cholic acid on the lipid metabolism of geese at low or high choline concentrations

Abstract

A previous study demonstrated that a dietary treatment of young geese with cholesterol and cholic acid raises lipid concentrations in the liver. The present study was carried out to investigate whether such a lipid accumulation caused by those hyperlipidemic compounds can be intensified by low dietary choline concentrations. Therefore, 38 eight‐week old geese were divided into four groups of 9 or 10 animals each and received a basal diet poor in choline which consisted predominately of maize and soy protein isolate over a period of 8 weeks. Treatment factors were supplementation of diets with cholesterol and cholic acid (0 vs. 5 g of cholesterol and cholic acid each per kg) and supplementation of choline chloride (0 vs. 1.5g/kg). Final body weights as well as carcass weights were neither influenced significantly by dietary treatment with cholesterol and cholic acid nor by low dietary choline concentrations. However, feeding diets supplemented with cholesterol and cholic acid markedly increased liver weights (two‐fold), hepatic triglyceride (3.7‐fold) and cholesterol (12‐fold) concentrations and percentages of monounsaturated fatty acids at the expense of saturated and polyunsaturated fatty acids in the liver. In geese fed diets with cholesterol and cholic acid, insufficient choline supply did not intensify, but even slightly reduced hepatic lipid accumulation. Geese fed diets with cholesterol and cholic acid exhibited markedly increased levels of cholesterol, triglycerides and phospholipids in plasma and very low‐density lipoproteins, regardless of the choline supply. Muscle tissue of geese fed diets supplemented with cholesterol and cholic acid exhibited also increased concentrations of triglycerides and cholesterol whereas the fatty acid composition of muscle lipids remained unchanged. Among geese without hyperlipidemic treatment, concentrations of triglycerides in plasma and very low‐density lipoproteins as well as the concentrations of phosphatidylcholine in liver and muscle tissue were not reduced by low dietary choline concentrations. Therefore, it is suggested that those animals were able to synthesize endogenous sufficient choline.