The effect of dietary cholesterol and cholic acid on lipid metabolism in young geese

The present. study investigated the effects of dietary cholesterol and cholic acid on the lipid metabolism of young geese. Forty 4-week-old geese were divided into four groups receiving either a basal diet containing predominately maize and soybean meal or the same diets supplemented with 0.5% of cholesterol, 0.5% of cholic acid or 0.5% cholesterol plus 0.5% cholic acid, over a period of 39 days. Food intake and body weight gains were identical within all the treatment groups. The feeding of cholesterol plus cholic acid increased liver weights by approximately 50%. The lipid metabolism was generally influenced only by cholesterol treatment. Cholic acid treatment per se did not influence the lipid metabolism; however, it amplified all the effects caused by dietary cholesterol. Geese that were fed cholesterol had markedly increased concentrations of cholesterol and triglycerides in the liver compared with geese that were fed the basal diets. Among the hepatic fatty acids, the mono-unsaturated group was markedly raised by dietary cholesterol whereas the saturated and polyunsaturated fatty acids were only slightly increased. There was also a marked increase of plasma cholesterol whereas plasma triglycerides were lowered by feeding cholesterol. Ail the individual lipoproteins, particularly very low-density lipoproteins exhibited increased percentages of cholesterol, at the expense of triglycerides and phospholipids. These alterations might be the consequence of an enhanced cholesterol secretion from the liver into blood. The activity of hepatic glucose-6-phosphate dehydrogenase in the liver was only slightly increased after feeding cholesterol suggesting that triglyceride accumulation in the liver was not caused by an enhanced de novo synthesis of fatty acids. The muscle of geese that were fed cholesterol plus cholic acid also exhibited elevated concentrations of cholesterol which might be the result of increased uptake of lipids deriving from the liver. The activities of transaminases in plasma were not elevated by feeding cholesterol, suggesting that the accumulation of cholesterol in the liver after feeding diets which included cholesterol was not associated with increased liver cell damage.