Effect of Some Dietary Factors and Drugs on Cholesterol Concentration in the Egg and Plasma of the Hen

Abstract

Studies were undertaken to determine the effect of dietary lipids and drugs on plasma and egg yolk cholesterol in the laying hen. Egg cholesterol concentrations were increased significantly when hens were fed diets containing either safflower oil, hydrogenated safflower oil, or coconut oil at a level of 30%, but only slightly when corn oil or animal fat was fed. Safflower oil at levels up to 15%, however, did not increase egg cholesterol. Egg cholesterol concentrations did not parallel blood levels when the different types of fat were fed except in cases where hypercholesterolemia was produced by feeding diets containing cholesterol. Increases in plasma and egg cholesterol due to feeding diets containing cholesterol (1%) were enhanced by dietary inclusion of either safflower oil (29%), lecithin (5%), or Tween 80 (5%), which increased the absorption of cholesterol. β-Sitosterol (1%) retarded the increase in plasma and egg cholesterol concentrations caused by dietary cholesterol. Feeding high or low vitamin A diets or niacin supplementation (0.1%) did not result in significant changes of the egg cholesterol content or counteract the effect of safflower oil. Administration of D-thyroxine by injection or as a dietary supplement resulted in decreased blood and increased egg cholesterol content.