Effect of dietary factors on serum and egg yolk cholesterol levels of laying hens.

Effects of dietary lipid factors (saturated and unsaturated oil, cholesterol and plant sterols) on the serum and egg yolk cholesterol levels of the laying hen were investigated. Single Comb White Leghorn laying hens, at thirty weeks of age, were used in two trials by feeding two basal diets containing 8.0% hydrogenated coconut oil or safflower oil, with or without supplemental cholesterol (1.0%), soysterols (2.0%) or combinations of both. Safflower oil, per se, had a superior property to hydrogenated coconut oil in suppressing cholesterol levels, in both serum and egg yolk. Cholesterol supplementation to the safflower oil basal diet resulted in a significant (P less than 0.01) elevation of serum and egg yolk cholesterol levels, whereas cholesterol in combination with hydrogenated coconut oil did not change the serum level. Cholesterol lowering effect of soysterols was clearly demonstrated in both serum and egg yolk by feeding soysterols alone as well as by feeding soysterols in combination with cholesterol.