The effect of dietary cholesterol level on lipid status and initiation of atherosclerosis in Japanese quail

The effect of variations in dietary cholesterol level on the development of hyperlipidemia, tissue cholesterol status and incidence of atherosclerosis was investigated in male Japanese quail of strain SEA (Susceptible to Experimental Atherosclerosis). Groups of 12, five-week-old, birds were fed one of four purified diets. The basal diet contained (weight %): soyprotein, 35; beef tallow, 10; glucose, 46; three atherogenic diets were prepared by replacing glucose with 0.25, 0.5 and 1.0% cholesterol in the basal diet formula. After 4 weeks, birds were killed and serum, thoracic aortae, brachiocephalic arteries, and liver were taken for analysis. Serum cholesterol was increased (relative to basal values) by 15, 127 and 229% for birds fed the 0.25, 0.5 and 1.0% cholesterol diets respectively; increases were due to elevations of cholesterol in the very low density lipoprotein (VLDL) and low density lipoprotein (LDL) fractions. Hepatic and arterial cholesterol levels increased with increasing dietary cholesterol levels, but there were significant, between-group differences in the case of liver cholesterol only. Lesion incidence was 0, 8, 43 and 50% for birds fed the basal, 0.25, 0.50 and 1.0% cholesterol diets respectively. The small dot-like, yellow lesions were found predominantly in the right brachiocephalic artery and to a lesser extent in the thoracic aorta; no lesions were found in the left brachiocephalic artery. The extreme rapidity with which Japanese quail of strain SEA develop early atherosclerotic lesions makes them an attractive animal model for studying the early development of atherosclerosis in man.