Dietary effects of corn oil, oleic acid, perilla oil, and evening [corrected] primrose oil on plasma and hepatic lipid level and atherosclerosis in Japanese quail.

To compare the atherogenecity of different fats and oils, a total of forty, 40-day-old male Japanese quails were fed one of the following diets for three months: basal diet (control), a diet-containing 15% corn oil (CO) and 2% cholesterol (CH), a diet-containing 15% oleic acid (OL) and 2% CH, a diet-containing 15% perilla oil (PE) and 2% CH, a diet-containing 15% evening [corrected] primrose oil (PR) and 2% CH. A higher plasma cholesterol concentration was found in the birds in the CO and OL groups, whereas the PE and PR groups showed a much lower level of plasma cholesterol than the CO and OL groups. In proportion to the increased plasma cholesterol, both CO and OL groups showed narrowing of the lumen of the ascending aorta and its large branches due to marked lipid-rich intimal thickening. Ultrastructural changes in the ascending aorta and its large branches were correlated with the degree of intimal thickening. The major foam cell types were macrophages and fibroblastic cells. The PE and PR groups showed the fewest lipid-rich intimal thickening lesions in their ascending aorta and its large branches. These findings suggest that the alpha-linolenic acid contained in perilla oil is less atherogenic than oleic and linoleic acid, and gamma-linolenic acid contained in evening [corrected] primrose oil has a tendency to decrease the plasma lipid level.