Influence of various dietary fats on hypercholesterolemia and atherogenesis in cockerels.

• It is evident that both dietary and metabolic factors influence plasma cholesterol levels and the development of experimental atherosclerosis. The type of fat normally consumed is one of the important dietary factors. Although the "polyunsaturated" fatty acids (consisting primarily of linoleic acid) are known to depress plasma cholesterol levels, it does not follow that an excess of dietary linoleic acid is necessarily more beneficial than a proper ratio of fatty acids of different chain length and saturation. The literature indicates a striking disparity between the effects of various dietary fats on plasma cholesterol levels in human beings and in animals.' We ourselves were unable, in earlier studies, to find consistent differences in hypercholesterolemia and atherogenesis in cockerels fed different saturated and unsaturated fats added to cholesterol supplemented chick starter mash. This may have been due to the presence in this mash of 3 to 5% of fatty acids of variable composition. In the present study, therefore, a fat-free, semi-synthetic diet was used as the basic ration,