A Substance in Lingcod Liver Oil which prevents Hypercholesterolæmia in Cholesterol-fed Chickens

Abstract

THE serum cholesterol-level in some animals is elevated above the normal value by the addition of cholesterol to the diet. In certain species, such as the chicken, cholesterol by itself brings about this increase; but in other species, exemplified by the rat, the presence of cholic acid is also required. The degree of hypercholesterolæmia is altered when certain vegetable and fish oils are added to the diet; but the observed effect of any one oil is dependent on the species of animal under investigation. De Groot and Reed¹ showed that cod liver oil and corn oil prevented the increase in plasma cholesterol in rats due to dietary cholesterol and cholic acid. Dam et al. ² investigated the effect of dietary cod liver oil and linseed oil in cholesterol-fed chickens, and found that both oils increased the hypercholesterolæmia caused by the dietary cholesterol. Similar experiments on chickens were performed by Wood and Biely³ using corn oil, tallow and various fish oils. Corn oil, tallow and herring oil were observed to increase the hypercholesterolæmia; but lingcod liver oil and halibut liver oil completely prevented the appearance of hypercholesterolæmia. Ratfish liver oil, dogfish liver oil and basking shark liver oil were intermediate in effect. In view of the diverse effects of the oils observed in the chicken studies, further investigations were carried out to obtain additional information about the mode of action of the oils. Corn oil, herring oil and lingcod liver oil were chosen for the investigation.