Relation of dietary cholesterol and fat to atheromatosis in laying and nonlaying hens

¹ Department of Clinical Science, University of Illinois College of Medicine, Chicago, Illinois

Twenty-four female chicks received a diet containing 0.05% cholesterol, 3% fat and 22% protein for 6 months. Then, 12 of them, 6 good layers and 6 non- or poor layers, received a diet containing 0.03% cholesterol, 2.4% fat and 14.25% protein for 52 weeks. The other 12 received a diet containing 0.08% cholesterol, 7% fat (6.5 gm/100 gm of diet being beef tallow, m.p. 42°C) and 17.44% protein, the relative energy values being 774 and 1001 calories, respectively. These diets were fed 12 months, at the end of which period the chickens were 18 months of age. In the 12 hens on the ‘low-fat, low-cholesterol’ diet, the incidence and severity of atheromatosis was 25% and 5%, respectively; in the 12 on the ‘high-fat’ diet it was 75% and 25%, respectively. There was no difference in the incidence and severity of atheromatosis between the ‘layers’ and ‘nonlayers.’ Since egg laying is associated with a marked hyperlipemia and not a hypercholesterolemia, these results show also that a hyperlipemia alone though present for almost one year does not increase the rate of accumulation of cholesterol in the arteries of hens.