Effect of Restricted Energy and Protein Intake on Atherosclerosis and Associated Physiological Factors in Cockerels

Abstract

Practical or semipurified diets, with and without added cholesterol, were fed to growing cockerels to determine the effect of dietary energy or protein restriction on systolic blood pressure, total serum cholesterol, total serum lipids, liver lipids and incidence of atherosclerosis in thoracic and abdominal aortas. The effect of dietary protein or energy restriction on systolic blood pressure was inconsistent. Variations in blood pressure appeared to be associated more with body weight than with restriction of protein or energy as such. Serum cholesterol, serum lipids and liver lipids were markedly increased when cockerels were fed diets containing cholesterol. Each was increased by protein restriction and decreased by energy restriction. Without added dietary cholesterol, serum cholesterol was not significantly affected by protein or energy restriction. Serum lipids were significantly increased, and liver lipids were slightly increased, when birds were fed protein-restricted diets without added cholesterol. Atherosclerosis was more prevalent when the diets contained cholesterol, and more severe in the abdominal than in the thoracic aorta, regardless of dietary treatment. Protein or energy restriction affected atherosclerosis, especially in the thoracic aorta, most when the diets contained cholesterol. Incidence of atherosclerosis in the thoracic aorta was reduced in energy-restricted, and increased in protein-restricted birds.