Cholesterol and Fatty Acid Synthesis in Chicks Fed Different Levels of Protein

Abstract
The effects of dietary protein level on cholesterol and fatty acid synthesis were studied in the chick. Increasing dietary protein increased cholesterol synthesis in liver and intestine but not in the remaining carcass. However, fatty acid synthesis was depressed in liver and carcass but not in the intestine when dietary protein was increased. The total plasma cholesterol level was significantly decreased by increasing dietary protein and therefore was inversely related to the rate of cholesterol synthesis, suggesting a higher cholesterol turn-over rate in chicks fed a high protein diet. However, chicks fed a high protein diet had a reduced plasma cholesterol level but an increased carcass cholesterol level. Therefore, the possibility of a shift of cholesterol from the liver-plasma pool to the carcass cannot be excluded. Increasing dietary protein levels significantly increased the relative contribution of the liver to cholesterol synthesis and shifted the site of fatty acid synthesis from liver to “carcass” and intestine.