Influence of Meal Frequency on in vivo Hepatic Fatty Acid Synthesis, Lipogenic Enzyme Activity, and Glucose Tolerance in the Chicken

Abstract

Chicks were allowed access to food for 2 hours per day (meal-fed) or were fed ad libitum. Tritiated water was administered intravenously, and the incorporation of tritium into fatty acids was used to estimate in vivo rates of fatty acid synthesis. Allowing the meal-fed chick access to a meal increased the hepatic rate of fatty acid synthesis up to 50-fold. Hepatic activities of malic enzyme and fatty acid synthetase were similar before and after the meal. The rate of fatty acid synthesis was greater in the fed meal-eater than in the ad libitum-fed chicken. Plasma free fatty acid levels were decreased and plasma triglyceride levels were increased when the meal-eater was fed. Oral and intravenous glucose tolerance tests were conducted. Meal-feeding did not impair glucose tolerance in the chicken, as has been reported in meal-fed humans. Unlike in the rat, intravenous glucose tolerance was not greatly influenced by meal pattern in the chicken. Oral glucose tolerance was improved in one of two experiments as a consequence of meal-eating. These results suggest that the chicken does respond to a shift in meal pattern.