The effect of non-protein energy sources on the ability of the chick to synthesize glucose-6-phosphatase

Two experiments were conducted to investigate the relationship of energy source, age and glucose-6-phosphatase activity in the chick. In the first experiment liver glycogen and glucose-6-phosphatase were assayed in chicks of four age groups being fed either a high-fat or high-carbohydrate diet. It was observed that the feeding of the high-fat diet resulted in higher glucose-6-phosphatase activity and lower glycogen levels than did the feeding of the carbohydrate diet. Age was found to significantly influence enzyme activity. Both glucose-6-phosphatase and liver glycogen were found to be negatively correlated in the fat fed chicks. In the second experiment chicks were fed either a high-fat or high-carbohydrate diet for 28 days. Liver glucose-6-phosphatase activity was determined in representative samples of chicks from each group to establish basal levels. The diets were then reversed for a three-day period, after which the chicks were returned to their initial diets. Glucose-6-phosphatase was analysed at each step. Variation in enzyme activity in the chicks initially fed the high-fat diet could be attributed to differences in body weight. However, those chicks originally fed the carbohydrate diet did exhibit a true metabolic adaption when fed the high-fat diet.