Energy relationships in growing chickens given daily injections of corticosterone

The energetic efficiency of growing chickens given daily injections of corticosterone was investigated by measuring metabolic activity and energy balance. Water consumption increased significantly within the first day of treatment; food consumption increased by the third day of treatment. Growth rate, which was suppressed during the first two days, returned to normal by the third day of treatment. Excreted water, dry matter and uric acid increased within the first day of treatment. Heat production was not changed by treatment; however, the CO2:O2 respiratory ratio (RQ) was increased by the third day and exceeded 1.0 on days 4 and 5 of treatment. Leg muscle weight was decreased and abdominal fat and liver weight were increased by corticosterone treatment. Balance data indicated that energy absorption efficiency was decreased and energy retention efficiency was increased by corticosterone treatment, confirming the RQ and carcase findings that greater amounts of energy were stored as fat.