Carnitine supplementation decreases heat production in racing pigeons during flight simulation

Four groups (A,B,C,D) of nine, trained, male racing pigeons were starved for one day after two months of high energy ration intake and then subjected to a respiration chamber test. One week before, groups A and B were orally supplemented with 90 mg of L-carnitine daily, whereas C and D were given a placebo. A and C underwent flight simulation by electro-stimulation of the breast muscles. Flight simulation increased heat production, prevented a decrease in respiratory quotient due to feed deprivation, decreased T-4 plasma levels and increased weight loss. Feed deprivation caused lower plasma T-3 and T-4 levels. L-Carnitine decreased the rise in heat production during electro-stimulation but did not influence respiratory quotient, weight loss or thyroid hormones. L-Carnitine supplementation in pigeons improved efficiency of energy usage during heavy exercise, thus preventing energy losses due to anaerobic metabolism.