Broiler Response to Diet Energy

ABSTRACT Male broiler chickens were fed corn-soybean diets providing 2,700, 2,900, 3,100 or 3,300 kcal ME/kg. In all experiments, each treatment was tested with three replicate groups of 30 birds grown to 49 d of age. In Experiment 1, birds consumed the various diets ad libitum whereas in Experiment 2, all birds received identical and restricted quantities of feed so as to ensure variable intakes of energy. In a third experiment, after 7 d of age, broilers had access to feed in two feeders that contained only the highest level of energy, or the 3,300 kcal ME/kg diet in combination with one of the other diets previously described. Providing diets of 2,700 to 3,300 kcal ME/kg for ad libitum consumption had no effect on growth rate (P> 0.05) and energy intake was constant; however, reducing the energy level of the diet did result in reduced carcas