Effect of environmental temperature, dietary energy, and feeding level on growth and carcass composition of male broiler chickens to 35 days of age

Abstract

The effect of environment and nutrient intake on growth and development of commercial-strain broiler chicks, cage-reared to 35 days, was observed. Treatments involved high versus control dietary energy; ad libitum versus 80% of ad libitum intake; and cold control versus environment. Treatments were arranged as a 2 × 2 × 2 factorial, with each represented by 14 cages with eight birds per cage. Environmental temperature was maintained at 15.5 °C versus 23.9 °C from day 21 to day 35. Birds in the cold environment weighed less at 35 days, as did birds subjected to 20% feed restriction (P < 0.01). Dietary energy level had no effect on body weight, although birds fed the high-energy diet consumed more energy and less protein (P < 0.01). Whole-body analysis revealed more fat in birds in the control environment and in those fed the high-energy diet. Feeding level had no effect on body composition. Comparable effects were seen in analysis of breast, thigh and drumstick portions. Details of significant interactions between the three treatments are discussed. Data suggest that feed intake is less dependent on energy requirement and perhaps more closely related to physical satiety. Broilers consume more energy when fed a very high energy diet, presumably because of a desire to achieve a certain physical intake of feed. However, when there is an apparent need to consume more energy because of a cooler environment, no adjustment occurs. Key words; Temperature, energy, carcass composition