| Experiments were conducted with broilers (Cobb 500) to: (1) evaluate the effects of lighting programs on broiler feed consumption, body weight gain, body composition, heat production, calorie need per gram of gain and energy cost of lean and lipid accretion as well as the coefficient to convert live body mass to metabolic body size; and (2) determine maintenance energy requirement and efficiency of gain of broilers during the grower phase. The lower energy need per unit gain for the 12L:12D lighting program reflects increased energetic efficiency. The impact of lighting was especially pronounced during the grower-finisher phases. The 12L:12D program was superior to the 1L:1D or 23L:1D program for ECV and performance as evidenced by better weight gain, FCR, less HP, higher ECV and higher energy retention while CO2 release was the least. Energy supplementation irrespective of source improved performance and gain composition. Maintenance energy need was unaffected by sex but efficiency of gain showed improvement in males over the females. |
