Broiler Breeder Performance in Response to Diet Protein and Energy

Abstract

Two hundred and forty Hubbard × Hubbard broiler breeders at 19 weeks of age were weight-sorted and transferred to individual laying cages where one of six experimental diets was provided to 41 weeks of age. Each diet was represented by 10 replicate groups of 4 individually caged and fed birds. Feed allocation was gradually increased to 150 g/bird per day, which provided 19 or 25 g crude protein and either 325, 385, or 450 kcal metabolizable energy (ME)/bird per day. Hens were inseminated every 7 days with .05 ml pooled semen from Hubbard males. Hen-day production was 1.6% lower with the high vs. low protein intake. Peak egg production occurred at 31 weeks and was 77.3, 87.9, and 84.1% for the low (L), medium (M), and high energy (H) intakes, respectively (P≤.01) . Egg weight increased as the protein or energy intake increased; yolk content increased as energy intake increased or as broiler breeders aged (P≤.01).Carcass fat, protein, and moisture content of defeathered 41-week-old breeders were L: 45.5, 44.4, 56.6; M: 49.0, 40.4, 54.8; and H: 58.4, 32.5, 50.4, respectively (P≤.01). There were no dietary effects on hatchability, embryonic mortality, or fertility. From 32 to 35 weeks of age the higher protein intake increased egg weight by 1.2 g (P≤.05) and chick weight by .6 g; whereas hatched live chick weight was 39.6, 39.7, and 41.0, for L, M, and H diets, respectively (P≤.05). Results indicate that 19 g protein and 385 kcal ME/day was sufficient to maintain normal reproductive performance through peak egg production.