Evaluation of Nutrient Specifications for Broiler Breeders

Abstract

Two experiments were conducted to determine if previously suggested nutrient requirements of broiler breeders (23 g protein, 850 mg sulfur amino acids, 4.5 g calcium, and 750 mg phosphorus/bird/day) are in excess and could be reduced during the laying period. In Experiment 1, Cobb color-sex broiler breeders were fed daily nutrient allowances that were 100.0, 96.3, 92.5, 89.4, and 86.6% of the suggested requirements. In Experiment 2, Cobb feather-sex breeders were fed daily allowances that were 92.5, 89.4, 86.6, 83.4, and 80.9% of the suggested requirements. Birds on all diets were fed the same energy level; however, energy varied with season to maintain body weight.Egg production, fertility, hatchability, egg weight, and shell quality were not significantly affected by the reductions in nutrient intake in either experiment. The diet with the lowest nutrient level (80.9% of the suggested requirement) was adequate, indicating a considerable margin of safety for the stated requirements. Body weight was quite variable but tended to decrease with nutrient restriction. Weights of broilers hatched from treated breeders were not significantly affected at 49 days of age by the breeder dietary treatments.These results indicate that broiler breeder diets formulated to meet presently suggested requirements have a large margin of safety and a reduction of specifications by approximately 10% is suggested. The revised daily intakes recommended are: 20.6 g protein, 754 mg sulfur amino acids, 400 mg methionine, 938 mg lysine, 1379 mg arginine, 256 mg tryptophan, 4.07 g calcium, 683 mg total phosphorus, and 170 mg sodium.