Performance of broiler chickens fed least-cost diets formulated to model predicted amino acid requirements

Abstract

Two 3-week battery brooder experiments were conducted with male broiler chicks to investigate the use of a model equation to predict amino acid requirements. In the first experiment, chicks were fed four diet treatments based on published recommendations (Guelph, (Summers & Leeson, 1976) NRC, 1977; Maryland, (Thomas et al. 1978); AEC, 1978), two diet treatments based on model-calculated recommendations (Hurwitz et al., 1978) and one commercial chick starter. A second experiment comparing one diet treatment each for a published (NRC), model-calculated and commercial recommendation was necessiated due to updating the model. In Experiment 1, significant differences ( p < 0.05) were noted in feed efficiency at 15 days in favour of birds on the commercial treatment relative to those receiving days in favour of birds on the commercial treatment relative to those receiving treatments based on published recommendations. Over the trial period, the commercial treatment and a model-based treatment supported a significantly ( p < 0.05) better feed efficiency than did the other published recommendations. The model-based diet treatment of Experiment 2 resulted in significantly ( p < 0.01) superior bird weights at 7 and 14 days and feed efficiency at 7 days ( p < 0.01) and 14 days ( p < 0.05) relative to both NRC (1977) and the commercial diet treatment. These results indicate the potential of using model-calculated amino acid recommendations for 0- to 3-week old broiler chickens.