Increasing amino acid density improves live performance and carcass yields of commercial broilers

It has been a tendency for broiler integrators in the US to reduce dietary nutrient density to lower overall input costs of broiler production. Dietary nutrient density is routinely scrutinized because feed represents over half of the live production costs. Numerous nutritionists and researchers from the supplier side of poultry production are arguing that the reduced dietary nutrient density regimen currently employed by some integrators is not an effective means of increasing profitability, especially when producing large, high-yield broilers for markets geared toward saleable white meat. This research evaluates nutrient density in various phases throughout life in Ross 508 male and female broilers to better understand the impact of reduced dietary nutrient density, mimicking the reduced dietary cost scenarios used by some broiler integrators. Diets were provided to broilers in 4 phases from 1 to 14, 15 to 28, 29 to 35, and 36 to 49 d of age, in which treatments of high (H), medium (M), and low (L) amino acid densities were used. The combinations of nutrient density and feeding phases resulted in treatments of 1) HHHH, 2) HHML, 3) HHLL, 4) HMML, 5) HMLL, 6) HLLL, 7) MMMM, and 8) LLLL. Male broilers were more sensitive to amino acid density reductions than females. Reduction of nutrient density in the early feeds was detrimental for most parameters tested. High nutrient density throughout life (HHHH) optimized breast meat yield, whereas reductions in nutrient density reduced growth and breast meat yield and increased corrected feed conversion and leaf fat. Integrators feeding slow-maturing, high-yield broilers with low and moderate nutrient dense diets may produce broilers with suboptimal growth and breast meat yield, although moderate diets may result in good feed conversion.