The effect of altering the dietary arginine to lysine ratio on the breast meat yield of broiler chickens at moderate and high temperatures

In 4 experiments broilers were housed at moderate or high temperatures and fed diets containing arginine:lysine (arg:lys) ratios ranging from 1.01 to 1.45 from 3 weeks of age until reaching a processing weight of 2.2 kg. The effects of temperature and arg:lys ratio on breast meat yield were determined. In the first 3 experiments, increasing the arg:lys ratio increased breast meat yield at moderate temperatures and reduced breast meat yield at high temperatures. Hypothesised response curves are presented to explain the different responses in breast meat yield to arg:lys ratio at moderate and high temperatures. Expt 4 was designed to test the validity of the hypothesised response curves. The pattern of the responses obtained from this experiment supports the hypothesis.