Responses of finishing broilers at high temperatures to dietary methionine source and supplementation levels

The methionine requirements of 3-6-week-old broilers kept at a constant 30�C or at diurnally cycling temperatures of 25-35�C were reduced compared with broilers kept at 21�C. The methionine requirements varied from 0.29 g/MJ of metabolizable energy (ME) at 2 1�C to 0.26 g/MJ of ME at 25-35�C to 0.22 g/MJ of ME at 30�C with total sulfur amino acid requirements of between 0.51 and 0.55 g/MJ of ME. The estimate at 21�C is similar to recommendations made by others for moderate temperatures. Differences in response to DL-methionine and methionine hydroxy analogue free acid were small.