Requirements of sulphur amino acids for broiler-type chicks after 4 weeks of age.

Five experiments at 4 local experiment stations in 1965 and 4 experiments at the same stations in 1966 were carried out to find the minimum level of sulphur amino acids in broiler finisher diet under the similar exmerimental design. In all the experiments, 2 types of basal diet were manufactured in a commercial feed mill. One type of basal diet contained 5% of fish meal and shown as F-O diet, and the other was all plant basal diet shown as S-O diet. In each experiment stations, 0, 0.1 or 0.2% of DL-methionine was supplemented to either F-O diet or S-O diet to prepare the experimental broiler fisher diets of various sulphur amino acids levels. Methionine and cystine contents of these two basal diets were determined microbiologically.Since heamorage was observed among the chicks in Aichi and Okayama Prefectural Poultry Experiment Stations in 1965, and hence vitamin K deficiency in the diet was suspected, the experiments _??_ repeated in 1966 with the similar experimental diets fortified with vitamine K.Four-week-old chicks of broiler-type cross-bred were reared on the experimental diet for 6 weeks in all the experiments. No statistically significant difference was observed in the performance of the chicks, that is growth rate, feed conversion (feed/gain) and ratios of ready-to-cook and chicken meat, between the chicks on the broiler finisher with and without additional DL-menthionine. Therefore, the minimum requirement of sulhpur amino acids for broiler-type chicks after 4 weeks of age will be not more than the level of sulphur amino acids in the S-O diet, which contained 0.32% of L-cystine and 0.29% of L-methionine, thus 0.61% of sulphur amino acids.