Relation between methionine and inorganic sulphate in broiler rations

In two experiments with 0-5 weeks old broiler chicks in battery-cages, it was examined whether the requirements for sulphur-containing amino acids in the ration could be reduced by addition of inorganic sulphate. The basal diet was a high energy practical-type broiler ration. The mineral mix included in this diet did not contain sulphates. The basal diet contained 0.73% methionine + cystine. By addition of synthetic methionine, experimental rations with 0.78, 0.82, 0.92 and 1.02% methionine + cystine, respectively, were obtained. The addition of methionine to the basal ration effected significant effects on weight gain (maximum 6-7% at 5 weeks of age) and on feed conversion (maximum 7-8% at 5 weeks of age). The addition of 0.1% Na2 SO4 (=0.068% inorganic sulphate) to the basal and the methionine supplemented diets resulted in an overall increase in weight gain at 5 weeks of age of 0.9% and a reduction in feed conversion of 1.2%; both effects were significant (P less than .05). However, the size of this effect proved to be independent on the contents of sulphur-containing amino acids in the ration. This indicates a small deficiency of the basal ration for inorganic sulphate.