Requirement of White Leghorn Laying and Breeding Hens for Methionine as Influenced by Stage of Production Cycle and Inorganic Sulfate

Four experiments were conducted with Single Comb White Leghorn hens fed diets deficient in methionine to determine the effect of such a deficiency on hatchability and to estimate the requirement of methionine for egg production at different stages of the laying cycle and the influence of inorganic sulfate on the requirement. In two experiments hatchability of fertile eggs was not affected by a methionine deficiency, while in two others an indication of lower hatchability was observed at the lowest level of methionine, but the differences were not statistically significant. The results indicate that a level of methionine adequate for optimum egg production and egg weight is also adequate for maximum hatchability. Adding methionine to a corn-soybean meal ration containing 16% protein failed to improve any of the parameters measured. In one experiment a significant response in egg production was obtained by adding methionine to a corn-soybean ration containing 14% protein, but not in a second experiment. Egg production and egg weight was always improved by the addition of methionine to a corn-pea ration containing 16% protein. An evaluation of the four experiments indicated that a methionine requirement of between 290 and 300 mg./hen/day was adequate for optimum egg yield. The requirement was higher for obtaining maximum egg weight than for obtaining maximum egg production when the corn-pea ration was used. A significant response to methionine supplementation of the corn-pea ration was obtained in the presence or absence of 0.2% potassium sulfate, and there was no statistically significant difference in egg production and egg weight between the unsupplemented diets with or without sulfate. These results suggest that the methionine requirement estimated in these experiments was for methionine per se rather than for methionine plus inorganic sulfate derived from methionine.