The Effect of Productive Energy Level of the Diet on the Methionine Requirement of the Chick

Abstract

THE nutrient requirements of the chick are commonly expressed in percent of diet. The purpose of this paper is to present data which indicate that nutrient requirements expressed as percent of diet cannot be considered as fixed values but vary as a direct function of the productive energy value of the diet. The data presented here deal only with the methionine requirement of the growing chick. The new concept, however, should apply to most of the nutrients required and o birds of all age groups. In a recent paper from this Laboratory (Rosenberg et al., 1955a) it was reported that the effect of dl-methionine in a broiler diet did not seem to depend on the level of methionine already present in the diet. Even when the diet contained more than the level of methionine said to be necessary by N.R.C. standards, additional dl-methionine resulted in a statistically significant improvement in …