The Isoleucine and Valine Nutrition of Young Laying Pullets as Influenced by Excessive Dietary Leucine

Abstract

THE usual approach to assuring both adequate and economic amino acid nutrition for layers has been to combine energy and protein concentrates and supplemental amino acids in such a way as to meet the requirements for essential dietary amino acids on a least-cost basis. In so doing, it has been assumed that the excesses of some amino acids programmed into the diet are deaminated and used as sources of energy to a varying degree depending upon the amino acid in question. Otherwise, the excesses have been assumed to be rather innocuous from a nutritional standpoint.However, the work of Harper et al. (1955) has stimulated investigations into the role of excesses of certain amino acids upon the metabolism and dietary requirements for others. Specifically, their data indicated that excess leucine increased the requirement for isoleucine.In a recent report from this laboratory by Bray (1969) it was theorized that a…