The l-Phenylalanine and l-Valine Requirement of the Turkey Poult and the Utilization of Their d-Isomers

Abstract

A PURIFIED diet in which a crystalline amino acid mixture served as the sole source of amino nitrogen was developed for the turkey poult by Snetsinger et al. (1962). This diet afforded the opportunity to study the poult’s requirements for amino acids other than those which are deficient in natural proteins. In addition, the free substitution of amino acids permissible in the amino acid mixture permitted the study of the utilization of d-isomers of amino acids over a wide range of dietary levels.In the report presented here the l-phenylalanine and l-valine requirement of poults fed a crystalline amino acid mixture were studied. The comparative utilization of d- or dl-mixtures of these two amino acids was also investigated.No information on the quantitative requirement of the poult for phenylalanine or valine is available, although a report by Vohra and Kratzer (1959) indicated that phenylalanine is a dietary essential amino acid for…