Relative Biological Value of dl-Methionine and Methionine Hydroxy Analogue in Chick Diets

Abstract

ALMOST all of the data presented in the literature indicate equal utilization of the d- and l- isomers of methionine. This subject was recently reviewed by Marrett et al. (1964). The relative utilization of dl-methionine and Methionine Hydroxy Analogue (MHA) is much more controversial than that of the activity of the d- and l- forms of methionine. Bird (1952) found MHA to be equal to dl-methionine in supporting performance of chicks when fed on an equimolar basis. Gordon and Sizer (1955) reported that MHA had equal activity to l-methionine and was more active than dl or d-methionine when added on an equimolar basis to a sulfur amino acid deficient chick diet. Sullivan and Bird (1957) compared MHA and dl-methionine on an equimolar basis in 12 and 14% protein chick diets and found the analogue failed by a wide margin to support performance equivalent to dl-methionine. The addition of either urea…