An Evaluation of the l-Methionine Activity of the Hydroxy Analogue of Methionine

Abstract

Three product forms of methionine hydroxy analogue were prepared for biological evaluation of their L-methionine activity for broiler strain chickens (Vantress x Arbor Acres). Two samples of the acid of the analogue HA-50, LMA-70 and one sample of a commercial grade (90%) MHA were standarized by gas liquid chromatography to contain a known amount of L-methionine activity as the free analogue acid. Each product form was tested in a separate experiment. The experimental chickens were fed a practical corn-soybean meal basal diet for the first seven days of the test. A semi-purified diet composed primarily of cerelose, isolated soybean protein and soybean meal was used for the remainder of the experimental period. HA-50 and the commercial form of the hydroxy analogue were formulated to contain 50% L-methionine activity. Hence, they were added to the diets at 0.1 and 0.2% and compared to the L-methionine standard which was added to levels of 0.05, 0.1 and 0.15%. LMA-70 was formulated to contain 70% L-methionine activity and was added to the experimental diets at 0.07 and 0.14% and compared to the L-methionine standard at the same levels used in the other experiments. Statistical analysis of four-week data revealed no difference between the biological response of L-methionine and the three forms of the analogue when tested at comparable L-methionine activity levels. The biological of the analogue products was in good agreement with the L-methionine activity determined by gas liquid chromatography.