Response of broilers to DL-methionine hydroxy analog free acid, DL-methionine, and L-methionine.

An experiment was designed to compare graded levels of DL-methionine hydroxy analog, free acid, 88% in aqueous solution; 2-hydroxy-4-(methylthio)butanoic acid (HMB), the aqueous solution of the sodium salt of DL-methionine (40%) (DLM), and crystalline L-methionine (LM) as sources of supplemental methionine activity. The experiment utilized 2160 broilers of each sex grown in separate pens to 7 weeks of age with a lysine-supplemented corn-soybean meal basal diet. These supplements produced a maximum 15% growth response over the unsupplemented basal diet. There were no statistically significant differences among the three sources in producing weight gain and feed conversion. There were no source X level interactions with regard to body weight gain. There was one source X level interaction (at 7 weeks) for feed conversion. The results support the conclusion that when synthetic sources of methionine activity are used to meet the requirement for total sulfur amino acids in practical corn-soybean meal diets for producing 7-week-old broilers, the chicks are capable of utilizing HMB, DLM, and LM with an efficiency that is indistinguishable.