Performance Comparisons Between DL-Methionine and DL-Methionine Hydroxy Analogue in Layers on an Unequal Molar Basis

Abstract

Based on the assumption that the bioavailability of DL-methionine hydroxy analogue free acid (MHA-FA) is 65% on a weight basis relative to DL-methionine (DLM), the bioavailability of MHA-FA was compared to DLM using molted hens. Five graded supplemental levels (0.012, 0.024, 0.036, 0.048, 0.060%) of Met from DLM (calculated as 99.7%) or MHA-FA (calculated as 65%) were added to a basal diet containing 14.97% protein and 0.27% Met. For the overall experimental period, differences between Met sources (P < 0.05) were obtained at 0.012 and 0.048% supplemental Met for feed consumption; at 0.012, 0.036, 0.048, and 0.060% supplemental Met for egg production and egg mass; at 0.048% supplemental Met level for egg weight; and at 0.012% supplemental Met for feed conversion. The results indicated the bioavailability of MHA-FA relative to DLM was greater than 65% on a weight basis or 74% on a molar basis (P < 0.05).