COMPARISON OF DL-METHIONINE AND METHIONINE HYDROXY ANALOG-FREE ACID IN BROILERS BY USING MULTIEXPONENTIAL REGRESSION-MODELS

1. Methionine hydroxy analogue-free acid (MHA-FA) was evaluated for biopotency compared to DL-methionine in a practical diet for broiler chicks. 2. Both methionine sources were added at equimolar concentrations of 0.03, 0.07, 0.11, 0.15, 0.20 and 0.25% to the diet. 3. A non-linear multi-exponential regression model was used to describe the weight gain and food conversion response to supplemental sources of methionine. 4. Compared with DL-methionine on an equimolar basis, bioefficacy of MHA-FA was calculated at 73% from weight gain and 68% from food conversion data, respectively. This corresponds to an efficiency of Alimet(R) between 60 and 64% relative to DL-methionine on a weight for weight basis.