Influence of Dietary Sodium Level on Utilization of Methionine from DL-Methionine and Liquid Methionine-Hydroxy Analogue

SUMMARY A study was conducted to determine if dietary Na levels influenced the utilization of 2 different sources of supplemental Met in diets for male broilers. A Met-deficient diet (0.33% Met by analysis) based on grain sorghum and soybean meal was fortified with either DL-methionine (DL-Met) or the liquid form of 2-hydroxy-4-methylbutanoic acid (HMB) to provide supplemental levels of Met ranging from 0.0 to 0.28% in increments of 0.04%. Using sodium bicarbonate as a variable, dietary Na levels were 0.15, 0.20, and 0.25% with a constant Cl level of 0.20%. The experimental treatments consisted of a 2 × 3 × 8 factorial arrangement with 2 Met sources (DL-Met and HMB), 3 Na levels (0.15, 0.20, and 0.25%), and 8 levels of supplemental Met (0, 0.04, 0.08, 0.12, 0.16, 0.20, 0.24, and 0.28%) for a total of 48 treatments. Each treatment was fed to 6 replicate pens of 5 male broilers from 1 to 21 d of age. There was no significant effect of Met source on BW, feed conversion, or mortality. Both Met level and Na level significantly affected these factors, with a significant interaction between Met level and Na level for both BW and feed conversion. Feeding the higher levels of Na at lower levels of Met supplementation had adverse effects on both BW and feed conversion, independent of source of supplemental Met. Results of this study indicated that in practical diets using equivalent levels of fortification, no significant differences were detectable in the utilization of the 2 sources of Met.