Barley Rations for Swine. II. The Influence of L-Lysine and DL-Methionine Supplementation of Barley-Soybean Meal Diets upon Rate and Efficiency of Gain and upon Nitrogen Retention of Growing Swine

Abstract

A 14% protein barley-soybean meal diet based on an 11.7% protein barley was supplemented with 0.2, 0.3 or 0.4% of L-lysine or with 0.05, 0.10, 0.15 or 0.20% of DL-methionine. When the diet was fed to growing pigs at the rate of 5.5% of W0.9kg. daily, the separate amino acid additions did not significantly affect nitrogen retention. A similar diet based on a 13.3% protein barley was supplemented with 0.1, 0.2 or 0.3% of L-lysine, or 0.05 or 0.10% of DL-methionine, or the combinations, and fed at the rate of 6.5% of W0.9kg. daily. Additions of 0.2 and 0.3% of L-lysine significantly (P<.01) increased nitrogen retention over that obtained with the basal diet. Methionine supplementation was without effect, and there was no lysine x methionine interaction. Nitrogen balance values based on 3-day collection periods were in close agreement with those based on 5-day periods. Supplementation of a 14% protein barley-urea diet with lysine significantly improved rate and efficiency of gain, but methionine alone, or in combination with lysine, was without effect. The results of these studies indicate that lysine is the first limiting amino acid in barley protein as well as in barley-soybean meal diets fed in meal form. However, they also suggest that methionine is not seriously limiting, if at all. Attention was drawn to the disparity between results obtained in these studies with the use of meal diets and those obtained with similar diets fed in pelleted form.