The effect of methionine supplementation upon the utilization of pea and alfalfa proteins by sheep.

Abstract

The results of three double reversal, nitrogen balance experiments conducted with mature ewes are presented. These experiments were designed to determine the effect of methionine supplementation upon the utilization of various amounts and sources of protein. When the results of the three experiments, in which five different rations were studied, are considered the addition of DL-methionine significantly increased nitrogen retention. The supplemental methionine had considerably greater effect when added to certain rations than when added to others. Possible reasons for these differences are discussed. L-methionine intake and excretion values were determined microbiologically in two of the experiments. The results of these analyses indicated that the supplemental methionine was either completely utilized or destroyed. When fed at approximately the same level of protein intake dehydrated alfalfa had a significantly higher biological value than field peas. The data presented suggest that some factors other than the level of protein intake or amino acid make-up influenced the utilization of protein in these experiments.