Effect of Lysine and Methionine Supplementation in Practical Broiler Diets Based on Groundnut Meal

Abstract

The feeding value of decorticated groundnut meal (GNM) as a sole vegetable protein supplement in broiler diets was studied. A basal diet containing 30% GNM was formulated, and was then supplemented with 0.25% L. lysine or 0.15% methionine or the two amino acids combined together in the same quantities. These four experimental diets, together with a fifth standard broiler diet containing 15% of each of GNM and sesame meal, were fed to dayold broiler chicks in a 6-weeks feeding trial. The feeding trial was arranged in a randomized block design with three replicates of five dietary treatments. The broiler performance parameters on these diets were assessed and compared for treatment differences. The results indicated that the birds fed the standard broiler diet attained the highest liveweight gain (P<0.05) and the best-feed conversion efficiency. On the other hand the birds fed the basal diet, with 30% GNM, attained a better liveweight gain than the birds fed the basal diet supplemented with lysine, methionine or lysine plus methionine (P<0.05). Feed consumption was markedly, though not significantly, depressed by the supplementation of the amino acids to the basal diet; and it was lowest on the methionine supplemented diet. The lowest livewieght gain (P<0.05) and the highest feed conversion ratio were attained on the lysine supplemented diet. These parameters were improved by supplementation of the basal diet with methionine or methionine plus lysine. These effects are attributed to dietary amino acid imbalance created by excessive intake of lysine and methionine from the respective supplemented diets, which negatively affected feed and 8 iv nutrients intake and the efficiency of amino acids utilization for tissue synthesis. It can generally be implied that the high incorporation level of GNM in the basal diet provided a suitable pattern of amino acids in relation to the NRC recommendations; and this has been distorted by the addition of either lysine or methionine or the two combined together which resulted in depressed broiler performance