Effects of low protein diets supplemented with high amino acids (methionine or lysine) on performance of broilers.

Aims: This study is to evaluate the effects of high level methionine or lysine supplementation on the performance and carcass characteristics of broilers fed low crude protein diets. Study Design: The experiment employed a complete randomized design; all data generated were subjected to analysis of variance. Place and Duration of Study: The experiment was carried out at the Teaching and Research Farm of the University of Ibadan, Nigeria between April and July 2011. Methodology: One hundred and ninety two unsexed day old broiler chicks were used in a six-week feeding trial. For each study four experimental diets were formulated such that they contained methionine at four dietary levels of 0.0%, 0.35%, 0.45% and 0.55% while the other four set contained lysine at four dietary levels of 0.0%, 0.60%, 0.70% and 0.80% respectively. The crude protein (CP) levels of T1-T4 in methionine or lysine diets are 24.25%, 19.70%, 15.15% and 10.60%. Results: Results indicated that broilers fed diet 1 with normal protein level without methionine and lysine had higher (P<0.05) body weight gain compared with others. Feed conversion also had the same statistical trend. It was observed that level of crude protein, lysine and methionine significantly reduced feed intake of the broilers. It was reported that Original Research Article American Journal of Experimental Agriculture, 4(5): 525-531, 2014 526 reduction of CP levels in the diets of the broilers with methionine or lysine supplementation did not give desirable result. This supplementation resulted in reduced feed intake, poor feed conversion and reduced body weight gain of the experimental broilers. Conclusion: The aim of the poultry farmer is to achieve optimum production with least inputs. From this study, it was concluded that reduction of crude protein content supplemented with lysine or methionine in broiler diets resulted in reduced feed intake and suboptimal body weight gain of the broilers.