Effect of various levels of energy (2800, 3000 and 3200 kcal ME/kg diet), protein (starter 20, 22, 23 and 25 per cent; grower 18, 20,22 and 24 per cent, and finisher 16,18,19 and 21 per cent), and limiting amino acids (per cent of diet and per cent of protein) on the body weight gain and retention of limiting amino acid was studied in hot season in broilers (0-8 weeks). Balance trials for lysine, methionine and cystine were conducted at 3rd, 6th and 8th week of age. The 2800 kcal ME/kg diet, and 25, 24 and 21 per cent protein with 1.2, 1.0 and 0.85 per cent lysine and 0.93, 0.72 and 0.6 per cent sulphur amino acids in starting, growing and finishing phases of growth respectively resulted in significantly higher weight gains. Increased energy levels in the diet increased the retention of amino acids while the increased levels of protein decreased the retention in different phases of growth. At the lower levels of protein, in all the phases of growth (starter 20 per cent, grower 18 per cent and finisher 16 per cent) retention of different amino acids was highest. Maximum retention was observed in starting phase followed by growing and finishing phases of growth. The interaction of energy protein and limiting amino acids influenced the retention of different amino acids significantly (P < 0.01).
