Response of growing egg type pullets (CARI Priya) to variable dietary energy and critical amino acids levels

Abstract

An experiment was conducted involving egg type chicks (CARI Priya) reared in battery cages to optimize energy to limiting amino acids profile ratio during different phases of growth in winter months. Day-old chicks (n=225) were distributed into five dietary treatments formulated with different levels of energy (kcal ME/kg) viz. T1: 2850, T2: 2700, T3: 2600, T4: 2500 at the fixed ratio with concentration of limiting amino acids, and T5: 2600 kcal ME with altered lysine and methionine concentration. Each dietary treatment was offered to four replicated groups of 11 to 12 each. In a second experiment, 112 growing pullets of 6-wk age were distributed to four dietary treatments formulated with different levels of energy (kcal ME/kg) viz. T1: 2700, T2: 2600, T3: 2500 with the fixed energy to amino acids ratio, and T4: 2500 kcal ME with altered lysine and methionine concentration to assess the optimum requirements for 6–12 weeks growth phase, Each dietary treatment was offered to four replicated groups of seven each. Successively, in the third experiment, the same 112 growing pullets of 12-wk of age were switched over to four dietary treatments consisting of different levels of energy (kcal ME/kg) viz. T1: 2900, T2: 2700, T3: 2500 with the fixed energy to amino acids ratio and T4: 2500 kcal ME with altered lysine and methionine. Each dietary treatment was offered to four replicated groups of 7 each upto 20 wk of age. The results indicated that the optimum levels of energy, CP, lysine, methionine and threonine were 2850 kcal ME/kg, 17.7%, 0.85%, 0.31% and 0.68% for gain and feed conversion efficiency during 0–6 wk of age. A diet with 2600 kcal ME/kg, 14.6% CP, 0.62% lysine, 0.28% methionine and 0.56% threonine was optimum for growing pullets during 6–12 weeks of age. Whereas, the optimum concentration in diet of pullets during 12–20 weeks of age was energy 2700 kcal ME/kg, lysine 0.48%, methionine 0.26%, methionine + cystine 0.52% and threonine 0.47%.