Determination of optimum levels of energy and protein in grower diet of Japanese quail (Coturnix coturnix Japonica)

In order to determine the optimal levels of energy and protein in grower diet of Japanese quail، 360 day old Japanese quails were used in a 3×3 factorial arrangement of dietary treatments that comprised three levels of metabolisable energy (2750، 2850، and 2950 Kcal/kg) and three levels of crude protein (24، 26 and 28 percent) with four replicates per treatment in a completely randomized design. Feed intake and body weight were measured weekly and feed conversion ratio was calculated. At 35 d of age، four birds (from both sexes) from each replicate were randomly selected and killed following blood sampling to evaluate carcass traits. The blood samples were assayed for the sera concentrations of growth hormone. Results indicated that birds fed on diets containing 2850 kcal/kg metabolisable energyand 26 percent protein had higher daily weight gain and better feed conversion ratio and carcass yield (P<0. 05). The sera concentration of growth hormone was higher in birds fed on diet containing 2750 kcal/kg metabolisable energy (P<0. 05). This study indicated that Japanese quails can grow faster and more efficiently on diet containing 2850 kcal/kg metabolisable energy and 26 percent protein. Therefore، the diet containing 2850 kcal/kg metabolisable energy and 26 percent protein could be recommended as dietary metabolisable energy and protein requirements for growing Japanese quails.