Abstract
Seven hundred and twenty of 14 day old Japanese quail chicks were used in this study to evaluate the effect of various dietary protein and calcium levels on growth performance, carcass traits, blood biochemical changes and nutrient digestibility of growing Japanese quail. The birds were individually weighed, randomly allocated into 6 groups of mixed sex (120 quails per each group). Quail chicks of groups 1, 2 and 3 were fed on the experimental diet containing 24% crude protein with standards calcium content according to NRC recommendation (0.8%) or 25% more calcium than NRC 1994, recommendation (1.0%) and 50% higher calcium than the requirement (1.2%%) for the three groups respectively, while chicks groups 4, 5 and 6 fed on the experimental diet containing 21% crude protein with 0.8 or 1.0 and 1.2% calcium respectively. The obtained data revealed that high protein diet reduced final body weight and total gain when compared with lower protein fed group. While 25% or 50% high calcium more than recommended requirement improved final body weight and total gain when compared with chicks group fed on the same protein level with standard calcium content. The best FCR and PER values were obtained by quail chicks group fed on lower protein level with 25% high calcium content. All treatment had no significant effect on blood picture, blood serum total protein, albumin, globulin, glucose, triglycerides and cholesterol concentrations. Regarding blood serum calcium and phosphorus concentrations, it was observed that higher protein diet with standard calcium level increased (P≥0.05) both calcium and phosphorus blood serum concentration by about 6.8% and 65.1% respectively, when compared with quail chicks group fed on low protein diet with standard calcium level. Moreover, 25% more calcium improve immune response parameters but all treatments had no effect on carcass traits. The obtained data revealed that higher protein feeding with standard calcium content of growing Japanese quail chick diets decreased Dry matter, Organic matter, Inorganic matter (ash), Crude protein, Ether extract, Crude fiber and nitrogen free extract digestibility by about 6.8%, 3.8%, 39.7, 0.17%, 1.8%, 7.9% and 3.7% when compared with quail chick group fed on lower protein containing diet with the standard level of calcium. It can be concluded that 21% crude protein with 1.0% calcium level improve growth performance, feed efficiency and some blood parameters of growing Japanese quail.

Key words: Protein levels, Calcium levels, Growing quail, Growth performance, Nutrient digestibility.