الفهرس 
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Abstract
The aim of this study was to investigate dietary supplementation effect of different Zn source to low crude protein diets on growth and productive performance, carcass traits as well as some nutritional and physiological parameters of growing and laying Japanese quails. For this purpose, two experiments were conducted: The 1st experiment: A total number of 450 unsexed one weeks of age Japanese quail chicks were randomly distributed into nine (3×3 factorial arrangement) treatment groups of 50 for each group to evaluate the effect of three levels of dietary CP (20, 22 and 24%) and three Zn sources (0 g of Zn/kg diet, 0.1 g ZnO/kg diet, and 0.1 g Zn-Met/kg diet) on growth performance, carcass traits, blood profile, and antioxidant parameters of growing Japanese quail during the period 1-5 wk of age. The 2nd experiment: A total number of 216 mature Japanese quail at eight weeks of age were randomly distributed into nine (3×3 factorial arrangement) treatment groups of 27 for each group to study the effect of three levels of CP (16, 18 and 20%) and three Zn source (0 g of Zn/kg diet, 0.1 g ZnO/kg diet, and 0.1 g Zn-Met/kg diet) on productive performance, egg quality, and blood constituents of laying Japanese quail. from our results, it could be concluded that dietary protein level for growing Japanese quails could be reduced to 20% without negative effects on their performance, carcass traits, and blood metabolites. We advise avoiding increasing the level of dietary protein, because using the low-CP diet with or without Zn source (ZnO or Zn-Met) gave similar results to high-CP levels (22 or 24%). During laying period, using 18% and 20% CP and zinc source can improve egg weight, some egg quality, liver and kidney function and all immunological and antioxidant parameters in laying Japanese quails.