A total number of 270 Japanese quail (180 females and 90 males) at 4 weeks of age were used in an experiment lasted 22 weeks. Experimental japanese quail (Coturnix coturnix japonica), were used in a 3x2 factorial arrangement. Quail were randomly divided into three treatment groups, each of 60 quail females and 30 males, that received three dietary protein levels (16, 18 or 20 % CP). Each quail group was randomly divided into two sub-groups (30 females and 15 males each). The first sub-group of each group received diet without any supplementation, while the second sub-group was given diets supplemented with a mixture of 50 mg Vitamin E (VE) and 1 mg Se selenium (Se) /kg diet. All diets were isocaloric (2900 kcal ME/kg) and isofibrous.
Results obtained could be summarized as follows:
-  Live body weight and body weight change were improved with the medium protein level (18%) followed by high protein (20%) and the low protein level (16%) during the whole experimental period.
- Egg weight was significantly (P<0.05) decreased, while egg number increased (P<0.05) with the decrease of protein level.
-  Feed intake recorded an increase (P< 0.05) with the decrease of protein level.
- Feed conversion ratio (g feed intake /g egg mass) revealed significantly worst (P<0.05) decrease by low protein level in diet.
-  Protein intake recorded an increase with increasing of protein level.
-  Efficiency of protein utilization was improved with low protein level 16% in the diet.
-  Hatchability recorded a non-significant difference (P>0.05) among groups.
-  Albumen % showed a significant (P<0.05) increase, while yolk  % decrease with  the increase of protein level.
-  Digestibility coefficients and the nutritive values expressed as DCP, TDN % and ME kcal/kg were significantly varied (P<0.05) among the different experimental diets, the different levels of protein did not significantly influence digestion coefficient of NFE.
- Supplementing diet with VE and Se affected the final live body weight and body weight change were significant (P<0.05) during the experimental period as compared to unsupplemented diets.
-  Improvement of egg number and egg mass by 10.45 and 15.39 % compared to that of the unsupplemented, respectively.
-  Feed intake recorded an increase (P<0.05) with the supplemented of VE and Se.
- Feed conversion ratio and hatchability percentage improved (P<0.05) with supplemented of VE and Se.
-  Digestibility coefficients and the nutritive values expressed as DCP, TDN % and ME kcal/kg were improved as compared to unsupplemented diets.
- sThe higher economical efficiency was obtained by using 18% CP with supplemented of VE and Se obtained the best economical efficiency.
-  Interaction between dietary protein levels, VE and Se supplementation, indicated that supplemented experimental diets with VE and Se resulted enhanced the performance of these diets especially with 18 % CP levels.
-   It could be concluded that crude protein level of 18 % supplemented with Vitamin E and selenium (50 mg VE and 1 mg Se /kg diet) in the laying Japanese quail diet improve the productive performance and the economic efficiency.