a total number of 216 laying hens and 108 cocks of Japanese quail at 6 weeks of age were randomly divided into 12 treatment groups (18 hens and 9 cocks in each). Each group of birds was sub-divided into three replicates each of six females and 3 males. Birds in all treatments were nearly similar in average initial body weights and average daily egg production. A 2x3x2 factorial design experiment was performed including two levels of calcium (2.0 and 2.5%), three levels of supplemented phytase (0, 500 and 1000 FTU/Kg diet) and two levels of vitamin D3 (1000 and 2000 ICU/Kg diet) during the experimental period from 6 to 16 weeks of age. Productive and reproductive performance, egg quality, some blood constituents and bone characteristics formation were studied.
The results obtained could be summarized as follows:
1 - Calcium level had no significant effect on body weight, egg production, egg number, egg weight, egg mass, egg quality traits, egg components studied and reproductive of Japanese quail layers during all experimental periods. While, feed intake was significantly (P<0.05) lower for hens fed the diet containing 2.5% calcium compared to those received 2% calcium during all the experimental periods. Also, feed conversion was significantly (P<0.05) decreased with increasing calcium level from 2.0% to 2.5% during 11–16 and 6-16 weeks of age.
2 -Values of carcass and dressing weights/100g pre-slaughter weight were significantly (P<0.01) higher for Japanese quail layers fed 2.5% calcium compared with those of layers fed 2% dietary calcium.
3 - Microbial phytase supplementation (500 and 1000 FTU/Kg) improved significantly (P<0.05 or P<0.01) all productive performance traits during all the experimental periods except for feed conversion, egg production, egg number and egg weight during 6-11 weeks of age.
4- Hatchability/ total eggs % and hatchability/ fertile eggs % were improved significantly (P<0.01) by increasing phytase level.
5- Layers fed 1000 ICU Vit. D3/Kg showed significant improvement in egg production (P<0.01) and egg number (P<0.05) during 11-16 weeks of age compared with those fed 2000 ICU Vit. D3/Kg diet
6 - Egg yolk % was increased significantly (P<0.05) of hens fed diets containing 1000 ICU Vit. D3, on the other hand shell % was increased significantly (P<0.05) of hens fed diets containing 2000 ICU Vit. D3
7 - Gizzard weight was increase significant (P<0.05) of hens fed diets containing 2000 ICU Vit. D3/Kg diet compared with 1000 ICU Vit. D3/Kg diet.
8 - Bone ash and bone calcium percentages were increased significantly (P<0.05) of Japanese quail layers fed diets supplemented with 2000 ICU Vit. D3/Kg diet compared with 1000 ICU Vit. D3/Kg
9 - All productive performance traits studied except egg weight during 6-11 weeks of age were significantly (P<0.05 or P<0.01) influenced by the interaction between calcium, phytase and Vit. D3 levels during all the experimental period. Also, hatchability/ total eggs, hatchability/ fertile eggs, yolk index and yolk % were significantly (P<0.05) affected by the interaction between calcium, microbial phytase supplementation and vit, D3 levels.
10 - Plucked, gizzard and dressing weights/ 100g pre-slaughter weight were significant effect (P<0.05) due to the interaction between calcium, phytase and Vit. D3 levels