A total number of 198 local Sinai laying hens (180 female + 18 males), 24-weeks-old, were weighed and divided into six dietary treatments to investigate the effect of dietary different levels and sources of crude fiber on productive and reproductive performance and nutrients digestibility during the laying period (24-40 weeks of age). The birds were fed a control diet contained 3.5 % crude fiber (CF) while, the remaining treatments were given moderate levels of dietary crude fiber by suing different levels of sunflower meal (SFM) and olive cake (OK). Results obtained could be summarized in the following:
1. The different levels of CF had significantly higher BW and CBW comparing with the control diet (3.2% CF) except for the diet contained 5.42% CF (8% OK).
2. The inclusion of different fiber levels in the diets resulted in significantly decreased egg number/hen, while egg weight was significantly improved for the all dietary CF treatments compared to the control diet except for the diet contained 5.42%CF where it did not actually differ from control diet.
3. Regarding to egg mass, no significant differences were found between the group fed diet contained 5.6 % CF and the control diet.
4. Feed conversion ratio was significantly lower for the birds fed diets with different levels of CF than control.
5. Diet containing 4.42%CF (7%SFM) resulted in a significant higher hatchability of set eggs compared to control and other treatments. In addition, the hatchability of fertile eggs tends to significantly increase in treatments fed 4.45, 4.42 and 5.6% CF (7% SFM, 4% OK and 7%SFM+4%OK) as compared to the control diet.
6. Embryonic mortality significantly decreased by the diets contained 4.45, 4.42 and 5.6% CF compared to control group meanwhile the other treatment did not actually differ from control diet.
7. All different levels of CF resulted in a significantly higher crude fiber and ether extract digestibility than control diet.