عنوان مقاله [English]
This experiment carried out to evaluate replacing effects of Oyster shell (OS) with filter cake (FC) of sugar beet industry on performance and quantity and quality of egg in laying hens .In this trial the filter cake in two physical forms of powder and pellet in five levels of 0, 25, 50, 75, and 100% replaced for oyster shell. Each treatment had 3 replications. The experiment lasted 3 periods of 28 days . Feed intake and egg weight were measured every week and egg quality was recorded every month. Results indicated that replacing OS with FC up to 50% level in the form of powder, had no significant effect on feed intake, egg weight, egg mass production , laying rate and feed conversion ratio (P>0.05). Replacing powder FC more than 50% caused significant reduction in egg mass production, laying rate and feed efficiency (P<0.05). However, using pellet FC at all levels had no significant effects on these traits. Replacing OS with FC had no significant effect on egg quantity and quality characteristics. It is concluded that the best and suitable level of replacing FC in powder or pellet form is 50 percent in laying hens nutrition.