부산대학교 도서관

A total number of 166 Sinai birds (144 female and 18 male) at 42 weeks - old were used, weighed and divided into six treatments of three replicates each to determine the nutritional requirement of calcium (Ca) and available phosphorous (Av P) for Sinai laying hens during 42 until 52weeks of age and the effects on laying performance parameter, egg quality, nutrients digestibility Ca and AvP retention Ca and P in the egg shell, tibia and blood serum, fertility and hatchability as well as economic efficiency were measured . The dietary levels of Ca and Av P included 3x2 factorial design (3 , 3.5 and 4% Ca, each contained 0.24 and 0.3 % Av P) . Resulted obtained could be summarized in the following: 1 - Increasing dietary calcium content up to 4% resulted in significantly decreased live body weight and change body weight in the end of the experimental period. 2 - H ens fed diet containing 3, 3.5%Ca and 0.3% Av P significantly increased egg production percentage . 3 - The feed conversion was improved by using diet contained 3% Ca + 0.3% AvP. 4 - N o significant effects of Ca, AvP and their interaction on egg quality. 5 - Increasing dietary Ca or AvP content in the diet significantly improved the fertility and hatchability . The best value of fertility and hatchability were recorded by hens fed diet containing 4%Ca + 0.3% AvP. And the chick weight and egg discarded percentage was significantly improved as dietary Av P increased u p to 0.3% and 3.5% Ca. 6 - The digestibility coefficients of nutrients were almost similar with dietary treatments except ether extract which was significantly improved by fed diet contained 3% Ca. 7 - A significant increase in tibia P content was recorded wit h in creasing dietary Ca at 4% level .8 - The diet of 3.5% Ca resulted in a significant increase blood and egg shell Ca concentration, also the egg shell and excreta P content were significantly increased with increasing the dietary Ca levels. 9 - The greatest value of economic efficiency was obtained by hens fed diet containing 3%Ca and 0.3%AvP. It could be concluded that the combination of 3% Ca and 0.3% AvP could be used in Sinai laying hens diets to obtain the maximize productive performance and economic efficiency as well as 3.5% Ca and 0. 3 % AvP inclusion during period from 42 to 58 weeks of age gave the maximize fertility and hatchability values . [ABSTRACT FROM AUTHOR]