EFFECT OF RETINYL ACETATE AS FEED SUPPLEM ENTATION CARRIED OUT BEFOREBREEDING EGG-PRODUCTION ON THE HATCHABILITY OF JAPANESE-QUAIL EGGS

The experimental animals used throughout ale experiments were Japanese quails (Coturnix coturnix japonica). Surplus vitamin A supplementatio n [officinal preparation (Vitamin A capsule 50 000 IU, EGIS, Budapest) containing retinyl acetate (RE), USP XIX quality] nras applied during one month mixed in a basic feed (Poultry layer LI. 15/2, Babolna) con taining 10 000 IU/kg Vitamin A. Of the hatching biological parameters, number of infertile and fertile eggs, as well as that of embryos died during incubation were determined. Eggs were collected to determine t heir measures and for retinoid analysis during the period of feed supp lementation. Retinoid and beta-carotene contents of eggs were determin ed by HPLC. It was found that tile mass of eggs increased significantl y as a result of RA supplementation, The increase was caused by the in crease of weight of yolk and albumen, Retinol content and concentratio n increased significantly (p<0.001) in the yolk of simultaneously anal yzed eggs. Increase of retinyl palmitate content of yolk was also obse rved clue to the RA supplementation, however that change was significa nt neither by the progress of feeding period nor in case of feeding ra supplementation in different doses. As a consequence of RA treatments , the quantity of beta-carotene stored in the yolk decreased. as compa red to the eggs laid in the control group. RA supplementation improved the fertility of eggs (p<0.05) and the parameters of hatchability and unanimously decreased the incidence of embryo mortality in Japanese q uail families. Trends of body-mass in newly hatched chickens showed th at grade of the transformation of the egg materials, i.e. use of avail able (stored) nutrients during incubation, improved significantly in t he groups receiving RA supplementation. Based on the results obtained: five-times increase of the vitamin A content of feed (50 000 IU/kg of feed) has been proposed one week before the collection of breeding eg gs.