Embryo Specifications at 19-d of Incubation in Different Cobb 500 BoilerBreeders age

420 hatching eggs were obtained from commercial, Cobb 500 breeder at 33 and 53 weeks of age, 210eggs for each breed age. Eggs individually weighed before and after incubation and incubatedfollowing usual hatchery practices. Individual embryo weight was recorded at 19d of incubation,relative embryo weight was calculated. A sample of embryo was used for measurement of chemicalcomposition based on method of AOAC, 1990. A completely randomized design was used. . Eggsweight from Old group was heavier (P<0.05) compared to eggs from Young group, 66.02 and 52.72g, respectively. Result indicated that embryo from O group had the heaviest weights in compare withthe Y group, 36.16 g and 31.48 g respectively. There was no significant differences (P>0.05) betweenY and O group in embryo dry matter, ash, fat, crude protein and nitrogen free extract content,although embryo fat content were increased numerically. There was significant differences (P<0.05)in embryo length at 19-d of incubation so embryo from O goup breeders are found to had moreembryo length than embryo in Y group. There was no significant differences (P>0.05) between Y andO group in heart weight. Our result revealed that as breeder age advanced, embryo weight and lengthincreased and embryo from old group had more residual yolk sac and this may cause moremalabsorbtion of yolk sac during incubation.

Keywords:

Embryo , Specification , Ross broiler breeder