Effect of Breeder Age on Embryo and Residual Yolk composition at 18-d of Incubation in Cobb 500 Boiler Breeders Hatching Egg


  • Iman Hajkhodadadi Department of Animal Science, Faculty of Agriculture and Natural Resources, ArakUniversity,Arak 38156-8-8349, Iran
  • M. Khodai-motlagh


This study was conducted to compare age effect on chemical composition of embryo at 18-d of incubation in Cobb strain. A completely randomized design was used in Experiment, with 2 treatments , 10 replicates in each treatment. 480 hatching eggs were obtained from commecial Cobb 500 breeder flock at 31(Y) and 51 (O) weeks of age, 240 eggs for each age. Eggs weighted individually before incubation and incubated following usual hatchery practices. Embryo weighted individually at 18d of age. A sample of embryo and residual yolk used for measurement of chemical composition There were significant difference (P<0.05) between Y and O group in egg weight. There were significant difference (P<0.05) among Y and O group in embryo and residual yolk weights so in O group egg yolk weight were increased in a significant trend. There was no significant differences (P>0.05) between Y and O group in embryo dry matter, embryo ash and embryo nitrogen free extract content. In the present study, a significant effect of breeder age on embryo weight was observed. Residual yolk and embryo fat in Y group was lower than O group and the difference was significant (P<0.05).Our finding revealed that larger proportion of the egg’s fat content left in there residual yolk sac of embryos from larger eggs.