Chicken embryogenesis: Influence of egg quality traits on embryo morphology

This study examined the chicken embryogenesis process vis-a-vis the eggs quality traits and morphological changes of developing embryo. 446 fertile eggs obtained from broiler breeder flock were incubated. From 1^st to 21^st embryonated day (ED), five eggs were randomly selected on weight equalization, weighed, broken and emptied to assess air cell depth and width, shell thickness, egg surface area, egg shape index, shell volume, moisture loss, embryo length, yolk-free wet embryo weight, internal organs, yolk sac weight, albumen and yolk pH, as well as hatchability and piping rate. Diameter of blastoderm formed in fertile eggs at 1^st ED was 24.26 mm. The blood ring observed at 2^nd ED increased by approximately 75%, from 19.74 mm to 34.48 mm at the 3rd ED. A well-developed cardiovascular system and heart beat was observed on 3^rd ED. From 4^th ED, there were progressive increase in the embryo length and YFWEBW with concomitant increase in weight of breast muscle and internal organs. Maximum intestine development (98% increase) occurred from 19^th to 21^st ED. The hatching curve shows progressive increase in hatched chicks until 509 h of incubation. Positive correlations (P<0.01) existed between air cell size and moisture loss, embryo length, YFWEBW, yolk sac, internal organs and breast muscle. This study confirms the linear relationship between chick weight and egg weight egg; y= 0.731 EW-1.645 while regression prediction for embryo weight was Y= 0.065EW₀ + 1.646 ED-14.429 and Y= 0.045 EW₁ + 1.576 ED-12.744 with high R² value. The study concluded that egg quality traits had significant effect on embryo development.