Study on the relationship between eggshell colors and egg quality as well as shell ultrastructure in Yangzhou chicken

Experiments were conducted to evaluate the relation between eggshell colors and egg quality as well as shell ultrastructure in Yangzhou chicken. A total of 120 eggs on the day of lay of New Yangzhou chickens were selected. The eggshell color, shape index, shell strength, shell thickness, egg weight, albumen weight, yolk weight, shell weight, yolk color, calcium content of shell, albumen and yolk were measured. Then the ultrastructure of transect and outer shell was observed through scan electron microscopy. The results showed that the tenderness of shell strength and shell thickness reduced as the shell color became shallow, however the pores in the shell and shape index increased. There were significant correlations between shell color and shell strength, shell thickness, and shell weight ( P < 0.05). There were no distinct correlations between shell color and egg weight, albumen weight, yolk weight, haugh unit, yolk color, calcium content in albumen and yolk ( P > 0.05). It was concluded that some egg quality traits such as shell strength, shell thickness, shell weight and shell ultrastructure could be assessed through the shell color.