ULTRASTRUCTURAL MEASUREMENTS OF THE EGGSHELL AS A TOOL TO DETECT THE CHICKEN BREED EFFECT ON EGGSHELL STRENGTH TRAIT

This trial was carried out to detect and investigate the influence of chicken breed (Fayoumi and Dandarawi as Egyptian native breeds) on the ultrastructural properties of eggshells by using scanning electron microscope (SEM) technique. At 26 weeks of age, twelve samples of eggshells were randomly taken from the eggs collecting from the two breeds (6 each). The eggshell samples were prepared according to the scanning electron microscopy procedures to investigate ultrastructural variants. The main results obtained could be summarized as follows: The eggshell of Fayoumi breed had a significantly higher effective thickness (palisade layer %) compared to Dandarawi counterpart. Per contra, both absolute and relative mammillary layer length was significantly lower in eggshells of Fayoumi breed compared to those of Dandarawi ones. With regard to total structural score, the results revealed that Fayoumi breed had a significant better structural score (lower value) to overall ultrastructural traits. Where, the corresponding figures were 22.5 and 27.5 for Fayoumi and Dandarawi breeds, respectively. It can be concluded that the eggs of Fayoumi breed were required high force to break its eggshell, consequently, increased shell strength compared to Dandarawi breed. The previous result was attributed to Fayoumi breed was a better ultrastructural of eggshell and shell quality compared to the eggshells of Dandarawi breed.