The effect of eggshell ultrastructure on hatchability percentage of eggs laid from naked neck, frizzled and normally feathered hens

Abstract

This experiment was designed to evaluate the effect of naked neck (Na) and frizzle (F) genes on eggshell ultrastructure at different intervals of incubation period. 81 eggshell samples (9 samples/ genotypes/ incubation studied intervals) were taken before incubation period, at 12 days of incubation period and after hatching. Before incubation period, the present results showed that the presence of Na or F genes in a single manner significantly increased the palisade layer compared to normally feathered genotype. The Na had effected used calcium from mammillary layer during embryonic development .It is well known that local strains enjoined with higher percentage of fertility. Introducing naked neck (Na) or frizzle (F) genes did not depress this higher fertility. Moreover, under high ambient temperature, naked neck and frizzled genotypes recorded higher fertility percentage than that recorded for normally feathered one. On the other hand, it is noticed that, naked neck gene decreased hatchability percentage; this may be attributed to the positive effect of naked neck gene on increasing the length of palisade layer of eggshell ultrastructure. The decreasing of hatchability associated with naked neck gene was a major cause that impeded the spread of using this gene in commercial strains. In order to solve this problem and avoiding the disadvantage of naked- neck gene, it could be beneficial to insert this gene in a commercial strain and select for a decreased palisade length.