Immunocompetence and Some Hematological Parameters of Naked Neck and Normally Feathered Chicken

Abstract

An experiment was conducted to evaluate the effect of naked neck (Na) gene, sex and their interaction on immunocompetence of chickens. Three genotypes (NaNa, Nana and nana) were the offspring of heterozygous naked neck (Nana) Fayoumi (Egyptian breed) males and females. They were reared under similar environmental, managerial and hygienic conditions. The present results showed that the NaNa birds had lower mortality rate as compared to Nana and nana counterparts. The NaNa genotype had significantly heavier 8wk-body weight and higher relative weights of bursa, spleen, heart and liver compared to nana sibs. With respect to cutaneous basophilic hypersensitivity (CBH) response, the presence of Na gene in a double state significantly increased dermal swelling response to phytohemagglutinin-P (PHA-P) injection compared to nana counterparts. The Nana genotype was intermediated in the most cases. Dermal swelling response to PHA-P, relative bursa weight and relative spleen weight were significantly affected by interaction between Na gene and sex. Concerning correlations between productive traits and immunocompetence, it could be speculated that the body weight was negatively correlated with relative lymphoid organs weight in all genetic groups. However, the body weight was significantly positive correlated with toe-web swelling measured at all times in NaNa and Nana genotypes. In conclusion, the difference among genetic groups in response to PHA-P and in some physiological response suggest that the NaNa genotype had higher cell-mediated immune response followed by Nana compared to nana genotype. Accordingly, introducing Na gene in susceptible strains may be benefit to increase immunocompetence of chicken.