Toll-like receptor mRNA expression, iNOS gene polymorphism and serum nitric oxide levels in indigenous chickens.

Toll-like receptor (TLR) family is one of the important members of innate immune system that recognizes conserved microbial patterns and induces innate immune response. They also act as a link to adaptive immune response. Nitric oxide (NO) is a multi-functional mediator with diverse physiological and immunological roles. In the present study TLR mRNA expression in heterophils, serum nitric oxide level and iNOS (inducible Nitric Oxide Synthase) gene polymorphism were investigated in cockerels of two Indian native chicken breeds, Aseel and Kadaknath. TLR (4 and 5) mRNA expression as quantified by real time RT-PCR revealed Kadaknath males expressed significantly (P < 0.01) higher TLR4 mRNA than Aseel males. iNOS gene polymorphism analyzed by PCR-RFLP method revealed difference in allele frequency. Kadaknath males had higher allele B frequency (0.81) than Aseel males (0.56). However, there were no genotype and breed effect on serum nitric oxide level. Based on the present study we conclude that Kadaknath has comparatively higher innate immunity levels than Aseel, however further investigations are needed.