A comparative analysis of disease resistance pattern and its possible association with growth hormone (GH) gene polymorphism was carried out in chicken. Crossbreds of Aseel, Kadaknath, Naked Neck and Frizzle with Dahlem Red were vaccinated against Newcastle disease at 7th day and infected with Infectious Bursal Disease Virus (IBDV) at 21 st day of age. Results of HI test performed against ND showed significantly least depression in the antibody titers following IBDV challenge in Kadaknath group, indicating least immunosuppression in the group. Similarly rise in antibody titer against IBDV was also least in this group.
The birds were evaluated for polymorphism at GH gene, intron IV segment by PCR-RFLP. Analysis revealed three different RFLP patterns. Bands with molecular size of 500, 600, 700 and 1200bp and 500, 700 and 1200bp, were mainly observed in Kadaknath (0.6 and 0.4 frequency, respectively).
Thus, Kadaknath crossbreds differed from the other three groups with reference to GH gene polymorphism and showed resistance to the IBD. This suggested a possible association between GH gene polymorphism and resistance to IBD in chicken.
Chicken, IBD, disease resistance, GH gene, PCR-RFLP
