Genetics of immunocompetence traits in Kadaknath native chicken

Immunocompetence status of 179 chicks belonging to Kadaknath breed of native chickens, were studied for four important immunocompetence (IC) traits, viz., humoral immune response (assessed by estimating the antibody response to sheep red blood cells using the haemagglutination (HA) test), cell mediated immune response (estimated as in vivo response to a mitogen (PHA-P)), serum IgG concentration (estimated using single radial immunodiffusion (SRID) assay) and serum lysozyme level (measured through ‘lysoplate assay’) with the objective of obtaining the immunocompetence profile and to estimate the effects of various genetic and non-genetic factors on these traits. Data were analysed by least squares analysis of variance taking sire and hatch as random and fixed effects, respectively. Least squares means of HA titre, CMI response, serum IgG and serum lysozyme were 7.49±0.25, 0.207±0.013 mm, 10.07±0.20 mg/ml and 2.02±0.05 μg/ml, respectively. Heritability estimates were medium to high but associated with higher standard errors. The phenotypic correlations (r_p) among IC traits were very low and not significantly different from zero. Genetic correlations (r_g) between CMI response and serum lysozyme was negative and high. It may be inferred that improvement for general immunocompetence profile of the birds could be achieved by selection for combination of different facets of host's immune systems.