Comparative evaluation of immunocompetence traits in broiler parent lines

Four immunocompetence traits viz. Response to sheep RBCs, CMI response, serum IgG and lysozyme levels were assayed in five broiler parent lines (coloured plumaged CSML and CSFL, white plumaged SML and SDL and naked neck lines) indigenously developed through long-term selection for 5 week body weight. A total of 100 birds per line at the age of 4–5 weeks of age were used for assaying immunocompetence traits. The data were analysed for the effect of line using one way ANOVA. The effect of line was found significant (P<0.05) on all the four immunocompetence traits. The highest HA titre against sheep RBCs were exhibited by Naked neck (7.923±0.383) and least in SML (6.280±0.296). CMI response was highest in CSFL (88.38%±6.95) and lowest in SDL (70.52%±4.28); whereas serum lysozyme (4.180±0.049 mg/ml) and IgG (5.27±0.26 mg/ml) levels were highest in SDL among the germpalsmanalysed. Overall means for response to sheep RBCs, CMI response, serum IgG and lysozyme levels were 6.822±0.170 (log₂ HA titre), 83.80%±2.83, 4.60±0.17 mg/ml and 3.318±0.029 mg/ml, respectively. Correlations among four immunocompetence traits were mostly low in magnitude.The results of present investigations indicatedthat the immnocompetencetraits varied among lines andare under and independent genetic control.