Genetics of growth traits in black turkey line selected for high humoral immune response

摘要

Growth performance of 108 poults belonging to the first generation of black turkey variety selected for high antibody titre against SRBC antigen, obtained in 2 hatches, maintained at this Institute were recorded for body weights from 0 to 12 weeks ofage at biweekly intervals and then at 16 weeks. The data were analyzed by least squares analysis of variance using mixed model wherein sire was taken as random and hatch and sex as fixed effects. Paternal half sib correlation was used for estimation of genetic and phenotypic parameters. Least squares means of body weight at hatch was 40.03±0.44 g, which crossed 1000 g by 16 weeks of age. Hatch effect was non-significant on body weights at all ages except at 12 and 16 weeks of age. Males were significantly heavier than the females from 2 weeks onward. The h2 estimates of the body weights at hatch, 12 and 16 weeks of age were very low but moderate (0.280±0.320 to 0.419±0.403) at other ages exhibiting the presence of additive genetic variance. The k values ranged from 23.049 to 24.537. The phenotypic correlations (rp) among body weights at different ages were positive, high and significant (P<0.05 or 0.01) except between hatch weight and body weights at 8,12 or 16 weeks. Most of the genetic correlations (r_G) among body weights were positive and more than unity. The rp had smaller magnitudes as compared to their corresponding r_G. The finding suggested that 4 or 8 weeks body weights might be used as selection criterion for improvement of body weightsat later ages.