A study on bilateral asymmetry in PD1, control broiler and Vanaraja commercial chickens

The study was conducted on 814 chicks of PD1, 124 Control broiler and 128 Vanaraja commercial chickens for 7 weeks body weight and bilateral asymmetries for shank length (SL) and shank width (SW). The inheritance of these traits in PD1 were studied. Body weight and trait size for SL and SW were significantly (P<0.05) higher in Control broiler followed by PD1 and Vanaraja irrespective of sexes except trait size for SL in PD1 and control broiler were non significant. Males recorded significantly (P<0.05) higher body weight and trait size in all the three genetic groups. Fluctuating asymmetry and relative asymmetries for SL and SW differed significantly (P<0.05) between genetic groups irrespective of sexes. Most of the bilateral asymmetry traits were significantly (P<0.05) lower in control broiler than PD1 and Vanaraja. Males recorded significantly (P<0.05) higher fluctuating, bilateral and directional asymmetries for SL in PD1. In control broiler and Vanaraja no significant (P<0.05) differences were observed between sexes for any of the bilateral asymmetry traits studied. The heritability estimates of different bilateral asymmetries in pooled sex were found to be low (0.00 to 0.17). Genetic and phenotypic correlation estimates between different traits were measured. Lower bilateral asymmetries in control broiler compared to PD1 and Vanaraja suggest that Control broiler being an unselected population the asymmetries were less compared to PD1 which was selected for shank length and Vanaraja which is a crossbred. Developmental stability was best in Control broiler followed by PD1 and Vanaraja.