Effect of Incorporating Early Feather Restriction Gene (KS) From Native Chicken to Purebred Chicken

Abstract

Fast growing chicken suffers more in a hot humid condition than a slow growing one. The slow feathering affects the insulation mechanism of the chicken, thus enhance birds ability to dissipate heat during heat stress to a greater extent. As a consequence, slow feathered birds are more adaptive to hot humid environmental conditions. This study was undertaken to investigate the effect of incorporating early feather restriction gene (KS) in exotic population. A total of 34 slow feathered (SF) native chicks with KS gene of 28-day-old were collected from different villages and markets and were reared up to sexual maturity. After attaining sexual maturity, 2 males and 8 females of SF native chicken were randomly chosen to make a di-allelic cross with rapid feathered (RF) Rhode Island Red (RIR) and Fayoumi (FY). The crossbred progeny of each cross were reared up to 105 days to assess growth, survivability, heat tolerance and carcass yield under hot humid Bangladeshi condition. The collected data were arranged in a 3(genotype)×2(feather pattern)×9(age) factorial experiment in a Completely Randomized Design (CRD) and analyzed by SAS. Among genotypes, the highest survivability was obtained in Desi×Fayoumi (96.7%) and in SF chicks (96.1%) and the lowest in Desi×RIR (91.5%) and in RF chicks (90.5%). The SF chicks exhibited an average 8% heavier live weight than that of their RF counterparts. The cloacal temperature varied among genotypes and between feathering patterns (FP); being highest in Desi×RIR (430C) and in RF chicks (41.60C) and lowest in RIR×Desi (400C) and in SF chicks (41.40C). In case of Desi×RIR, RIR×Desi and Desi×Fayoumi, cloacal temperature increased linearly by 0.047, 0.044 and 0.0320C for each gram of live weight increase. Further, the cloacal temperature increased linearly by 0.036 and 0.0440C for the increase of each gram of live weight gain in case of RF and SF chicks, respectively. There was no significant (P>0.05) difference of dressing percentage for the effect of either genotype or FP (55.4% for SF vs. 46.6% for RF birds). Genotype and FP had significant effects (P<0.05; P<0.01) on total meat yield; being highest in Desi×RIR (24.6%) and in SF birds (26.2%) and lowest in Desi×Fayoumi (21.4%) and in RF birds (20.6%). Breast meat yield of SF birds (9.2%) was significantly (P<0.01) higher than that of RF birds (7.1%). The highest thigh meat yield was obtained in Desi×RIR (7.6%) and in SF birds (8.3%) and the lowest in Desi×Fayoumi (6.7%) and in RF counterparts (6.0%). The highest drumstick meat yield was obtained in RIR×Desi (5.6%) and in SF birds (5.9%) and the lowest in Desi×Fayoumi (5.0%) and in RF birds (4.8%). Genotype and FP had significant interaction effect on total meat yield as well as fractional meat yields. The study revealed that incorporation of ‘Ks’ gene in the exotic one by crossing with native chicken and rearing under hot humid environment may be a means of improving growth, survivability, heat tolerance and carcass yield.