Abstract
Indigenous chicken breeds often exhibit desirable meat quality but slower growth. This study evaluated growth, body size, slaughter traits, meat quality, and heterosis in reciprocal crosses between Guizhou recessive white (GW) and Qiandongnan Xiaoxiang (QX) chickens. A complete diallel cross produced four populations (WW: GW♂ × GW♀; QQ: QX♂ × QX♀; QW: QX♂ × GW♀; WQ: GW♂ × QX♀). To assess growth dynamics, body weight was recorded from hatch to 18 weeks and fitted with Logistic, Gompertz, and Von Bertalanffy models. At 18 weeks, 160 birds (40 per group, equal sex ratio) were assessed for body size, carcass yield, and meat quality. The results showed clear paternal effects. For instance, WQ (GW sire) outperformed QW (QX sire): WQ roosters had higher body weight at 18 weeks (1784.1 g vs. QW, p < 0.05) and greater heterosis (12.38%, 95%CI: 9.15-15.61 vs. 2.54%, 95%CI: -0.66-5.74). WQ hens also showed stronger heterosis despite similar body weight to QW hens (8.05%, 95%CI: 5.04-11.04 vs. 4.05%, 95%CI: 0.67-7.43). Growth curves were generally best described by the Von Bertalanffy model (R(2) ≥ 0.998), except in QW roosters, where the Gompertz model fitted better. Hybrid progeny (WQ and QW) showed improved slaughter traits over QQ, with WQ roosters exhibiting higher heterosis rates (14.09-30.71%) than QW (1.08-21.93%). Meat tenderness was superior in QQ, while QW showed advantages over WQ in tenderness and water retention. Overall, crossbreeding enhanced growth and carcass traits, and using GW as the male parent (WQ) was most effective. These findings provide practical evidence for improving Qiandongnan Xiaoxiang chickens through crossbreeding. Moreover, the observed paternal effects on growth traits suggest the need for further investigation into underlying mechanisms such as genomic imprinting and growth-related hormonal pathways.