Evaluation of growth performance, meat quality and carcass characteristics of slow and fast-growing broiler chickens under commercial conditions✰

The global demand for animal protein is increasing, and poultry production remains a key source of affordable and widely accepted white meat. Fast-growing broiler genotypes are traditionally preferred for their production efficiency; however, differences in biological performance among genotypes may also influence product characteristics. This study evaluated growth performance, the influence of genotype and sex on meat quality parameters, and carcass traits in fast-growing (Ross 308, slaughtered at d 42) and slow-growing (Hubbard JA57, slaughtered at d 56) broiler chickens. While sustainability and animal welfare provide a broader context for alternative production systems, this research focuses on measurable quality and yield outcomes. A total of 4000 birds were raised under commercial conditions to provide a robust comparative analysis. The results indicate that genotype significantly affected several meat quality traits ( P<0.001 ). Fast-growing Ross 308 broilers exhibited higher breast meat peak shear force (30.74 N vs 15.77 N) and higher shear energy values (117.75 N·mm and 53.46 N·mm; P<0.001 ) compared with slow-growing Hubbard JA57 broilers, indicating significantly tougher breast meat. In contrast, slow-growing broilers showed lower shear force values, reflecting more tender meat. Although pH values did not differ significantly between genotypes (6.6–6.9), differences were observed in expressible moisture content (EMC) and cooking loss, with fast-growing female breast meat showing the highest EMC (10.2%) and slow-growing female thigh meat the lowest (2.4%). Moreover, genotype and sex significantly affected some color parameters and carcass part yields, with Hubbard males exhibiting the highest leg percentage and Ross 308 females recording the highest breast meat yield ( P<0.001 ). These findings demonstrate that growth rate-related genetic differences involve trade-offs between production efficiency and specific meat quality traits. Overall, this study highlights that while fast-growing lines maximize breast yield, slow-growing lines offer enhanced meat tenderness.