Performance and meat quality of Label Rouge chickens at different slaughter ages

ABSTRACT: This study evaluated the performance parameters, carcass characteristics, and meat quality of Label Rouge chickens raised under an alternative system as a function of age at slaughter. The design was completely randomized with a 5×2 factorial arrangement, with slaughtering at five ages (70, 90, 120, 150, and 180 days) and two sexes. A total of 240 birds (Pescoço Pelado strain) were used, including 120 females and 120 males. Performance, carcass, physicochemical, proximate composition, and muscle fiber traits were evaluated. Rearing time and sex had significant effects on performance-related traits, with better results for males. The interaction between slaughter age and sex had a significant effect on the carcass and physicochemical parameters, which cause different responses in males and females with increasing slaughter age. For the proximate composition and muscle fiber analysis, the interaction between the parameters studied only had a significant effect on ether extract in the breast. The increase in age resulted in chickens with higher live and carcass weight at slaughter but lower performance indices. Females had lower carcass yield and greater deposition of abdominal fat. Females had lower tenderness in the drumstick and males in the breast with increasing slaughter age, and both cuts had more intense color and redness and reduced lightness starting at the slaughter age of 90 days.

摘要：本研究以屠宰日龄为变量，评估了替代养殖体系下饲养的红标肉鸡（Label Rouge）的生长性能参数、屠宰性状及肉品质。试验采用完全随机设计，设置5×2因子组合，分别于5个日龄（70、90、120、150、180日龄）开展屠宰，并设置两个性别水平。试验共使用240羽佩斯科索佩拉多（Pescoço Pelado）品系肉鸡，公、母鸡各120羽。本试验测定了生长性能、屠宰性状、理化指标、常规营养成分及肌纤维特性。养殖时长与性别对生长性能相关性状具有显著影响，公鸡的生长性能表现更优。屠宰日龄与性别的交互作用对屠宰及理化参数存在显著影响，随着屠宰日龄增加，公、母鸡呈现出不同的响应模式。针对常规营养成分与肌纤维特性的分析结果显示，各研究参数间的交互作用仅对胸肌粗脂肪（ether extract）含量存在显著影响。日龄增加会使屠宰时的活体重与胴体重提升，但生长性能指标随之下降。母鸡的屠宰率更低，腹部脂肪沉积量更高。随着屠宰日龄增加，母鸡的腿肉嫩度下降，公鸡的胸肉嫩度下降；且自90日龄屠宰起，两种肉块的颜色更深、红度更高，亮度则有所降低。