Performance and meat quality of Label Rouge chickens at different slaughter ages/Parametros de producao e qualidade da carne de frangos Label Rouge em diferentes idades de abate

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 (Pescoco 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. Key words: feed conversion, free-range chicken, muscle. O objetivo deste estudo foi avaliar os parametros de desempenho e as caracteristicas de carcaca e qualidade da carne de frangos Label Rouge criados em sistema alternativo em funcao do aumento da idade de abate. O delineamento foi inteiramente casualizado (DIC) disposto em esquema fatorial (2x5), sendo dois sexos (macho e femea) e cinco idades de abate (70, 90, 120, 150 e 180 dias). Foram utilizadas 240 aves (Pescoco Pelado), sendo 120 femeas e 120 machos, sendo avaliados os parametros de desempenho, carcaca, fisico-quimicos, composicao centesimal e fibra muscular. Com o aumento no tempo de producao houve efeitos dos periodos de producao e sexo em relacao a variaveis de desempenho, com melhores resultados para os machos. Para os parametros de carcaca e fisico-quimicos, houve interacao entre sexo e idade de abate, revelando comportamento diferenciado para machos e femeas com aumento da idade de abate. Para a composicao centesimal e analise das fibras musculares, somente para extrato etereo no peito foi verificado in