Debut M, Berri C, Baéza E, Sellier N, Arnould C, Guémené D, Jehl N, Boutten B, Jego Y, Beaumont C, Le Bihan-Duval E
Station de Recherches Avicoles, Institut National de la Recherche Agronomique-Centre de Tours, 37380 Nouzilly, France.
Poult Sci. 2003 Dec;82(12):1829-38. doi: 10.1093/ps/82.12.1829.
The present study was aimed at estimating the genetic variability between lines of breast and thigh meat quality (pH decline, color, drip loss, and curing-cooking yield) by comparing a slow-growing French label-type line (SGL) and a fast-growing standard line (FGL) of chickens exposed to different preslaughter stress conditions. The birds were slaughtered under optimal conditions or after exposure to 2 h of transport or acute-heat stress (2 h at 35 degrees C). Relationships between meat quality and stress sensitivity were investigated by measuring struggle during shackling and tonic immobility (TI) duration, 1 wk before slaughter, as an indicator of the basal level of fear of the birds. Although most of the meat quality indicators varied between the 2 lines, differences were muscle dependent. In concordance with a lower ultimate pH, curing-cooking yield of thigh meat was decreased for the FGL birds. In contrast, these birds had a higher curing-cooking yield and a lower drip loss of breast meat resulting from a less rapid pH decline in this muscle compared with SGL birds. Thigh meat characteristics were influenced by both preslaughter stresses, but no significant effects were detected for breast meat. The main effect of heat stress in thigh meat was a decrease of the ultimate pH and led to paler color and lower curing-cooking yield; opposite effects were obtained for transport. Breast meat was much more sensitive to physical activity of birds on the shackle line. Longer durations of wing flapping on the shackle line gave more rapid initial pH decline. Whatever the line, no relationship between TI duration and meat quality characteristics or activity was observed. The present study suggested that SGL birds could be at disadvantage due to more struggle during shackling and accelerated postmortem glycolysis, which is detrimental to the quality of breast meat.
本研究旨在通过比较暴露于不同宰前应激条件下的慢速生长法国标签型品系（SGL）和快速生长标准品系（FGL）鸡，评估胸肉和腿肉品质（pH值下降、颜色、滴水损失和腌制-烹饪产量）品系间的遗传变异性。这些鸡在最佳条件下屠宰，或在经历2小时运输或急性热应激（35摄氏度下2小时）后屠宰。通过在屠宰前1周测量束缚时的挣扎程度和强直静止（TI）持续时间，作为鸡恐惧基础水平的指标，研究肉质与应激敏感性之间的关系。尽管大多数肉质指标在两个品系间存在差异，但差异因肌肉而异。与较低的最终pH值一致，FGL品系鸡的腿肉腌制-烹饪产量降低。相比之下，由于与SGL品系鸡相比，该肌肉的pH值下降较慢，这些鸡的胸肉腌制-烹饪产量较高，滴水损失较低。腿肉特征受两种宰前应激的影响，但未检测到对胸肉有显著影响。热应激对腿肉的主要影响是最终pH值降低，导致颜色变浅和腌制-烹饪产量降低；运输则产生相反的效果。胸肉对鸡在束缚线上的身体活动更为敏感。在束缚线上扑翅时间越长，初始pH值下降越快。无论品系如何，均未观察到TI持续时间与肉质特征或活动之间的关系。本研究表明，SGL品系鸡可能处于劣势，因为在束缚时挣扎更多，且宰后糖酵解加速，这对胸肉品质不利。
