Kannan G, Heath J L, Wabeck C J, Owens S L, Mench J A
Department of Poultry Science, University of Maryland, College Park 20742, USA.
Poult Sci. 1998 Feb;77(2):322-8. doi: 10.1093/ps/77.2.322.
This experiment was conducted to determine the effect of elevated plasma corticosterone (CORT) levels on meat quality characteristics. Male broilers (Arbor Acres) were either 1) fed a diet containing corticosterone (CORT) prior to processing, 2) transported by truck for 3 h before processing, or 3) processed without either of the above treatments. Six crates of birds (10 birds per crate; two crates per treatment) were stunned or killed using CO2 gas. Six birds per crate were processed and blood samples were collected during exsanguination for plasma CORT analysis. Meat samples were collected from carcasses either at 20 min or at 4 h post-mortem. At each sampling time (ST), Pectoralis superficialis samples were collected and either individually quick frozen (IQF) in liquid nitrogen or aged on ice (AOI) for 24 h prior to pH, ratio of inosine to adenosine nucleotides (R-value), cooking loss, shear value, and color analyses. The IQF Biceps femoris samples were used for pH, R-value, color, and heme pigment analysis. Mean (+/- SEM) CORT concentrations were 12.9+/-2.57, 11.7+/-1.38 and 7.9+/-0.79 ng/mL, respectively, in the CORT, transported, and control groups. There were significant treatment by ST (P < 0.05) and ST (P < 0.001) effects on the R-value of IQF P. superficialis samples. The CORT group had the highest L* value (P < 0.01) and the lowest a* value (P < 0.06). There was also a significant main effect of ST on shear values (P < 0.05) of AOI P. superficialis samples, with the means higher at 4 h than at 20 min post-mortem. The R-value of IQF B. femoris samples was markedly influenced by treatment (P < 0.001) and ST (P < 0.001). The results indicate that artificially elevating circulating CORT concentrations results in lighter meat color in broilers.
本实验旨在确定血浆皮质酮（CORT）水平升高对肉质特性的影响。雄性肉鸡（艾维茵肉鸡）分为三组：1）在屠宰前饲喂含皮质酮（CORT）的日粮；2）在屠宰前用卡车运输3小时；3）不进行上述任何处理直接屠宰。每组六笼鸡（每笼10只；每种处理两笼），采用二氧化碳气体致昏或宰杀。每笼选取六只鸡进行屠宰，并在放血过程中采集血样用于血浆CORT分析。在宰后20分钟或4小时从屠体采集肉样。在每个采样时间点（ST），采集胸浅肌样本，要么在液氮中单独速冻（IQF），要么在冰上熟化（AOI）24小时，然后进行pH值、肌苷与腺苷核苷酸比率（R值）、蒸煮损失、剪切值和颜色分析。IQF的股二头肌样本用于pH值、R值、颜色和血红素色素分析。CORT组、运输组和对照组的平均（±SEM）CORT浓度分别为12.9±2.57、11.7±1.38和7.9±0.79 ng/mL。IQF胸浅肌样本的R值存在显著的处理与采样时间交互作用（P < 0.05）以及采样时间主效应（P < 0.001）。CORT组的L值最高（P < 0.01），a值最低（P < 0.06）。AOI胸浅肌样本的剪切值在采样时间上也存在显著主效应（P < 0.05），宰后4小时的均值高于宰后20分钟。IQF股二头肌样本的R值受处理（P < 0.001）和采样时间（P < 0.001）的显著影响。结果表明，人为提高循环CORT浓度会导致肉鸡的肉色变浅。
