PDF(Pubmed)
Abstract：
Forty castrated Holstein calves underwent an adrenocorticotropic hormone (ACTH) challenge to assess the effects of premortem stress on the longissimus lumborum (LL) following harvest. LL biopsies were collected before the challenge, at different harvest times (2, 12, 24, and 48 h; n = 10), and after 14 d aging. The expression of small heat shock proteins (SHSPs), deglycase 1 (DJ-1), and troponin were analyzed. Blood was analyzed throughout the ACTH challenge and at harvest for cortisol, oxidative stress, and complete blood count (CBC). Color and myofibrillar fragmentation index (MFI) were measured in aged samples. Unexpectedly, calves from different harvest times differed (p = 0.05) in cortisol response. Calves were divided into two different cortisol response groups (high or low; n = 20). Statistical analysis assessed the effects of cortisol response (n = 20), harvest time (n = 10), and their interaction. Harvest time altered SHSPs (p = 0.03), DJ-1 (p = 0.002), and troponin (p = 0.02) expression. Harvest time and cortisol response impacted steak color (p < 0.05), and harvest time altered steak pH (p < 0.0001). Additionally, various CBCs were changed (p < 0.05) by harvest time. Harvest time changed (p = 0.02) MFI. These data demonstrate that the protein expression, color, and MFI of the LL may be influenced by premortem stress.
摘要：
40只cast割的荷斯坦小牛接受了促肾上腺皮质激素（ACTH）的挑战，以评估采收后死前应激对腰长肌（LL）的影响。LL活检在挑战前收集，在不同的收获时间（2、12、24和48小时；n=10），老化14d后。小热休克蛋白（SHSPs）的表达，deglycase1(DJ-1),和肌钙蛋白进行了分析。在整个ACTH激发和收获时分析血液中的皮质醇，氧化应激，全血细胞计数（CBC）。在老化样品中测量颜色和肌原纤维碎裂指数(MFI)。出乎意料的是,不同收获时间的小牛皮质醇反应不同（p=0.05）。小牛分为两个不同的皮质醇反应组（高或低；n=20）。统计分析评估了皮质醇反应的影响（n=20），收获时间(n=10)，和他们的互动。收获时间改变了SHSP(p=0.03)，DJ-1（p=0.002），和肌钙蛋白(p=0.02)表达。收获时间和皮质醇反应影响牛排颜色(p<0.05)，和收获时间改变牛排pH(p<0.0001)。此外,各种CBCs随收获时间的变化而变化(p<0.05)。收获时间改变(p=0.02)MFI。这些数据表明，蛋白质表达，颜色,LL的MFI可能会受到死前压力的影响。
