Huang J C, Yang J, Huang F, Huang M, Chen K J, Xu X L, Zhou G H
Department of Engineering, Nanjing Agricultural University, Nanjing 210095, China Key Laboratory of Meat Processing and Quality Control, Ministry of Education China, College of Food Science and Technology, Nanjing Agricultural University, Nanjing 210095, China.
Key Laboratory of Meat Processing and Quality Control, Ministry of Education China, College of Food Science and Technology, Nanjing Agricultural University, Nanjing 210095, China.
Poult Sci. 2016 Oct 1;95(10):2455-63. doi: 10.3382/ps/pew206. Epub 2016 Jul 18.
The objective of this study was to determine the effects of fast pH decline during the early postmortem period on calpain activity and the degradation of cytoskeletal proteins in broilers. Eighty broilers were randomly categorized into two groups: physical restraint (PR) and free struggle (FS). M. pectoralis major (PM) was used for determination of calpain activity, shear value, ultrastructure of myofibrils, and the degradation of desmin, titin, nebulin, and troponin-T. The pH (6.05) of FS group is significantly low than PR group (6.38) at 0.3 h postmortem. Fast pH decline during the early postmortem period led to a decrease of μ/m-calpain activities at 0.3 and 3 h postmortem (P < 0.05), but did not affect the ultimate μ/m-calpain activity. An initial fast decrease in pH increased the degradation of desmin, titin, nebulin, and increased the 30 kDa degradation fragments of troponin-T. Therefore, the fast pH decline during the early postmortem period decreased the μ/m-calpain activity and increased the degradation of cytoskeletal proteins in broiler muscle. It is possible that the fast pH decline experienced an earlier activation of calpains that resulted in earlier protein degradation and ultimately lower shear force.
本研究的目的是确定宰后早期pH值快速下降对肉鸡钙蛋白酶活性及细胞骨架蛋白降解的影响。80只肉鸡被随机分为两组：物理束缚（PR）组和自由挣扎（FS）组。取胸大肌（PM）测定钙蛋白酶活性、剪切值、肌原纤维超微结构以及结蛋白、肌联蛋白、伴肌动蛋白和肌钙蛋白T的降解情况。宰后0.3小时，FS组的pH值（6.05）显著低于PR组（6.38）。宰后早期pH值快速下降导致宰后0.3小时和3小时μ/ m-钙蛋白酶活性降低（P < 0.05），但不影响最终的μ/ m-钙蛋白酶活性。pH值最初的快速下降增加了结蛋白、肌联蛋白、伴肌动蛋白的降解，并增加了肌钙蛋白T的30 kDa降解片段。因此，宰后早期pH值快速下降降低了肉鸡肌肉中μ/ m-钙蛋白酶活性，并增加了细胞骨架蛋白的降解。宰后早期pH值快速下降可能使钙蛋白酶更早被激活，从而导致蛋白质更早降解并最终使剪切力降低。
