Abstract

Summary The disruption of structural integrity could affect flesh quality changes. This study investigated the disruption of muscle integrity and the affecting factors in postmortem fish at 4 °C for 5 days storage. Haematoxylin–eosin staining indicated that profound disruption of structural integrity was observed for the changes of dissolved nucleus, irregular shape of myofibrils and loose attachment. The increased activities of β-N-acetyl-glucosaminidase (NAG) and α-Glucosidase (AG) enzymes confirmed the profound disruption of integrity in postmortem muscle. The abnormal up-regulated gene expressions of claudin-11, claudin-12, claudin-15a, claudin-15b and myosin light chain kinase (MLCK) implied the disrupted intercellular integrity. The impaired cellular integrity and the increased oxidative damage was due to the decreased antioxidant capacity, which was regulated by the decreased transcriptional levels of antioxidant enzymes. Collectively, this study provided a partial molecular mechanisms for the disruption of structural integrity and the changes of flesh quality in postmortem fish muscle.