Study On The Occurs Of Apoptosis And Its Effect On Skeletal Muscle During Postmortem Ageing Of Duck

After animal bleeding, all cells will be in anoxia and will receive no more nutriments. In such conditions, calcium ion will sharly elevate; ATP compounds will degradate; the pH value will fall down during storage.Under these unfavourable environmental modifications, apoptosis will be engaged in cell, but the program is of concern in postmortem muscle and the influencere of the program on the cellular structures and meat quality main unknown. The phase in that apoptosis processes and the biochemical and structural changes in dying cells also main unkown. The solution for these issues is beneficial to understand the mechanisms the conversion of muscle into meat. In an effort to further, this study was conducted to explore the changes of cellular environment, verify the cell death program, quantify the level of apoptosis of the activating process of caspases-3in differernt skeletal muscles of duck during postmortem storage. In addition, this study focuses on the hypothesis that injection of calcium chloride can result in color and shear force by regulating caspases activities.1. The occurs of apoptosis and effect facts of duck skeletal muscle during postmortem ageingThis experiment investigate whether the duck skeletal muscle cells apoptosis occurs and what factors affect it and provide new experimental evidence for further use of the mechanism of apoptosis mature mechanism to clarify the water in poultry meat. Analysis detected after slaughter, the duck breast and thigh meat of bcl-2, bax and mitochondrial cytochrome-C content, TUNEL detect changes of the number of positive-apoptotic nuclei as well as post-mortem ATP metabolism and pH changes situation. The results showed that the duck skeletal muscle after slaughter bax/bcl-2protein ratio were significantly raised (p<0.05), mitochondrial cytochrome-C content was significantly lower (p<0.05),0.5-8h skeletal muscle after slaughter, the number of positive apoptotic nuclei were significantly increased (p<0.05); content of ATP and pH value in the postmortem0.5-8h showed a significant downward trend (p<0.05). The results of bax pro-apoptotic protein expression levels was dominant, the quick emancipation of mitochondrial cytochrome-C and the sharp increase of the number of positive apoptotic nuclei showed that there was a process of apoptosis postmortem in the duck skeletal muscle cells evidently. Consumption of ATP and the pH value reduction provide a necessary environment within the cell apoptosis and, the degree of apoptosis may reach a peak around8h postmortem in duck skeletal muscle.2. The impact of caspase-3activation on the tenderness of duck skeletal muscle during postmortem conditioningTo investigate whether the caspase-3is activated postmortem and involved in the hydrolysis of the cytoskeleton process in duck, provide new experimental evidence to explain the postmortem conditioning of waterfowl by the mechanism of apoptosis. The cytoplasm of cytochrome-C levels, active caspase-3,-8and-9and cleaved PARP fragment expression of duck breast and thigh meat after slaughter were detected by immunochemical analysis, changes of caspase-3,-8and-9activity and the changes of shear force value were also evaluated. Results showed that cytochrome-c levels in cytosol were increased significantly(p<0.05), caspase-3,-8and-9were split into17kDa,18kDa and23kDa fragments and there was higher activities at postmortem respectively(p<0.05). PARP as a marker protein of caspase enzyme system was split into small fragments; Shear force values of breast and thigh meat were also significantly decreased at4-24h after slaughter(p<0.05). Correlation analysis showed that caspase-8and-9activities were positively correlated to the reported caspase-3activities and the shear force of muscles were negatively correlated with the activities of caspase-3after slaughter in muscles(p<0.01). The results of procaspase-3was significantly activated and the activities was increased indicated that the postmortem activation of caspase-3appears to be involved in both caspase-8and caspase-9pathway; cleaved PARP and shear force values was reduced induced that caspase protease might have direct or indirect effects on maturation process during postmortem conditioning.3. The impact of apoptosis on the color, cooking loss and MFI changes of duck skeletal muscle during postmortem conditioningThis experiment investigate that the duck skeletal muscle cells apoptosis affect changes of aging index and provide new experimental evidence for further use of the mechanism of apoptosis mature mechanism to clarify the water in poultry meat. Analysis detected after slaughter, the duck breast and thigh meat of color, cooking loss, and MFI changes situation. The results showed that the duck skeletal muscle after slaughter L*values were significantly raised at0.5-8h postmortem(p<0.05), then decreased; a*values were significantly raised at0.5-8h postmortem(p<0.05); b*values were significantly raised at0.5-8h postmortem(p<0.05); cooking loss of the duck breast and thigh meat were significantly raised at0.5-8h postmortem(p<0.05). MFI values of the duck breast and thigh meat were significantly raised at0.5-24h postmortem(p<0.05). Correlation analysis showed that apoptosis rates were positively correlated to the color(L*values, a*values, b*values), cooking loss, MFI values(p<0.05) and the shear force of muscles were negatively correlated with the apoptosis rates(p<0.01) at0.5-96h postmortem. Caspases-3activities were positively correlated to the color(L*values, a*values, b*values), cooking loss, MFI values(p<0.05) and the shear force of muscles were negatively correlated with the apoptosis rates(p<0.01) at0.5-8h postmortem. The duck skeletal muscle cell apoptosis and its degree of deepening were related to changes of meat color, waterholding capacity and tenderness, and it occur with meat quality changes of duck at the same time.