| Huai swine is an old and Chinese local pig breeds in the middle-lower reaches of the Huaihe river. Since its high adaptability, resistance to crude feed and slow growth rate, Donghai Huai swine has high meat quality and unique flavor characteristics. This study was conducted to investigate the meat characteristic of Donghai Huai swine and the relationship between NO concentrations and muscle tenderness, which provide theoretical basis for the development, utilization and conservation of Donghai Huai swine, and framework for research and development of local swine in China.A total of20healthy and same age weaning Donghai Huai swines were selected. When the average body weight of Huai swine was77kg, green fodder was supplemented to basal diet. When the average body weight of Huai swine was77kg and98kg,4pigs were randomly selected to slaughter. I part meat, II part meat, III part meat and Ⅳ part meat were sampled to determine carcass performance and meat characteristics. In addition, the signals of nNOS and sGCβ1in the musculus soleus and the longissiums were measured using immunohistochemistry. The concentrations of NO and muscle tenderness in longissimus dorsi muscle were determined.Results showed below:(1) Dressed percentage of Donghai Huai swine in98kg body weight group (76.62%) was significantly higher than those in77kg body weight group (P<0.05). Backfat thickness and body length of Donghai Huai swine in98kg body weight group were significantly higher than those in77kg body weight group (P<0.05). Compared to77kg body weight group, the water percentage of Donghai Huai swine in98kg body weight group decreased significantly (P<0.01), but intramuscular fat of Donghai Huai swine in98kg body weight group increased significantly (P<0.01). Furthermore, backfat thickness and lean meat percentage, fat percentage and lean meat percentage, pH and ham percentage were a strong negative correlation (P<0.05). However, the percentage of Intramuscular fat and percentage of suet oil, percentage of fat was a strong positive correlation (P<0.05).(2) The concentrations of linolenic acid of I part meat (P>0.05), Ⅱ part meat (P＜O.05), Ⅲ part meat (P<0.05) and IV part meat (P>0.05) of Donghai Huai swine in98kg body weight group were higher than those in77kg body weight group, suggesting extend the feeding time and green fodder supplementation changed same concentrations of fatty acids. Moreover, concentrations of polyunsaturated fatty acid of I part meat and III part meat in in98kg body weight group were higher than those in77kg body weight group. From the perspective of polyunsaturated fatty acid nutrition, Muscle fatty acid composition of Huai swine in98kg body weight group was better than in77kg body weight group.(3) The amount of glutamate, delicious amino acids, essential amino acids and total amino acids of Huai swine in77kg body weight group were higher than those in98kg body weight group, suggesting that muscle amino acid content showed a declining trend with increase of age.(4) IHC showed that the positive signals of nNOS were distributed in the cytoplasm and the positive signals of sGCβ1were localized in the verge of the cell in musculus soleus. The positive signals of nNOS and sGCβ1were localized in the sarcolemma of the longissiums. Concentration of nitric oxide and muscle tenderness were a strong positive correlation in the process of muscle tenderness.In conclusion, Donghai Huai swine showed high slaughter performance, low water percentage and high amount of intramuscular fat characteristics, which meet demand of high meat quality for people. Concentrations of fatty acids in Donghai Huai swine were increased by extend the feeding time. Furthermore, the positive signals of nNOS and sGCβ1were distributed in the musculus soleus and the longissiums and concentration of nitric oxide and muscle tenderness were a strong positive correlation in the process of muscle tenderness, suggesting that NO regulate the process of muscle tenderness. |
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