运输时间和温度对生猪应激和猪肉品质的影响

Effects of transportation time and temperature on pig stresses and pork quality

为了研究运输时间和温度对生猪应激及猪肉品质的影响,该文以三元杂交猪杜长大为研究对象,测定了运输前、运输3、6、9h以及运输温度-10~0℃、0~10℃、10~20℃、20~30℃等条件下生猪的血液生化指标、宰后猪肉p H值、肉色等指标。结果表明：运输6 h后三元猪出现应激反应,9 h以后应激反应显著增强（P〈0.05）,运输6 h以上三元猪与运输3 h相比,宰后45 min p H值显著降低（P〈0.05）,肉色分级显著升高（P〈0.05）,肉品质降低;运输温度低于10℃时三元猪出现应激反应,-10~0℃时应激反应显著增强（P〈0.05）,-10~0℃和20~30℃条件下宰后24 h p H值显著高于0~10℃和10~20℃（P〈0.05）,肉品质降低。因此,为防止生猪运输应激及改善猪肉品质,生猪运输时间应小于6 h,运输温度为10~20℃。该研究结果对屠宰行业减少生猪应激提高猪肉品质提供参考。

Because of the pig stress, 20 000 tons of PSE （pale soft exudative） and DFD （dark firm dry） meat were engendered in Beijing every year. Transportation time and temperature were studied, since other factors which caused pig stress made no difference in Beijing. In order to investigate the effects of different transportation time （0, 3, 6, 9 h） and temperature （-10-0℃, 0-10℃, 10-20℃, 20-30℃） on pig stress and pork quality, a total of 84 Duroc x Landrace Large × White barrows were transported to the same abattoir, and＇ the barrows had been raised up to （104＋4） kg by the same person. The transportation speed was 60-70 km/h and the transportation density was 2.2 pigs per square meter. The pigs were transported without stops. During loading and unloading, in the farm and at the abattoir the pigs were gently handled, and no whips and electric prods were used. No food was available while the water was continually available during the transportation. The pigs were stunned electrically with 125 V on head and 75 V on heart. The blood constituents were used as the indicators of pig stress, and the pork quality traits including the pH values 45 min and 24 h after slaughter and the pork color grade were measured in this study. The results showed that the alanine aminotransferase （ALT） in blood plasma after 6 h transportation increased significantly （P〈0.05） compared to that after zero and 3 h transportation, which meant the pigs presented stress reaction after 6 h transportation, and the ALT, aspartate transaminase （AST）, lactate dehydrogenase （LDH）, cortisol （COR） after 9 h transportation increased significantly （P〈0.05） compared to those after zero, 3 and 6 h transportation, which meant the stress was significantly stronger after 9 h transportation. The pork pH values 45 min after slaughter through 6 and 9 h transportation were significantly lower than those after 3 h transportation （P〈0.05）. In the same time, the pork color grades （above 4） were significantly higher than those after 3 h transportation （P〈0.05） which caused the pork quality to decrease. Pigs presented stress reaction when they were transported at the temperature of under 10℃ since the AST and alkaline phosphatase （ALP） increased significantly （P〈0.05）, and the stress was significantly stronger when they were transported at the temperature of under 0℃ since the creatine kinase （CK）, LDH and COR increased significantly （P〈0.05） compared to the other conditions. The porkpH values 24 h after slaughter at the transportation temperature of-10-0℃and 20-30℃ were significantly higher （P〈0.05） than those at 0-10℃ and 10-20℃ which caused the pork quality to decrease. The research identified that the pigs in Beijing should be transported within 6 h and at 10-20 ℃ in order to reduce the impact of stress and improve pork quality.