待宰时间和致晕方式对生猪应激及猪肉品质的影响

国内外对于生猪宰前因素已经做过大量的研究,但总体来讲,对于待宰时间的研究一直没有形成定论;由于生产成本等问题,国内对于CO2致晕的应用与研究均较少;对于不同的电击晕方式,在同一体系下的成批量的比较涉及很少,另外对于应激指标的选择一直没有统一的标准。该文研究了在电击晕、二氧化碳致晕和不同待宰时间(3、6和12h)条件下,杜大长三元杂交猪血液应激指标和猪肉品质的变化。结果显示:待宰3h的生猪血液指标显著低于另外2种方式,而二氧化碳致晕方式使得生猪血液中乳酸含量、肌酸激酶含量、皮质醇含量和乳酸脱氢酶含量显著低于不击晕和电击晕方式。不同待宰时间对胴体背最长肌宰后24h的温度、pH值、蒸煮损失、明亮度、红色度和黄色度没有显著影响(P>0.05),但是待宰3h的生猪胴体宰后45min的pH值和温度明显较低,汁液损失和剪切力也显著小于待宰6和12h的值;而与不击晕和电击晕方式相比,二氧化碳致晕产生的猪肉宰后45min的pH值和温度较低、汁液损失较大、明亮度较大、红色度和黄色度值较小。因此生猪待宰3h并通过二氧化碳致晕产生的应激反应与猪肉品质影响最小。生产中应加强对待宰时间和致晕方式的控制,并注意利用各种处理方法对肉品质影响的协同作用,从而最大程度实现猪肉品质的改良。

Effects of lairage time and stunning onstress and the meat quality of pigs

Much research has been done on pre-slaughter factors, both at home and abroad. In summary, no conclusion has been formed about lairage time. Regarding the high cost of production or other factors, the application and study of carbon dioxide stunning is poor in our country. There has been little research comparing different ways of stunning. In this paper, changes in blood parameters and meat quality in Duroc ×Large White ×Landrace pigs stunned by electricity or carbon dioxide after different lairage times (3 h, 6 h and 12 h), were studied. The results showed that the blood parameters of pigs with 3 h lairage time were significantly lower than for the other two methods, while lactate, creatine kinase, cortisol and lactate dehydrogenase in carbon dioxide stunning were significantly lower than in non-stunning and electric stunning. Different lairage times had no significant effect on the longissimus muscle values of pH, temperature, cook loss, lightness, a * and b * color coordinate values at 24 hours post-slaughter (P>0.05), but pigs with 3 h resting time had significantly lower pH values and temperature at 45 min post-slaughter. Drip loss and shear force values at 24 hours post-mortem were also significantly lower than at the lairage time of 6 h and 12 h. Compared with non-stunning and electric stunning, stunning with carbon dioxide produces lower pH values and temperature at 45 min post-slaughter, higher drip loss and lightness values, and lower a*and b* color coordinate values. The research identified that pigs which had the minimum stress response and the minimal effect on the meat quality were stunned by carbon dioxide after 3 h lairage time. In conclusion, more attention should be paid to lairage time and the way of stunning, as well as to the influence of the synergy of various processing methods for meat quality in order to realize the maximum degree of improvement in pork quality.