Rocha L M, Dionne A, Saucier L, Nannoni E, Faucitano L
1Department of Animal Science,Laval University,Quebec City,Canada,G1V 0A6.
3Olymel Fork,568 Chemin de l'Écore,Vallée-Jonction,Canada,GOS 3JO.
Animal. 2015 Apr;9(4):707-14. doi: 10.1017/S1751731114002766. Epub 2014 Nov 17.
The objectives of this study were to assess the relationship between blood lactate variation measured at the plant, and pork quality variation on a large sample size and under commercial preslaughter handling conditions. A total of 600 pigs were randomly chosen on arrival at a commercial slaughter plant and blood samples taken from the ear vein at unloading (UN), after lairage (LA), in the restrainer (RE; before stunning) and at exsanguination (EX) were analysed for lactate content using a Lactate Scout Analyzer (LSA). In order to have a large range of measures, pigs were distributed into two groups; one kept in lairage overnight (G1) and the other for 2 to 3 h (G2) before slaughter. Meat quality was assessed in the Longissimus thoracis (LT), Semimembranosus (SM) and Adductor (AD) muscles by measuring the pH 30 min postmortem (pH1) and at 24 h postmortem (pHu), the colour and the drip loss. Blood lactate levels did not differ between G1 and G2 (P>0.05). A reduced muscle lactate and glucose contents (P=0.02 and P=0.004, respectively) resulting in a lower (P<0.001) glycolytic potential (GP) was observed in the LT muscle of G1 pigs when compared with G2 loins. In the LT muscle of G1 pigs, the lower GP resulted in an increased pHu (r=-0.67; P<0.001), decreased drip loss (r=0.57; P<0.001) and darker colour (r=0.50; P<0.001) compared with G2. In both G1 and G2 pigs, the lower GP was correlated to higher pHu value in the SM and AD muscles (r=-0.73; P<0.001). The greatest correlation was observed in G2 between blood lactate levels at LA and pHu value of the SM and AD muscles (r=0.46 and r=0.44, respectively; P<0.001 for both muscles). The second greatest correlation was found between blood lactate levels at EX and pH1 value in the SM muscle in both groups (r=-0.37 and r=-0.41, respectively; P<0.001 for both groups). Based on the results of this study, it appears that blood lactate levels, as measured by the LSA, reliably reflect the physiological response of pigs to perimortem stress and may help explain the variation in pork quality.
本研究的目的是在大样本量和商业宰前处理条件下，评估在屠宰场测得的血液乳酸变化与猪肉品质变化之间的关系。在一家商业屠宰场，共随机挑选了600头猪，在卸载时（UN）、休息后（LA）、在致昏前的保定栏中（RE）以及放血时（EX）从耳静脉采集血样，使用乳酸分析仪（LSA）分析乳酸含量。为了获得广泛的测量结果，将猪分为两组；一组在屠宰前在栏中饲养过夜（G1），另一组饲养2至3小时（G2）。通过测量宰后30分钟（pH1）和24小时（pHu）的pH值、颜色和滴水损失，对胸最长肌（LT）、半膜肌（SM）和内收肌（AD）的肉质进行评估。G1组和G2组之间的血液乳酸水平没有差异（P>0.05）。与G2组猪的腰大肌相比，G1组猪的LT肌肉中肌肉乳酸和葡萄糖含量降低（分别为P=0.02和P=0.004），导致糖酵解潜能（GP）较低（P<0.001）。在G1组猪的LT肌肉中，较低的GP导致pHu升高（r=-0.67；P<0.001），滴水损失降低（r=0.57；P<0.001），颜色变深（r=0.50；P<0.001）。在G1组和G2组猪中，较低的GP与SM和AD肌肉中较高的pHu值相关（r=-0.73；P<0.001）。G2组中，LA时的血液乳酸水平与SM和AD肌肉的pHu值之间的相关性最高（分别为r=0.46和r=0.44；两组肌肉的P均<0.001）。两组中，EX时的血液乳酸水平与SM肌肉中pH1值之间的相关性次之（分别为r=-0.37和r=-0.41；两组的P均<0.001）。根据本研究结果，似乎通过LSA测量的血液乳酸水平能够可靠地反映猪对宰前应激的生理反应，并可能有助于解释猪肉品质的差异。
