本文旨在研究硫辛酸（ LA）和敌草快（ diquat）对育肥猪生长性能、血浆和空肠氧化还原状态及空肠细胞凋亡的影响。采用2×2双因子试验设计，腹腔滴注diquat（每千克体重0、8 mg）和饲粮中添加 LA（0、800 mg／kg）为2个主效应，共形成4个组。选取24头体重为（70．64±3．61） kg的健康大白阉公猪，随机分为4个组，每组6个重复，每个重复1头猪。试验期29 d。于试验第1天开始在育肥猪饲粮中添加LA，直到试验结束；于试验第15天腹腔滴注diquat，无diquat刺激育肥猪滴注等量的生理盐水。于试验第29天收集血浆和空肠样品，用试剂盒检测血浆和空肠组织的抗氧化指标，免疫印迹杂交（ Western blotting ）试验检测空肠热休克蛋白70（ HSP70）和半胱氨酸天冬氨酸蛋白酶－3（ caspase⁃3）的蛋白质相对表达量。结果表明：1）饲粮添加LA和腹腔滴注diquat对育肥猪的空肠超氧化物歧化酶（ SOD）活性有极显著的交互作用（ P＜0．01），对育肥猪的生长性能、血浆和空肠其他抗氧化指标以及空肠HSP70和caspase⁃3的蛋白质相对表达量均无显著交互作用（ P＞0．05）。2）腹腔滴注diquat极显著降低了育肥猪的平均日采食量（ ADFI）和平均日增重（ ADG），血浆SOD、谷胱甘肽过氧化物酶（ GSH⁃Px）和过氧化氢酶（CAT）活性，空肠 SOD、锰超氧化物歧化酶（ MnSOD）活性和总抗氧化能力（ T⁃AOC）（ P＜0．01）；极显著升高了料重比（F／G）、血浆丙二醛（MDA）含量、空肠过氧化氢（H2O2）含量、空肠HSP70和caspase⁃3的蛋白质相对表达量（ P＜0．01）。饲粮中添加LA使育肥猪的ADFI显著升高（ P＜0．05），ADG极显著升高（ P＜0．01），空肠MnSOD活性极显著升高（ P＜0．01），空肠HSP70的蛋白质相对表达量显著降低（P＜0．05），空肠 caspase⁃3的蛋白质相对表达量有降低的趋势（ P＝0．052）。3）在diquat刺激下，饲粮中添加LA使育肥猪的ADFI和ADG极显著升高（ P＜0．01），血浆SOD活性显著升高（ P＜0．05），空肠SOD和MnSOD活性极显著升高（ P＜0．01）。综上所述，腹腔滴注diquat引起了育肥猪强烈的氧化应激，导致了育肥猪生长性能下降、血浆和空肠氧化还原系统失衡，并引起空肠细胞凋亡。饲粮中添加LA有缓解diquat所致的育肥猪氧化应激的作用，并能减缓空肠氧化及细胞凋亡。%The aim of this study was to investigate the effects of lipoic acid ( LA) and diquat on growth per⁃formance, redox status of plasma and jejunum and cell apoptosis of jejunum of finishing pigs. According to 2×2 double⁃factor test design, intraperitoneal injection of diquat (0 or 8 mg per kg body weight) and dietary LA ( 0 or 800 mg/kg) as the two main factors, and 4 groups were formed. Twenty⁃four healthy Large white castrates with the body weight of (70.64±3.61) kg were randomly allocated to 4 groups with 6 replicates per group and 1 pig per replicate. The trial period lasted for 29 days. LA were added in diets all in the trial. Intrap⁃eritoneal injection of diquat at day 15 and non⁃challenged pigs were injected intraperitoneally with the equal a⁃mount of physiological saline. Plasma and jejunum samples were collected at day 29 for determination of an⁃tioxidative indices using kits. Western blotting assays was conducted for determination of jejunum heat shock protein 70 ( HSP70) and caspase⁃3 protein relative expression levels. The results showed as follows:1) there was a significant interaction of dietary LA and intraperitoneal injection of diquat on jejunum superoxide dis⁃mutase (SOD) activity of finishing pigs (P<0.01), and no significant interactions on growth performance, other antioxidant indices of plasma and jejunum and protein relative expression levels of HSP70 and caspase⁃3 of jejunum of finishing pigs were found ( P>0. 05 ) . 2 ) Intraperitoneal injection of diquat significantly de⁃creased average daily feed intake ( ADFI) and average daily gain ( ADG) , the activities of SOD, glutathione peroxidase ( GSH⁃Px) and catalase ( CAT) of plasma, the activities of SOD and manganese superoxide dis⁃mutase (MnSOD) and total antioxidant capacity (T⁃AOC) of jejunum of finishing pigs (P<0.01); and sig⁃nificantly increased the ratio of feed to gain ( F/G) , the contents of malondialdehyde ( MDA) of plasma and hydrogen peroxide (H2O2) of jejunum and protein relative expression levels of HSP70 and caspase⁃3 of jeju⁃num of finishing pigs (P<0.01). Dietary LA significantly increased ADFI (P<0.05), ADG (P<0.01) and the activity of MnSOD of jejunum (P<0.01), and significantly decreased protein relative expression level of HSP70 of jejunum of finishing pigs ( P<0.05) , but had a tendency to decrease protein relative expression level of caspase⁃3 ( P=0.052) . 3) Dietary LA significantly increased ADFI and ADG ( P<0.01) , the activities of SOD of plasma (P<0.05) and SOD and MnSOD of jejunum (P<0.01) of finishing pigs challenged with diquat. In conclusion, intraperitoneal injection of diquat causes strong oxidative stress of finishing pigs, leads to the reduction of growth performance, imbalance of redox system of plasma and jejunum and cell apoptosis of jejunum . Dietary LA can suppress the oxidative stress caused by intraperitoneal injection of diquat, and may al⁃leviate jejunum oxidation and apoptosis.
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