本试验以大肠杆菌型脂多糖（LPS）建立氧化应激模型，探讨了谷氨酰胺（GLN）对断奶仔猪氧化应激的影响。选用24头28日龄的健康三元（杜×长×大）断奶仔猪，随机分成3组，每组8个重复，每个重复1头猪。对照组和应激组饲喂基础饲粮，GLN组饲粮在基础饲粮中添加1% GLN，试验期为30 d。在试验第22、25、28和30天，应激组和GLN组仔猪分别按每千克体重腹腔注射100 μg LPS，对照组仔猪腹腔注射相同剂量的灭菌生理盐水，第30天进行前腔静脉采血并屠宰采取所需肠道样品，检测氧化应激相关指标。结果显示：1）LPS攻毒前各组血清抗氧化能力指标均无显著差异（P>0.05）。LPS攻毒后，应激组血清丙二醛（MDA）含量显著高于对照组（P<0.05）；GLN组血清MDA含量和超氧化物歧化酶（SOD）活性显著低于应激组和对照组（P<0.05）。2）LPS攻毒后，在十二指肠黏膜中，GLN组过氧化氢酶（CAT）和锌铜超氧化物歧化酶（CuZuSOD）基因相对表达量显著高于应激组（P<0.05）。在空肠黏膜中，GLN组CAT、锰超氧化物歧化酶（MnSOD）、谷胱甘肽过氧化物酶1（GPX1）和谷胱甘肽过氧化物酶4（GPX4）基因相对表达量显著高于对照组和应激组（P<0.05），对照组GPX4基因相对表达量显著高于应激组（P<0.05）。在回肠黏膜中，GLN组和应激组CAT基因相对表达量显著低于对照组（P<0.05），GPX4基因相对表达量显著高于对照组（P<0.05）；GLN组MnSOD基因相对表达量显著高于对照组和应激组（P<0.05），CuZnSOD基因相对表达量显著高于对照组（P<0.05）。结果表明，GLN在一定程度上可以缓解断奶仔猪因LPS引起的氧化应激，以期为实际生产中减少氧化应激提供一定的理论基础。

This study was conducted to evaluate the effects of glutamine (GLN) on oxidative stress of weaned piglets based on the oxidative stress model by Escherichia coli lipopolysaccharide (LPS). Twenty-four 28-day-old healthy crossbred (Duroc×Landrace×Largewhite) weaned piglets were randomly assigned into three groups with eight replicates per group and one piglet per replicate. The piglets in control group and stress group were fed the basal diets, and the others in GLN group were fed the basal diet supplemented with 1% GLN. The experiment lasted for 30 days. At days 22, 25, 28 and 30 of the experiment, the piglets in stress group and GLN group were injected intraperitoneally with 100 μg LPS per kg body weight, whereas piglets in control group were injected intraperitoneally with the same dosage of sterile saline. At day 30, blood samples were collected by precaval vein and the intestinal tract samples were collected after slaughter for detection of the oxidative stress related indexes. The results showed as follows:1) serum antioxidant capacity indexes had no significant differences among all groups before LPS challenge (P>0.05). After LPS challenge, the content of malondialdehyde (MDA) in serum in stress group was significantly higher than that in control group (P<0.05), and the content of MDA and the activity of superoxide dismutase (SOD) in serum in GLN group were significantly lower than those in stress group and control group (P<0.05). 2) After LPS challenge, the relative gene expression levels of catalase (CAT) and Cu-Zn superoxide dismutase (CuZuSOD) in duodenum mucosa in GLN group were significantly higher than those in stress group (P<0.05). The relative gene expression levels of CAT, manganese superoxide dismutase (MnSOD), glutathione peroxidase 1 (GPX1) and glutathione peroxidase 4 (GPX4) in jejunum mucosa in GLN group were significantly higher than those in control group and stress group (P<0.05), and the relative gene expression levels of GPX4 in control group was significantly higher than that in stress group (P<0.05). The relative gene expression level of CAT in ileum mucosa in GLN group and stress group was significantly lower than that in control group (P<0.05), and the relative gene expression level of GPX4 was significantly higher than that in control group (P<0.05). The relative gene expression level of MnSOD in ileum mucosa in GLN group was significantly higher than that in control group and stress group (P<0.05), and the relative gene expression level of CuZnSOD was significantly higher than that in control group (P<0.05). The results suggest that GLN can alleviate oxidative stress of weaned piglets challenged by LPS to some extent, thereby provide a theoretical basis for reducing oxidative stress in actual production.