谷氨酰胺干预断奶仔猪肠道黏膜受损中免疫能力的作用

The Effects of Glutamine on the Immunity in the Intestinal Mucosa of Weaned Piglets with Lipopolysaccharide Challenge

本试验旨在研究日粮中添加谷氨酰胺(Gln)对大肠杆菌型脂多糖(LPS)诱导肠道黏膜损伤后断奶仔猪免疫性能的影响。选取28日龄健康断奶仔猪24头,随机分为3组,每组8个重复。其中,空白对照组和LPS组饲喂常规基础日粮,Gln组饲喂添加1%谷氨酰胺的基础日粮。试验期30d,于试验期第22、25、28、30天对LPS组和Gln组腹腔注射LPS(按体重以100μg·kg-1给予),空白对照组腹腔注射等体积的无菌生理盐水。第30天对仔猪进行前腔静脉采血并屠宰采取所需样品,检测血清中免疫球蛋白、相关炎症因子浓度及各肠段中这些炎症因子基因的表达丰度。与空白对照组相比,LPS组和Gln组血清IgM水平显著提高40.00%和62.86%(P<0.05);LPS组血清IL-8含量显著提高7.11%(P<0.05),而Gln组则无明显变化。不论在LPS攻毒前还是攻毒后,日粮添加Gln均可显著提高仔猪血清IL-17含量(P<0.05)。与空白对照组相比,LPS组和Gln组十二指肠中IL-8mRNA表达水平显著降低了35.06%和44.16%(P<0.05)。对于IL-12βmRNA的表达水平,在空肠和回肠中Gln组中的表达水平较LPS组高,但在十二指肠中有所降低(P>0.05)。在十二指肠与空肠中,IL-17αmRNA的表达丰度在三组间存在差异(P<0.05),特别是在十二指肠和回肠中,Gln组的表达丰度达到最高;LPS组和Gln组空肠中IL-17αmRNA相对表达量显著降低58.16%和56.07%(P<0.05)。结果提示,日粮中添加1%的谷氨酰胺能够在一定程度上改善LPS诱导肠道损伤后断奶仔猪的免疫力,减轻应激反应造成的机体损伤。

This study was conducted to evaluate the effects of dietary glutamine（Gln）supplementation on the immunity in the lipopolysaccharide（LPS）-challenged weaned piglets.A total of twenty-four healthy piglets were weaned at 28 days,and randomly assigned into three treatmentgroups（8pigs per treatment）：（1）control group（basal diet）;（2）LPS group（basal diet）;（3）Gln group（basal diet＋1.0% glutamine）.The experiment lasted for 30 days.On day 22,25,28 and 30of the trial,piglets in the LPS and Gln groups were administered intraperitoneally with LPS（100μg·kg-1 body weight）,whereas pigs in the control group were injected intraperitoneally with the same volume of sterile saline.After the whole feeding period,blood samples were taken from jugular vein,then pigs were bled by exsanguination to collect samples,which were used to determine the immune parameters.The results showed that,compared with the control group,the concentration of serum IgM in the Gln and LPS groups remarkably increased by40.00% and 62.86%（P〈0.05）,respectively.After LPS challenge,the concentration of serum interleukin-8（IL-8）in the LPS group was significantly decreased by 7.11%（P〈0.05）,but there was no difference between the Gln group and control group（P〈0.05）.No matter with LPS challenge or not,Gln supplementation was remarkably increased serum interleukin-17（IL-17）content（P〈0.05）.Compared with the control group,in the duodenum,the mRNA expression of IL-8in LPS group and Gln group was remarkably decreased by 35.06%（P〈0.05）and44.16%（P〈0.05）.The mRNA expression of IL-12βin the jejunum and ileum of Gln group were higher than that in the LPS group（P〈0.05）.In the duodenum and jejunum,there were differences in the mRNA expression of IL-17αamong the three groups（P〈0.05）,and the expression of IL-17αin the Gln group was the greatest in the duodenum and ileum;in the jejunum,the mRNA expression of IL-17αin LPS group and Gln group was remarkably decreased by58.16%（P〈0.05）and 56.07%（P〈0.05）.Collectively,dietary supplemented with 1% Gln could improve the immunity of weaned piglets challenged with LPS to some degree,thereby alleviating immunological stress.