凝结芽孢杆菌BC-HYI改善脂多糖损伤蛋雏鸡肠道作用的研究

本试验旨在探究凝结芽孢杆菌BC-HYI调节脂多糖(LPS)损伤蛋雏鸡肠道作用。选取1日龄京红蛋雏鸡180只,随机分为5组,每组6个重复,每个重复6只,重复之间体重接近。空白对照组(CON组)和模型组(LPS组)饲喂基础饲粮,连续灌服生理盐水;3个益生菌组饲喂基础饲粮,同时分别连续灌服低、中、高剂量的凝结芽孢杆菌BC-HYI (浓度分别为106、107、108CFU/mL),连续灌服28 d,28 d后灌服LPS,灌服浓度为2 mg/kg,灌服剂量为200μL/只,试验周期为6 h,分别记为LOW+LPS、MID+LPS、HIGH+LPS组。6 h后采血,剖检、收集蛋雏鸡十二指肠、空肠、回肠肠道组织及空肠黏膜。结果表明:与空白对照组相比,LPS灌服后,蛋雏鸡十二指肠、空肠、回肠的绒隐比以及空肠黏膜黏液蛋白2(MUC2)、闭合蛋白(Occludin)和闭锁小带蛋白-1(ZO-1)mRNA相对表达量显著降低(P<0.05),血清二胺氧化酶(DAO)活性及D-乳酸(D-Lac)、肿瘤坏死因子-α(TNF-α)含量,空肠黏膜分泌型免疫球蛋白A(SIgA)和白细胞介素-10(IL-10)的含量,空肠黏膜Toll样受体4(TLR4)和核因子-κB (NF-κB)的mRNA相对表达量和蛋白表达量显著提高(P<0.05)。与LPS组相比,中、高剂量凝结芽孢杆菌BC-HYI极显著上调十二指肠、空肠、回肠绒隐比(P<0.01),极显著下调空肠黏膜TLR4和NF-κB的mRNA相对表达量和蛋白表达量(P<0.01),显著下调蛋雏鸡血清DAO活性及D-Lac和TNF-α含量(P<0.05);凝结芽孢杆菌BC-HYI显著提高空肠黏膜MUC2、Occludin和ZO-1的mRNA相对表达量(P<0.05);凝结芽孢杆菌BC-HYI对空肠黏膜SIgA和IL-10含量无显著影响(P>0.05)。综上所述,凝结芽孢杆菌BC-HYI对LPS损伤有缓解作用,能降低肠道通透性,下调TLR4/NF-κB信号通路中TLR4和NF-κB的mRNA相对表达量和蛋白表达量,从而改善LPS灌服后的肠道损伤,提高蛋雏鸡肠道健康。

Bacillus coagulans BC-HYI Improving Lipopolysaccharide Induced Intestinal Injury in Layer Chickens

The aim of this study was to explore Bacillus coagulans BC-HYI improving lipopolysaccharide(LPS)induced intestinal injury in layer chickens. The 180 one-day-old Jinghong layer chickens were randomly divided into 5 groups with 6 replicates in each group and 6 layer chickens in each replicate. The weight between replicates was close. The blank control group(CON group)and the model group(LPS group)were fed a basic diet and continuously perfused with normal saline. The three probiotic groups were fed the basic diet and continuously perfused with 106,107 and 108 CFU/mL Bacillus coagulans BC-HYI,respectively for 28 days. After28 days,LPS was perfused with a concentration of 2 mg/kg and a dose of 200μL/chick,the test period was6 h,and they were recorded as LOW+LPS,MID+LPS and HIGH+LPS groups,respectively. After 6 h,blood was collected,and the duodenum,jejunum,ileum and jejunal mucosa were collected. The results showed that compared with the CON group,after LPS administration,the ratio of villus length to crypt depth(V/C)in intestine of duodenum,jejunum and ileum and the mRNA relative expression levels of mucin 2(MUC2),Occludin and zonula occludens protein-1(ZO-1)in jejunal mucosa decreased significantly(P<0.05);and serum diamine oxidase(DAO)activity,D-lactic acid(D-Lac)and tumor necrosis factor-α (TNF-α)contents,jejunal mucosal secretory immunoglobulin A(SIgA)and interleukin-10(IL-10)contents,the mRNA relative expression levels and protein expression levels of Toll like receptor 4(TLR4)and nuclear factor-κB(NF-κB)in jejunal mucosal significantly increased(P<0.05). Compared with LPS group,medium and high doses of Bacillus coagulans BC-HYI significantly increased the V/C in intestine of duodenum,jejunum and ileum(P<0.01),and the mRNA relative expression levels and protein expression levels of TLR4 and NF-κB in jejunal mucosa significantly decreased(P<0.01),and the DAO activity and D-Lac content in serum significantly decreased(P<0.05);Bacillus coagulans BC-HYI significantly increased the relative mRNA expression levels of MUC2,Occludin and ZO-1 in jejunal mucosa(P<0.05);there was no significant difference in the contents of SIgA and IL-10 in jejunal mucosa(P>0.05). In conclusion,Bacillus coagulans BC-HYI can alleviate LPS injury,reduce intestinal permeability and down regulate the expression of gene and protein of TLR4 and NF-κB in TLR4/NF-κB signaling pathway,so as to improve the intestinal injury after LPS administration and improve the intestinal health of layer chickens.Chinese Journal of Animal Nutrition,2022,34(2):951-960]