地衣芽孢杆菌对脂多糖诱导的仔猪肝脏炎症及抗氧化功能的影响

Effects of Bacillus licheniformis on lipopolysaccharide-induced liver inflammation and antioxidant function in weaned piglets

【目的】本文旨在研究地衣芽孢杆菌(Bacillus licheniformis HJ0135)对脂多糖(lipopolysaccharide,LPS)应激断奶仔猪肝脏指数、炎症因子、抗氧化功能及相关基因表达的影响。【方法】选择24头28日龄健康状况良好的三元杂交断奶仔猪(杜×长×大),随机分成4个试验组:对照组(control,CON),500 mg/kg地衣芽孢杆菌HJ0135组(BL)、LPS应激组(LPS)以及LPS+500 mg/kg地衣芽孢杆菌HJ0135组(BL-LPS),在试验第28天,给LPS组和BL-LPS组仔猪腹腔注射1.5 mL浓度为1 mg/mL的LPS,给CON组和BL组仔猪注射等量生理盐水,1.5 h后屠宰并采样。【结果】与CON组相比,BL组血清谷草转氨酶(aspartate aminotransferase,AST)和谷丙转氨酶(alanine aminotransferase,ALT)的含量降低,肝脏的总抗氧化能力(total antioxidant capacity,T-AOC)提升且过氧化氢酶(catalase,CAT)和总超氧化物歧化酶(total superoxide dismutase,T-SOD)活性均增强。肝脏中促炎因子白细胞介素-6(interleukin-6,IL-6)含量减少,同时肿瘤坏死因子-α(tumor necrosis factor-α,TNF-α)含量下降,肝脏CAT、SOD1、SOD2、谷胱甘肽过氧化物酶-1(glutathione peroxidase,GSH-Px1)、核因子E2相关因子(nuclear factor erythroid 2-related factor 2,Nrf2)、醌氧化还原酶1(NADPH:quinine oxidoreductase 1,NQO1)、Toll样受体4(Toll-like receptors 4,TLR4)、髓样分化因子(myeloid differentiation factor 88,MyD88)和核因子-κB(nuclear factor kappa beta,NF-κB)的基因表达水平增高;与LPS组相比,BL-LPS组肝脏指数降低,血清AST和ALT的含量降低,肝脏中CAT、GSH-Px、T-AOC含量均提高,而丙二醛(malondialdehyde,MDA)含量降低。另外,肝脏炎症因子白细胞介素-1β(interleukin-1β,IL-1β)、IL-6和TNF-α含量减少,而白细胞介素-10(interleukin-10,IL-10)的含量增加,肝脏CAT、SOD2、GSH-Px1、Nrf2、TLR4、MyD88和NF-κB的基因表达量提高。【结论】断奶仔猪日粮中添加地衣芽孢杆菌HJ0135,能够激活Nrf2和TLR4相关基因表达,降低脂多糖刺激引起的肝脏损伤和炎症因子的分泌,提高断奶仔猪抗氧化能力。

[Objective]To investigate the protective effects of Bacillus licheniformis HJ0135 on the liver index,inflammatory cytokines,antioxidant function,and related gene expression of the weaned piglets exposed to lipopolysaccharide(LPS).[Methods]A total of 24 healthy 28-day-old weaned piglets(Duroc×Landrace×Yorkshire)were randomly assigned into 4 groups:control(CON)group,500 mg/kg B.licheniformis HJ0135(BL)group,LPS stress(LPS)group,and LPS+500 mg/kg B.licheniformis HJ0135(BL-LPS)group,with 6 piglets in each group.On day 28 of the experiment,the piglets in the LPS and BL-LPS groups were injected intraperitoneally with 1.5 mL of 1 mg/mL LPS,and those in the CON and BL groups with equal amounts of saline.All the piglets were sacrificed after 1.5 h.[Results]Compared with the CON group,BL treatment decreased the content of aspartate aminotransferase(AST)and alanine aminotransferase(ALT),increased the total antioxidant capacity(T-AOC),the activities of catalase(CAT)and total superoxide dismutase(T-SOD),reduced the levels of interleukin-6(IL-6)and tumor necrosis factor-α(TNF-α)in the liver,and up-regulated the expression of CAT,superoxide dismutase 1(SOD1),SOD2,glutathione peroxidase 1(GSH-Px1),nuclear factor erythroid 2-related factor(Nrf2),NADPH:quinone oxidoreductase 1(NQO1),Toll-like receptor 4(TLR4),myeloid differentiation factor 88(MyD88),and nuclear factor-κB(NF-κB)in the liver.Compared with the LPS group,BL-LPS treatment decreased liver index and serum AST and ALT levels,increased the levels of CAT,GSH-Px,and T-AOC,and reduced the content of malondialdehyde(MDA),interleukin-1β(IL-1β),IL-6,and TNF-α.In addition,BL-LPS treatment up-regulated the mRNA levels of CAT,SOD2,GSH-Px1,Nrf2,TLR4,MyD88,and NF-κB in the liver.[Conclusion]Dietary B.licheniformis HJ0135 can activate the expression of Nrf2 and TLR4-related genes,reduce liver damage and inflammatory cytokine secretion induced by lipopolysaccharide,and improve the antioxidant capacity in weaned piglets.