蒲公英甾醇对AFB_(1)性肝损伤肉鸡肝组织氧化应激的影响

Effect of Taraxasterol on Oxidative Stress in Liver Tissue of Broilers with AFB_(1) Induced Liver Injury

旨在探讨蒲公英甾醇对黄曲霉毒素B 1(AFB_(1))性肝损伤肉鸡肝组织氧化应激的影响。将120只肉鸡随机分成6组:空白组,模型组,蒲公英甾醇低、中、高剂量组(25、50、100 mg·kg^(-1)BW)及阳性组(300 mg·kg^(-1)水飞蓟宾)。除空白组饲喂基础日粮外,其余各组饲喂含有0.5 mg·kg^(-1)AFB_(1)的日粮,连续喂养21 d建立肉鸡肝损伤模型,且每日在饮水中给予各组对应浓度的药物。试验期间记录各组肉鸡体重和采食量并计算料重比;通过试剂盒检测肉鸡血清中肝功能指标谷草转氨酶(aspartate aminotransferase,AST)、谷丙转氨酶(alanine aminotransferase,ALT)、γ-谷氨酰转移酶(gamma-glutamyltransferase,GGT)、总胆红素(total bilirubin,TBIL)、碱性磷酸酶(alkaline phosphatase,ALP)的含量;通过试剂盒检测肉鸡肝组织中活性氧(reactive oxygen species,ROS)、丙二醛(malondialdehyde,MDA)、超氧化物歧化酶(superoxide dismutase,SOD)、过氧化氢酶(catalase,CAT)、谷胱甘肽(reduced glutathione,GSH)的含量;RT-qPCR法和Western blot法分别检测肉鸡肝中核因子E2相关因子2(nuclear factor erythroid2-related factor 2,Nrf2)、Kelch样ECH关联蛋白1(Kelch-like ECH-associated protein 1,Keap1)、血红素氧合酶1(Heme Oxygenase-1,HO-1)、NAD(P)H:醌氧化还原酶1(NAD(P)H:Quinone oxidoreductase-1,NQO1)mRNA及蛋白表达量。结果显示,蒲公英甾醇高剂量组在14、21 d可提高AFB_(1)性肝损伤肉鸡的体重(P<0.05)并降低料重比(P<0.05);试验21 d后,蒲公英甾醇高剂量组降低AFB_(1)性肝损伤肉鸡血清中肝功能指标ALT(P<0.05)、AST(P<0.01)、GGT(P<0.01)、TBIL(P<0.01)和ALP(P<0.01)的活性;蒲公英甾醇高剂量组抑制AFB_(1)性肝损伤肉鸡肝中ROS和MDA含量(P<0.01),并提高SOD(P<0.01)、CAT(P<0.05)和GSH(P<0.05)活性;蒲公英甾醇高剂量组可上调AFB_(1)性肝损伤肉鸡肝中Nrf2(P<0.05)、NQO1(P<0.01)和HO-1(P<0.05)mRNA及蛋白表达水平,下调Keap1 mRNA(P<0.05)及蛋白表达水平。综上,蒲公英甾醇可通过调控Nrf2/Keap1信号通路抑制肉鸡肝中ROS、MDA的过量产生并提高抗氧化物SOD、CAT、GSH含量,增强肝抗氧化功能,且明显改善肝功能并提高其生长性能,从而对AFB_(1)诱导所致的氧化损伤具有明显抑制作用。

This study aimed to further explore the effect of taraxasterol on liver tissue oxidative stress cauesed by aflatoxin B 1(AFB_(1))in broiler chickens.One hundred and twenty broilers were randomly divided into six groups:normal group,model group,taraxasterol low-,medium-and high-dose groups(25,50,100 mg·kg^(-1)BW)and positive group(300 mg·kg^(-1)silibinin).Except the normal group,which was fed a basal diet,the other groups were fed a diet containing 0.5 mg·kg^(-1)AFB_(1) for 21 consecutive days to establish a liver injury model,the corresponding concentrations of medication were administered daily in drinking water during this period to each group.The body weight of broilers in each group were recorded and the feed-to-gain ratios were calculated;Liver function indexes asaspartate aminotransferase(AST),alanine aminotransferase(ALT),gamma-glutamyltransferase(GGT),total bilirubin(TBIL),alkaline phosphatase(ALP)in broilers were determined by kits.The contents of reactive oxygen species(ROS),malondialdehyde(MDA),superoxide dismutase(SOD),catalase(CAT),and glutathione(GSH)in broiler liver tissues were determined by kits.The expression of nuclear factor erythroid2-related factor 2(Nrf2),Kelch-like ECH-associated protein 1(Keap1)and heme oxygenase-1(Heme Oxygenase-1),NAD(P)H:Quinone oxidoreductase-1(NQO1)mRNA and protein in brolier liver were determined by RT-qPCR and Western blot.The results showed that the body weight was increased(P<0.05)and the feed-to-weight ratio was decreased(P<0.05)in broilers with AFB_(1)-induced liver injury at 14 and 21 days in the high dose group of taraxasterol.After 21 days,it was shown by the results that the activities of ALT(P<0.05),AST(P<0.01),GGT(P<0.01),TBIL(P<0.01),and ALP(P<0.01),which are indicators of hepatic function,were reduced in the serum of broilers with AFB1-induced liver injury in the high dose group of taraxasterol.ROS and MDA content were inhibited(P<0.01),while SOD(P<0.01),CAT(P<0.05)and GSH(P<0.05)activities were increased in the liver of broilers with AFB1-induced liver injury in the high dose group of taraxasterol.The mRNA and protein expression levels of Nrf2(P<0.05),NQO1(P<0.01)and HO-1(P<0.05)were up-regulated.The mRNA(P<0.05)and protein expression levels of Keap1 were down-regulated in the livers of broilers with AFB_(1)-induced liver injury in the high dose group of taraxasterol.In conclusion,taraxasterol can inhibit the overproduction of ROS and MDA and increase the content of antioxidants SOD,CAT,and GSH in broiler liver by regulating the Nrf2/Keap1 signaling pathway,enhance the hepatic antioxidant function,and significantly improve the liver function and growth performance,which can have a significant inhibitory effect on the oxidative damage caused by the induction of AFB_(1).