复方板蓝根口服液对雏鸡白痢沙门氏菌病的防治研究

Study on the Prevention and Treatment of White Diarrhoea Salmonella in Chick by Compound Radix Isatidis Oral Solution

【目的】为开发中药防治畜禽沙门氏菌病,根据沙门氏菌病中兽医辩证进行中药组方,为今后畜禽养殖减抗限抗的替代疗法提供参考。【方法】采用倍比稀释法检测复方板蓝根口服液对鸡白痢沙门氏菌的最小抑菌质量浓度(minimum inhibitory concentration,MIC)和最小杀菌质量浓度(minimum bactericidal concentration,MBC),扫描电镜观察菌体形态变化。试验选取150羽1日龄雏鸡,随机取出30羽做空白组,其余120羽人工感染鸡白痢沙门氏菌,制备雏鸡感染模型。将感染雏鸡随机分为模型组、中药治疗组、西药治疗组和中药预防组,每组30羽。观察雏鸡的发病率及死亡率。于治疗后1、3和5 d检测血清中IL-1β和TNF-α的含量;实时荧光PCR检测禽β-防御素6(avian beta-defensin 6,AvBD6)和鸡Toll样受体15(chicken toll-like receptor 15,ChTLR15)在雏鸡小肠中的转录水平。【结果】体外试验结果显示:MIC和MBC分别为62.5和125 mg/mL;扫描电镜下可见菌体出现溢缩,断裂形成许多残体,形状不规则。中药预防组可降低雏鸡的发病率及死亡率。与模型组相比,中药预防组和中药治疗组均可降低IL-1β和TNF-α含量。而ChTLR15和AvBD6在感染初期表达量高,治疗后期趋于正常。【结论】复方板蓝根口服液对鸡白痢沙门氏菌有明显的抑制作用,其杀菌机制是通过改变菌体的形态结构使细菌丧失活性。试验证实复方板蓝根口服液可有效预防雏鸡沙门氏菌感染,并能有效降低体内炎性因子水平,减轻炎症反应。

[Purpose]To develop Chinese traditional medicine for the prevention and treatment of salmonellosis in livestock and poultry,according to the Chinese traditional veterinary syndrome differentiation of salmonellosis,the traditional Chinese medicine prescription is used to provide a reference for the replacement therapy of antibiotic use in livestock and poultry breeding in the future.[Method]We detected the minimum inhibitory concentration(MIC)and minimum bactericidal concentration(MBC)of compound radix isatidis oral solution(CRIOS)by vitro antibacterial activity,and observed the morphological changes of bacteria by scanning electron microscope.One hundred and fifty 1-day-old chicks were selected for clinical trials,30 chicks were randomly selected into blank group,the remaining 120 chicks were artificially infected the Salmonella pullorum strains for preparing the chicken infection model.Infected chicks were randomly divided into model group,Chinese medicine treatment group,western medicine treatment group,and Chinese medicine prevention group,30 chicks per group.The morbidity and mortality of chicks were observed.Serum levels of IL-1βand TNF-αwere measured at 1 day,3 days,and 5 days after treatment.The transcriptional levels of avian-β-defensin-6(AvBD6)and chicken toll-like receptor 15(ChTLR15)in chicks’small intestine were detected by Real-time PCR.[Results]The MIC and MBC were 62.5 mg/mL and 25 mg/mL,respectively.Scanning electron microscopy showed that the bacteria appeared contractile,and many of the residues were broken and irregularly shaped in vitro.Clinical trials showed that Chinese medicine prevention could reduce the morbidity and mortality of chicks.Compared with the model group,the Chinese medicine prevention group and the Chinese medicine treatment group could reduce the contents of IL-1βand TNF-α.And the AvBD6 and ChTLR15 had a high expression level in the early stage of infection and tend to be normal later in treatment.[Conclusion]The results of this experiment indicate that CRIOS has an obvious inhibitory effect on S.pullorum,and its bactericidal mechanism is to change the morphological structure of the bacteria to make the bacteria lose activity.Clinical trials have confirmed that compound radix isatidis can effectively prevent Salmonella infection in chicks,and can effectively reduce the level of inflammatory factors in the body and reduce the inflammatory response.