蝇蛆抗菌肽对白痢病鸡肠道黏膜免疫及基因表达影响的研究

Modern poultry industries are pursuing the sustainable development with characteristics of safety, quality, high efficiency, pollution-free, from the traditional mode depending on quantitative growth to modern mode depending both on quality and and ecological benefits. During this process, frequent applications of antibiotics have caused drug resistance, affecting the body's immune system, resulting in the failure of immune, which causes serious harm to the livestock industry. The early research results of china natural fund showed that the maggot antimicrobial peptides (AMPs) can effectively cure pullorum diseases with more advantages than antibiotics. But the maggot antibacterial peptide solution treatment pullorosis disease mechanism is not clear, and the difference with antibiotic treatment mechanism had never been discovered. Based on the previous research,we treated pullorosis artificially infected dead chickens and cultivation of feces bots with salmonella, produced a high expression of antimicrobial peptides, determined peptide solution of maggots fed with antibacterial, maggots , the purified antimicrobial peptide and antibiotics which had an effect on the scours sick chicken intestinal mucosal immune and gene expression difference, so as to discuss the mechanism of Salmonella pullorum treatment by feeding salmonella specific processing maggot antimicrobial peptide,besides explored the difference between antimicrobial peptides and antibiotics in treating of pullorosis artificially infected in chickens, immunology as well as gene expression,and furthermore provided a basis for the application of antibacterial peptides in poultry raising industry.

养禽业现追求“安全、优质、高效、无公害”的可持续发展，由数量增长为主的传统模式转向数量、质量和生态效益并重。其中抗生素频繁应用引起耐药性，影响机体免疫力，致使免疫失败，对畜牧业造成严重危害。前期自然基金项目的研究表明，蝇蛆抗菌肽和抗生素均能有效治疗鸡白痢病，蝇蛆抗菌肽的优势显而易见，但是，蝇蛆抗菌肽治疗鸡白痢病的机理不清楚，与抗生素治疗机理的区别更未有过研究。本项目在前期研究基础上，用沙门氏菌处理由白痢病死鸡以及粪便培养的蝇蛆，使其产生高表达量的抗菌肽，并测定饲喂蝇蛆抗菌肽粗提液、纯化的蝇蛆抗菌肽、蝇蛆活体和抗生素等对白痢病鸡肠道黏膜免疫、基因表达的变化和差异，从而探讨饲喂沙门氏菌特异处理蝇蛆产生的蝇蛆抗菌肽治疗鸡白痢病的作用机理，同时探讨蝇蛆抗菌肽与抗生素在治疗鸡白痢病免疫学和基因表达方面的区别，为蝇蛆抗菌肽在养禽业的应用提供依据。

养禽业现追求“安全、优质、高效、无公害”的可持续发展，由数量增长为主的传统模式转向数量、质量和生态效益并重。其中抗生素频繁应用引起耐药性，影响机体免疫力，致使免疫失败，对畜牧业造成严重危害。沙门氏菌特异处理蝇蛆产生的蝇蛆抗菌肽治疗鸡白痢病的作用机理，以及与抗生素治疗鸡白痢病肠道免疫学和基因表达方面的差异还不清楚。通过项目实施，发现鸡白痢沙门氏菌诱导的蝇蛆抗菌肽对鸡白痢沙门氏菌的抑菌作用显著高于其它细菌诱导的蝇蛆抗菌肽并获得了高抑菌活性的蝇蛆抗菌肽组分。明确了蝇蛆抗菌肽的有效活性成分，并用蝇蛆抗菌肽的有效活性成分替换抗生素治疗白痢病鸡，对白痢鸡肠道黏膜免疫和相关基因差异表达进行了研究。蝇蛆抗菌肽能引起白痢鸡小肠乳酸杆菌和回肠肥大细胞数量增加，同时能促进鸡回肠黏膜TGF-β4 mRNA表达，并且对鸡空肠黏膜TNF-α mRNA的表达水平高于抗生素治疗组，抗生素治疗白痢鸡后导致十二指肠肥大细胞和杯状细胞数量降低。还发现白痢或腹泻鸡粪和病死鸡培养的蝇蛆产生的蝇蛆抗菌肽可显著提高肉仔鸡 RBC、总蛋白、白蛋白、球蛋白的含量，降低炎症细胞和白痢鸡肠道细菌数量，蝇蛆抗菌肽还能提高黄羽肉鸡的白蛋白和免疫球蛋白（IgG和IgM）含量和蛋白质表观代谢率，还能提高鸡的胸腺指数、脾脏指数和法氏囊指数，效果优于抗生素组。蝇蛆抗菌肽治疗腹泻小鼠的结果显示，腹泻鼠肠道十二指肠内的TNF-α的含量显著降低，而抗菌肽治疗组小鼠肠道内的大肠杆菌数显著降低，乳酸杆菌数呈显著升高趋势，IL-6含量显著下降。蝇蛆抗菌肽可以抑制小鼠乳腺组织中金黄色葡萄球菌的生长，降低小鼠乳腺组织损伤，对小鼠乳腺炎有一定治疗作用。以上研究均确定了蝇蛆抗菌肽，对鸡白痢病或腹泻或小鼠腹泻或乳腺炎均具有良好的预防和治疗效果，明确了蝇蛆抗菌肽与抗生素在治疗鸡白痢病免疫学和基因表达方面的区别，为蝇蛆抗菌肽在养禽业的应用提供理论支撑。