Immunization of broiler chickens against necrotic enteritis

坏死性肠炎是由厌氧细菌产气荚膜梭菌引起的肉鸡重要疾病。它通常通过在水或饲料中以预防剂量使用各种抗菌素来控制。然而，由于公众对在动物生产中使用抗菌药物的担忧，欧洲几年来一直禁止将抗菌药物用于“促进生长”和预防疾病的目的。这样的禁令可能会在加拿大和美国实施。此外，许多生产者希望饲养不使用抗菌药物的动物，因为这可能会带来市场优势。令人惊讶的是，人们对NE的免疫力知之甚少。该实验室最近的一项研究首次表明，有可能成功地对肉鸡进行坏死性肠炎免疫。本研究表明，免疫能力与毒株有关，而与无毒株无关。我们正在开展这项工作，找出那些对感染免疫的鸡对有毒细菌的哪些蛋白质有反应，或者对有毒细菌有独特的反应。我们已经确定了大约9种蛋白质，其中3种已经被表征。我们希望用部分或全部这些蛋白质以及α毒素对肉鸡进行免疫，并确定哪种蛋白质能提供抗感染的免疫力。然后，我们将开发这种蛋白质作为抗原来保护鸟类免受这种严重感染。

Necrotic enteritis is an important disease of broiler chickens caused the anaerobic bacterium Clostridium perfringens. It is usually controlled by use of various antimicrobials  administered at prophylactic doses either in water or feed.  However, because of public concern about the use of antimicrobial drugs in animal production, use of antimicrobial drugs for "growth promotional" and disease prophylactic purposes has been banned for several years in Europe.  Such a ban may occur in Canada and United States. In addition, many producers would like to rear animals without antimicrobial drugs for the market advantage this may give. Surprisingly little is known about immunity to NE.A recent study  from this laboratory showed for the first time that it is possible to immunize broiler chickens successfully against necrotic enteritis. This study showed that immunizing ability was associated with virulent but not with avirulent strains.  We are developing this work by finding out which proteins of the virulent bacteria are responded to by chickens that have become immune to infection or are unique to virulent bacteria. We have identified about 9 proteins, three of which have been characterized.We would like to immunize broiler chickens with some or all of these proteins, as well as with alpha toxin, and determine which provide immunity against infection. We will then develop the use this protein as an antigen to protect birds against this serious infection.