Immunization of broiler chickens against necrotic enteritis

坏死性肠炎是由产气荚膜梭菌引起的肉鸡的一种重要疾病。它通常是通过使用各种抗菌剂来控制的，这些抗菌剂在水或饲料中以预防性剂量给药。然而，由于公众对在动物生产中使用抗菌药的担忧，欧洲几年来一直禁止使用抗菌药来促进生长和预防疾病。但加拿大和美国可能会出现这样的禁令。此外，许多生产商希望在没有抗菌药物的情况下饲养动物，以获得这可能带来的市场优势。令人惊讶的是，人们对新城疫的免疫力知之甚少。该实验室最近的一项研究首次表明，有可能成功地免疫肉鸡对抗坏死性肠炎。这项研究表明，免疫能力与强毒菌株有关，但与强毒菌株无关。我们正在通过找出对感染具有免疫力或对强毒细菌独有的鸡对强毒细菌的哪些蛋白质做出反应来开展这项工作。我们已经鉴定了大约9种蛋白质，其中3种已经确定。我们希望用这些蛋白质中的部分或全部以及阿尔法毒素来免疫肉鸡，并确定哪些蛋白质能提供对感染的免疫力。然后我们将开发利用这种蛋白质作为抗原来保护鸟类免受这种严重感染的方法。

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.