Immunization of broiler chickens against necrotic enteritis

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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.