A Vaccine to Prevent Egg Layer Peritonitis in Chickens.

A series of studies was undertaken in specific-pathogen-free white leghorn chickens for the development of a chicken model of avian pathogenic (APEC) peritonitis. Once established, this model was then used to measure the effectiveness of a siderophore receptor and porin proteins (SRP) APEC vaccine. Initially, five pilot studies were performed to compare the serotype, challenge route, and dose of inoculum that resulted in pathologies characteristic of the peritonitis observed in commercial layer facilities, such as widespread organ infection, atrophy, discoloration, corrugation of yolk sacs, and the presence of caseous exudate.