Development and Evaluation of an delta aroA / delta htrA Salmonella enteritidis Vector Expressing Eimeria maxima TRAP Family Protein EmTFP250 with CD 154 (CD 40L) as Candidate Vaccines against Coccidiosis in Broilers

Coccidiosis is caused by parasites of the genus Eimeria, belonging to phylum Apicomplexa. EmTFP250 is a high molecular mass, asexual stage antigen from Eimeria maxima (EM) strongly associated with maternal immunity in newly hatched chickens. Cloning and sequence analysis predict the antigen to be a novel member of the Thrombospondin-Related Adhesive Protein (TRAP) family. Three novel attenuated Salmonella enteritidis strains (delta SE) expressing TRAP oligopeptides in association with a potential immune-enhancing CD 154 sequence, on the outer membrane protein lamB, were developed. Broiler chicks were grouped based on treatment and 10⁸ cfu/chick of vectors expressing one of three sequences, or vehicle alone, was orally administered to each group. At 21 d of age, all groups were challenged with 10⁴ sporulated oocysts/chick orally. Mortality at 5d post-challenge was markedly different (p