Objective: To cultivate hybrid strains from three geographic isolates of Eimeria tenella and to explore the possibility of developing vaccine candidates.
Methods: Three parental strains were selected from five geographic isolates of E. tenella through immune experiment, and hybrid strains were cultivated. The genomic DNA of the three parental strains and their filial generation were analyzed by random amplified polymorphic DNA (RAPD) technique with 30 optimization primers screened from 200 primers, the hybrid strains were isolated from the filial generation by RAPD. Chicken were inoculated with hybrid strains, and challenged with different strains to compare the immunogenicity and immunoprotection.
Results: Immunogenicity and immunoprotection of the three strains isolated from Guangzhou, Baoding and Changchun were stronger than those of other strains. Hybridization was performed to cultivate hybrid strain. Two hybrid strains were isolated from Changchun x Baoding and Guangzhou x F1 by RAPD. The result of immune experiment proved that immunoprotecion of F1 and F2 were higher than their parental strains.
Conclusion: Two hybrid strains have been cultivated from the three geographic isolates of E. tenella, with the immunogenicity of their parental strains. Chicken immunized by F2 strain have shown strong resistance against the infection of the geographic strains, with an average protection rate of 84%.