Development Of Hybridization Among The Different Geographic E.tenella And Establishment Of Culture In Vitro Technology

Coccidiosis, which is caused by Eimeria spp all over the world, is a very severe parasitosis to poultry. Chemotherapy has been restrained to control coccidiosis because of appearance of drug-resistant strains and drugs residues. The development of vaccine against coccidiosis becomes more and more important in recent years. The immune mechanism of coccidiosis is not clearly now, and common antigen among species and strains have not been found. The vaccines could not to protect coccidian invention completely that come from different species and strains. In aboard, researchers have already cultivated hybrid strain by using hybriding technique and have got genetics sign from parent strain, for example: common antigen etc. All the reports about anti-drug strain are excessive. In this paper the F2 were cultivated from Heilongjiang strain(H),Liaoning strain(L),Jilin strain(J),Gansu strain (G),Beijing strain (B) by single sporocyte Hybrid technique.The selection of parent strains: The chicken which is 10 days, were challenged by oocysts of H, L, J, B and G strains. Through detection of OPG,changing of faces, pathologies of appendices, body weight etc, the G, B, J were selected as parental generation.The method of RAPD: Five parental generations and their filial generations were analyzed by RAPD technique. The result showed that there are certain difference in five strains. The similarity(SI) is from 0.6022 to 0.6971. The average similarity is 0.6497. The similarity of parental generation is different from that of filial generation which is from 0.9838 to 0.9913. The similarity coefficient and relationship tree were drawn according to the similarity. So the method of RAPD to identify different E. tenella strains were established.The establishment of culture in vitro: To make F2 hybrid strains inoculated in the 10-12 days old chicken embryo. After increasing vaccination doses and the number of embryos consecutively, to precipitate coccidian accommodate the chicken embryo until the 9th generation with the doses from each chincken embryo 40,000 sporozoite to 10,000. After 22ed generation we established the chicken adapted strain of F2 strain.Chicken were infected by E. tenella from different geographical strain by hybreed technique and gametogenesis were happened in vivo at random to get equal amount of original and hybreed type zygocyte. The hybreed type of E. tenella were collected after RAPD determination from oocysts, moreover, the common antigen were to analysis among different geographical strains. The results provided a basis on further studying the immune mechanism of coccidian and finding the common antigen of different coccidial strains.