Study On Immunogenicity And Attenuated Method Of E.tenella Hybridization F2 Strain

Coccidiosis is a kind of protozoosis in intestinal tract of chicken which has a broad distribution, serious perniciousness and mainly infringed enterocyte.The characteristics of the disease are of very high morbidity and mortality, hemorrhagic cecitis, bloody flux.It has become one kind of important diseases in poultry industry.Nowadays,medicines are main method in prevention and cure of coccidiosis.The development of anti-coccidiosis agents is confined tremendously by the problems of chemicals residual and drug fast strains widespread to be emerged.Immunoprophylaxis is a sort of ideal method to control coccidiosis.Using vaccine to control this disease not only can solve coccidial drug resistance thoroughly but also can produce green foods and make meat and eggs safe.Physic and chemistry methods to attenuate oocysts of hybridization F2 strains were explored in this paper, and meanwhile immunoprotection of attenuate oocysts and regularity of rise and fall on antibody OD value in serum were investigated.E.tenella oocysts of hybridization F2 strains were amplified by routine method.Then E.tenella oocysts of hybridization F2 strain were attenuated by using physics and chemistry methods.First,oocysts of hybridization F2 strain were attenuated in a certain power and different supersonic time and put attenuated oocysts in the 4℃refrigerator.Then chemical preparation was prepared.Oocysts and chemical preparation were mixed through agitating well-distributed,then put it in the 4℃refrigerator for 40 days. Immunogenicity experiment was taken by chicken through oral administration attenuated oocysts. Statistical analysis was undertaken by using counted number of oocysts,faeces score,average weight gain,and immune survival rate.ELISA experiment to determine OD value of serum antibody was established.According to indirect ELISA empirical method procedure,optimal coating concentration of dissolubility oocyst antigen,optimal working concentration of enzyme conjugate,optimal dilution of serum were determined.Dynamic change regularity of serum antibody OD value after immunizing chicken using E.tenella oocysts hybridization F2 strain were attenuated through physics and chemistry methods.Experiment manifestation,poison of oocysts were weaken by using supersonic attenuation inl0 minutes and chicken was immunizd by using 4~103 attenuated oocysts on 7th day and 14th day through oral administration.Average weight gain was reached 155g per chicken at 7day after attack.The difference was significant compared with control group which only reached 25g average weight gain per chicken.Immune survival rate had reached 100%. Chemical preparations were prepared by using several chemicals.Immune response can be induced very well when immunizing dose was 8×10~3 attenuated oocysts per chicken on 7th day and 14th day by oral administration.Average weight gain was reached 165g per chicken after 7day attack.The difference was significant compared with control group which only reached 25g average weight gain per chicken.Immune survival rate had reached 100%. E.tenella vaccine of hybridization F2 strain was successfully prepared by this experiment.Immunogenicity was maintained very well through using chemical preparations and supersonic attenuate oocysts.Antibody detection can be utilized through established indirect ELISA method.Regularity of dynamic state of serum antibody after immunizing chemical preparations and supersonic attenuate oocysts was revealed,and this kind research was laid a foundation for theory and practice in the future.