Development,immunogenicity And Anti-coccidiosis Effect Of Hybridization Among Different Geographic E.tenella

Eimeria poses a risk to all livestock species as a cause of coccidiosis,reducing productivity and compromising animal welfare.Members of the phylum Apicomplexa can cause the intestinal disease coccidiosis in many animals.Seven species specifically infect the domestic chicken causing malabsorptive or haemorrhagic enteritis,with species-specific sites of development and foci of pathology within intestinal tract.Pressure to reduce drug use in food chain results in the development of cost-effective vaccines against Eimeria.In this paper the F2 was cultivated from Shandong strain?S?,Jilin strain?J?,Heilongjiang strain?H?,by single sporocyte Hybrid technique and analyzed by using RAPD.After this,E.tenella oocysts of hybridization F2 strain were attenuated by using physics and chemistry methods,and coccidiosis resistance was observed.The research is as follows.Cultivate hybridization F2:Single sporocyte?S,J?was fed chicken and receive oocysts.The gene DNA of their offspring was extracted and analyzed by using RAPD.Oocyst DNA of 16strains of E.teaella were tested,and one strain was deter-mined hybridization F1.The similar value?Si?between this strain and its two parents was 0.8348-0.8340,far less than the average Si?0.9604?between other offspring and parent strains,and far greater than the average value of other offspring?0.6627?.The hybrid F1 was further hybridized with Heilongjiang strain.The gene DNA of 16 strains was extracted and analyzed by using RAPD,and one strain with similar value of0.8357⁰.8354 was determined hybridization F2.Immunogenicity and attenuated method of E.tenella hybridization F2 strain:Physic and chemistry methods were used to attenuate oocysts of hybridization F2 strains.Oocysts were attenuated by ultrasonic cell disruptor?power 200W,10min?or mixed with chemical contains sodium azide for 40 days at 4?.After immunization,statistical analysis was undertaken by using counted survival rate,average weight gain,fecal score,oocysts in feces,cecal lesion score,and the change of antibody OD value.The results indicate that,ultrasound-induced weakening of E.tenella hybrid F2 strain oocysts for 10 min can completely break the coccidia oocysts but still maintain good immunogenicity.The chicks were immunized with 4×10³ oocysts on 7th day and 14th day,and the average weight gain of chicks at 7th day after attack was 89.01g.The difference was significant compared with control group which only reached 21.31g average weight gain.Immune survival rate had reached 100%.The chicks were immunized with 8×10³ chemical attenuated oocysts on 7th day and 14th day,and the average weight gain of chicks at 7th day after attack was90.61g.The difference was significant compared with control group and immune survival rate had reached 100%.Other indicators also showed that the immune effect was useful,and antibody changes were detected in serum using indirect ELISA every 7 days.Therefore,sonicating the hybrid F₂ oocysts at a certain power and using the chemical attenuating agent to weaken the F₂strain oocysts can reduce the virulence and maintain good immunogenicity.The weakened oocysts can be used as a vaccine.The results can be applied to modern large chicken farms to prevent coccidiosis and offered base for immunity mechanism of E.tenella.7th day and 14th day is the best immunization time for chicks.4×10³ ultrasonic weakened oocysts and 8×10³ chemical attenuating weakened oocysts were the optimal immune dose.The oocysts weakened by these two methods were made into attenuated vaccines,and they were put into Changchun Jixing Industrial Co.,Ltd.,Jilin Dexiang Animal Husbandry Co.,Ltd.,Zhengda Group Deda Co.,Ltd.using two methods of drinking water and seedlings.In four chicken farms,a total of 880,000 chicks were immunized.According to the statistics of the cooperative company,the attenuated vaccine increased economic benefits for the poultry industry and reduced the damage caused by coccidiosis.