Study Of Drug Resistance Of Three Eimeria Tenella Strains In Anhui Province

The intestinal disease known as coccidiosis caused by protozoan parasites of genus Eimeria is one of the most economically devastating diseases in the poultry industry world wide. Of all species of Eimeria, Eimeria tenella is one of the most ubiquitous and the most pathogenic for chicken.The drug resistance has caused great losses to the production,and it has been the biggest barrier to control the coccidiosis in chichen.In order to find the infection of coccidia in Chaohu, Luan and Feidong of Anhui province , chicken's fresh excrement is gathered from folowing counties in such area.The infection percentage is 100% .Oocyst collected by the up-and-down method is identified in morphology aspect.The results show that all of the seprated ooganium are subordinates in Eimeria. We improve the single-occyst technology on previous experiment to obtain purebred occyst of Eimeria. tenella.The Body-testing method is used to test the drug resistance of the three strains from Chaohu,Lu,an,and Feidong to six anticoccidials: Monensin ,Salinomycin ,Sulfachlorpyrazine, Maduramicin, Toltrazurila and Diclazuril. The criteria used for evaluation the resistance include anticoccidianl index (ACI),reduction of lesion scores(RLS),percent of optimum anticoccidial activity(POAA) and relative caecum oocyst production(ROP). The results show that Chaohu strain has a liaght resisrence to Diclazurl,isalinomycin and Monensin,but has a moderate resistance to Maduramicin,a serious resistance to Toltrazurila and Sulfachlorpyrazine. Lu,an strain assums sensitive to Maduramicin ,but has a light resistence to salinomycin, a moderate resistence to Sulfachlorpyrazine,a serious resistence to Toltrazurila and Diclazuril.Feidong strain has a light resistence to salinomycin and Maduramicin,but has a moderate resistence to Toltrazurila and Diclazuril,a serious resistence to Monensin.According to the result of Body-testing method ,three strins have serious resisitence to Sulfachlorpyrazine ,Toltrazurila and Diclazuril .With the outset density of 100×10^-6,0.05×10^-6,10×10^-6,we induce three resistant strains for Sulfachlorpyrazine, Toltrazurila and Diclazuril. Taking Shanghai and Nanjing sensitive standard strains as the reference,dis-continual polyacrylamide gel electrophoresis is used to analyze eight E.tenella strains'lactic dehydrogenase (LDH), glucose phosphoric acid isomerase (GPI) and the glucose - 6- phosphoric acid dehydrogenase (G6PD) isozyme spectrum. The Sulfachlorpyrazine drug restance strain has a LDH special isozyme spectrum,but has no relationship with GPI isozyme. The Toltrazurila and Diclazuril drug restance strain are separately presented a GPI specificity isozyme spectrum. The Toltrazurila drug restance strain has a special G6PD isozyme spectrum,but the Sulfachlorpyrazine and Diclazuril drug restance has no relationship with G6PD isozyme.Finally, the efficacy of anticoccidiosis is evaluated with Nifedipine and Monensin combined by weight gains,lesion scores of caecum and anticoccidial indexs(ACI) in chicken infected with Eimeria.tenella.The results show that Nifedipine(12×10^-6) combined with Monensin(120×10^-6) has the best efficacy,whose lesion scores of caecum is 1,and ACI is 188.3.