Isolation And Identification Of E. Mfus And E. Preacox From Jiangsu Province

Chicken coccidiosis caused by protozoan parasites of the genus Eimeria is one of the most economically devastating diseases in poultry industry worldwid. There were seven species of Emeria we can easily identify:E. tenella、E. necatrix、E. acervulina、E. maxima、 E. brunetti、E. mitis and E. praecox.The epidemiology of coccidiosis in18chicken farms of Jiangsu province was investigated. Results showed that66.7%(12/18) of the chicken farm were infected with the coccidiosis. To identify the species of the Eimeria, ITS1-PCR was performed. It was found that E. tenella had the highest rate of infection (91.7%). Other species infection rates were as follows:E acervulina (33.3%), E. brunetti (8.3%), E. maxima (58.3%), E. mitis (50.0%), E. necatrix (50.0%), and E. praecox (33.3%).A modified single-oocyst isolation technique was used and two strains of E. mitis and E.praecox were isolated. Furthermore, we identified the Jiangsu strains through morphology and molecular biology method. The result showed that the size of E. mitis-JS were15.3μm×13.6μm in average [(13.8-18.2)μm×(12.0～16.7)μm], and the oocysts body exponent was (1.13). While the E. praecox-JS was (18.3-22.1)umx(15.1～18.9)μm and19.5μm×16.1μm in average size, The oocyst body exponent was (1.21). Then, the oocysts were crushed and the DNA was extracted. Two sets of primers were designed and utilized to amplify two different fragments with sizes306bp and368bp.200Roman roosters aging7-day-old, sub-divided into10groups each with20individuals, were infected with E.mitis and E.praecox oocysts at different doses (1000,5000,10000,100000and200000) by mouth. The results showed that all doses of oocysts could cause weight loss in the experimental chicken besides causing varying degrees of intestinal lesions. When the dose was at10000, the average difference in weight gain was significant (P<005) between the infected group and the control group. Both E. mitis-JS and E. preacox-JS can cause intestinal villi breakdown, epithelial cell degeneration and necrosis. Those groups treated with high doses showed red blood cell infiltration in the liver and spleen. Serological tests Detecting the levels of IgG in blood serum and IgA in intestines by ELISA, revealed a significant increase in IgG and IgA levels in chicken which were challenged with E. mitis and E. preacox, with a dose containing5000oocysts.The immunogenicity of E. mitis-JS and E. praecox-JS was studied.7-day-old Roman roosters distributed into8groups each with20individuals, were immunized with two kinds of oocysts at different doses (100,500,1000,5000) by mouth.14days later, all of the roosters were challenged with100000ooccysts. The immunogenicity of E. mitis-JS and E. preacox-JS were investigated by analyzing the average weight gain, OPG (ooccysts per gram). The results showed that the best immunizing does of these two strains was5000oocysts per rooster, for they give the strongest immune response.