Immunization of V-line rabbits against intestinal coccidiosis by using attenuated Eimeria oocysts.

Abstract

The present work aimed to study the immunization of V-line rabbits against coccidiosis by using attenuated Eimeria oocysts by different methods (UV irradiation , formalin and freezing-thawing ) on Eimeria oocysts and its effect on immune pattern of V-line rabbits. For this aim, Eimeria species (E. exigua,E. flavescens, Emedia, E magna, E. irresidua, E.nagpurensis, E. coecicola and E. intestinalis)were collected from infected and dead rabbits. The collected Eimeria species were sporulated in potassium dichromate 2.5% and divided into four parts ; 1stpart exposed to UV for an hour ,2nd part exposed to six freeze-thaw cycles, 3rd part was diluted with 2.5 ml of formalin 37% and 4th part left without treatment. Fifteen V-line rabbits were classified into 4 groups;G1 was treated by formalin treated Eimeria oocysts,G2 was inoculated by UV irradiated Eimeria oocysts, G3 was inoculated by freezing-thawing oocysts and G4 was inoculated by nontreated Eimeria oocysts. Challenge by non-attenuated Eimeria was carried in 14th day post inoculation. Fecal samples were collected from all groups from 6th to 35thdays, identified and count. Blood samples were collected at days (zero,7th ,14th ,21st,28th and 35th) for determination of cellular and humeral immunity. The obtained results recorded that immunization of rabbits by UV irradiated Eimeria oocysts showed low number of oocysts in feces before and after challenge compared to other groups. The same group showed high level of IgG .It recommended that immunization of rabbits by UV irradiated Eimeria oocysts could protect rabbits against coccidiosis.