Attenuation of eimeria tenella with immersion various concentration of formaldehyde in inducing protective immunity after challenge test by featuring macroscopic and microscopic caecum

Background: Eimeria tenella parasite is one of the most pathogenic coccidia that can infect chickens. The strategy for prevention and control of coccidiosis is done by administering anticoxidia drugs and live oocyst vaccines. However, anticoxidia can cause resistance to coccidiosis. So it is necessary to make vaccines (attenuation) using formalin or formaldehyde. Aim: The purpose of this study was to determine whether the attenuation of the pathogenicity E. tenella with immersion various concentrations of formaldehyde can induce protective immunity and the concentration of formaldehyde that is most effective in inducing protective immunity for attenuation of E. tenella in featuring cecal macroscopic and microscopic (lesion score). Method: Twenty-five chickens at three weeks old were divided randomly into five groups. Challenge test did after the first infection. The first infection was inoculated tenella by divided the first group (P0) is chicken group was inoculated with 0% formaldehyde soaked E. tenella at 1 x 104 doses as control, the 2nd, 3rd and 4th groups (P1; P2, P3 and P4) were inoculated 0.15%, 0.3%, 0.6% and 1.2% of formaldehyde soaked E. tenella at the same doses, respectively. On challenge test performed two weeks after the first infection by inoculated 15x103 infective oocysts of E. tenella. Result: The results showed that the attenuation of E. tenella with immersion various concentrations of formaldehyde can induce protective immunity by featuring cecal macroscopic and microscopic (lesion score). Conclusion: The most effective concentration of formaldehyde in inducing protective immunity of the attenuation pathogenicity E. tenella was 1.2%.