Comparative Analysis of Egg Adapted Vaccines and Salinomycin against Coccidiosis in Chicks

Abstract

Coccidiosis is one of the most economically devastating disease caused by intracellular protozoan parasite of genus Eimeria. It is an important intestinal infection associated with metabolic and structural changes in the intestinal mucosa of the host. Since last few decades anticoccidial drugs are being used but due to abundant use of drugs, resistant Eimeria strains developed. In the present study three types of eggs adapted vaccines namely; egg adapted gametocytes, sonicated gametocytes and formalin inactivated gametocytes has been developed for controlling coccidiosis. Comparative efficacy of salinomycin and egg adapted vaccines against coccidiosis was investigated. Total of ninety, day old chicks (birds) were divided into six groups (A-F). On 5 th day of age three groups were vaccinated orally with 0.2ml vaccines to its corresponding group. On 21 st day of age all groups except control were given infection orally with dose of 10,000 oocyst/bird through dropper. On 5 th day post inoculation 60mg/kg salinomycin was given to infected unvaccinated medicated group to check the comparative effectiveness of vaccines and drug. Body weight gain, feed consumption, feed conversion ratio were investigated till end of experiment. While bloody diarrhea, oocysts excretion were investigated at the first and second week of post infection. Blood samples were also collected from each group on 5 th, and 15 th day of vaccination as well as on 7 th day of infection. For histopathological examination tissue samples from intestine and caeca were taken on day 7 th post inoculation from all groups. Gametocytes vaccinated and salinomycin treated group had significantly higher (P=0.002) body weight gain, feed consumption when compared with formalin and sonicated vaccinated and infected non-medicated unvaccinated groups respectively. Gametocytes vaccinated group showed feed conversion ratios similar with salinomycin medicated group showing significant association of (P=0.001). Mild bloody diarrhea and lowest oocyst count was shown by gametocyte vaccinated and salinomycin treated groups. Gametocytes vaccinated and salinomycin medicated group showed survival rate of 100% similar to negative control. Blood samples collected after infection were analyzed for biochemical tests. The results showed significant decrease in albumin concentration and increase level of uric acid, ALP, AST, ALT and creatinine in infected non medicated unvaccinated, formalin inactivated gametocytes and sonicated gametocytes vaccinated groups. Histopathological examination showed Eimeria induced lesion were mild in gametocytes vaccinated, medicated and control group. While in non-immunized infected group the lesions were severe. On blood collected at day 5 th and 15 th post vaccination from vaccinated groups, indirect hemagglutination test were applied for detection of antibodies. Results of IHA test showed that in gametocytes vaccinated group blood hemagglutination is maximum as compared to remaining two vaccinated groups.