Aim: To compare the efficacy between saponin adjuvanted paratuberculosis killed vaccine and Freund's incomplete (FIC) adjuvanted paratuberculosis vaccine in mice model.
Materials and Methods: The study was conducted for a period of 11 months using 80 Swiss albino mice by dividing into four groups (Group I-mice vaccinated with killed Mycobacterium avium subspp. paratuberculosis (MAP) adjuvanted with saponin, Group II- for FIC, Group III- Saponin control and Gr IV- FIC control). Faecal shedding, changes in body weight, presence of local reactions and clinical symptoms, were evaluated. Serological assays for humoral and cell mediated immune response were determined by agar gel immunodiffusion (AGID) and nitric oxide test (NO) respectively. A total of 76 serum samples, 52 faecal samples and 20 tissue samples were collected at different intervals during the study period. ZN staining; AGID test and nitric oxide test were employed for analysis of samples.
Results: A total of 38 samples (37 faecal and 1 tissue sample) and 18 serum samples were recorded as positive by ZN staining and AGID test respectively from all four groups of mice. Significant decrease in faecal shedding of organisms was observed in Group I mice vaccinated with saponin adjuvanted vaccine in comparison to Group II. Gain in body weight of Group I mice was recorded as higher than Group II. NO test revealed increase in the concentration of NO level in both vaccinated group but more significant in Group I.
Conclusion: The tests results obtained revealed that killed MAP vaccine adjuvanted with saponin have higher protective efficacy in terms of reduced faecal shedding, gain in body weight, less side effects, absence of attributable specific symptoms of Johne's disease, etc. in comparison to killed MAP vaccine adjuvanted with FIC. The present study also reveals that AGID and NO estimation tests are specific tests which can be employed for diagnosis and comparison of efficacy of paratuberculosis vaccine