Determination of lowest immune protective titer against Salmonella gallinarum and Salmonella pullorum in chicken vaccinated with BAU-Salmonella bivalent vaccine

Abstract

Objective: The research work was conducted to determine the duration of protective efficacy and lowest immune protective titer of Salmonella bivalent vaccine containing Salmonella gallinarum and Salmonella pullorum prepared at the Livestock and Poultry Vaccine Research and Production Centre (LPVRPC) of Bangladesh Agricultural University (BAU), Mymensingh, Bangladesh. Materials and methods: The experimental chickens were subdivided into four main groups (A, B, C and D). Group A and B were vaccinated with BAU-Salmonella bivalent vaccine with dosed 0.5 mL intramuscularly at the age of seven weeks followed by a booster vaccination at 12 weeks of age while group C and D served as unvaccinated control. The sera samples were obtained at 7, 12, 15, 18, 23, 27, 30, 32, 34, 36 and 41 weeks of age of birds. Results: Significantly elevated level of immune response in terms of antibody production resulted from booster vaccination. Vaccinated chicken showed protective resistance following virulent challenge with isolates of S. gallinarum and S. pullorum (**P < 0.01) till 41 weeks, whereas unvaccinated control birds failed to resist the virulent challenge infection. Conclusion: BAU-Salmonella bivalent vaccine showed lowest immune protective titer up to seven months following booster vaccination.