Trial for Preparation and Evaluation of Autogenous Killed Vaccine Against Some Locally Isolated Strains of Salmonella enterica from Chickens in Egypt

Abstract

A trivalent killed Salmonella vaccine was developed and its efficacy was evaluated in specific pathogen free (SPF) chickens. One hundred and forty SPF chickens divided to two groups were used to evaluate the efficacy of our vaccine. Vaccinated chickens were primed with the prepared vaccine at the age of two weeks and were boosted three weeks later comparing to unvaccinated chickens. All chickens were divided into subgroups which challenged orally with 1mL (5x107 CFU/mL) of Salmonella Typhimurium (ST), Salmonella Montevideo (SM), or Salmonella Blegdam (SB) strains, three weeks post boosting of the vaccine. The protection rate was evaluated based on the clinical signs, the mortality, and bacterial fecal shedding. Moreover, we used ELISA technique to evaluate the humoral immune response against Salmonella strains. Our trivalent killed Salmonella vaccine elicited 85% protection rate in challenge test with reduction of bacterial fecal shedding.