The optimization of a prevention program utilizing a novel trivalent inactivated Salmonella bacterial vaccine to protect poultry from Salmonella infections was evaluated in this study. A total of 50 brown nick layers were divided into 5 groups, A to E, each containing 10 hens. Group B hens were immunized with the SG9R vaccine, group C chickens were immunized with the trivalent inactivated Salmonella bacterial vaccine, and group D hens were primed with SG9R and boosted with the trivalent inactivated Salmonella bacterial vaccine. Group E hens were injected with sterile PBS. All hens in groups B to E were orally challenged with a mixture of wild-type S. Enteritidis, S. Typhimurium, and S. Gallinarum (approximately 6×10⁹ CFU/ 0.2 ml/bird). Serum IgG titers, CD3+CD4+ T-cell levels, and CD3+CD8+ T-cell levels in group D were significantly higher than those in group A. Additionally, all animals in groups A to D showed no clinical symptoms and survived after the virulent challenges, whereas all chickens in group E died following the challenge. The challenge strains of S. Enteritidis, S. Typhimurium, and S. Gallinarum were not isolated from the liver, spleen, cecum, and cloaca of group D chickens. These findings indicate that priming with SG9R and boosting with a trivalent inactivated Salmonella bacterial vaccine can be an effective approach for preventing Salmonella infections by inducing robust protective humoral and cellular immune responses in chickens.

We previously developed a novel attenuated Salmonella Typhimurium (S.Typhimurium) △lon△cpxR vaccine. This study was conducted in order to examine whether this vaccine could effectively protect growing piglets against Salmonella infection. Pregnant sows in group A were primed and boosted with the vaccine, whereas pregnant sows in group B received sterile PBS-sucrose. After farrowing, newborn piglets in groups A and B were challenged with a wild type virulent S. Typhimurium at three weeks of age. During the study, serum IgG titers of piglets in group A were significantly higher than those of piglets in group B (P<0.001). In addition, clinical signs were observed in 5.9% of piglets in group A during the entire experimental period after the challenge, while diarrhea was observed in 81.6% of piglets in group B. These results indicate that vaccination of the pregnant sows resulted in effective protection in piglets against Salmonella infection.