The Efficacy of a Trivalent Inactivated Salmonella Vaccine Combined with the Live S. Gallinarum 9R Vaccine in Young Layers after Experimental Infections with S. Enteritidis, S. Typhimurium, and S. Infantis

Abstract

Worldwide, poultry infections by Salmonella are the cause of significant economic losses, not only due to reduced production (due to fowl typhoid disease), but also considering the efforts and control measures that must be constantly applied, especially due to zoonotic serovars. Poultry is a common reservoir of Salmonella and its transmission into the food chain is a risk for humans. The vaccination of layers plays an important role in the overall efforts to prevent Salmonella infections. An inactivated trivalent vaccine was prepared with S. Enteritidis, S. Typhimurium, and S. Infantis strains. Infection trials were performed to evaluate the efficacy of three vaccination schedules using inactivated and live S. Gallinarum 9R vaccines. For this purpose, at week 5 of life, one subcutaneous dose of live S. Gallinarum 9R vaccine (1–5 × 107 CFU) was given to Groups 1 and 2. At weeks 8 and 11 of life, chickens were also vaccinated with one (Group 1) or two (Groups 2 and 3) intramuscular doses of the inactivated oil-adjuvant trivalent vaccine (1 × 108 CFU/dose of each antigen). Group 4 consisted of chickens that remained unvaccinated (control). At week 14 of life, the efficacy of the vaccination plans was evaluated in three separate inoculation trials with S. Enteritidis, S. Typhimurium, or S. Infantis. After vaccination with the inactivated vaccine, homologous antibody production was observed, and after challenge, a significant reduction in the faecal shedding, invasion, and colonization of S. Typhimurium and S. Infantis was achieved by all vaccination schedules, while the vaccination with at least one dose of the live S. Gallinarum 9R vaccine was necessary to obtain such a significant protection against S. Enteritidis infection.

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

“…2). Our results were agreeing with the findings of previous studies (Deguchi et al 2009;El-Enbaawy et al 2013;Huberman et al 2022) which reported the efficacy of Salmonella inactivated vaccines to reduce the bacterial fecal shedding after challenged with the same serovars or serovars related to the same serogroups. It had been previously reported that vaccination of breeder chickens with inactivated vaccine reduced Salmonella prevalence and loads in their broiler progeny (Crouch et al 2020a).…”

Holistic Strategies to Control Salmonella Infantis: An Emerging Challenge in the European Broiler Sector

“…Likewise, Huberman et al (2022) developed an inactivated trivalent vaccine with an oil adjuvant, which was administered to day-old layers at 8 and 11 weeks of age. The study demonstrated effective protection against S. Infantis colonization [128].…”

Salmonella Infection in Poultry: A Review on the Pathogen and Control Strategies

“…Despite the absence of robust cell-mediated immunity, killed vaccines are preferred over live vaccines due to biosecurity and safety reasons [198]. Additionally, multivalent inactivated vaccines are required to contain the spread of a wide range of Salmonella serovars present in poultry [199,200].…”

“…It has been shown that greater levels of IgA and IgY antibodies were produced in the bile and serum following the simultaneous use of live attenuated and killed Salmonella vaccines in broilers [201]. The combined use of both live and killed vaccination programs successfully reduced S. Typhimurium and S. Infantis colonization in young layers, providing broad protection [199]. 6.9.3.…”