Effect of killed salmonella bacterin vaccines on immunological response and hen day egg production in layers.

Authors: SHAJI, SYAMILY - University Of Georgia; Shanmugasundaram, Revathi; SHETH, PARIMAL - Endovac Animal Health; SELVARAJ, RAMESH - University Of Georgia

Submitted to: Poultry Science Association Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 5/24/2023
Publication Date: N/A
Citation: N/A

Interpretive Summary: N/A

Technical Abstract: Salmonella is the leading cause of food-borne zoonotic disease across the globe. Human Salmonellosis is caused by the consumption of contaminated poultry meat, eggs, and meat products. Vaccination has emerged as an alternative control strategy to antimicrobials for mitigating Salmonella colonization in layers and decreasing egg contamination. In this study, we evaluated the efficacy of two killed Salmonella bacterin vaccines, administered intramuscularly in layers. The first vaccine had 97% S. Typhimurium and 3% Immune Plus® with preservatives and adjuvants. The second vaccine was synthesized with 77% S. Typhimurium, 10% Klebsiella strain KP9580, 10% Klebsiella strain KPZBT01, and 3% Immune Plus® with preservatives and adjuvants. 120- 14-week-old Salmonella-free Hy-Line W-36 pullets were allocated into three groups: 1) Control, 2) vaccine 1, and 3) vaccine 2 with 40 birds per group. Birds in groups 2 and 3 were vaccinated with 500 µl (Endovac) Salmonella killed bacterin vaccines (1) and (2) at 17 weeks of age, and a booster dose was given at 19 weeks of age on the right pectoralis muscle. At 20, 21, 22, 23, and 24 weeks of age, serum anti-Salmonella IgY was quantified using ELISA. Egg production was recorded daily to calculate the hen day egg production (HDEP). Data were analyzed by one-way ANOVA. When the main effects were significant (P < 0.05) between treatments and the difference between means were analyzed by using Tukey’s HSD. Birds given vaccines 1 and 2 at 22 weeks of age showed higher serum anti-Salmonella IgY levels than the control group by 186% and 168%, respectively (P < 0.05). At 23 weeks of age, birds vaccinated with vaccine 2 had 370% greater levels of anti-Salmonella IgY in serum compared to the control group. The vaccines did not decrease egg production in layers. There was no significant difference in HDEP between vaccinated and control birds. The geometric mean titers of vaccines 1 and 2 were 793.7 and 606.9, respectively, at 22 weeks of age. These results indicate that the killed bacterin vaccine increases serum antibody titer and could be a potentially viable vaccine candidate against Salmonella infection in layers. Keywords: Salmonella typhimurium, Vaccine, Antibody response, Hen day egg production, Layers.