Phagovet

In-feed Bacteriophage and Salmonella vaccines

The use of live Salmonella vaccines has been a successful tool for poultry growers to effectively prevent Salmonella infections in their flocks. However, some producers have incorporated bacteriophages into their management practices in hopes of reducing Salmonella contamination.

However, it was unclear whether these bacteriophages could also affect the efficacy of the live Salmonella vaccine.

In a recent study, chickens were administered both live Salmonella vaccine and bacteriophage. The results showed that the presence of the bacteriophage did not affect colonization and protection by the live vaccine.

These results suggest that producers can safely include bacteriophage in their management plan without fear of compromising their vaccination program.

These findings were published in a research note published by authors E A Kimminau, T P Karnezos, K N Russo, J A Baxter, R D Berghaus, M Jones, and C L Hofacre: In-feed Bacteriophage does not impact efficacy of live Salmonella vaccine.

Findings include:

  • Dietary bacteriophages have the potential to reduce contamination of feed with Salmonella by directly lysing the bacteria.
  • Poultry farmers typically vaccinate with live Salmonella vaccines that could potentially be lysed by bacteriophages.
  • The objective of this study was to investigate whether bacteriophages in the diet affect the colonization of a live Salmonella vaccine.
  • A total of 210 male Ross broilers were divided into 3 treatments, each consisting of 2 replicates. Each replicate contained 35 birds.
  • T1 was the control treatment in which no Salmonella vaccine was administered, T2 was the control treatment in which Salmonella vaccine was administered, and T3 was the control treatment in which Salmonella vaccine and a bacteriophage in the feed were administered.
  • On Day 3, four birds per pen were examined for cecal and liver/spleen colonization with the Salmonella vaccine. 28 days later, ten birds per replicate were tested for Salmonella using cloacal swabs. Forty-two days later, the experiment was terminated, birds were weighed, and performance was calculated. Fifteen birds per replicate were additionally examined for cecum.
In-feed Bacteriophage does not impact efficacy of live Salmonella vaccine

Abstract

Dietary bacteriophages potentially can serve as a step to reduce Salmonella contamination of feed through direct lysis of the bacteria. However, poultry producers commonly vaccinate with live Salmonella vaccines, which could potentially be lysed by dietary bacteriophages.

The objective of this study was to evaluate if dietary bacteriophages impacted the colonization of a live Salmonella vaccine. A total of 210 day-of-hatch Ross male broiler chicks were divided into 3 treatments consisting of 2 replicate per treatment. Each replicate contained 35 birds. T1 was the challenge control, given no Salmonella vaccine, T2 was challenged and given Salmonella vaccine and T3 was challenged, given Salmonella vaccine as well as dietary bacteriophage.

Salmonella vaccine was administered day of hatch.

  • On d 3, four birds/pen were sampled for Salmonella vaccine colonization of ceca and liver/spleen. The remaining birds were challenged with 5 × 107 CFU of nalidixic acid- resistant Salmonella enteritidis (S.E.).
  • On d 28, ten birds/replicate were sampled via cloaca swabs to culture for S.E.
  • On d 42, the trial was terminated, birds were weighed, and performance was calculated. In addition, 15 birds/replicate were sampled for cecal cultures of S.E.

On d 3, T1 had 0% vaccine strain isolated, and significantly lower (P = 0.009) cecal prevalence compared with T2 (75%) and T3 (38%) being intermediate.

  • T1 (0%) had significantly lower liver/spleen vaccine strain prevalence (P = 0.002) compared with T3 (88%) and T2 (63%) being intermediate.
  • No significant differences (P > 0.05) were observed among treatments in Salmonella prevalence in d 28 cloacal swabs.
  • No significant differences (P > 0.05) were observed in d 42 cecal Salmonella prevalence between all treatments.
  • No significant differences in bird weight were observed between treatments d 0 to 42 (P > 0.05). However, T2 and T3 had lower mortality and adjusted feed conversion ratio (FCR; P < 0.05) compared with T1.

Therefore, the dietary bacteriophage did not interfere with colonization or protection afforded by the live Salmonella vaccine.

Keywords: ABF; Salmonella; Salmonella vaccine; bacteriophage; food Safety.

Copyright © 2022 The Authors. Published by Elsevier Inc. All rights reserved.