The Journal of Poultry Science (Jan 2023)

Effects of Newcastle Disease/Infectious Bronchitis Vaccine and Feeding Yeast Products on the Innate Immune System in the Proventriculus and Ileum of Broiler Chicks

  • Yukinori Yoshimura,
  • Takahiro Nii,
  • Naoki Isobe

DOI
https://doi.org/10.2141/jpsa.2023005
Journal volume & issue
Vol. 60, no. 1

Abstract

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The aim of this study was to determine whether Newcastle disease/infectious bronchitis (ND/IB) vaccination and yeast product diet supplementation modulate the expression of innate immune molecules in the proventriculus and ileum of broiler chicks. One-day-old male broiler chicks were divided into four groups (V–Y– (control), V–Y+, V+Y–, and V+Y+ groups, where V and Y represent vaccination and yeast product supplementation, respectively). Chicks in the V+Y– and V+Y+ groups were immunized with the live ND/IB vaccine, whereas chicks in the V–Y– and V–Y+ groups were not. Chicks in the V–Y+ and V+Y+ groups received feed containing yeast products from day 4, whereas chicks in the V–Y– and V+Y– groups did not. The proventriculus and ileum were collected on day 7 to analyze the expression of seven Toll-like receptors (TLRs) and Dectin-1. In the proventriculus, compared with those of the V–Y– control group, the TLR7 and TLR21 expression levels were higher in the V+Y– group; however, there were no differences in the expression levels of any TLR or Dectin-1 in the ileum. There were also no differences in the expression of avian β-defensins and cathelicidin-1 in the proventriculus and ileum between the control and treatment groups. The expression of granzyme in cytotoxic cells and interleukin (IL)-1B was upregulated by ND/IB vaccination in the proventriculus. Supplementation with yeast products upregulated only granzyme expression in the ileum and downregulated IL-6 expression in the proventriculus in chicks immunized with the ND/IB vaccine. Thus, we concluded that ND/IB vaccination is effective at enhancing the innate immune system in the proventriculus of chicks, at least until day 7 post-hatching, whereas the effects of diet supplementation with yeast products may be limited, at least under the present study conditions.

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