AUTHOR=Milby-Blackledge Allison , Farnell Yuhua , Zhao Dan , Berghman Luc , Laino Craig , Muller Melissa , Byrd J. Allen , Farnell Morgan 

TITLE=Serum cytokine profile of neonatal broiler chickens infected with Salmonella Typhimurium

JOURNAL=Frontiers in Physiology

VOLUME=15

YEAR=2024

URL=https://www.frontiersin.org/journals/physiology/articles/10.3389/fphys.2024.1359722

DOI=10.3389/fphys.2024.1359722

ISSN=1664-042X

ABSTRACT=<p>The avian immune system responds to <italic>Salmonella</italic> infection by expressing cytokines and chemokines. We hypothesized that the immune status of <italic>Salmonella</italic> Typhimurium (ST) challenged neonatal broilers would differ from the uninfected treatment. The objective of this experiment was to evaluate 12 cytokines. Day of hatch male chicks were randomly allocated into a control or ST challenged group. At day three of age, sterile diluent or 5.0 × 10<sup>8</sup> CFU of ST was given orally to each chick. Blood was obtained 24 h post challenge and serum separated for later analysis (n = 30 chicks/treatment). Significant (<italic>p</italic> ≤ 0.05) increases in <bold><italic>pro-inflammatory cytokines</italic></bold>-interleukin-6 (IL-6), IL-16, and IL-21; <bold><italic>anti-inflammatory cytokines</italic></bold>- IL-10; <bold><italic>chemokines</italic></bold>-regulated on activation, normal T cell expressed and secreted (RANTES), macrophage inflammatory protein-1β (MIP-1β), and MIP-3α; <bold><italic>colony stimulating factors</italic></bold>-macrophage colony-stimulating factor (M-CSF); and <bold><italic>growth factors</italic></bold>-vascular endothelial growth factor (VEGF) were observed in the serum of the challenged chicks when compared to the control. No significant differences were observed in IL-2, interferon gamma (IFNγ), and IFNα. These data indicate the detection of mucosal immune responses in broiler chickens following ST infection. The heightened levels of pro-inflammatory cytokines, chemokines, and colony stimulating factors align with known inflammatory mechanisms, like the influx of immune cells. However, the elevation of IL-10 was unexpected, due to its immunoregulatory properties. Notably, the rise in VEGF levels is compelling, as it suggests the possibility of tissue repair and angiogenesis in ST infected birds.</p>