Organic acids impede Salmonella infection of chicken macrophage-like cell line (HD11) by modulating itaconate gene expression.

Most human salmonellosis cases are linked to the consumption of poultry products contaminated with Salmonella enterica serovar Typhimurium. In poultry, infections cause intestinal inflammation, decreased weight gain, lower egg production, and potential economic losses for the poultry sector. This study examined the effects of a natural antimicrobial mixture (AuraShield, As) on Salmonella enterica serovar Typhimurium SE10/72 infection of chicken macrophage-like cells (HD11), focusing on infection inhibition, inflammatory response, cell viability, metabolic changes, and oxidative stress. The HD11 macrophage-like cell line was used in three infection scenarios: HD11 cell pretreatment, co-incubation with As, and co-incubation with As-pre-treated bacteria. The results showed that the natural antimicrobial mixture significantly reduced bacterial infection levels in macrophage-like cells without affecting cell viability. Low infectivity rates were also observed, along with a significant reduction in the expression of pro-inflammatory cytokines (IFN-β, IL-1β, IL-6, IL-8, IL-10). We have observed that itaconate increases, via Irg1 expression, in HD11 cells exposed to 0.25% As, alongside a significant decrease in the isocitrate lyase (AceA) gene expression in bacteria. The findings provide insights into the potential use of AuraShield as a feed additive to improve poultry health and resistance against bacterial pathogens, by minimising Salmonella infection risk and the associated inflammatory response in macrophage-like cells. The observed modulation of metabolic and oxidative stress markers further suggests a multifaceted mode of action, presenting a promising pathway for alternative antimicrobial strategies in poultry health management.