A Preliminary Investigation of the Anti-Salmonella Enteritidis Potential of Quercetin in Chickens Using Network Pharmacology, Molecular Docking, and In Vitro Antibacterial Assays

Salmonella Enteritidis is a major threat to poultry health and food safety, underscoring the need for safe alternatives to conventional antibiotics. In this study, quercetin, a natural flavonoid with antibacterial and immunomodulatory properties, was evaluated using an integrated approach combining network pharmacology, molecular docking, in vitro antibacterial assays, and preliminary in vivo validation. Potential targets of quercetin and Salmonella Enteritidis were identified from the TCMSP and GeneCards databases, followed by protein–protein interaction analysis, topological screening, and GO/KEGG enrichment analyses. Five core targets, namely IL1B, IL6, STAT1, PTGS2, and IFNG, were identified and were mainly enriched in immune- and inflammation-related pathways. Molecular docking suggested favorable interactions between quercetin and these predicted targets. In vitro, quercetin showed moderate antibacterial activity against Salmonella Enteritidis, with a minimum inhibitory concentration of 256 μg/mL and a minimum bactericidal concentration of 512 μg/mL. In vivo, quercetin alleviated intestinal histopathological damage and reduced the transcriptional expression of the five target genes in infected chicks in a dose-dependent manner, with more evident effects at doses of 512 mg/kg or higher. These findings provide preliminary evidence that quercetin may exert both direct antibacterial and host-associated protective effects against Salmonella Enteritidis, although the underlying mechanisms require further validation.