Copper supplementation alters piglet gut microbiota and competitive dynamics with Salmonella Typhimurium (microbiomejournal.biomedcentral.com)

• High copper diet reduced beneficial bacteria (Bifidobacterium, Lactobacillus) in piglets.
• Copper resistance genes (sil/pco) are common in E. coli from high-copper piglets.
• Salmonella ST34 uses T6SS to outcompete E. coli in copper-rich conditions.

"A study published in Microbiome (March 2026) shows that high dietary copper (150 ppm) in weaned piglets reduces relative abundance of beneficial bacteria like Bifidobacterium and Lactobacillus while favoring copper-resistant Escherichia coli. The Salmonella Typhimurium ST34 clone, which carries SGI-4 conferring copper resistance, outcompetes E. coli in copper-rich environments through its Type VI Secretion System. This suggests that copper supplementation in pig feed may inadvertently promote Salmonella colonization."