Gut microbial responses to antibiotic withdrawal and alternative feed additives in weaned pigs.

This project evaluates the effects of antibiotics (ANT), zinc oxide (ZnO), and a phytogenic cocktail (COK) on growth performance, inflammation, and fecal microbiota in weaned pigs during the nursery period. A total of 96 piglets were assigned to four dietary treatments: CON (basal diet), ANT, ZnO, and COK. ZnO improved growth performance and reduced inflammatory cytokines, whereas COK produced moderate but consistent improvements in growth and fecal stability. Microbiome profiling revealed treatment associated shifts in several bacterial taxa, including increased Streptococcus in ANT and reduced Muribaculaceae and Roseburia in ZnO. These results highlight the distinct physiological and microbiome responses to antibiotic, zinc oxide, and phytogenic supplementation during early life in pigs.