Lean DLY Pig-Derived Fecal Microbiota Promotes Growth Performance by Modulating Gut Microbiota: Serum Metabolic Profiles in Obese Ningxiang Pigs

Fecal microbiota transplantation (FMT) has demonstrated potential in reshaping gut microbiota to improve animal phenotypes, yet its application in lean-type to obese-type pigs like Ningxiang (NX) pigs remains unclear. To address this, we investigated the effects of Lean Duroc × Landrace × Yorkshire (DLY) pig-derived fecal microbiota on the growth, gut microbiota composition, and serum metabolism of obese NX pigs. Thirty-six 50-day-old castrated male NX pigs of similar initial body weight were randomly assigned to either a control group or FMT group. The trial lasted for 35 days. Results indicated that FMT significantly improved the average daily gain and increased nutrient digestibility. Serum biochemical analysis revealed elevated levels of globulin and total protein and reduced low-density lipoprotein cholesterol in the FMT group. In addition, 16S rRNA sequencing demonstrated that FMT modified gut microbiota composition and diversity, enriching beneficial genera such as Blautia, Agathobacter, Faecalibacterium, and Eubacterium_coprostanoligenes_group. Untargeted serum metabolomics further revealed altered metabolite profiles linked to lipid and amino acid metabolism. Correlation analysis further revealed a link between these enriched bacteria and metabolites changes. Overall, these findings demonstrate that transplantation of the fecal microbiota from lean DLY pigs significantly improved the growth performance of obese NX pigs by improving nutrient digestibility and modulating the gut microbiota–host metabolic axis.