In Vitro Fermentation Characteristics of Fructo-oligosaccharides and Their Effects on Reproductive Performance and Associated Metabolic Syndromes in Peripartum Sows

Background/Objectives: Sows face peripartum metabolic syndrome (PPMS), characterized by inflammation, oxidative stress, and insulin resistance, driven by gut microbiota dysbiosis. This study aimed to evaluate fructo-oligosaccharides (FOS) as a nutritional intervention to modulate gut microbiota and alleviate PPMS, improving reproductive efficiency. Methods: In vitro fermentation assessed FOS fermentability (gas kinetics, short-chain fatty acids [SCFAs]), while a randomized trial (n = 60 sows) evaluated 10 g/day FOS from gestational day (GD) 90 to farrowing. Key outcomes included reproductive performance, PPMS biomarkers (inflammatory/oxidative stress markers), and gut microbiota via 16S rRNA sequencing. Results: In vitro, FOS promoted sustained butyrate production (14.3 +/- 1.2 mM) and a biphasic gas profile aligning with distal gut transit. In sows, FOS reduced lactational backfat loss by 23% (P < 0.05) and shortened weaning-to-estrus interval by 1.8 days (P < 0.05). Fecal lipopolysaccharide (LPS, decrease 48% at GD109, P < 0.001) and plasma reactive oxygen species (ROS, decrease 41% at lactation day 3, P < 0.01) were attenuated, with increased immunoglobulin G (IgG, increase 33% at GD109, P < 0.001). Microbiota analysis showed enriched butyrate producers (Roseburia, Treponema) and a lower Firmicutes/Bacteroidota ratio (1.9-2.7-fold, P < 0.01), preserving community structure. Conclusions: Late-gestation FOS supplementation mitigates PPMS by enhancing gut-derived SCFAs, reducing inflammation/oxidative stress, and improving reproductive cyclicity, offering a precision nutrition strategy for sustainable swine production.