Multi-omics analysis reveals Parabacteroides distasonis and Kineothrix alysoides as potential key bacterial species associated with anemia in sows

BACKGROUND: Sow anemia has been reported to be associated with reduced reproductive performance. Additionally, anemia may alter gut microbiota composition. However, the gut microbiota and metabolic signatures specifically linked to sow anemia status remain poorly understood. RESULTS: Compared with normal sows, anemic sows had lower hemoglobin levels at gestational days 30, 90, and 110 (P < 0.0001). The litter size (16.68 vs. 17.13), live litter size (14.34 vs. 15.13), healthy litter size (13.40 vs. 14.36), and litter weight (18.77 vs. 19.50) of anemic sows were lower than normal sows, but there was no significant difference. Iron transport-related genes showed that placental ferritin expression was significantly higher in normal sows than in anemic sows (P = 0.003). Serum antioxidant analysis showed that total antioxidant capacity was significantly lower in anemic sows than in normal sows at gestational days 90 (P = 0.026) and 110 (P = 0.017). Superoxide dismutase activity was significantly lower in anemic sows than in normal sows at gestational day 90 (P = 0.004) and showed a decreasing trend at gestational day 110 (P = 0.072). Fecal 16S rRNA analysis revealed distinct gut microbiota compositions between normal and anemic sows. Untargeted metabolomics showed distinct intergroup separation, with significant enrichment of the cytochrome P450 pathway at gestational days 30 and 110 (P < 0.05). Furthermore, multiple bacterial taxa showed significant positive correlations with hemoglobin levels, including Christensenella hongkongensis, Gimesia aquarii, Shigella dysenteriae, Massiliimalia massiliensis, Kineothrix alysoides, Mediterraneibacter gnavus, Parabacteroides distasonis, and Treponema sp. Marseille-Q3903 (P < 0.05). CONCLUSION: This study reveals the gut microbial and metabolic characteristics between normal and anemic sows. Two key bacterial species, P. distasonis and K. alysoides, were identified as associated with anemia status in sows.