AUTHOR=Li Xujie , Li Dengpan , Wang Chunhui , Li Qiao , Nie Yajing , Zhang Liming , Xu Jin , Ma Youji 

TITLE=Metagenomic insights into the effects of Chive seed flavonoid on intestinal fermentation, morphology, and microbiota composition in sheep

JOURNAL=Frontiers in Microbiology

VOLUME=Volume 16 - 2025

YEAR=2025

URL=https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2025.1590400

DOI=10.3389/fmicb.2025.1590400

ISSN=1664-302X

ABSTRACT=Chive seed flavonoid (CSF) exhibits antioxidant, digestive, and immunomodulatory properties, yet their effects on ruminant intestinal development and microbial ecosystems remain underexplored. This study systematically evaluated CSF supplementation (0.25% of concentrate) on intestinal morphology, volatile fatty acids (VFAs) dynamics, and microbiota composition in 16 weaned Hu lambs (3 months; 19.57 ± 1.56 kg initial weight) using histomorphometry, VFA quantification, and full-length 16S rRNA sequencing. Animals were randomly allocated to a control (basal diet) or CSF-supplemented group (T), following a 7-day adaptation and 90-day experimental protocol. Key findings revealed: (1) The T group demonstrated increased jejunal and ileal villus length (p < 0.05), elevated villus height-to-crypt depth ratio (V/C; p < 0.05), thickened muscular layers (p < 0.05), and reduced crypt depth (p < 0.05). (2) CSF supplementation significantly elevated acetate, propionate, butyrate, and total VFAs (p < 0.05) in ileum, cecum, colon, and rectum, with notable jejunal propionate and total VFAs increases (p < 0.05). (3) Upregulated expression of ileal and cecal genes (IGF1, CD81, CTNNBL1, SLC39A8) linked to tissue morphogenesis and VFAs absorption was observed in the T group (p < 0.01). (4) Full-length 16S analysis demonstrated CSF-enhanced microbial diversity and selective enrichment of Cyanobacteriota, Bacillus, Acetobacterium, and Streptomyces [Linear Discriminant Analysis Effect Size (LEfSe) analysis]. Regional microbial shifts included Bacteroidota proliferation in the small intestine and rectum, Actinomycetota dominance in duodenum/cecum/colon, and ileal enrichment of Bacillota, Clostridium, and Streptomyces. KEGG pathway analysis confirmed CSF-driven enhancements in carbohydrate/energy metabolism, immune regulation, and intestinal barrier pathways (p < 0.05). In conclusion, dietary supplementation with 0.25% CSF improved intestinal morphology, increased the production of VFAs, and optimized microbial composition, thereby promoting intestinal health in sheep. This study provides a theoretical basis for the application of CSF in promoting healthy production in sheep.