Fermented cotton stalks preserve colonic epithelial integrity in Hu sheep via the microbiota–metabolite–NF-κB/MLCK axis and mitigate the adverse effects of direct feeding

Background: This study aimed to compare three cotton-stalk processing strategies-grinding (FS), steam explosion (PH), and microbial fermentation (FJ)-and to clarify whether fermented cotton stalks preserve colonic epithelial integrity through a microbiota-metabolite-NF‑κB/MLCK axis in Hu sheep. Methods: = 5 per treatment) containing 40% processed cotton stalks (FS, PH, or FJ) for 8 weeks. Results: < 0.05). Conclusion: Fermentation‑based processing of cotton stalks enhanced growth performance and promoted a favorable hindgut fermentation and microbial-metabolic milieu, thereby reinforcing colonic barrier integrity via inhibition of NF‑κB/MLCK‑associated inflammatory signaling, supporting fermented cotton stalk as a practical strategy to valorize cotton residues for ruminant feeding while mitigating gossypol‑related hindgut stress.