Advances in Biological Functions and Applications of Feeding Microorganism-derived Extracellular Vesicles

Feeding microorganism-derived extracellular vesicles (FMEVs), secreted by probiotic strains authorized in China's Catalogue of Feed Additive Varieties, are emerging as key mediators of microbial benefits in livestock. These nanoscale, bilayer-bound vesicles carry diverse bioactive cargo and have been shown to modulate gut microbiota, enhance epithelial barrier integrity, regulate immune signaling, and support metabolic homeostasis. Their structural stability, strain specificity, and natural capacity for biomolecule delivery underscore their potential as next-generation postbiotics. This review systematically summarizes current knowledge on the biogenesis, molecular composition, and functional mechanisms of FMEVs. Moreover, we evaluate their translational prospects as feed additives, with emphasis on challenges in large-scale production, quality control, and standardization. Finally, we highlight unresolved research questions and outline future directions to facilitate the application of FMEVs in sustainable animal production.