Effects of aging on gut microbiota nearly throughout zebrafish lifespan

Aging profoundly influences vertebrate gut microbiota, yet lifespan patterns remain poorly characterized. Utilizing the wild-type zebrafish model, this study pioneers a longitudinal investigation of gut microbiota dynamics from adulthood (> 3 months) to old age (> 3 years). We identified a significant (P < 0.05) correlation between gut microbiota composition and host age. Notably, alpha-diversity was relatively stable and highest between 8–32 months, indicating this period as optimal for gut microbiota studies. The relative abundance of dominant phyla (Pseudomonadota, Actinomycetota, and Fusobacteriota) varied significantly (P < 0.05) across aging stages. Crucially, these phylum-level changes were predictable using their representative genera or amplicon sequence variants (ASVs). This work delineates lifelong aging effects on gut microbiota in a vertebrate model and identifies key microbial biomarkers and an optimal sampling window.