Tissue accumulation of dietary zearalenone in largemouth bass and multi-organ impairment revealed by microbiome-metabolome foodomics: Potential implications for aquatic food-chain safety

Low-dose ZEN caused apparent growth enhancement with subclinical gut-liver injury. • High-dose ZEN inhibited growth and caused severe gut-liver damage. • ZEN accumulated in tissues: liver > intestine > muscle. • High-dose ZEN induced gut dysbiosis and hepatic metabolic disorders. • ZEN perturbed RAS/glycerophospholipid pathways; muscle residues pose exposure risk. Zearalenone (ZEN), an estrogen-like mycotoxin, represents an emerging hazard in aquatic food supply chains, as contaminated aquafeeds transfer ZEN to farmed fish and then to consumers. Juvenile largemouth bass ( Micropterus salmoides ), a widely consumed aquaculture species, were subjected to subchronic dietary ZEN exposure (0, 100, and 1000 μg kg −1 feed) for 28 days. Integrated 16S rRNA microbial profiling and untargeted hepatic metabolomics characterized dose-dependent toxic responses and food-chain transfer risk. ZEN exhibited tissue-specific accumulation (liver > intestine > muscle); muscle ZEN residue reached 2.4 μg kg −1 under high-dose exposure. Low-dose ZEN elicited apparent growth enhancement accompanied by subclinical hepatic and intestinal injury, whereas high-dose ZEN induced growth retardation, hepato-intestinal histopathological lesions, intestinal tight-junction gene down-regulation, and elevated serum alanine aminotransferase and aspartate aminotransferase. High-dose ZEN triggered gut microbiome dysbiosis: commensal genera ( Mycoplasma , Rhodococcus ) were depleted while pathobiont Sphingomonas bloomed. Key hepatic metabolic pathways including ABC transporters, renin-angiotensin system, and glycerophospholipid metabolism were perturbed. Microbiome-metabolome integrative analysis revealed a dose-dependent shift from positive toward predominantly negative microbe-metabolite correlations, indicating collapse-like reorganization of host-microbe associations. Notably, even a dietary ZEN concentration around the current regulatory limit (nominal 100 μg kg −1 ; measured 140.6 μg kg −1 ) elicited subclinical intestinal injury in this species. Human dietary exposure assessment indicated low acute risk via consuming ZEN-contaminated largemouth bass, yet long-term cumulative risk for vulnerable subgroups cannot be ignored. Our foodomics findings provide hazard-characterization data that may inform, but do not by themselves establish, future re-evaluation of ZEN maximum limits in aquafeeds to safeguard aquatic food safety and public health.