Zearalenone-induced hepatointestinal toxicity in laying hens: unveiling the role of gut microbiota and fecal metabolites

Zearalenone (ZEN), a mycotoxin produced by Fusarium species, is known for its reproductive toxicity as an estrogen analogue. However, there are limited knowledge about its hepatointestinal toxicity, as well as the role that gut microbiota and metabolites play in this process. In this study, a total of 24 thirty-week-old hens were fed to investigate the hepatointestinal toxicity subjected to long-term ZEN consumption at 2.0 mg/kg for 90 d. And we employed uncultured 16S rRNA sequencing for gut microbiota and untargeted metabolomics for fecal metabolites assessment. Notably, ZEN induced significant hepatic damage, as evidenced by hepatocyte necrosis, inflammatory cell infiltrate, increased liver lipopolysaccharide (LPS) and blood aspartate aminotransferase (AST) levels (P < 0.05). The decreased villus height, disruption of simple columnar epithelial cells, and exposure of the mucosal intrinsic layer were observed in the intestine. The gut microbial community composition and metabolites differed between ZEN group and control group. ZEN group exhibited higher gut microbial diversity (P < 0.05), lower Firmicutes/Bacteroidetes ratio and Lactobacillus abundance, and higher abundance in the genus such as Bacteroidetes, Parabacteroidetes and Desulfovibrio. Metabolomic analysis showed that ZEN treatment altered biosynthesis of siderophore group nonribosomal peptides and phenylpropanoids, metabolism of amino acid, digestion and absorption of vitamin and ABC transporters. Differential metabolites suggested that ZEN increase the risk of estrogen disorder, nucleic acid degradation, intestinal oxidative stress and inflammation. Neural network analysis showed that Ruminococcus was positively correlated with glyceric acid, and Prevotella was positively correlated with phenylacetylglycine. Both metabolites were positively correlated with blood AST level (P < 0.05), suggesting that intestinal microbe Ruminococcus and Prevotella might exacerbate liver damage by producing these harmful metabolites. Overall, we conclude that ZEN has damaged hepatointestinal system and the altered gut microbiota with resultant metabolite changes contribute to the adverse hepatointestinal effects of ZEN on laying hens. This study underscores the need for monitoring and mitigating ZEN exposure in poultry diets, highlighting its broader implications for animal health and food safety.