Effects of Intestinal Microorganisms on Metabolism and Toxicity Mitigation of Zearalenone in Broilers

Zearalenone (ZEN) is an estrogenic mycotoxin, and chickens are relatively insensitive to it. In this study, the effects of intestinal microorganisms on ZEN metabolism and toxicity mitigation in broilers were studied by two experiments. Firstly, in vitro, ZEN was incubated anaerobically with chyme from each part of the chicken intestine to study its intestinal microbial metabolism. Then, in vivo, we explored the effects of intestinal microbiota on ZEN by inhibiting intestinal microorganisms. Broilers were fed a control diet, 2.5 mg/kg ZEN diet, microbial inhibition diet or 'microbial inhibition +2.5 mg/kg ZEN' diet. In vitro, the results showed that the rates of ZEN degradation by microorganisms in the duodenum, ileum, caecum, and colon were 56%, 12%, 15%, and 17%, respectively, and the microorganisms could convert ZEN into Zearalenol (ZOL). After microbial inhibition in vivo, the content of ZEN and its metabolites in excreta of broilers increased significantly, and antioxidant damage and liver damage were aggravated. 16S rRNA sequencing results showed that antioxidant indices and the content of ZEN and its metabolites in excreta were significantly correlated with the relative abundance of Streptococcus, Lactococcus and Enterococcus, etc. In conclusion, the intestinal microorganisms of broilers play an important role in ZEN metabolism and ZEN-induced antioxidant and liver injury mitigation, among which the key bacteria include Streptococcus, Lactococcus and Enterococcus, etc.