Isolation and Characterization of a Deoxynivalenol-Degrading Bacterium Bacillus licheniformis YB9 with the Capability of Modulating Intestinal Microbial Flora of Mice.

Shiwei Wang,Qianqian Guo,Hong Wei,Qiuqiu Hou,Lixin Shen,Jian Zhang,Yanmei Sun

doi:10.3390/toxins12030184

Abstract

Deoxynivalenol (DON) is one of the most prevalent food- and feed-associated mycotoxins. It frequently contaminates agricultural commodities and poses serious threats to human and animal health and leads to tremendous economic losses globally. Much attention has been paid to using microorganisms to detoxify DON. In this study, a Bacillus licheniformis strain named YB9 with a strong ability to detoxify DON was isolated and characterized from a moldy soil sample. YB9 could degrade more than 82.67% of 1 mg/L DON within 48 h at 37 °C and showed strong survival and DON degradation rate at simulated gastric fluid. The effects of YB9 on mice with DON intragastrical administration were further investigated by biochemical and histopathological examination and the gut microbiota was analyzed by 16S rRNA Illumina sequencing technology. The results showed that DON increased the levels of aspartate aminotransferase (AST), alanine aminotransferase (ALT), and creatinine (Cr), decreased those of immunoglobulin G (IgG) and IgM in serum, and resulted in severe pathological damage of the liver, kidney, and spleen. By contrast, YB9 supplementation obviously inhibited or attenuated the damages caused by DON in mice. In addition, YB9 addition repaired the DON-induced dysbiosis of intestinal flora, characterized by recovering the balance of Firmicutes and Bacteroidetes to the normal level and decreasing the abundance of the potentially harmful bacterium Turicibacter and the excessive Lactobacillus caused by DON. Taken together, DON-degrading strain YB9 might be used as potential probiotic additive for improving food and feed safety and modulating the intestinal microbial flora of humans and animals.

Highlights

Mycotoxins are the toxic secondary metabolites of fungi and often contaminate agricultural commodities and cause serious safety issues to humans and animals due to their high occurrence incidence globally [1,2]
It was found that the immune system was sensitive to DON and DON indigestion decreased the immunoglobulin G (IgG)
More than 20 colonies that could grow on LB agar plate containing 1 mg/L DON were screened from the moldy samples

Summary

Introduction

Mycotoxins are the toxic secondary metabolites of fungi and often contaminate agricultural commodities and cause serious safety issues to humans and animals due to their high occurrence incidence globally [1,2]. Deoxynivalenol (DON), notorious as vomitoxin, is one of the most prevalent trichothecene mycotoxins and is frequently detected in agricultural commodities with high concentrations [3]. The toxicity of DON primarily depends on its epoxide group, and it can bind with ribosomal subunit to impair eukaryotic protein synthesis and cause serious damage to human and animal organs [4,5]. DON exposure increased the relative weight of liver and caused up-regulation of pro-inflammatory cytokines TNF-α and IL-1β as well as the occurrence of mild fibrosis and piecemeal necrosis in the liver [11,12,13]. It was found that the immune system was sensitive to DON and DON indigestion decreased the immunoglobulin G (IgG)

Methods

Results

Conclusion