br Material and methods br Results

Material and methods
Results
Discussion Liver plays a key role in the metabolism and detoxification of DON (Peng et al., 2017). However, various DON investigations generated inconsistent results, with some showing hepatotoxicity of DON, while others not. For example, one report stated that DON (4.59 mg/kg feed) alone had no effect on the liver histology activity index (HAI) in young pigs (Renner et al., 2017), however, mice fed with DON-contaminated (2.45 ± 0.13 mg/kg) wheat for 51 days showed different degrees of vacuolar degeneration, necrosis and fatty changes and mild fibrosis in the liver as well as increased ALT, AST, blood creatinine (Scr) and blood urea nitrogen (BUN) levels in serum (Wang et al., 2017). In 2011, the 72nd JECFA analyzed data from 42 countries and estimated total human intake of DON ranging from 0.2 μg/kg bw/day in the African diet to 14.5 μg/kg bw/day in the Middle Eastern diet (Tardivel et al., 2015). Therefore, in the present study, we chose the administration dose of DON at 25 μg/kg bw/day in mice based on previous studies (Tardivel et al., 2015) for the reason that this low dose exposure of DON mimic the estimated mean human dietary exposure, of which the potential risks are still poorly understood. In the current study, we observed low-grade inflammatory alterations after DON administration compared with control group. In consistent with alterations in liver tissues, three systematic inflammatory biomarkers (IL-1β, IL-6 and TNF-α) were significantly elevated in DON group in response to low dose of DON administration. The statistically up-regulated ALT activity in DON group demonstrated that low dose of DON could influence liver function. DON did not statistically up-regulate AST activity when compared with control group. We proposed that DON exposure at 25 μg/kg bw/day was insufficient to injure hepatocellular mitochondria and then led to a release of AST. Together, our results suggested that low dose of DON could induce low-grade pi3k inhibitor in liver and slightly influence liver function. Since previous studies have thoroughly and comprehensively investigated DON-induced inflammation in liver (Sahu et al., 2010; Tardivel et al., 2015), we paied an extra attention to the roles of microbiota in response to DON exposure, for which we chose the above-mentioned parameters to verify basic pathological state and liver function. The gut microbiota has been attracting tremendous scientific interest due to its extensive involvement in host's metabolism. However, the findings so far on relationship between DON and gut microbiome are conflicting and relevant studies are still scarce. Therefore, in order to further investigate and verify the correlation between DON and gut microbiota, we used 16S rRNA gene sequencing to explore potential gut microbial dysbiosis under low dose of DON exposure. Bioinformatic analysis indicated that DON notably increased the relative abundance of Parabacteroides and Enterobacter while it decreased the abundance of Lactobacillus, Lachnospiracea incertae sedis and Odoribacter genera. In previous studies, Parabacteroides were elevated in an alcoholic liver disease model related to liver inflammation (Zhang et al., 2017). It is similar to our findings showing a slight DON-induced liver inflammation characterized by infiltration of lymphocytes. Enterobacter species could be linked with diverse liver diseases for their domination in the gut of patients with alcoholic hepatitis (Parker et al., 2017), primary biliary cirrhosis (Lv et al., 2016) and liver abscess (Luo et al., 2016). The increase in Enterobacter in the current study also indicated that gut microbiota was associated with DON-induced liver damage. Lactobacillus, the abundance of which was diminished upon DON exposure in our study, have also been reported to be used as probiotics that suggested its anti-inflammation effect. Besides, Odoribacter that changed in our experiment could link with consumptions of carbohydrates, especially fiber (Wu et al., 2011; Luo et al., 2017), which accords with previous studies that found DON might also impact on the metabolism of carbohydrates. It is important to mention here that although these changes in metabolism could explain the observed changes in microbiota, alteration of the production of mucus and mucins induced by low dose of DON could also be responsible of the dysbiosis (Pinton et al., 2015).