Toxicological Effects Of Deoxynivalenol On Zebrafish And Biological Detoxification Of Deoxynivalenol

Deoxynivalenol(DON)is one of the most harmful mycotoxins to wheat in the world,which is widely presented in wheat and its products,grain,oil,food and feed,etc.,entering the food chain through feed,flour and other forms,causing serious toxic effects on humans and animals,posing a potential risk to the health of organisms,and causing serious economic losses to livestock around the world,it is a global challenge to detoxify DON pollutionisa.The biological detoxification method is considered as safe,effective and economical method,and the use of microorganisms and enzyme preparations can provide an effective means to overcome the limitations of physical and chemical methods for mycotoxin reduction.In this study,DON was used to treat zebrafish,and the toxicological effects of DON on zebrafish were studied based on intestinal metabolome and transcriptome analysis,as well as liver transcriptome analysis.Subsequently,the degradation rate of DON was studied by using microbial flora and specific enzymes from different sources,and the influence of DON on microbial flora was obtained by high-throughput sequencing,and the catalytic mechanism of enzymes was explored by molecular docking analysis.The main research and results of this paper are as follows:1.As one of the common biological models,the adult zebrafish was used for toxicological effects study after 25,50 and 100 μg/m L DON treatment,respectively.DON could not be degraded immediately,the intestine and liver of zebrafish were affected by DON treatments by morphological studies.Through metabolome and transcriptome analysis,a total of 27100 intestinal metabolites and 859 differential metabolites were detected in zebrafish,with 577 up-regulated and 282down-regulated quantities.Further analysis results showed that there were total of 342 intestinal metabolites species,16 differential metabolic species,and 9 upregulated species.Transcriptome differential analysis involved lnc RNA and m RNA differential expression analysis.The total number of lnc RNA differentially expressed genes in zebrafish intestinal was 3259,including 2325 up-regulated genes and 934down-regulated genes,respectively.The total number of m RNA differentially expressed genes was 3111,including 1939 up-regulated genes and 1172down-regulated genes,respectively.The total number of lnc RNA differentially expressed genes in zebrafish liver was of 306,with the 95 upregulated genes and 211down-regulated genes.The number of m RNA differentially expressed genes was2077,including 866 upregulated genes and and 1211 downregulated gene,respectively.DON was completely degraded after 15 days in the water after zebrafish feeding with the initial DON concentration of 50 ppm and 100 ppm.And two strains were isolated and identified as Pseudomonas rhodesiae and Acinetobacter lwoffii,respectively in the solution,further DON degradation analysis of the two isolates respectively showed that DON were 29.1% and 39.3% reduced after 36 hours cultivation,respectively.2.The degradation of DON by microbiota and the products after degradation were studied by four typical samples from chicken coop(exp J),sheep house(exp Y),wheat field(exp T)and horse stable(exp M),with degradation rates of 57.4%(exp J),28.8%(exp Y),42.0%(exp T)and 69.6%(exp M)after 96 h,respectively.High-throughput sequencing compared the bacterial diversity of samples before and after vomitoxin treatment to understand how vomitoxin affected microbial flora,paving the way for screening of vomitoxin detoxified microbial single bacteria or group flora.3.Enzyme preparations is a safe and efficient method for biological detoxification.Dep A can oxidize DON to 3-keto-DON,and Dep B can convert3-keto-DON to 3-epi-DON.The genes coding Dep A and Dep B were synthesized and expressed by cell free expression system and in E.coli,their optimal reaction conditions of the two enzymes were obtained through preliminary enzymatic kinetic experiments,and the key amino acid active sites of Dep A enzyme was Gln213 and the key amino acid active site of Dep B enzyme was Arg244 through molecular docking simulation analysis.In this study,the toxicology of DON on the intestine and liver of adult zebrafish was studied for the first time,and biological detoxification was further studied through the degradation of DON by microbial flora and enzymes.The results will be useful for further DON biodetoxification study and application.