Screening Of Bacillus Subtilis Detoxification For Deoxynivalenol And Application Study

Vomitoxin(VX)belongs to the group B of trichothecenes,which chemical name is Deoxynivalenol(DON).It has the highest detection rate and the highest content of mycotoxins.It has been reported that VX is one of the most harmful toxins to animal production.At present,most of the methods of detoxification of VX in China are physical treatment,but because of adsorbing toxin and nutrients at the same time,it is not widely used.In recent years,probiotic Bacillus subtilis has been reported many times to have good detoxification function and probiotic performance.It can stably detoxify in vivo while protecting and enhancing intestinal health.It has become a the most promising detoxifier of mycotoxin poison and contributions on the sustainable development of animal husbandry can be made.In this study,Bacillus subtilis strains with both detoxification and probiotic properties were successfully screened from probiotic strains derived from animal intestines and feces,and their detoxification characteristics were preliminarily studied.The detoxification effect in vivo and in vitro was verified,which provided theoretical and technical support for the development of detoxification animal microecological agents.1.Selection and evaluation of probiotic strainsBy using DON as the sole carbon source to preliminarily screen probiotic strains preserved in laboratory,6 superior strains,which can survive with the presence of DON,will be screened out.With DON for substrate,by rescreen,WXBs-042 with superior performance in detoxification was selected.The strains were identified by morphological observation and biochemical index.After identification of 16S rRNA gene and phylogenetic analysis,WXBs-042 was identified as Bacillus subtilis.2.Study on biological characteristics of Bacillus subtilis WXBs-042The results of growth curve showed that WXBs-042 entered logarithmic growth period at about 2 hours,logarithmic growth period at about 4 hours and then entered stable and declining period.In terms of antibacterial activity,WXBs-042 can inhibit activity of Salmonella,Escherichia coli K88,K99,0139 and 0157,but has no antibacterial activity on Staphylococcus aureus.The results of strain tolerance showed that WXBs-042 could tolerate high temperature,simulated gastric juice and 0.3%bile salt.3.Detoxification of Bacillus subtilis WXBs-042The results of the study on the detoxification characteristics of WXBs-042 showed that the detoxification effect of WXBs-042 on DON was positively correlated with the action time;the detoxification effect of WXBs-042 on DON was not related to the pH of the detoxification environment;the detoxification effect of WXBs-042 fermentation broth on DON was different in different treatment groups,among which the fermentation inactivation group was best,which the detoxification rate was 72.16%.The stability of the bacterium-DON complex was evaluated and proved to be good.It was preliminarily determined that the detoxification mode of WXBs-042 was a dual function of degrading and detoxifying a small amount of fermentation supernatant and adsorbing and detoxifying bacteria.4.Verification of research findings by animal testsAnimal testing scheme:blank control group,negative control group,probiotic group,drug attack group,mixed group,prevention group I,prevention group II and treatment group.DON and probiotics were administered by concentrated and timely gavage.BALB/c mice were dissected on the 14th and 28th days of the experiment,the production performance,serum biochemical parameters,changes of liver and jejunum sections were analyzed.The detoxification effect of WXBs-042 in mice and its beneficial effects were analyzed.1.The results of production performance of BALB/c mice showed that WXBs-042 could significantly increase the body weight and average daily body weight gain of BALB/c mice(P<0.05),improve the production performance of BALB/c mice;DON could significantly reduce the weight and average daily gain of mice(P<0.05);WXBs-042 could alleviate the change of weight and average daily gain of BALB/c mice caused by DON poisoning(P<0.05).2.The results of serum biochemical indexes showed that the serum biochemical indicators of BALB/c mice in probiotics group were not significantly different from those of blank and negative control groups(P>0.05);the serum biochemical indicators of ALT and AST in DON group were significantly higher than those of control group(P<0.05),while the addition of WXBs-042 could significantly alleviate the poisoning phenomenon(P<0.05).3.Liver slice showed that WXBs-042 could not damage the liver tissue structure of BALB/c mice;DON destroyed the liver tissue structure of BALB/c mice,leading to inflammatory cell infiltration,hepatocyte rupture and dissolution and other pathological changes.The addition of WXBs-042 could alleviate this phenomenon.4.Jejunal pathological sections showed that DON destroyed the structure of jejunal villi in BALB/c mice.Epithelial cell exfoliation and shortening of jejunal villi were observed.Gastric administration of strain WXBs-042 could promote the growth of jejunal villi and alleviate the damage of jejunal villi by DON treated.The above results showed that WXBs-042 could not only play a probiotic role and improve the production performance of BALB/c mice,but also play a detoxification role in animals,effectively alleviate the damage caused by DON,and prevent group II was the best way of prevention.