Toxicity Inhibtion Of Bacillus Subtilis WB600 On Different Concentrations Of Lead Exposed Crucian Carp

Bacillus subtilise WB600 plates were plated in solid medium containing different concentrations of lead solution(3 replicates per concentration)and were counted after incubation overnight.The results showed that the strain has a high lead tolerance and its highest tolerance is 900mg/L Pb.Bacillus subtilise WB600 was added to the pellet feed for fish and the live bacteria level in the feed was finally brought to 10~9 CFU/g by adding a freshly concentrated bacterial liquid.Individual uniform Carassius surplus,were randomly divided into 8 groups.Respectively,group?(blank control group);group?(probiotics control group)and the probiotics treatment groups?,?and?were 0.05 mg/L Pb+WB600,0.5 mg/L Pb+WB600,1.0 mg/L Pb+WB600 respectively;Lead exposure groups?,?and?were0.05,0.5,1.0 mg/L Pb.Sixty days after the experiment,blood,brain,gill,hepatopancreas,trunk kidney,intestine and back muscles were collected and tested for lead content,antioxidant enzyme activity index,immune-related index,and intestinal microstructure variety.Comparing the changes of lead accumulation in different tissues of Carassius aurous,we found that Bacillus subtilise WB600 could significantly reduce the amount of lead in each tissue of carasses aurous.However,with the increase of lead concentration,the influence on lead metabolism of carasses aurous brain and muscle gradually decreased.Compared with the control group,the superoxide dismutase(SOD)activity,reducing glutathione(GSH)content,and total antioxidant capacity(T-AOC)of hepatopancreas and trunk kidney of carasses aurous in probiotic positive control group were significantly improved.The catalase(CAT)activity in hepatopancreas was decreased,with no significant difference;the catalase(CAT)activity in trunk kidney was increased significantly;the contents of serum immunoglobulin(IgM)and lysozyme(LZM)in the probiotics control group,were significantly increased;the villus height,width,and muscle thickness of the intestinal and distal intestine were significantly increased.At0.05 mg/L lead exposure,compared with the lead exposure group,in probiotic treatment group,the SOD,CAT and GSH levels of carasses aurous hepatopancreas and trunk kidney were significantly improved,the level of T-AOC in hepatopancreas was not significantly increased,and the level of T-AOC in trunk kidney was significantly increased;At 0.5 mg/L lead exposure,compared with the lead exposure group,in probiotic treatment group,the GSH content of carasses aurous hepatopancreas and trunk kidney,the SOD and CAT active of carasses aurous trunk kidney were significantly increased;the levels of SOD,CAT,T-AOC in carasses aurous hepatopancreas,and T-AOC in classic trunk kidney were not significantly increased.At 1 mg/L lead exposure,compared with the lead exposure group,in probiotic treatment group,the GSH,T-AOC levels of carasses aurous hepatopancreas and trunk kidney were significantly improved;the SOD and CAT active of carasses aurous trunk kidney was significantly increased;the SOD and CAT active of carasses aurous hepatopancreas were not significantly increased.Exposing to three concentrations of lead,compared with the lead-exposed group,the levels of serum immunoglobulin(IgM),lysozyme(LZM)activity,and amino levulinic acid dehydrates(ALAD)activity were increased in the probiotic treatment group;among them,the content of IgM in group VIII was significantly higher than that of group VII.The activity of LZM in group IV was significantly higher than that of group III,and the activity of ALAD in group VI was significantly higher than that of group V.Compared with the lead exposure group,villi height,height and muscular thickness of the distal intestine and proximal intestine were increased in varying degrees in probiotic treatment group,and has good villus integrity;among them,there was a significant difference in the distal intestine villus height and muscle thickness.Thus,under long-term exposure to lead at different concentrations,feeding of Bacillus subtilise WB600 has positive effect on the approximative enzyme activity,immune-related indicators and intestinal structure of carp,which can relieve the toxic effects of lead on the carp.