Study On The Preparation Of Zearalenone Biol Ogical Detoxificating Agent And Its Effect On Growing-finishing Swine Production And Detoxification

Zearalenone(ZEN)is a kind of estrogen-like mycotoxins,widely exists in a variety of food crops and has great harmfulness to swine.In this study,the probiotic and enzyme combination of efficient ZEN degradation was prepared,and fed to the finishing pigs for studying the growth performance and effectiveness of ZEN detoxification.The experiment was divided into three parts.Probiotics with ZEN-degradation ability were screened and combined in vitro in first part.The probiotics stored in our laboratory were inoculated in the liquid medium,and then ZEN was added to the culture medium.After incubation with the strain for 24 h,the content of ZEN in the liquid was measured by enzyme-linked immunosorbent assay kit and then the degradation rate was calculated.The results showed that the degradation rates of Bacillus subtilis K3,Bacillus subtilis K4 and Candida utilis were 91.73%,92.07% and76.68%.The distribution of the active components for ZEN degradation was also investigated.It was found that the components of Bacillus subtilis were distributed in the supernatant of fermentation broth.The active components of Candida utilis were distributed in the supernatant and cell.The degradation rates of ZEN were detected at different time points.The results showed that ZEN degradation rates of Bacillus subtilis and Candida utilis were 95.04% and 79.75% after 16 h fermentation(P<0.05),thereafter there was no significant difference among the time points(P>0.05).The study also found that the viable counts of Bacillus subtilis K3,Bacillus subtilis K4 and Candida utilis in YPD culture medium were more than that in LB culture medium.Therefore,YPD was selected as the co-culture medium of three kinds of bacteria.The design for determining the optimal ratio of 3 strains was divided into nine treatments,3 replicates in each treatment,and the ZEN degradation rate was measured after 16 h.The results showed that the optimal ratio of Bacillus subtilis K3,Bacillus subtilis K4 and Candida utilis was 2:2:1,and the highest ZEN degradation rate was 92.21%(P<0.05).Then,the crude enzyme from Aspergillus oryzae was combined with the compound probiotics at different ratios for degrading ZEN effectively.It showed that when the ratioof compound probiotics and Aspergillus oryzae crude enzyme was 2:1,the ZEN degradation rate was the highest,reaching 95.15%(P<0.05).Study on the effect of ZEN biodegradation preparation production performance of the growing-finishing pigs was conducted in the three part.A total of 120 healthy pigs with body weight around 34 kilograms were randomly divided into 5 groups,3 repetitions in each group,four sows and four boars in each repetitions and the feeding experiment was conducted for 60 days.Group A was basal diet containing 86.16 ?g/Kg ZEN,group B containing 300 ?g/Kg ZEN without biological degradation agent,group C containing 300?g/Kg ZEN with 0.5 Kg/t biological degradation agent,group D containing 300 ?g/Kg ZEN with 1.0 Kg/t biological degradation agent,group E containing 300 ?g/Kg ZEN with1.5 Kg/t biological degradation agent.After the feeding experiment,three sows were selected to be slaughtered from group A,B and D according to the vulva swelling and growth performance indicators.The results showed that the vulva area of young sows in group A had no change,while other groups were significantly increased within 15 d.The vulva area of young sows in group B was the largest in five groups,followed by group C.After 15 d,The vulva area of young sows in each group had no significant changes.The activity of amylase in pig feces of group C,D and E were significantly higher than that in group B(P<0.05),but without significant difference for protease activity(P>0.05).Although there was no significant difference in the number of the E.coli in each group(P>0.05),it was found that the E.coli decreased with the increase of the biological degradation agent addition.It was also detected that microbial similarity coefficient in pig faeces of group C,D and E was above 50%,while it was less than 50% in group A and B.Similarly,the microbial similarity coefficient in the contents of large intestine in group D was also higher than that in the group A and group B,indicating that gut microflora was more state by ZEN-biodegradation preparation.There was no significant difference in DG,ADFI,F/G and the digestibility of CP,EE,P and Ca among 5 groups(P>0.05).Although there was no significant difference in the heart,liver,spleen,kidney and uterine indexes in group A,B and D(P>0.05),the uterine index in group B was higher than that of group A and group D.The residual ZEN in liver,serum,uterus,long dorsal muscle was not detected.Serum biochemical analyses indicated that serum glucose content in group B was higher than group E(P<0.05)and the other serum biochemical indexes had no significant differences(P> 0.05)..The residual ZEN in jejunum of group B was significantly higher than that in group A and group D(P<0.05),and there was no significant difference between group A andgroup D.By comparing the residual ZEN in large intestine group A,B and D,it was found that the residual ZEN in group B was almost the same as group D(P>0.05),which was significantly higher than group A(P<0.05).The m RNA expression of estrogen receptor(ER?)gene in ovarian tissue was not significantly different among group A,B and D(P>0.05).In this study,a biological degradation agent for efficient ZEN degradation in vivro was obtained.The results showed that it could relieve the vulva swelling of young sows,maintain the stability of intestinal microflora and reduce ZEN harm to animals.