Mechanism Of Degrading ZEA By ANSB01G Strain And Its Application Effect In Animal Production

Experiment1:The aim of this research was to analyze and evaluate the contamination situation of zearalenone (ZEA) in ingredients and complete feeds in Beijing region. Results showed that the detection rate of ZEA in corn, soybean meal, bran, DDGS, swine complete feeds were100%,54.45%,100%,100%and100%, respectively; the over standard rate were0.00%,0.00%,0.00%,41.18%and0.00%, respectively; and the average content were109.08,9.19,14.92,882.68and58.88μg/kg, respectively. These results indicated that the average content of ZEA in DDGS was the highest. Moderate contamination rate and severe contamination rate in DDGS were23.53%and17.65%. Therefore, ZEA contamination was widely found in both feeds and feedstuffs.Experiment2:The aim of this research was to screen for probiotics caplable of degrading zearalenone and to study on its degradation characteristics. A bacteria ANSB01G strain which could degrade ZEA was isolated from79kinds of animal intestinal chyme, moldy feed and food, or soil samples. The results showed that ANSB01G strain was able to degrade88.65%of ZEA in liquid mediun. About84.58,66.34and83.04%of ZEA were degraded by ANSB01G in naturally contaminated maize, DDGS and swine complete feed, respectively. According to bacterial morphology, physiological and biochemical characteristics and16S rDNA identification results, ANSB01G is a Bacillus subtilis strain. The Bacillus subtilis ANSB01G has a good antibacterial activity on Escherichia coli, Salmonella typhimurium and Staphylococcus aureus, and has a high survival rate and tolerance in high temperature, acid or bile salt conditions. This experiment studied the ZEA degradation by ANSB01G strain in different pH, different reaction time and different reaction temperature. Both heating and treatment with proteinase K significantly reduced the ZEA degradation activity of the culture supernatant, indicating that ZEA degradation might be an enzymatic reaction.Experiment3:The aim of the research was to study on the purification and separation of enzyme and products of ZEA degraded by ANSB01G. Extracellular proteins with ZEA transformation activity was precipitated with ammonium sulfate, and then purified by the ion-exchange chromatography, hydrophobic chromatography and Sephadex-Molecular sieve chromatography method. The result showed that the apparent molecular masses are less than44.3kDa. Mass spectrum (Q-TOF) of the degradation products indicated that the first step of ZEA degradation is to bind the phenolic hydroxyl of ZEA and the γ-carboxyl of glutamate, and the following reactions were the lactone ring of ZEA hydrolysis, decarboxylation, reduction of carbonyl and dehydration.Experiment4:The aim of this research was to investigate the effect of MLJ(Bacillus subtilis ANSB01G) on prepubertal female gilts when exposed to ZEA. In this experiment, a total of18prepubertal female gilts were randomly allocated to three treatments with6replicate per treatment (one pig per replicate). The gilts in each treatment were randomly with one of the three diets:control (basal diet with normal corn; T1(Diet was prepared by substituting corn naturally contaminated by ZEA for all normal corn in basic diets, The concentrations of ZEA in diet is238.57μg/kg); T2(Diet was prepared by mixing the diets of T1with2kg/T of MLJ). The total viable count of MLJ was1×109CFU/g. This experiment lasted for24days. The results showed that ZEA in diets significantly increased the vulva size and reproductive organs weight of gilts in T1group compared with the control group (P<0.05), and the addition of MLJ to diets naturally contaminated by ZEA can ameliorate these symptoms as observed in the T2group. The presence of low doses of ZEA (238.57μg/kg) in the diet (T1group) had no significant effect (P>0.05) on the level of FSH, LH, and E2in serum of gilts, but the level of PRL in group T1was increased significantly (P<0.05). The gilts of T1group showed conspicuous cell enlargement and fatty degeneration of the corpus uteri, atrophy and cavitation of mature follicular tissue and swelling, inflammation, and lymphocyte infiltration of liver cells as compared to that in Control group. The addition of MLJ in the diet (T2group) can alleviate these hyperestrogenic effects caused by ZEA, maintaining the body of gilt in a healthy status. The results indicated that the short-term (24days) feeding diet concentrated with ZEA (238.57μg/kg of diet) can cause deleterious effects on prepubertal female gilts, and addition of2kg MLJ into a ton diet can effectively ameliorate these detrimental effects and alleviate ZEA toxicosis in gilts.Experiment5:The aim of this research was to investigate the effect of MLJ (Bacillus subtilis ANSB01G) on female broilers when exposed to ZEA. A total of180female Ross308broilers were randomly assigned to3treatments with6replicate of10birds each. Control group (C) comprised basal diet with normal corn; Treatment1(T1) was prepared by substituting corn naturally contaminated by ZEA for all normal corn in basic diets (The concentrations of ZEA in diet is248.76μg/kg); Treatment2(T2) was prepared by mixing the diets of T1with1kg/T of MLJ. The total viable count of MLJ was1×109CFU/g. This experiment lasted for42days. The result showed that there were no significant effects on growing performance, relative weight of organ, meat quality and antioxidant capacity of serum and liver from female broilers in C, T1and T2groups (P>0.05). The results indicated that the adverse effect of low level (248.76μg/kg of diet) of ZEA in diet of female broilers was slight.