Biosynthesis Of Selenium Nanoparticles And Its Detoxification Effect Against Deoxynivalenol On Laying Hens

Selenium nanoparticles(SeNPs)as a new form of selenium attracts much attention in the last several years.Besides the traditional bioactivities like enhancing immunity and anti-oxidative ability,its new characteristics,lower toxicity and easier absorbed,also became the highlights of SeNPs that raised people's concern around the world,especially biosynthesized SeNPs by microorganism.Deoxynivalenol(DON)is one kind of mycotoxin which spreads widely around the world.It seriously contaminates feed and its raw materials like corn and wheat,badly threating the healthy development of animal breeding industry.In some researches these years,researchers found DON-induced oxidative stress played an important role in its cytotoxicity.In this research,one isolate was isolated and identified,and then used to synthesize SeNPs which were used to protect layers from DON.Identification of isolate strain tolerating sodium selenite(Na2SeO3).One isolate from pig farm showed potential ability to tolerance high concentration of Na2SeO3.Based on some researches related with biosynthesizing SeNPs through bacteria,this isolate was used to synthesize SeNPs.Firstly,the wild strain was identified through morphological characteristics,physiological and biochemical responses,and molecular biological methods,finally classified as Bacillus licheniformis.Na2SeO3 was added to 200 mL Luria-Bertani nutrient solution in a 500mL flask,and its final concentration is 200 ?g/mL.Then,LB solution was incubated in a shaker incubator at 37 ?for 24 hours.After that,bacteria were harvested,washed using 0.9%NaCl solution and then homogenized through sonication.The purified solution was detected by Transmission Electron Microscope(TEM),X-ray energy dispersive spectrometer(EDS)and the biological activities of free radical scavenging anti-bacterial growth.The results showed us that 1)the average meter of nanoparticles was 81 nm through accounting 200 signal particles,and ranged from 50-110 nm.The shape of nanoparticles was spherical and uniformity;2)DPPH assay showed that red nanoparticles could scavenge free radical.Compared with BHT,the scavenging ability of SeNPs was significantly lower than that of BHT at the same concentration.There was no significant difference between SeNPs and SeO32-;3)The concentration of 24 ?g/mL SeNPs showed biological activity on significantly inhibiting pathogenic S.aureus and Salmonella,also had a little effect on E.coli,but without significance.SeNPs alleviating deoxynivalenol(DON)toxicity on laying hens.Ninety-six 35-week-old healthy laying hens were randomly assigned into four groups,each of which included 3 replicates of 8 layers,and feed with four kinds of diets:uncontaminated basal diet(control group),10mg/kg DON contaminated basal diet(DON group),lOmg/kg DON and 0.5mg/kg SeNPs(DON+SeNPs group)contaminated basal diet and 0.5mg/kg SeNPs(SeNPs group)basal diet.The whole period is 5 weeks.DON caused egg production rate and soft shelled or cracked egg rate increased in DON group,while two rates in DON+SeNPs group were improved significantly by SeNPs(P<0.01).No differences were observed in egg quality(egg weight,Haugh units,yolk color,eggshell strength and eggshell thickness)in four groups.T-AOC and GPx activities in serum were significantly decreased(P<0.05)and MDA content in liver were significantly elevated(P<0.01)in hens fed DON contaminated basal diet compared with those fed with basal diet,but the values were reversed in the DON+SeNPs group.Furthermore,compared with control group,the levels of Bax and Caspase-3 significantly upregulated(P<0.01)and the level of Bcl-2 significantly downregulated(P<0.05)in hens in DON group,but the values were reversed by SeNPs in DON+SeNPs group.These results showed that SeNPs could provide effective protection against DON toxicity on laying hens probably via alleviating DON-induced oxidative stress and apoptosis,and provide a light for a novel anti-mycotoxin agent.