Study On Isolation, Screening And Characterization Of Probiotic Bacillus From Swine

Pig diarrhea can make the production performance of sows to reduce and also affect thegrowth of piglets,which result in severe financial losses to the pig industry in livestockproduction.Pig diarrhea is mainly caused by Escherichia coli,Salmonella and other pathogens.Inorder to inhibit the growth of pathogen and prevent swine diarrhea,breeders applied antibioticswhich increase resistant strains and drug residue in feeding. It is necessary to find a newpreparation which can replace or instead of antibiotics to inhibition of pathogen.Someexperiments found that inhibiting intestinal bacteria is effectively, safely and non-toxic byProbiotic Bacillus and it is also can produce a variety of nutrients.23Bacillus strains antagonistic to Escherichia coli and Staphylococcus aureus were isolatedfrom jejunal mucosa of healthy piglets, and5of them possess higher antagonistic activity. Thestrain named JN-16was isolated and tolerant to bile salts, artificial intestinal juice and gastricjuice. The results of molecular biology and biochemical experiments demonstrated that JN-16was Bacillus subtilis.The results of antibacterial experiments showed that the antibacterialactivity of broth was strongest when the JN-16was cultured at33℃or37℃for24h usingglucose as carbon source, soy peptone as nitrogen source, pH=6.5. Antimicrobial peptidesubstances was extracted from antimicrobial peptide hydrochloric acid precipitation and organicsolvent methanol extraction in fermentation liquid. Oxford Cup found that antimicrobial peptidehave better effect in inhibiting E.coli (inhibition zone diameter14.3mm) and Staphylococcusaureus (inhibition zone diameter17.5mm).However,The effect of antibacterial protein extract bysalting out method is inot obvious in inhibiting E.coli (inhibition zone diameter12mm) andStaphylococcus aureus (inhibition zone diameter12mm) effect.Application Antibacterial proteinwas preliminary purified by dialysis method and inhibit effect is very apparent to bacteria.Theanimal model was establishment by Salmonella and though paraffin sections and HE stainingcan be seen under the microscope that the test mice intestinal villi damage.Bacillus subtilis canregulate intestinal flora that can increase the beneficial lactic acid bacteria,reduce intestinalpathogen and also protect the intestinal mucosafrom damage.This strain can be used as feedadditives, and laid foundation for development of probiotics.