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Diarrhea is one of serious diseases in intensive pig production conditions,especially inthe period of piglets.The incidence of diarrhea is quite high,causing the great economiclosses.Probiotics can adjust the micro ecological balance,inhibit the pathogenic bacteria inthe gut.Probiotics has the incomparable vitues than the antibiotics that they can prevent thedevelopment of drug resistance.Bacillus is one of the probiotics that they can resistant thehigh temperature,acid and alkali.Bacillus can produce protease,amylase and so on inanimal intestinal,help the body breaking down the nutrients,improve feed conversionrate,reduce the production cost.Z-27strains of bacillus isolated from feces of healthy piglets using the bile acid salttablet enzyme tablet and pathogenic bacteria plate method.Z-27strains has the strongtolerance in the stomach juice test,intestinal juice test,high temperature test and safety testand is non-toxid in the mice.The test analysed fermentation liquid of Z-27.Organicimpregnant extraction,salt out,high peotein enzyme sensitivity,were made.It figured outthat the pathogenic resistance substance were peptides.Through morphologicalobservation,physiological,MIDI acids and16SrDNA gene sequence analysis foridentifying its species by the China agricultural preservation management center,it isconfirmed that Z-27is Bacillus subtilis.To increase the concentration of Z-27fermentation liquid and sporeconcentration,we optimized the fermentation.Single-factor test and orthogonal experimentmethord indicated the concentration production of Z-27strains:corn meal in1%,soybeancake powder in1.5%, MnSO4·H2O in0.07%,NaH2PO4·2H2O in0.2%,Na2HPO4·2H2O in0.4%.The optimum fermentation conditions were:original Ph value was7.0,inoculationamount was2.0%,formentation temperature was37℃,rotate speed was220r·min-1,volumewas50mL/250mL and incubation period was34h.After optimization,the concentrationproduction of Z-27was improved to1.83×109cfu·m L-1.Spore production rate was up95%.Effects of feeding Z-27preparation to post-weaning piglets were studied bydetermining the number of bacteria,digestive enzyme activity and conventional nutrients inthe feces of piglets.Results showed that E.coli in fecal,samples of the test group weredecreased by61.0%. Lactobacillus, Bifidobacterium and Bacillus respectively were increased by46.0%,47.4%and39.8%, compared with the control group. Protease,α-amylase, cellulase and lipase activity in fecal samples of the test group respectively wereincreased by an average of62.99%,34.56%,133.10%and66.57%, compared with thecontrol group. Crude protein, starch, crude fat and crude fiber decreased by30.51%,52.13%,18.44%and26.73%respectively, compared with the control group,inorganiccomponent content no change. Average daily gain of piglets in the test group increased by9.38%. Feed weight ratio decreased by4.94%.Diarrhea rate fell by83.22%.The resultswere similar in fattening pigs tests.Research showed that Bacillus subtilis Z-27preparation had functions ofmaintaining microecological balance,improving intestinal digestive enzymes ofpost-weaning piglet,improving feed conversion rates,improving the growth performance ofpiglets and preventing diarrhea effectively.
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