Study On Isolation Of Bacillus Coagulans And Microecological Modulater Application On Feeding Piglets

A strain of acidogenic Bacillus was isolated from soil with modified MRS medium.This strain explored visible antibacterical effects on common pathogenic bacteria such as Escherichia coli O139(E.coli K99),Salmonella typhimurium O4Hi (ST O4Hi),Staphylococcus aureus.It was identified as Bacillus coagulans by physiological and biochemical experiments and the sequence analysis of 16S rDNA.The viability of this strain remained 91%when incubated in stimulated gastric juice for 30 minutes.It was tolerant against 3.0%of bile concentration and proved to be innoxious by mice experiment.The result of research showed this strain had applied potential as microecologicals.The culture condition of Bacillus coagulans was optimized at the shaking flask lever.Firstly,Plackett-Burman design was used to evaluate the effects of nine factors related and two of the most significant factors,glucose and CaCO₃,were selected. Then,with three factors glucose,CaCO₃ and tryptone,the path of steepest ascent and center combination experiment were used further optimized medium.The result of optimal medium was as follow:glucose 16 g/L,NaCl 4 g/L,yeast extract 6 g/L, tryptone 20 g/L,beef extract 6 g/L,KH₂PO₄ 2 g/L,MgSO₄,MnSO₄ 0.25 g/L,CaCO₃ 3g/L.The density of B.coagulans reached 2.1×10⁹ cfu/mL.Microecological modulater A,B were used for feeding piglets.The mixture of microecological modulater A and B at a ratio of 2:3 was added into piglets feed for piglets.In order to test their efficacy including daily weight gain,total weight gain, feed conversion and control of diarrhea,two kinds of piglets(large×White×Landrace) and(White×Large) were selected for experiment.The result of twice experiments indicated the optimization of additive probiotic for piglets feed were that the mixture of microecological modulater was 0.02%during 21-35 d and 0.1%during 35-50 d.Copare with the group of antibiotic,total weight gain was not notable difference,but diarrhea rate reduced to 51.7%.