Isolation Of Bacillus As Animal Probiotics And Biolocigal Characters And Effect Of Selected Strains

The series consequences of antibiotics abuse cause panic in the society. To find a safty and nontoxic replacer is imperative. Probiotics is just the good choice. After many years practice and research, Bacillus spp. is benefit to the growth and development of animals. Bacillus sp. can not only inhibit the growth of pathogenic bacteria, also produce nutritious substances, and is one of the most potential sources of probiotics.Acorrding to the isolation methods and standards of probiotics, 288 strains are isolated from the intestine of healthy Gallus domesticcus and selected 18 stains Bacillus spp. continue the folowed experiments. These strains are identified by 13 biochemical and physicological reactions, and fall into Bacillus subtilus, Bacillus licheniformis, Bacillus cereus, Bacillus megaterium and Bacillus coagulans.The inhibition growth in vitro test of 5 srains of animal pathogenic bacteria (E. coli, Staphylococcus aureus, Salmonella typhimurium, Streptococcus suis, Proteus mirabilis) showed that the 6 strains of isolates work well. All selected strains were tested in poor nurturious situation, 4 strains can produce xylanase, 2 strains can produce cellulase and 5 strains can produce pyhate, but the enzyme activity isn't large.The safty of all the strains are tested by injected to and feed to Kunming mouse. In the experiment of feed mouse and piglets, the results was that Bacillus can promot the growth of mouse, and they can reduce the number of E.coli ,increase the number of Lactobacillus sp.inthe intestine, they also can prevent diarrhea in piglets prominantly, the incidence drop to 29.4% from74.9%. 3 Bacillus exteners were injected to different mouse, in the dejecta the number of E. coli and hydrous rate inapparently change, but the number of Lactobacillus climb notablly.The above-mentioned experiments indicate strain BC261 is a good candidate. In order to choose a perfect culture medium with different ingredients, after a series of comparative tests, and the result is that: peptone 1.5% (w/v), corn syrup 2.0% (v/v), soluble starch 2.5% (w/v), NaH₂PO₄ alleviant 0.4 % (w/v) .