| Methods: According to the results of digestive parameters developing model with age and documents published, pH, moisture, digestive enzymes level , bile acid level and retention time of chyme in crop, proventriculus and gizzard, small intestine were made respectively. Pig bile salt, several commercial digestive enzymes products, such as pepsin, trypsin, lipase and amylase, were used to imitate secretive digestive enzymes and bile acid, and established a digestive parameters and operating procedure in broiler model. The livability of living Bacillus licheniformis preparation at different gastrointestinal tract conditions in broiler model was studied;Living Bacillus licheniformis, Lactobacillus casei, Lactobacillus plantarum ,and three mixed strains were respectively added to intestinal digestive conditions at 21d in vitro, after centrifugal metabolic liquids was tested to inhibit indicator strains on agar medium's surface;To study the effects living B.licheniformis on the changes of digestive enzymes ,polysaccharides, One normal control group and one experiment group were established in simulating digestive gastrointestinal tract at 21d and 42d in vitro.There were four replication in every group. Results: Living B.licheniformis can resistant to low pH and the survival rate of the cells was 52.5% ,60.4% at 14d and 21d respectively in proventriculus and gizzard conditions. It can endure bile acid in small intestine conditions. The metabolite of the strain exhibited inhibitory activity against common pathogenic bacteria. Living B.licheniformis can improve the activity of amylase(P<0.05)and lipase(P>0.05)and increase the content of polysaccharides(P<0.01)at 21d and 42d in vitro. Conclusion: B.licheniformis fulfilled the characteristics of a good probiotics.It can survive enduring the environment of the gastrointestinal tract, it can inhibit the pathogenic bacteria in the intestinal tract, and can secrete digestive enzymes and extra polysaccharides. |
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