Isolation,identification and biological characteristics analysis of probiotics from calves
In this study,probiotics were isolated from the feces of healthy calves and its probiotic properties were analyzed.The probiotics were identified by morphological observation and 16S rDNA sequencing followed by analysis of their antibacterial activity and antibacterial substances.The growth curve and acid production curve were established to explore their adhesion ability and tolerance.The safety was evaluated by drug sensitivity test and hemolysis test.The results showed that four probiotics were identified as Lactobacillus agilis,Pediococcus pentosaceus,Lactobacillus salivarius and Lactobacillus johnsonii that displayed antibacterial activities against Escherichia coli O111:K58(B4),Staphylococcus aureus and E.coli K99.The antibacterial substances of strain 12 and 30 were organic acids and hydrogen peroxide.Bacteriocins were found in strain 26 in addition to organic acids and hydrogen peroxide.Strain 14 produced organic acids and bacteriocin.They showed good growth characteristics,acid production ability,strong cell adhesion ability,strong tolerance to bile salt solution and artificial gastroenteric fluid,strong sensitivity to antibiotics,and no hemolytic.The four probiotics strains isolated in this study met the need of searching for antifungal substances,and provided a theoretical basis for the prevention and treatment of bacterial diarrhea in calves.
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