Probiotic Characteristics and Antibacterial Activity of Lactobacillus casei Strain YG-01
[Objective]The present study was aimed to evaluate the probiotic properties and inhibitory activity against pathogenic bacteria of Lactobacillus casei(L.casei)YG-01 isolated from cheese,and provide a theoretical reference for the application of this strain in food animal production practices.[Method]This study evaluated the drug sensitivity,intestinal colonization ability,digestive tract environmental tolerance,modulation of intestinal microbiota,inhibition of pathogenic bacteria activity,and growth promotion effect of the L.casei YG-01 strain.[Result]The drug sensitivity test showed that L.casei YG-01 was highly sensitive to common antibiotics such as minocycline,erythromycin,clarithromycin,clindamycin,and penicillin.Using carboxyfluorescein diacetate,succinimidyl ester(cFDA-SE)labeled L.casei YG-01 for oral administration in rabbits,the detection rates of L.casei YG-01 in rabbit jejunum,ileum and colon on the first day were 70.9％,59.3％and 66.0％,respectively,and the high colonization levels(＞35％)were maintained on the 11th day after oral administration.The viable numbers of L.casei YG-01 were higher than 1 X 105 CFU/mL in simulated gastric juice at pH 2.5,3.5 and 4.5,simulated intestinal juice,2 g/L cholate concentration and 9％NaCl solution.In vitro antibacterial tests showed that L.casei YG-01 significantly inhibited the growth of pathogenic bacteria in the intestines,such as Escherichia coli O157,Yersinia enterocolitica,Salmonella,Shigella,and Vibrio parahaemolyticus,while having no inhibitory effect on the probiotic bacterium Lactobacillus rhamnosus.Oral administration of L.casei YG-01 significantly increased average daily feed intake and average daily gain,but inhibited the proliferation of bacteria from the phyla Firmicutes and Proteobacteria.[Conclusion]L.casei YG-01 exhibited excellent probiotic properties,as it could significantly inhibit the proliferation of pathogenic bacteria in the intestines and improve food animal growth performance.These findings laid a foundation for the development of microbiota-based preparations using the L.casei YG-01 strain.
Lactobacillus casei YG-01probiotic characteristicsantibacterial activitymicroecological preparations
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