Isolation,Identification and Probiotic Characteristics of Streptococcus alactolyticus from Intestinal Tract of Zi Geese
[Objective]The aim of this study was to isolate and screen potential probiotic strain from the intestinal tract of Zi geese to improve their health status,and analyze its probiotic properties.[Method]The contents of different intestinal tract of healthy Zi geese were collected,diluted in gradient and coated on(CaCO3-MRS)solid medium containing calcium carbonate.After anaerobiccultivation,the isolates were identified through morphology,biochemical tests,16S rRNA gene PCR amplification,respectively.The probiotic properties of the isolates were screened by acid resistance and antibacterial tests.The antibacterial ability,antibiotic sensitivity,acid and bile salt tolerance,gastric and intestinal fluid tolerance were evaluated,and the growth curve and acid production curve were measured.[Result]4 suspected lactic acid bacteria strains were isolated from the intestinal tract of healthy Zi geese,named RS-1,RS-2,RS-3 and RS-4,of which RS-3 had good probiotic properties.The colony morphology of RS-3 in CaCO3-MRS medium was smooth,light yellow and round colony with obvious calcium-soluble ring,Gram-positive Bacillus.The results of biochemical tests showed that the isolates could ferment maltose,cellobiose,sucrose,raffinose,inulin and lactose,as well as mannitol,sorbitol and salicin.The results of esculin test and 1％sodium hippurate test were positive,and the isolates were initially determined to be lactic acid bacteria.16S rRNA gene sequence analysis showed that 4 isolates were all Streptococcus alactolyticus,and the tolerance of RS-3 was better than that of the other three strains.The fermentation broth of RS-3 had a good inhibitory effect on Staphylococcus aureus.The diameter of inhibitory zone was more than 10 mm,and it was resistant to kanamycin,amicacin,roxithromycin,sulfadiazine,lincomycin,polycolistin B and norfloxacin.Moreover,RS-3 had tolerance to acid,bile salts artificial gastric and intestinal fluids.The mice grew well after administration of RS-3.[Conclusion]4 isolates enterogenic Streptococcus alactolyticus of Zi geese were isolated in this experiment,of which RS-3 had good antibacterial and probiotic properties with acid and bile salt tolerance,and could be used as a reliable strain source for the subsequent development of probiotic preparations for geese.
Zi geeseStreptococcus alactolyticusintestinal tractprobioticsmicroecology
万方数据
维普
