RESUMEN
@#Objective To isolate and identify Lactobacillus paracasei and Bacillus subtilis from feces of northern white geese.Methods Lactobacillus paracasei and Bacillus subtilis,numbered S00834-8 and IS00439-2 respectively,were isolated from feces of 30 52-week-old northern white geese and cultured in specific medium,and identified by 16S DNA sequencing. The two strains were cultured for different time duration(0,2,4,6,8,10,12,14,16,18,20,22,24,36 and 48 h),at different temperature(34,36,37,38 and 40 ℃)and pH(5. 5,6. 0,6. 5,7. 0,7. 5 and 8. 0). The growth characteristics of the strains were evaluated according to the A600values measured by UV-Vis spectrophotometer. At the same time,the acid and bile salt tolerance(pH 2. 0,2. 5,3. 0,3. 5 and 7. 0,bile salt concentration 0,0. 3%,0. 5%,1. 0% and 1. 5%)and the antibiotic tolerance were tested. Results The strains S00834-8 and IS00439-2 were Lactobacillus paracasei subspecies tolerance H and Bacillus subtilis KA9,respectively. The strain S00834-8 cultured under the optimum condition of the culture medium with pH 6. 0,at 37 ℃,for 12 h,had good bile resistance and gastric acid resistance,which was moderately susceptible to piperacillin,norfloxacin,amikacin,gentamicin and tetracycline,and susceptible to levofloxacin,streptomycin and chloramphenicol. The strain IS00439-2 best cultured in the culture medium with pH 7. 5,at 36 ℃,for 8 h,showed good bile resistance and gastric acid resistance,which was moderately sensitive to levofloxacin and tetracycline,while sensitive to piperacillin,norfloxacin,streptomycin and chloramphenicol. Conclusion Goose-derived Lactobacillus paracasei subspecies tolerance H and Bacillus subtilis KA9 have good acid resistance and bile salt resistance,which are expected to be candidate strains for goose-derived microecological preparations.