草鱼肠道乳酸菌的分离鉴定及适用性能评价

Applicability,Identification and Isolation of Lactic Acid Bacteria from Grass Carp Intestine

为给渔用中草药发酵提供良好的益生菌来源,从健康草鱼肠道内分离鉴定得到12株乳酸菌,选择2株乳酸乳球菌(CR1、CR2)和2株粪肠球菌(CR3、CR4),从生长速度、耐酸、耐胆盐、安全性、抑菌能力、药敏测试等方面对4株乳酸菌进行益生效果评价。结果显示:①乳酸乳球菌CR1、CR2生长速率较粪肠球菌CR3、CR4快,且4 h后差异显著(P<0.05)。②菌株CR4对酸的耐受能力较弱,CR2对胆盐耐受能力较弱。③4株菌株均无致病力。④4株菌株对大肠杆菌均表现为高度敏感,CR1和CR4对维氏气单胞菌表现为高度敏感,CR2和CR3表现为中度敏感。⑤菌株CR1对9种抗生素中的7种敏感,对恩诺沙星中度敏感,仅对丁胺卡那耐药,而CR2、CR3和CR4都仅对其中4~5种抗生素敏感,对恩诺沙星、头孢他啶和丁胺卡那都表现出不同程度的耐药性。综合以上结果表明,乳酸乳球菌CR1具有较好的益生特性,可作为发酵渔用中草药饲料添加剂的益生菌。

In order to provide a good source of probiotics for the Chinese herbal fermentation in fishery,12 lactic acid bacteria strains isolated from intestine of healthy grass carp(Ctenopharyngodon idella)were identified,and then two strains of Lactococcus lactis(CR1,CR2)and two strains of Enterococcus faecalis(CR3,CR4)were preliminary screened out.The probiotic effects of these four strains of lactic acid bacteria were evaluated in terms of strain growth rate,acid resistance,bile salt tolerance,safety,antibacterial ability and drug sensitivity test.The results showed that:1)The growth rate of Lactococcus lactis CR1 and CR2 was faster than that of Enterococcus faecalis CR3 and CR4,with a significant difference after 4 hours(P<0.05).2)Strain CR4 was weak-tolerant to acid,strain CR2 was weak-tolerant to bile salts.3)The four strains showed non-pathogenic.4)The four strains all were highly sensitive to Escherichia coli;CR1 and CR4 were highly sensitive to Aeromonas veronii,and CR2 and CR3 were moderately sensitive.5)Strain CR1 was sensitive to seven out of nine antibiotics,moderately sensitive to enrofloxacin,and only resistant to amikacin;strains CR2,CR3 and CR4 were only sensitive to four or five antibiotics,and showed varying degrees of tolerance to enrofloxacin,ceftazidime and amikacin.Based on our data,Lactococcus lactis CR1 can be used as a feed additive probiotic in fishery fermented Chinese herbal medicines.