边鸡肠道乳酸菌的分离鉴定及筛选

Isolation,identification and screening of Lactic acid bacteria from intestinal tract of Bian chicken

以边鸡的肠道内容物为材料,应用MRS琼脂双层培养基进行培养,通过菌株形态观察、革兰染色、生理生化试验、16S rDNA基因序列分析与系统发育进化分析对菌株进行分离鉴定;对分离到的菌株进行生长曲线测定及耐酸、耐胆盐试验和抑菌试验。结果显示,分离鉴定到3株乳酸菌(I、L和G)分别为卷曲乳杆菌、约氏乳杆菌和唾液乳杆菌。通过测定生长曲线发现I和G较L早进入对数期,生长速度较快,具有良好的生长特性;3株菌均对大肠杆菌、沙门菌和金黄色葡萄球菌有较强的抑菌活性,均对低pH和胆盐环境耐受。结果表明,筛选发现I和G更适合作为研制微生态制剂的菌株,该试验为研制饲料添加剂提供优良菌株和科学依据。

The intestinal contents of the Bian chicken were used as materials,and cultured by MRS agar double-layer medium.Isolation and identification of strains were carried out by morphological observation,gram staining,physiological and biochemical tests,16 S rDNA gene sequence analysis and phylogenetic analysis;the isolated strains were tested for growth curve,acid resistance,bile salt test and bacteriostatic test.Three strains(I,L and G)of Lactic acid bacteria were isolated,which were Lactobacillus crispatus,Lactobacillus johnsonii and Lactobacillus salivarius.By measuring the growth curve,it was found that I and G entered the logarithmic phase earlier than L,and the growth rate was faster and had good growth characteristics.All the three strains had strong antibacterial activity against Escherichia coli,Salmonella and Staphylococcus aureus,all were resistant to low pH and bile salt environment.Screening found that I and G were more suitable as strains for the development of microecological preparations.This test provides excellent strains and scientific basis for the development of feed additives.