从健康大鳍鳠（ Mystus macropterus）肠道菌群分离得到25株细菌，通过对菌株胞外酶活力及对鱼类常见病原菌抑制作用进行筛选，从中筛选出一株益生菌DQHY-7菌株。对DQHY-7菌株安全性进行检测，并结合菌株形态观察、生理生化试验，对DQHY-7菌株进行了初步鉴定。结果显示： DQHY-7菌株具有较强的分泌纤维素酶、淀粉酶和蛋白酶能力，能够抑制大肠杆菌（ Escherichia coli）、嗜水气单胞菌（ Aeromonas hydrophila）和荧光假单胞菌（ Pseudomonas fluorescens）的生长。急性毒性试验表明，浓度为1.0×108 CFU/mL的DQHY-7菌悬液对大鳍鳠没有致病性。结合DQHY-7菌株菌落生长形态和生理生化特性，初步鉴定为枯草芽孢杆菌（ Bacillus subtilis）。研究结果表明DQHY-7菌株可以作为一个新的饲用微生态制剂候选菌种。%25 bacterial strains isolated from intestinal tract of Mystus macropterus were used for testing the ectoenzyme -producing ability and the antagonistic effects against three common pathogenic bacteria .The toxicity of strain DQHY -7 screened as potential probiotic for M.macropterus was evaluated.DQHY-7 was identified according to its morphological , physiological and biochemical characteristics.The results indicated that DQHY -7 had high ectoenzyme -producing ability including amylase , cellulose and protease , and DQHY -7 could produce chemical inhibitor to Escherichia Coil, Aero-monas hydrophila and Pseudomonas fluorescens.It was non-pathogenic for M.macropterus when the concentration of DQHY-7 was at 1.0 ×10 8 CFU/mL.Combined with the physiological and biochemical characteristics , DQHY-7 could be de-terminedas Bacillus subtilis preliminarily.This study had revealed that DQHY -7 would be wsed as a candidate strain of mi-croecological in aquaculture.
展开▼
