4株对虾肠道益生菌的筛选及鉴定

SCREENING AND IDENTIFICATION OF FOUR PROBIOTIC BACTERIA ISOLATED FROM INTESTINE OF SHRIMP

采用体外拮抗试验的方法,先从不同生长阶段的对虾肠道中分离的96株细菌中筛选出4株对病原菌(鳗弧菌、副溶血弧菌、哈维氏弧菌)有拮抗作用的细菌;进一步通过固体扩散法和液体混合法确定LV060806、LV060808的产物对鳗弧菌有明显抑制作用,LV060806、LV060815的产物对副溶血弧菌有明显抑制作用,LV060810、LV060815的产物对哈维氏弧菌有明显抑制作用。溶血试验证实这些菌株不产生溶血素,不具有潜在的致病性;动物安全性实验证实菌株浓度在106cfu/ml以下对实验对虾无明显的毒害作用。随后测定了其16SrRNA基因序列,分析了相关细菌相应序列的同源性,构建了系统发生树,结合菌株表型特征和生理生化特性最终鉴定结果为:LV060806、LV060808为Vibrio natriegens;LV060810、LV060815为V.alginolyticus。

96 bacteria strains were isolated from the intestine of different-aged shrimps. Four stains showing antagonism against three pathogenic indicator vibrios, Vibrio anguillarum, V. harveyi, and V. parahaemolyticus were selected, and their inhibitory activities were tested. The inhibitory of the stains was tested in solid diffusion assay and liquid blend assay; and showed no pathogenicity to artificially infected shrimp. The 16S rRNA of strains were sequenced and compared with those of relative strains. Strains LV060806, LV060808 were identified as V. natriegens, and LV060810, LV060815 as V. alginolyticus in physiology and biochemistry shown molecular phylogenetic dendrogram.