金钱鱼循环水养殖系统水体细菌的多样性

The bacterial diversity in spotted scat rearing water generated by recirculating aquaculture system

以实验室循环水养殖系统养殖金钱鱼1周和1个月后的2组养殖水体样品(分别为A、B)作为研究对象,滤膜抽滤富集水样中的细菌,提取细菌基因组DNA,采用Mi Seq高通量测序方法测序16S r DNA的PCR扩增产物,进行细菌多样性比较分析、物种组成分析及聚类分析。结果表明:从2个样品测序中获得15 259条有效序列,其中A样品为9 092条,B样品为6 167条;在97%相似度下将其聚类,共产生90个OTUs(operational taxonomic units);多样性指数分析表明,A样品细菌群落多样性明显大于B样品的;样本中的细菌种类包含8个门、16个纲、28个目、38个科、48个属,其中A样品以变形菌门(Proteobacteria)的海单胞菌属(Thalassospira)和弧菌属(Vibrio)占优势,相对丰度分别为14.51%和13.29%,B样品以拟杆菌门(Bacteroidetes)的Aureispira和Dyadobacter占优势,相对丰度分别为44.67%和17.63%。表明随着时间的推移,鱼体生长产生的可溶性代谢产物和溶解性有机物逐渐积累以及水体p H的变化,改变了细菌生长的微环境,出现了细菌种群演替和适应的现象。

The diversity of bacterium in the spotted scat（Scatophagus argus） rearing water by recirculating aquaculture system was investigated. Two groups of water samples, A and B, were taken from one week and one month rearing water. Bacterium in the water samples were enriched by membrane filtration, their bacterial 16 S r DNA was extracted, were sequenced by Mi Seq high throughput sequencing. The resultant 16 S r DNA were subject to Clustering analysis, which generated 15 259 valid tags for the two smaples. With 9 092 for A sample and with 6 167 for B sample. These sequences were clustered to 90 OTUs（operational taxonomic units） with 97% similarity. The analysis of diversity indices indicated that the diversity of A sample were significantly greater than that of B sample. The species composition analysis showed that the species of bacterium in the samples covered 8 Phylums, 16 Classes, 28 Orders, 38 Families and 48 Genera. Among them, Thalassospira and Vibrio in Proteobacteria were dominating in sample A, with relative abundance of 14.51% and 13.29%, respectively; Aureispira and Dyadobacter in Bacteroidetes were dominating in sample B, with relative abundance of 44.67% and 13.29%, respectively. This study may indicate that the growth of fish, the accumulation of soluble metabolites and dissolved organic matters, changed the environment of growth of bacterium and caused population succession and adaptation.