凡纳滨对虾(Litopenaeus vannamei)循环水养殖塘挂膜式生物滤器内微生物的多样性

Microbial Diversity in Bio-Filter of the Recirculating Aquaculture System for Litopenaeus vannamei

中文关键词: 凡纳滨对虾  循环水养殖  生物滤器  生物膜  微生物多样性  纳米纤维膜

英文关键词: Litopenaeus vannamei  Recirculating aquaculture  Bio-filter  Biofilm  Microbial diversity  Nano-Membrane

中文摘要:

      为了解凡纳滨对虾(Litopenaeus vannamei)养殖过程中挂膜式生物滤器内不同位置间微生物群落结构多样性的差异，采集已运行46 d的挂膜式生物滤器内挂膜上部外侧和内侧、下部内侧和外侧及收集盘5个不同位置的微生物，采用分子生物学手段，通过16S rRNA基因高通量测序法对生物滤器内微生物进行多样性分析，并对不同位置间功能性微生物进行对比。结果显示，在门水平上，5个不同位置共鉴定出10个主要类群，其中，变形菌门(Proteobacteria)所占丰度比例较大，为主要优势类群，硝化螺旋菌门(Nitrospirae)在挂膜内外两侧检出比例均较高(平均4.3%)，收集盘内则较低(0.33%)，存在显著性差异。共鉴定出41种优势属，其中地杆菌属(Pedobacter)为绝对优势种属，短小盒菌属(Parvularcula)为次优势属，二者丰度比例均在10%以上，硝化螺旋菌属(Nitrospira)为第三优势属，挂膜不同位置丰度比例(平均4.31%)显著高于收集盘内比例(0.28%)。挂膜上氨氧化细菌(AOB)平均丰度比例为1.70%，硝化细菌(NOB)平均比例为6.99%，是系统中主要去除氨氮和亚硝酸氮的微生物。生物滤器各部位微生物物种多样性丰富，微生态系统稳定，可有效维持循环水系统的水质。生物滤器硝化作用主要在上部进行，下部净化能力较弱，收集盘内基本没有硝化能力。生产中应合理配置挂膜数量，科学设计挂膜长度以提高生物滤器的净化效率。

英文摘要:

      In order to study the biodiversity of microbial community structure and explore the water quality purification mechanism of bio-filter in the recirculating aquaculture system for Litopenaeus vannamei, microorganism samples were collected from 5 different positions which were the outer and inner surfaces of the upper part of nano-membrane, the outer and inner surfaces of the lower part of the nano-membrane, and the collecting tray. Microbial diversity, functional microorganisms and purifying capacity among different samples were analyzed according to molecular biological methods and 16S rRNA gene pyro sequencing. The results showed that 10 phyla were identified in 5 different positions, in which Proteobacteria was the dominant group. Nitrospirae was detected in the nano-membrane (4.3%), while with low abundance in the collecting tray (0.33%). Ammonia oxidizing bacteria and nitrite oxidizing bacteria in nano-membrane were the primary microorganisms to remove nitrogen and the proportions were 1.70% and 6.99%, respectively. There were 41 dominant species identified in total. Among which, Pedobacter was absolutely dominant, Parvularcula was the second dominant species, and both abundance ratios were above 10%. Nitrospira was the third dominant species, whose average abundance on membrane (4.31%) was significantly higher than that in the collecting tray (0.28%). Rich biodiversity of microorganism and stable microorganism ecosystem in the biological filter had a crucial role in buffering water quality. The analysis of effective biomass indicated that nitrification happened mostly in the upper part of the biological filter, and the nitrification effect was weakened in the lower part, while almost disappeared in the collecting tray. Therefore, in order to improve efficiency of nitrification, the hanging membrane density and length should be scientifically designed and rationally distributed.