仿刺参—中国明对虾—斑节对虾混养下水体微生物组成和多样性

Bacterial Community and Diversity Analysis in a Polyculture System of Sea Cucumber Apostichopus japonicus with Chinese Shrimp Fenneropenaeus chinensis,and Tiger Shrimp Penaeus monodon

2018年6—9月,在辽宁省辽东湾沿岸约3.33 hm2、水深1.5 m的仿刺参轮放轮捕池塘中,混养中国明对虾(30000尾/hm2)和斑节对虾(7500尾/hm2)。养殖期间不投饵,每月15日前后采集养殖池塘水样1次,通过16S rRNA扩增子的高通量测序,定量分析混合养殖池塘水体细菌群落的多样性及丰度变化,以探索该养殖水体中微生物群落的多样性及组成结构的动态变化特征。试验结果显示,混养水体中主要细菌为变形菌门(51.5%),其次为放线菌门(23.6%)、拟杆菌门(11.3%)和厚壁菌门(9.1%)。聚类分析表明,养殖前期(6—7月)和后期(8—9月)池塘水体中细菌群落具有明显的差异,养殖后期池塘水体微生物群落的丰富度和多样性明显上升;变形菌门的丰度和拟杆菌门的丰度在养殖前期明显高于后期,放线菌门的丰度呈先降后升的趋势,而厚壁菌门在养殖后期丰度明显高于养殖前期。试验结果表明,混养过程中,水体微生物群落特异性富集远洋杆菌属和假交替单胞菌属,通过水环境微生态结构变化提高了水体抵抗富营氧化的能力。养殖后期,水体微生物群落中假单胞菌、微酸菌纲和梭状芽孢杆菌的特异性富集,增强了养殖池塘对于氨氮和亚硝酸盐的去除能力,促进了水质的净化,降低了养殖物种感染疾病的风险,提高了养殖虾的成活率。

Sea cucumber Apostichopus japonicas was polycultured with Chinese shrimp Fenneropenaeus chinensis(30000 ind/hm2),and tiger shrimp Penaeus monodon(7500 ind/hm2)in a 3.33 hm2 and a water depth of 1.5 m pond in coastal Liaoning Province in Liaodong Bay from June to September 2018,with catching and stocking in rotation and without feeding,and the changes in diversity and abundance of the bacterial community were quantitatively analyzed in the water samples collected around the 15th of each month in the polyculture pond through the high-throughput sequencing of 16S rRNA amplicon to explore the dynamic changes in diversity and composition structure of the microbial community in the polyculture pond during the culture period.The results showed that the most important bacteria in the polytrophic waters was Proteobacteria(51.5%),followed by Actinobacteria(23.6%),Bacteroidetes(11.3%)and Firmicutes(9.1%).Cluster analysis showed that there were significant differences in the bacterial communities in the pond waters between the early period of aquaculture(June to July)and the late period(from August to September):significant increase in the abundance and diversity of the microbial communities in the pond waters in the later period.The abundance of Actinomycota showed a trend of first decreasing and then increasing,while the abundance of the Firmicutes in the late stage of culture was significantly higher than that in the early stage of culture.The dominant phyla in the water of A.F.P ponds were Proteobacteria,Actinobacteria,Bacteroidetes,and Firmicutes.The relative abundance of Proteobacteria was higher in the initial half of polyculture period than that in the latter half one,with lower relative abundance of Firmicutes in the early half of polyculture periods.The sequencing also indicated that the enriched Pelagibacter and Pseudoalteromonas enhanced the ability of algae degradation,promoted the resistance to eutrophication caused by feed,and contributed to maintain the environmental conditions for the survival and growth of cultured species.Moreover,the accumulation of Pseudomonas,Acidimicrobiia,and Clostridia in the latter half of polyculture period potentially improved the ammonia and nitrite removal,promoting the water quality,and reduced the infection risk of cultured species.