青石斑鱼海水循环水养殖水体的细菌群落特征

Bacterial community characterization of rearing water of marine recirculating aquaculture systems for yellow grouper (Epinephelus awoara)

摘要:

[目的] 为揭示工厂化循环水青石斑鱼养殖水体的细菌群落特征,比较患病养殖池与健康养殖池的细菌群落结构差异,探讨细菌群落结构与青石斑鱼病害相关的相关性。[方法] 采用Illumina Miseq高通量测序方法,分析比较了患病和健康养殖水体细菌群落结构、α-多样性指数(包括多度、均一度和系统发育多样性);并结合传统方法从患病青石斑鱼病灶部位分离疑似病原菌。[结果] 患病和健康养殖水体中细菌群落的α-多样性并无太大差异,但主坐标分析与热图样本聚类分析表明细菌群落结构明显不同。二者的优势细菌门均为Proteobacteria、Verrucomicrobia和Bacteroidetes,但它们的相对丰度差异显著。患病养殖水体中α-Proteobacteria (25.07%)和γ-Protebacteria (22.74%)丰度相当,而健康养殖水体中γ-Protebacteria (40.49%)显著高于α-Proteobacteria (10.87%)。患病水体的Verrucomicrobia丰度(26.4%)远高于健康水体(10.9%);而Bacteroidetes的相对丰度则相反(12.3% vs 20.9%)。主要的差异类群包括α-Proteobacteria的Rhodobacteraceae和Rhodospirillaceae,γ-Proteobacteria的Alteromonadaceae、HTCC2188和Oceanospirillaceae,Verrucomicrobia的Verrucomicrobiaceae和Bacteroidetes的Cryomorphaceae。更表现在核心微生物类群的差异,健康养殖池水体以Glaciecola、HTCC、Sediminicola、Prevotella等对于养殖动物有益或无害的属为核心微生物;而患病养殖池水体则以Vibrio、Rubritalea、Oleibacter等病原菌或对养殖动物不利的属为核心微生物。从患病青石斑鱼的皮肤、肝脏和脾脏共分离得到弧菌20株,Acinetobacter haemolyticus 1株。[结论] 患病的青石斑鱼循环水养殖水体中的细菌群落明显不同于健康养殖水体,特别是核心微生物的差异,其以Vibrio等病原菌或对养殖动物不利的属为主。该结果为青石斑鱼循环水养殖系统的管理、病害的诊断和监测提供理论与实验基础。

Abstract:

[Objective] This study was aimed to reveal the bacterial community characteristics of rearing water of marine recirculating aquaculture system for yellow grouper (Epinephelus awoara), and compare the differences between bacterial community structure of healthy rearing water and sick rearing water in order to elucidate the relationship between bacterial community and fish disease. [Methods] The next generation sequencing method was used, and the bacterial community structure and α-diversity indices (species richness, species evenness and phylogenetic diversity) between the rearing water of healthy and diseased groups were studied and compared. In addition, the traditional cultivation method was used to isolate suspected pathogens from the niduses of diseased yellow groupers. [Results] There was no significant difference between the α-diversities of healthy and diseased rearing water bodies, however, the results of principal coordinates analysis (PCoA) and the sample clustering of heatmap showed that the bacterial communities of healthy and diseased rearing water bodies were quite different. Although phyla Proteobacteria, Verrucomicrobia and Bacteroidetes were all the predominant ones in both communities, their relative abundance varied greatly. In diseased community, the relative abundances of α-Proteobacteria (25.07%) and γ-Protebacteria (22.74%) were similar, whereas the proportion of γ-Protebacteria (40.49%) was much higher than α-Proteobacteria (10.87%) in the healthy community. The differences of Verrucomicrobia and Bacteroidetes between the healthy and the diseased rearing water were also significant with relative abundances of 10.9% and 26.4%, and 20.9% and 12.3%, respectively. The significantly different families were Rhodobacteraceae and Rhodospirillaceae within class α-Proteobacteria; Alteromonadaceae and HTCC2188 within class γ-Protebacteria; Verrucomicrobiaceae within Verrucomicrobia; Cryomorphaceae within Bacteroidetes. The healthy and the diseased communities owned specific core microbes themselves. Glaciecola, HTCC, Sediminicola and Prevotella were the core genera in healthy rearing water, and Vibrio, Rubritalea and Oleibacter in diseased rearing water. Twenty strains of Vibrio spp. and one of Acinetobacter haemolyticus were isolated from skin, liver and spleen of diseased yellow grouper. [Conclusion] The shift of bacterial community structure and relative abundance of rearing water will help monitor the healthy status of recirculating aquaculture system. Our study provides theory and experimental basis to diagnosis and monitor of Vibrio disease for yellow grouper recirculating aquaculture system.