浮游细菌群落结构及其与网箱养殖鱼病害的关系

Structure of bacterioplankton community and its relationship with bacterial diseases of fish maricultured in cage

为了揭示深水网箱养殖区养殖过程中浮游细菌群落结构及其与网箱养殖鱼类细菌性病害的关系,采用Illumina测序技术对海南后水湾深水网箱养殖水样进行16S rRNA基因高通量测序。结果表明,检测到浮游细菌种群归属于36个门、56个纲、98个目、235个科、807个属,香农-威纳指数范围为2.47~4.5,说明该养殖区水体中浮游细菌具有丰富的多样性。变形菌门是主要优势门类,其次为拟杆菌门、放线菌门、厚壁菌门和蓝细菌门;主要类群为Cobetia属、弧菌属(Vibrio)、假交替单胞菌属(Pseudoalteromonas)、盐单胞菌属(Halomonas)等,不同养殖期优势类群差异较大,其中休养期以Cobetia属、玫瑰变色菌属和嗜冷杆菌属为主;养殖初期以Cobetia属、假交替单胞菌属、Kushneria属和弧菌属为主;养殖中期优势类群为Cobetia属、盐单胞菌属、交替单胞菌属(Alteromonas)、弧菌属和假交替单胞菌属;养殖后期优势类群为GpIIa属和Cobetia属。潜在致病菌弧菌属相对丰度在不同养殖期差异较大,在养殖初期、中期含量较高,而在非养殖期和养殖后期含量较低,与网箱养殖卵形鲳鲹细菌性病害发病规律相吻合,表明由于弧菌引起的鱼类病害为养殖区的主要细菌性病害类型。

To explore the structure of bacterioplankton community and its relationship with bacterial diseases of marine fish aquacultured in cage, bacterial communities from sea water sampled in a deep-water cage mariculture area at Houshuiwan Bay, Lingao, Hainan were analyzed through Illumina Miseq sequencing based on 16S RNA gene. The results showed that bacterioplankton species detected in the sea water samples belonged to 36 phyla, 56 classes, 98 orders, 235 families and 807 genera, with their Shannon-Wiener index ranging from2.47 to 4.5, which indicated a high diversity of bacterioplankton in the deep-sea cage mariculture area at Houshuiwan Bay. Proteobacteria were the main dominant phylum at all the sampling sites, followed by phyla Bacteroidetes, Actinobacteria, Firmicutes and Cyanobacteria. Dominant genera were Cobetia, Roseovarius and Psychrobacter in the non-mariculture period(March), Cobetia, Pseudoalteromonas, Kushneria and Vibrio in the early period of mariculture(May), Cobetia, Halomonas, Alteromonas, Vibrio and Pseudoalteromonas in the mid-period of mariculture(July and September), GpIIa and Cobetia in the late period of mariculture. Vibrio,potential pathogens, varied greatly during the mariculture and its abundance was found higher in the early period and mid-period of mariculture, and the lower in the non-and late mariculture periods, which was consistent with the incidence of bacterial diseases of fish in the deep-water cage mariculture area, indicating that vibriosis was the main bacterial disease of fish in the mariculture area.