凡纳滨对虾小型温棚养殖模式水体微生物群落的研究

Study on bacterial community structure in rearing water in small greenhouse of Litopenaeus vannamei

小型温棚养殖模式(下称小棚模式)是近年来凡纳滨对虾(LitopenaeuSvannamei)养殖的热点模式。为阐明小棚模式养殖水体微生物群落的特点,探究该模式高产、高效的原因,基于16SrRNA基因的测序结果,对第2、第44、第69和第96天小棚模式养殖水体的微生物群落组成和功能进行了分析。结果表明:凡纳滨对虾小棚养殖后期,水体微生物群落的丰富度和多样性显著高于前期;在整个养殖过程中,门水平主要优势菌为变形菌门、拟杆菌门和放线菌门,其中变形菌门丰度在第69天显著增加,放线菌门丰度前期较高,后期下降;属水平优势菌属中Candidatus_Aquiluna的丰度在第2天最高(28.7%);海命菌属(Marivita)在中期富集,在第69天丰度最高(9.94%);黄杆菌属(Flavobacterium)的丰度随着养殖时间逐渐增加,在第96天达到最高(11.63%)。通过PICRUSt2预测微生物群落的功能,丰度前20的代谢功能项在第69和第96天的丰度显著高于第2天,尤其萜类和聚酮类代谢、脂类代谢、异种生物降解和代谢等功能均高度富集,通过FAPROTAX鉴定得出,化能异养类菌的丰度在养殖后期显著增加。环境因子关联分析发现,总氮(TN)和化学需氧量(COD)对小棚模式水体微生物群落结构的影响最大,海命菌属、Candidatus_Aquiluna、红小梨形菌属(Rhodopirellula)等微生物发挥了固碳、降氮、降磷的作用。综上所述,在高密度、高氮磷的环境条件下,小棚模式的水体微生物在保持水环境稳定和增强对虾免疫与抗病能力方面发挥了重要作用。

In recent years,small greenhouse haSbeen a hot model of LitopenaeuSvannamei culture.In order to elucidate the structure and changeSof the microbial community in the rearing water of L.vannamei culture in small greenhouse and explore the reasonSfor high yield and high efficiency of thiSmodel,we analyzed the composition and function of the microbial community on 2nd,44th,69th and 96th day of water in the small greenhouse based on 16SrRNA sequencing results.The resultSshow that the richnesSand diversity of water microbial community at late stage of small greenhouse were significantly higher than those at early stage.During the whole culture process,the dominant bacteria at the phylum level were Proteobacteria,BacteroideteSand Actinobacteria,among which the abundance of Proteobacteria increased significantly on 69th day,and the abundance of Actinobacteria increased at early stage but decreased at later stage.At genuSlevel,the abundance of Candidatus_Aquiluna waSthe highest on 2nd day(28.7%).Marivita waSenriched at middle stage,with the highest abundance on 69th day(9.94%).The abundance of Flavobacterium gradually increased with the culture time,reaching the highest on 96th day(11.63%).PICRUSt2 predictSthe function of the microbial communities,and the abundanceSof metabolic function in the top 20 were significantly higher on 69th and 96th day than on 2nd day.In particular,the functionSof terpenoidSand polyketideSmetabolism,lipid metabolism,xenobioticSbiodegradation and metabolism were highly enriched.Through FAPROTAX identifying,the abundance of chemoheterotrophy increased significantly at the late stage.The correlation analysiSof environmental factors showSthat total nitrogen(TN)and chemical oxygen demand(COD)had the greatest impactSon the microbial community structure in greenhouse model.MicroorganismSsuch aSMarivita,Candidatus_Aquiluna and Rhodopirellula played the roleSin sequestration of carbon and reduction of nitrogen and phosphorus.In conclusion,under the high density and high nitrogen and phosphoruSculture conditions,the water microbial community in the small greenhouse played an important role in maintaining the stability of water environment and enhancing the immunity and disease resistance of prawns.