两种混养方式对异枝江蓠(Gracilaria bailinae)生长性能、表面附生细菌群落及抗生素抗性基因的影响

为揭示"鱼-藻"和"鱼-虾-藻"混养对异枝江蓠(Gracilaria bailinae)生长性能、表面附生细菌群落和抗生素抗性基因(antibiotic resistance genes,ARGs)的影响,阐明异枝江蓠表面附生细菌群落与生长性能、ARGs之间的关系,利用16S rDNA高通量测序技术和Real-time qPCR技术分析了异枝江蓠表面附生细菌群落和ARGs的组成与差异,冗余分析(RDA)探讨细菌群落与生长性能、ARGs之间的关联。结果表明:(1)"鱼-虾-藻"混养会促进异枝江蓠的生长性能,增加表面附生细菌群落的多样性。(2)异枝江蓠表面附生细菌群落主要属于变形菌门、蓝藻门、浮霉菌门和拟杆菌门,不同混养方式中优势菌属组成不同,"鱼-虾-藻"混养优势菌属多样性较高。(3)"鱼-虾-藻"混养的异枝江蓠ARGs/MGEs的相对丰度大多高于"鱼-藻"混养。(4)RDA分析表明,生长性能主要与Ralstonia、Blastopirellula等显著相关,ARGs/MGEs主要与Nitrosomonas、Alteromonas、Pleurocapsa;CC-7319等显著相关。"鱼-虾-藻"混养能够增强异枝江蓠的生长性能,提高异枝江蓠表面附生细菌群落的多样性。但"鱼-虾-藻"混养能够增加异枝江蓠ARGs/MGEs的相对丰度,存在一定的生态风险。因此,在注重经济效益的同时也要关注可能存在的对人类健康的危害。研究结果将有助于海水养殖环境的优化,为大型海藻在海水养殖业中的应用与推广提供理论基础。

EFFECTS OF TWO TYPES OF POLYCULTURE MODE ON GROWTH PERFORMANCE, SURFACE EPIPHYTIC BACTERIAL COMMUNITY AND ANTIBIOTIC RESISTANCE GENES OF GRACILARIA BAILINAE

To study the effects of“fish-algae”and“fish-shrimp-algae”polyculture on growth performance,antimicrobial resistance genes(ARGs),and surface bacteria community of Gracilaria bailinae,and to elucidate the correlation between bacterial community with growth performance and ARGs,the composition and differences of bacterial communities and ARGs of G.bailinae were analyzed by 16S rDNA high-throughput sequencing and real-time qPCR.The correlation between bacterial communities with growth performance and ARGs was investigated by redundancy analysis(RDA).The results show that(1)the polyculture of“fish-shrimp-algae”promoted the growth performance and increase the diversity of surface epiphytic bacterial community of G.bailinae.(2)The main phyla of the epiphytic bacteria community were Proteobacteria,Cyanobacteria,Planctomycetes,and Bacteroidetes.The composition of dominant genera was different in different types of polyculture.The diversity of dominant genera was higher in“fish-shrimp-algae”polyculture.(3)The relative abundance of ARGs/MGEs in G.bailinae cultured with fish and shrimp was higher than that in G.bailinae cultured with fish.(4)RDA analysis showed that the growth performance was significantly correlated with Ralstonia and Blastopirellula,and ARGs/MGEs was significantly correlated with Nitrosomonas,Alteromonas,and Pleurocapsa_PCC-7319.Therefore,the polyculture of“fish-shrimp-algae”could enhance the growth performance and improve the diversity of surface epiphytic bacterial community of G.bailinae.It should be noted that“fish-shrimp-algae”could increase the relative abundance of ARGs and MGEs of G.bailinae,may pose an ecological risk.Therefore,attention should be paid to the possible harm to human health while improving economic benefits.This study contributed to the optimization of mariculture environment and provided a theoretical basis for the application and promotion of macroalgae in mariculture.