不同养殖模式下罗氏沼虾肠道菌群结构特征及其与环境因子的关系

通过高通量测序技术分析不同养殖模式对罗氏沼虾(Macrobrachium rosenbergii)肠道菌群结构的影响,冗余分析(RDA)肠道菌群与水环境因子的关系。实验设置6种养殖模式:罗氏沼虾单养(MP组)、罗氏沼虾+浮萍(Lemna minor)(PP组)、罗氏沼虾+鲢(Hypophthalmichthys molitrix)(PF组)、罗氏沼虾+背角无齿蚌(Anodonta woodiana)+鲢(PMF组)、罗氏沼虾+背角无齿蚌+浮萍(PMP组)、罗氏沼虾+背角无齿蚌+浮萍+鲢(PMPF组)。养殖64 d,测定水环境因子(浊度、DO、pH、Chl.a、COD、BOD、NO_3-N、NO_2-N、NH_3-N、TN、TP、PO_4-P、TOC)及肠道菌群结构。结果表明:罗氏沼虾不同养殖模式对水体浊度、PO_4-P、TN和Chl.a具有显著影响(P0.05),MP组PO_4-P浓度最大且显著大于其他组(P0.05)。肠道细菌多样性指数MP组最大(4.08),最低为PMF组(1.27)。变形菌门(Proteobacteria)、软壁菌门(Tenericute)和厚壁菌门(Firmicutes)在虾肠道中相对丰度较大。不同养殖模式最大优势菌存在较大差异,其中MP、PMP和PMPF组为气单胞菌属(Aeromonas)、PP组为柠檬酸杆菌属(Citrobacter)、PF和PMF组为Candidatus Hepatoplasma。肠道细菌与环境因子相关性分析表明:TP对罗氏沼虾肠道菌群具有显著影响(P0.05);肠棕气单胞菌(Aeromonas enteropelogenes)、有益菌肠球菌(Enterococcus)和格氏乳酸菌(Lactococcus garvieae)与NO_3-N和TN呈正相关,红细菌属(Rhodobacter)和假单胞菌(Pseudomonas vranovensis)与TP呈正相关。可见,养殖模式可通过影响水体营养盐尤其是氮磷含量影响罗氏沼虾肠道微生物群落结构。

Effects of different cultural patterns on microbial communities in the intestine of Macrobrachium rosenbergii and interactions with environment factors

Microbial communities in the intestine of Macrobrachium rosenbergii under six cultural patterns were evaluated by high-throughput pyrosequencing technology. The interactions between microbial and water environment were also analyzed by RDA (Redundancy analysis). The cultural patterns included prawn monoculture group (MP), prawn with aquatic plant (Lemna minor) group (PP), prawn with silver carp (Hypophthalmichthys molitrix) group (PF), prawn with mussel (Anodonta woodiana) and H. molitrix group (PMF), prawn with mussel and aquatic plant group (PMP), prawn with A. woodiana, L. minor and H. molitrix group (PMPF). Four replicates of each treatment were set up. After 64 days of culturing, the microbial communities and physico-chemical factors were assessed. There were significant differences in turbidity, soluble phosphorus (PO₄-P), total nitrogen (TN) and chlorophyll-a (Chl.a) among groups, and PO₄-P concentration in MP group was significantly higher than those in other groups (P<0.05). Shannon diversity index of intestinal bacteria was the highest in the MP group (4.08), and the lowest in the PMF group (1.27). Proteobacteria, Tenericute and Firmicutes were the major dominant phyla in intestine of M. rosenbergii in the six groups. The major dominant genus was different in six groups, which was Aeromonas in MP, PMP and PMPF groups, and Citrobacter in PP group, and Candidatus and Hepatoplasma in PF and PMF groups. The interaction analysis between intestinal bacteria and environmental factors showed that total phosphorus (TP) had significant effects on the intestinal bacterial community of M. rosenbergii (P<0.05), Adaptation of microorganisms to the environment factors was different, and the abundance of Aeromonas enteropelogenes, beneficial Enterococcus and Lactococcus garvieae were positive correlation with NO₃-N and TN. Rhodobacter and Pseudomonas vranovensis were positive correlation with TP. Conclusively, cultural patterns can affect the intestinal bacterial community of M. rosenbergii by affecting the nutrient concentration in the water, especially nitrogen and phosphorus.