对虾病害发生的微生物生态学过程机制研究

Frequent occurrence of disease is one of the major bottle-necks of the development of shrimp-culture industry. Microbial community plays crucial and pivotal roles in shrimp-culture ecological system, and is closely related to the occurrence of shrimp diseases. But so far, our understanding of microbial community structure and function in aquaculture systems is still at the initial stage and the related cognition are often sole and fragmented. The conclusions of the different experiments from different research groups, or even the same group, often appear to be inconsistent. This project intends to build a microbial ecological experiment system with a consistent specification for shrimp-culture environment, in order to investigate the relationships among environment ecological factors, microbial community, and healthy status of shrimp with a global and dynamic perspective of aquaculture system. The ecological statistical analyses are applied to characterize the diversity and composition of microbial community and the dynamics in their relationships with the healthy status of shrimp and to quantify the driving effects of climate, water physicochemical parameters, and shrimp activity on microbial community succession in the entire duration of culture. Meanwhile, the data from the series experiments at seasonal- and annual-scales with enough biological replicates will be deeply mined to modify and generalize the characteristics of microbial community, thus providing more abundant and deep insights into the relationship between microbial community and the healthy status of shrimps and preliminarily setting up a theoretical framework of mechanisms in microbial ecological processes in shrimp-culture system. This project will provide a solid theoretical basis for the developments of prevention-control techniques and products of shrimp disease.

病害频发是当前对虾养殖业发展的重要瓶颈之一，微生物群落在对虾养殖生态系统中发挥着核心和枢纽作用，与对虾病害发生密切相关。但迄今为止，我们对微生物群落结构和功能及其动态演替过程的认识还处于初步阶段，许多认知呈孤立和分散状态,并且经常出现不同研究组甚至同一研究组不同实验的结论相互矛盾。本项目拟构建规范一致的对虾养殖环境微生物生态实验体系，从养殖系统全局和动态的角度研究环境生态因子-微生物群落-对虾健康度三者之间的关系，应用生态统计学解析对虾养殖全程中微生物群落的多样性和组成结构特征及其与对虾健康度的关系的动态变化模式，量化气候、水体理化和对虾活动对微生物群落演替的驱动作用。在多生物学重复、季节和年度重复中去修正和归纳微生物群落特征，丰富和深化对微生物群落与对虾健康和病害关系的内涵和外延的认知，初步建立对虾养殖系统环境微生物生态过程机制理论框架，为对虾病害防控技术和产品的研发提供扎实的理论基础。

背景：病害频发是对虾养殖业发展的重要瓶颈之一，微生物群落在对虾养殖生态系统中发挥着核心枢纽作用，与对虾病害发生密切相关。但是，我们对微生物群落结构功能及其动态演替过程的认识还处于初步阶段，急需进行系统深入的研究。.主要研究内容：1）研究了发病养殖塘细菌群落的分化特征，探究了病原载量与细菌群落紊乱度的统计学关系，解析了不同品系对虾肠道细菌群落对低温胁迫的响应；2）研究了育苗全周期对虾幼体细菌群落动态演替及其群落构建机制，开展了成虾养殖阶段全程微生态跟踪分析；3）研究了外加碳源、益生菌、牡蛎壳等的添加对养殖系统微生物群落结构的动态影响。.重要结果：1.对虾肠道细菌群落稳态与其健康高度相关。证据：1）发病对虾肠道细菌群落在时序上较不稳定，且呈多样性分化，而健康虾肠道细菌群落表现出较高的时序稳态，且其核心细菌组各分类元的相互作用强于病害虾；2）抗低温对虾品系的肠道细菌群落表现出更好的稳定性；3）添加葡萄糖或者蔗糖提高对虾成活率，同时其肠道菌群稳态增强；4）乳酸菌对对虾的益生作用也与对虾肠道菌群稳态的提高相关。2.红杆菌科细菌在对虾肠道细菌群落中起着核心作用。证据：1）红杆菌是对虾育苗和养成全生命周期中的主要细菌类群；2）对虾发病时，其肠道中红杆菌丰度显著减少；3）葡萄糖或蔗糖的添加在改善对虾生长性能的同时，红杆菌相对丰度提高；4）红杆菌相对丰度与弧菌或支原体的相对丰度呈负相关；5）大粒径生物絮团中高丰度的红杆菌与对虾健康相关性更强；6）从对虾肠道分离出的一株具有体外抑制弧菌作用的红杆菌G18饲喂对虾后抑制了弧菌在对虾胰腺中的定植。.科学意义：1）通过塑造和调控肠道菌群保护和恢复细菌群落稳态是提高对虾抗逆防病能力的有效策略；2）对虾肠道细菌群落稳态特征可作为对虾良种筛选的指标之一，3）以红杆菌科为代表的对虾肠道细菌群落稳态支柱菌可能是重要的新型抗逆防病益生菌资源。