刺参繁殖期高能量需求的摄食行为响应与调控机制

Sea cucumber Apostichopus japonicus is an important marine aquaculture species in China. Increasing energy demand is a serious challenge to A. japonicus during reproduction. Feeding is the only way for energy intake of sea cucumber, however, the characteristics and regulatory mechanisms of feeding behavior during reproduction are still poorly studied. On the basis of previous studies, this study focuses on behavioral response to high energy demand, and regulatory mechanism of gut microbiota in feeding behavior during reproduction. Combining by timelapse camera, infrared camera, sport camera, high-throughput sequencing technology and LC-MS technology, behavioral basis of the dynamic feeding efficiency during reproduction are studied, then behavioral basis of the changing feeding preference during reproduction are revealed, and molecular regulation mechanism of gut microbiota and its metabolites in feeding behavior are clarified. These data not only provide new insights into behavioral physiology of sea cucumber, but also provide theoretical support for the technologies of broodstock rearing of sea cucumber.

刺参是我国重要的海珍品，因性腺发育导致的能量需求升高是刺参繁殖阶段面临的主要生理问题，摄食是刺参能量摄入的唯一途径，但刺参繁殖期摄食行为与调控机制研究基础还相对薄弱。基于前期研究基础，本项目聚焦刺参摄食行为对繁殖期高能量需求的响应特征、肠道菌群对摄食行为的调控机制两个关键科学问题，通过应用缩时摄像、红外摄像、运动摄像、高通量测序、液相色谱-质谱联用等技术方法，研究刺参在繁殖期摄食效率变化的行为基础，阐明刺参在繁殖期摄食选择性转换的行为基础，查明肠道菌群及代谢物对刺参摄食行为的调控机制，进而实现刺参行为生理学的新认知，以期为科学培育亲参提供数据支撑。

刺参是我国传统海珍品，亲参培育是刺参增养殖过程中的核心技术环节，而繁殖期行为学研究是亲参培育技术体系的理论基础。本项目以刺参繁殖期性腺发育能量需求与营养来源分析、刺参摄食效率对繁殖期高能量需求的响应特征、刺参摄食选择性对繁殖期高能量需求的响应特征、肠道菌群及代谢物对刺参繁殖期摄食行为的调控机制为主要研究内容，以期阐明刺参繁殖期的关键行为适应策略。在能量需求方面，通过碳氮稳定同位素标记与有机质积累动态监测，发现刺参在繁殖期的能量需求出现显著升高，且维持性腺发育的营养全部依赖于外源性摄食。在摄食效率方面，随着性腺发育，发现刺参摄食个体比例、摄食量、摄食率与摄食节律都出现了显著下降，而空腹代谢率出现了显著上升，表明刺参通过降低摄食效率以满足性腺发育的氧气需求。在摄食选择性方面，发现刺参在繁殖期对沉积物中的细粒径与动物性碎屑表现出了明显的选择偏好性，表明刺参通过转换食性来满足性腺发育的高能量需求。在肠道菌群方面，发现刺参肠道菌群组成及代谢物存在明显的季节性变化，在繁殖期出现的优势菌群与关键营养物质的消化吸收具有协同关系，表明刺参可通过改变肠道菌群以加强对营养物质的消化吸收，进而满足性腺发育的高能量需求。本研究结果可为刺参亲参的高效培育提供重要理论依据。