长牡蛎食物组成的高通量测序分析

Analysis of food sources of Crassostrea gigas using high-throughput sequencing techniques

中文关键词: 胃含物  18S rDNA  高通量测序  长牡蛎  桑沟湾

英文关键词: Stomach contents  18S rDNA  High-throughput sequencing  Crassostrea gigas  Sanggou Bay

中文摘要:

      为了更加细致地甄别滤食性贝类的食物组成，于2019年8月，以北方规模化典型养殖海湾——桑沟湾养殖的长牡蛎(Crassostrea gigas)为研究对象，运用Illumina高通量测序技术对长牡蛎的胃含物及所处养殖水体中的真核生物进行分析研究。结果显示，扩增18S rDNA V4区平均得到111,359个有效序列短片段，在97%相似性水平上划分OTUs (operational taxonomic units)，聚类后得到239个类别。其中，长牡蛎胃含物中的真核生物分属于34个门，绿藻门(Chlorophyta)、甲藻门(Pyrrophyta)、链形植物(Streptophyta)、硅藻门(Bacillariophyta)和原生动物(Protozoa)等为主要类群。所处养殖水体中的真核生物分属于37个门，绿藻门、脊索动物门(Chordata)、节肢动物门(Arthropoda)、甲藻门和硅藻门等为主要类群。结果表明，浮游植物是长牡蛎的主要食物来源，链型植物和原生动物也有一定的贡献，分别占总食物贡献量的10.43%和4.11%。研究结果为深入认识滤食性贝类的摄食生态学及其在养殖生态系统物质循环和能量流动中发挥的作用提供了数据支撑。

英文摘要:

      Filter-feeding bivalves have a wide range of food sources, including phytoplankton, organic detritus, and zooplankton, among others. In order to identify the food composition of filter-feeding bivalves, Crassostrea gigas cultured in Sanggou Bay, a typical northern large-scale mariculture bay, were used in the experiment. The eukaryotic composition of the stomach contents of C. gigas and of the ambient seawater column were analyzed using Illumina sequencing technology, in August 2019. Overall, 111,359 reads were optimized, and 239 operational taxonomic units were recognized by amplifying the 18S rDNA V4 loci sequences. The eukaryotes found in the stomach contents of C. gigas belonged to 34 phyla, with the majority belonging to Chlorophyta, Pyrrophyta, Streptophyta, Bacillariophyta, and Protozoa. As for the composition of the ambient seawater, the eukaryotes belonged to 37 phyla and they were mainly classified under Chlorophyta, Chordata, Arthropoda, Dinophyceae, and Bacillariophyta. The analysis showed that phytoplankton is the main food source for C. gigas, although Streptophyta and Protozoa accounted for a non-negligible portion of the total food content—10.43% and 4.11%, respectively. These results provide insights to further understand the feeding ecology of filter-feeding bivalves, as well as their role in material cycles and energy flow in mariculture ecosystems.