基于DNA宏条形码技术的沙氏下鱵幼鱼食性分析

为详细了解鱼类早期生活史阶段的食物组成,以黄海北部海水池塘养殖环境下不同发育阶段的沙氏下鱵(Hyporhamphus sajori)幼鱼为对象,提取其胃含物及水环境样品DNA,选用18SrDNA V4区作为分子标记进行扩增,通过DNA宏条形码技术(DNA metabarcoding)鉴定其食物组成及摄食选择性。结果显示, 33日龄沙氏下鱵幼鱼胃含物样品中共检出17个物种门类,其中节肢动物门(45.29%)序列数占比最高,其他物种序列数占比超过1%的门类依次为绿藻门(20.34%)、硅藻门(12.35%)、甲藻门(12.42%)、纤毛虫门(2.41%)、链形植物门(1.75%)、鞭毛虫门(1.24%)和子囊菌门(1%),同期水环境样品中甲藻门序列数占绝对优势(76.64%),其次分别为纤毛虫门(2.52%)、刺胞动物门(1.50%)、异鞭藻门(1.34%)、丝足虫门(1.12%); 63日龄沙氏下鱵幼鱼胃含物样品中共检出18个物种门类,其中节肢动物门序列数占绝对优势(97.31%),其他门类物种序列数占比均小于1%,同期水环境样品中甲藻门(57.92%)为优势门类,其他物种序列数占比超过...

Preliminary dietary analysis of Hyporhamphus sajori juveniles based on DNA metabarcoding

As a core research field in trophic ecology and biology, fish dietary analysis enables the understanding of the food composition and functional role of target predators in ecosystems. In this study, the 18S rDNA high-throughput sequencing method was used to investigate the diet composition of Hyporhamphus sajori juveniles in an aquaculture pond in the northern Yellow Sea for providing more details about the feeding behavior of juvenile fish. A standardized process of DNA metabarcoding analysis was used, including stomach and water collection, DNA extraction, genetic marker amplification, sequencing, and bioinformatic analyses. The results showed that 17 phyla were detected from the stomach contents of 33-day-old H. sajori in which Arthropoda (45.29%) was the dominant phylum, followed by Chlorophyta (20.34%), Pyrrophyta (12.42%), Bacillariophyta (12.35%), Intramacronucleata (2.41%), Streptophyta (1.75%), Sarcomastigophora (1.24%), and Ascomycota (1%). A total of 15 phyla were detected from the environmental water samples, including Pyrrophyta, Intramacronucleata, Cnidaria, Heterokontophyta, and Cercozoa, in which Pyrrophyta (76.64%) was the dominant phylum. Additionally, 18 phyla were detected from the stomach contents of 63-day-old H. sajori, in which Arthropoda (97.31%) was the dominant phylum. Additionally, 15 phyla were detected from the environmental water samples, including Pyrrophyta (57.92%), Intramacronucleata (10.97%), Bacillariophyta (8.05%), Chrysophyta (4.54%), Cryptophyta (3.88%), Heterokontophyta (3.85%), Cnidaria (2.30%), Arthropoda (1.61%), and Chlorophyta (1.07%). The results showed that the food composition differed between H. sajori juveniles at different developmental stages, and the diet of H. sajori mainly included Arthropoda, Chlorophyta, and Bacillariophyta, which is consistent with the previous study findings utilizing traditional morphological identification, except for Fungi, Intramacronucleata, and Streptophyta, which were identified only in the present study. Therefore, DNA metabarcoding is helpful for analyzing the diets of fish species and showed advantages over traditional food analysis based on morphology in identifying fish dietary components.