Abstract:In order to study the effects of environmental factors on the intestinal flora structure of turbot (Scophthamus maximus), we used high-throughput sequencing to explore the bacterial community structure and diversity in juvenile turbot intestines, the culture environment, and biological baits. The results showed that 547621 effective sequences were detected in nineteen samples, and they could be classified into 3771 operational taxonomic units (OTUs), among which 3038, 1090, 87, and 777 originated from the aquaculture water, the biological baits, healthy juvenile turbot intestine, and diseased juvenile fish intestine, respectively. There were 57 OTUs shared between the healthy juvenile turbot intestine and the biological baits, 0 OTU shared between the healthy juvenile turbot intestine and aquaculture water, 481 OTUs shared between the diseased juvenile fish intestine and the biological baits, 31 OTUs shared between the diseased juvenile fish intestine and the aquaculture water. The effect of biological bait on microbial diversity of intestinal tract of juvenile fish was much greater than that of environment. In total, the predominant phyla in the turbot intestine were Bacteroidetes, Firmicutes, and Proteobacteria. The intestinal microflora of healthy juvenile turbot can be clustered into 8 phyla, and the intestinal microflora of the diseased juvenile fish could be clustered into 19 phyla. Compared with the healthy juveniles, the community structure of the predominant phyla was imbalanced at the intestinal level of the diseased juvenile fish. Furthermore, analysis of the 100 most abundant bacterial OTUs in the different samples revealed that the species dominant in the intestinal bacteria of juvenile fish was closely related to the dominant species in the biological baits. Meanwhile, the intestinal dominant bacteria species of each diseased juvenile are different. This study provided the basis for healthy culture and micro-ecological regulation of turbot.
