大菱鲆仔稚鱼发育早期肠道菌群结构形成的影响因素

为研究鱼类发育早期肠道菌群结构的演变过程及影响因素,运用高通量测序技术,分析了处于不同发育阶段的大菱鲆(Scophthalmus maximus)仔稚鱼肠道、受精卵、不同类型的饵料和水源中的菌群结构,以及它们之间的相关性。结果显示,以不同的OTU(Operational Taxonomic Units,可操作分类单元)作为分类依据,发现大菱鲆仔稚鱼的肠道菌群结构在开口摄食后不久已趋于稳定,其优势菌与受精卵所携带的细菌关联较大。并且在大菱鲆仔稚鱼不同的发育时期,这一菌群的结构非常稳固,几乎不受水和饵料中优势细菌的影响而发生改变。乳球菌属的Lactococcus piscium菌株一直是大菱鲆仔稚鱼肠道中的优势菌种,在不同发育时期的优势度高达45%~65%。本研究还发现,大菱鲆仔稚鱼肠道可能对定植的菌种具有选择性,一些水环境和饵料中的非优势菌,如Streptococcus sp.,Pseudomonas sp.,Carnobacterium sp.等细菌也会定植于肠道,成为大菱鲆肠道中的次优势菌。

Factors that influence intestinal microflora formation in larval turbot(Scophthalmus maximus L.)

) is a cold-water marine fish. In recent years, with the expansion and improvementof turbot farming, bacterial disease has severely affected turbot development, especially in larvae. Becausethe fish have the special requirements for the living environment, disease occurrence is the result of interactions amongfish, pathogens, and the environment. The gastrointestinal flora plays an important role in fish growth and development,and is closely related to disease occurrence. Therefore, it is necessary to investigate the gastrointestinal flora of larvalfish. In this study, factors that influence gastrointestinal microflora formation and succession in turbot larvae were investigatedby high-throughput sequencing. The intestinal tract microflara and their relationships with different developmentstages (e.g., larvae and fertilized eggs), chlorella, rotifer, artemia, pellet feed, and tank inlet water were analyzed.The results revealed that the intestinal tract microflora of turbot larvae was stable after initial feeding and wasdirectly affected by bacteria in fertilized eggs. Meanwhile, microflora structure was stable during turbot larval developmentand barely influenced by the bacteria in water and feed. The dominant bacterium was at arelative proportion of up to 45%65% in larval intestines. In addition, the relative abundance of this bacterium in fertilizedeggs reached 10.4%. Basing on these results, we suggest that the gastrointestinal tract of turbot larvae may be selectivefor the colonized bacteria. Some bacteria in water and feed, such as the