Louvado Antonio, Castro Carolina, Silva Davide A M, Oliveira Vanessa, Conceição Luís E C, Cleary Daniel F R, Gomes Newton C M
Department of Biology and Centre for Environmental and Marine Studies (CESAM), University of Aveiro, 3810-193 Aveiro, Portugal.
Flatlantic-Actividades Piscícolas, SA 3070-732 Praia de Mira, Portugal.
Microorganisms. 2023 Feb 17;11(2):520. doi: 10.3390/microorganisms11020520.
Live feed enrichments are often used in fish larvicultures as an optimized source of essential nutrients to improve larval growth and survival. In addition to this, they may also play an important role in structuring larval-associated microbial communities and may help improve their resistance to diseases. However, there is limited information available on how larval microbial communities and larviculture water are influenced by different live feed enrichments. In the present study, we investigated the effects of two commercial rotifer enrichments (ER) on turbot () larval and post-larval gut-associated bacterial communities during larviculture production. We evaluated their effects on bacterial populations related to known pathogens and beneficial bacteria and their potential influence on the composition of bacterioplankton communities during larval rearing. High-throughput 16S rRNA gene sequencing was used to assess the effects of different rotifer enrichments (ER1 and ER2) on the structural diversity of bacterial communities of the whole turbot larvae 10 days after hatching (DAH), the post-larval gut 30 DAH, and the larviculture water. Our results showed that different rotifer feed enrichments were associated with significant differences in bacterial composition of turbot larvae 10 DAH, but not with the composition of larval gut communities 30 DAH or bacterioplankton communities 10 and 30 DAH. However, a more in-depth taxonomic analysis showed that there were significant differences in the abundance of Vibrionales in both 10 DAH larvae and in the 30 DAH post-larval gut fed different RE diets. Interestingly, the ER1 diet had a higher relative abundance of specific amplicon sequence variants (ASVs) related to potential -antagonists belonging to the Roseobacter clade (e.g., and at 10 DAH and at 30 DAH). In line with this, the diet was also associated with a lower relative abundance of and a lower mortality. These results suggest that rotifer diets can affect colonization by members in the guts of post-larval turbot. Overall, this study indicates that live feed enrichments can have modulatory effects on fish bacterial communities during the early stages of development, which includes the relative abundances of pathogenic and antagonist taxa in larviculture systems.
活体饵料强化剂常用于鱼类育苗，作为优化的必需营养素来源，以促进幼体生长和提高存活率。除此之外，它们在构建与幼体相关的微生物群落方面可能也发挥着重要作用，并可能有助于提高幼体的抗病能力。然而，关于不同的活体饵料强化剂如何影响幼体微生物群落和育苗用水的信息有限。在本研究中，我们调查了两种商业轮虫强化剂（ER）在大菱鲆幼鱼和幼鱼后期养殖生产过程中对其肠道相关细菌群落的影响。我们评估了它们对与已知病原体和有益细菌相关的细菌种群的影响，以及它们在幼鱼培育过程中对浮游细菌群落组成的潜在影响。利用高通量16S rRNA基因测序来评估不同轮虫强化剂（ER1和ER2）对孵化后10天（DAH）的整个大菱鲆幼体、30 DAH的幼鱼后期肠道以及育苗用水中细菌群落结构多样性的影响。我们的结果表明，不同的轮虫饵料强化剂与10 DAH的大菱鲆幼体细菌组成的显著差异有关，但与30 DAH的幼体肠道群落组成或10和30 DAH的浮游细菌群落组成无关。然而，更深入的分类分析表明，在喂食不同RE日粮的10 DAH幼体和30 DAH幼鱼后期肠道中，弧菌科的丰度存在显著差异。有趣的是，ER1日粮中与属于玫瑰杆菌属潜在拮抗剂相关的特定扩增子序列变体（ASV）的相对丰度更高（例如，10 DAH时为 和 ，30 DAH时为 ）。与此一致的是，该日粮还与较低的 相对丰度和较低的死亡率相关。这些结果表明，轮虫日粮可以影响大菱鲆幼鱼后期肠道中 成员的定殖。总体而言，本研究表明，活体饵料强化剂在发育早期阶段可对鱼类细菌群落产生调节作用，这包括育苗系统中致病和拮抗类群的相对丰度。
