Fiedler Alexander W, Drågen Martha K R, Lorentsen Eirik D, Vadstein Olav, Bakke Ingrid
Department of Biotechnology and Food Science, Norwegian University of Science and Technology, Trondheim, Norway.
Front Microbiol. 2023 Jul 6;14:1177972. doi: 10.3389/fmicb.2023.1177972. eCollection 2023.
The bacterial colonization of newly hatched fish is important for the larval development and health. Still, little is known about the ontogeny of the early microbiota of fish. Here, we conducted two independent experiments with yolk sac fry of Atlantic salmon that were (1) either reared conventionally, with the eggs as the only source for bacteria (egg-derived microbiota; EDM) or (2) hatched germ-free and re-colonized using lake water (lake-derived microbiota; LDM). First, we characterized the gut and skin microbiota at 6, 9, and 13 weeks post hatching based on extracted RNA. In the second experiment, we exposed fry to high doses of either a fish pathogen or a commensal bacterial isolate and sampled the microbiota based on extracted DNA. The fish microbiota differed strongly between EDM and LDM treatments. The phyla Proteobacteria, Bacteroidetes, and Actinobacteria dominated the fry microbiota, which was found temporarily dynamic. Interestingly, the microbiota of EDM fry was more stable, both between replicate rearing flasks, and over time. Although similar, the skin and gut microbiota started to differentiate during the yolk sac stage, several weeks before the yolk was consumed. Addition of high doses of bacterial isolates to fish flasks had only minor effects on the microbiota.
新孵化鱼类的细菌定殖对幼体发育和健康很重要。然而，人们对鱼类早期微生物群的个体发育仍知之甚少。在此，我们对大西洋鲑鱼的卵黄囊仔鱼进行了两项独立实验，实验对象为：（1）传统饲养的仔鱼，以鱼卵作为细菌的唯一来源（卵源微生物群；EDM）；（2）无菌孵化并用湖水重新定殖的仔鱼（湖源微生物群；LDM）。首先，我们根据提取的RNA，在孵化后6周、9周和13周对肠道和皮肤微生物群进行了表征。在第二项实验中，我们将仔鱼暴露于高剂量的鱼类病原体或共生细菌分离株中，并根据提取的DNA对微生物群进行采样。EDM和LDM处理之间的鱼类微生物群差异很大。变形菌门、拟杆菌门和放线菌门在仔鱼微生物群中占主导地位，且发现其具有暂时的动态变化。有趣的是，EDM仔鱼的微生物群在重复饲养瓶之间以及随时间推移都更加稳定。尽管皮肤和肠道微生物群相似，但在卵黄囊阶段，即在卵黄被消耗前几周，它们就开始分化。向鱼瓶中添加高剂量的细菌分离株对微生物群的影响很小。
