Deng Yale, Kokou Fotini, Eding Ep H, Verdegem Marc C J
Aquaculture and Fisheries Group, Wageningen University and Research, Wageningen, The Netherlands.
Anim Microbiome. 2021 Nov 27;3(1):81. doi: 10.1186/s42523-021-00145-w.
Fish gut microbial colonisation starts during larval stage and plays an important role in host's growth and health. To what extent first colonisation could influence the gut microbiome succession and growth in later life remains unknown. In this study, Nile tilapia embryos were incubated in two different environments, a flow-through system (FTS) and a biofloc system (BFS); hatched larvae were subsequently cultured in the systems for 14 days of feeding (dof). Fish were then transferred to one common recirculating aquaculture system (RAS1, common garden, 15-62 dof), followed by a growth trial in another RAS (RAS2, growth trial, 63-105 dof). In RAS2, fish were fed with two types of diet, differing in non-starch polysaccharide content. Our aim was to test the effect of rearing environment on the gut microbiome development, nutrient digestibility and growth performance of Nile tilapia during post-larvae stages.
Larvae cultured in the BFS showed better growth and different gut microbiome, compared to FTS. After the common garden, the gut microbiome still showed differences in species composition, while body weight was similar. Long-term effects of early life rearing history on fish gut microbiome composition, nutrient digestibility, nitrogen and energy balances were not observed. Still, BFS-reared fish had more gut microbial interactions than FTS-reared fish. A temporal effect was observed in gut microbiome succession during fish development, although a distinct number of core microbiome remained present throughout the experimental period.
Our results indicated that the legacy effect of first microbial colonisation of the fish gut gradually disappeared during host development, with no differences in gut microbiome composition and growth performance observed in later life after culture in a common environment. However, early life exposure of larvae to biofloc consistently increased the microbial interactions in the gut of juvenile Nile tilapia and might possibly benefit gut health.
鱼类肠道微生物定殖始于幼体阶段，对宿主的生长和健康起着重要作用。首次定殖在多大程度上会影响后期肠道微生物群落的演替和生长仍不清楚。在本研究中，尼罗罗非鱼胚胎在两种不同环境中孵化，即流水系统（FTS）和生物絮团系统（BFS）；孵化后的幼体随后在这些系统中饲养14天（投喂天数，dof）。然后将鱼转移到一个共同的循环水养殖系统（RAS1，共同养殖环境，15 - 62dof），随后在另一个RAS（RAS2，生长试验，63 - 105dof）中进行生长试验。在RAS2中，给鱼投喂两种非淀粉多糖含量不同的饲料。我们的目的是测试养殖环境对尼罗罗非鱼幼体后期肠道微生物群落发育、营养物质消化率和生长性能的影响。
与FTS相比，在BFS中养殖的幼体生长更好，肠道微生物群落也不同。在共同养殖环境后，肠道微生物群落在物种组成上仍存在差异，而体重相似。未观察到早期养殖历史对鱼肠道微生物群落组成、营养物质消化率、氮和能量平衡的长期影响。尽管如此，BFS养殖的鱼比FTS养殖的鱼有更多的肠道微生物相互作用。在鱼类发育过程中，观察到肠道微生物群落演替存在时间效应，尽管在整个实验期间仍存在一定数量的核心微生物群落。
我们的结果表明，鱼类肠道首次微生物定殖的遗留效应在宿主发育过程中逐渐消失，在共同环境中养殖后，后期生活中未观察到肠道微生物群落组成和生长性能的差异。然而，幼体早期接触生物絮团持续增加了尼罗罗非鱼幼鱼肠道中的微生物相互作用，可能有利于肠道健康。
