Gastrointestinal (GI) or gut microbiota play essential roles in host development and physiology. These roles are influenced partly by microbial community composition. During early developmental stages, ecological processes underlying the assembly and successional changes in host GI community composition are influenced by numerous factors including dispersal from the surrounding environment, age-dependent changes in the gut environment, and changes in dietary regimes. However, the relative importance of factors to gut microbiota are not well understood. We examined effects of environmental (diet and water sources) and host early ontogenetic development on diversity and compositional changes in gut microbiota of a primitive teleost fish, the lake sturgeon (Acipenser fulvescens), based on massively parallel sequencing of the 16S rRNA gene. Fish larvae were raised in environments that differed in water source (stream vs filtered groundwater) and diet (supplemented vs non-supplemented Artemia). We quantified gut microbial community structure at three stages (pre-feeding, one, and two weeks after exogenous feeding began). Diversity declined and community composition differed significantly among stages, however, only modest differences associated with dietary or water sources treatments were documented. Many taxa present in the gut were over or under-represented relative to neutral expectations in each sampling period. Findings indicate dynamic relationships between gut microbiota composition and host gastrointestinal physiology, with comparatively smaller influences associated with rearing environments. Neutral models of community assembly could not be rejected, but selectivity associated with microbe-host GI tract interactions through early ontogenetic stages were evident. Results have implications for sturgeon conservation and aquaculture production specifically, and applications of microbial-based management in teleost fishes generally.

IMPORTANCE We quantified effects of environment (diet and water sources) and host early ontogenetic development on diversity and compositional changes in gut microbial communities based on massively parallel sequencing of the 16S rRNA gene from GI tracts of larval lake sturgeon (Acipenser fulvescens). Gut microbial community diversity declined and community composition differed significantly among ontogenetic stages, however only modest differences associated with dietary or water sources treatments were documented. Selectivity associated with microbe-host GI tract interactions through early ontogenetic stages were evident. Results have implications for lake sturgeon and early larval ecology and survival in natural habitat and conservation and aquaculture production specifically, as well as applications of microbial-based management in teleost fishes generally.

胃肠道（GI）或肠道菌群在宿主发育和生理中起重要作用。这些作用部分受到微生物群落组成的影响。在发展的早期阶段，宿主胃肠道群落组成的组装和连续变化所依据的生态过程受许多因素的影响，包括从周围环境的扩散，肠道环境的年龄依赖性变化以及饮食制度的变化。但是，人们对肠道菌群因素的相对重要性还不甚了解。我们检查了环境（饮食和水源）的影响，并主持了早期个体发育对原始硬骨鱼，st鱼（Acipenser fulvescens）肠道菌群多样性和组成变化的影响），基于16S rRNA基因的大规模并行测序。鱼幼虫生长在水源（溪流与过滤的地下水）和饮食（补给与非补给的卤虫）不同的环境中）。我们在三个阶段（预喂养，外源喂养开始后的一和两周）量化了肠道微生物群落结构。在各阶段之间，多样性下降，社区组成显着不同，但是，只有与饮食或水源处理有关的适度差异被记录下来。相对于每个采样周期的中性预期，肠道中存在的许多分类单元都过高或过低。研究结果表明肠道菌群组成与宿主胃肠道生理之间的动态关系，与饲养环境相关的影响相对较小。社区装配的中性模型不能被拒绝，但是通过早期个体发育阶段与微生物-宿主胃肠道相互作用相关的选择性是显而易见的。

重要性我们量化的多样性和基于由幼鲟鱼湖的胃肠道16S rRNA基因的大规模平行测序肠道微生物群落的组成变化的环境的影响（饮食和水源）和主机早期个体发育（鲟毛鼠）。在个体发育阶段，肠道微生物群落多样性下降，群落组成显着不同，但是仅记录了与饮食或水源处理相关的适度差异。通过早期个体发育阶段与微生物-宿主胃肠道相互作用相关的选择性是显而易见的。结果对have鱼和早期幼虫的生态学以及自然栖息地，保护和水产养殖生产中的生存，以及基于微生物的管理在硬骨鱼中的应用具有重要意义。