Environmental temperature is one of the critical factors affecting fish development. The aim of this study was to examine the impact of three different rearing temperatures (16°C, 19°C and 22°C) throughout the endogenous feeding phase of the Siberian sturgeon Acipenser baerii. This was performed by assessing i) larval survival and growth, ii) immunofluorescence localization and expression of genes involved in muscle development and growth - myog and Igf1, and iii) stress status through the expression of thermal stress genes - Hsp70, Hsp90α and Hsp90β - and whole body cortisol. Overall survival rate and larval weight did not differ significantly across temperatures. Larvae subjected to 22°C showed faster absorption of the yolk-sac than larvae subjected to 19°C or 16°C. Both at schooling and at the end of the trial, larvae reared at 16°C showed significantly lower levels of cortisol than those reared at 19°C or 22°C. IGF-1 immunopositivity was particularly evident in red muscle at schooling stage in all temperatures. The expression of all Hsps as well as the myog and Igf1 genes was statistically higher in larvae reared at 16°C but limited to the schooling stage. Cortisol levels were higher in larvae at 22°C, probably because of the higher metabolism demand rather than a stress response. The observed apparent incongruity between Hsps gene expression and cortisol levels could be due to the lack of a mature system. Further studies are necessary, especially regarding the exogenous feeding phase, in order to better understand if this species is actually sensitive to thermal stress. This article is protected by copyright. All rights reserved.

中文翻译：

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不同饲养温度如何影响西伯利亚鲟Acipenser baerii幼虫的生长和应激状态

环境温度是影响鱼类发育的关键因素之一。本研究的目的是检查三种不同的饲养温度（16°C、19°C 和 22°C）在整个西伯利亚鲟Acipenser baerii 的内源喂养阶段的影响。这是通过评估 i) 幼虫存活和生长，ii) 参与肌肉发育和生长的基因的免疫荧光定位和表达 - myog 和 Igf1，以及 iii) 通过表达热应激基因 - Hsp70、Hsp90α 和 Hsp90β 的应激状态来进行的 -和全身皮质醇。总存活率和幼虫重量在不同温度下没有显着差异。处于 22°C 的幼虫表现出比处于 19°C 或 16°C 的幼虫更快地吸收卵黄囊。在上学和审判结束时，在 16°C 饲养的幼虫的皮质醇水平明显低于在 19°C 或 22°C 饲养的幼虫。IGF-1 免疫阳性在所有温度的学龄期红肌中尤为明显。在 16°C 饲养的幼虫中，所有 Hsps 以及 myog 和 Igf1 基因的表达在统计学上更高，但仅限于学龄期。22°C 时幼虫的皮质醇水平较高，这可能是因为较高的新陈代谢需求而不是应激反应。观察到的 Hsps 基因表达和皮质醇水平之间的明显不一致可能是由于缺乏成熟的系统。需要进一步研究，特别是关于外源喂养阶段，以便更好地了解该物种是否真的对热应激敏感。本文受版权保护。版权所有。