How different rearing temperatures affect growth and stress status of Siberian sturgeon Acipenser baerii larvae

• Published in: Journal of Fish Biology
• Main Authors: Lucia Aidos, Alessandra Cafiso, Daniela Bertotto, Chiara Bazzocchi, Giuseppe Radaelli, Alessia Di Giancamillo
• Other Authors: Aidos, Lucia, Cafiso, Alessandra, Bertotto, Daniela, Bazzocchi, Chiara, Radaelli, Giuseppe, Di Giancamillo, Alessia
• Format: Article in Journal/Newspaper
• Language: English
• Published: London: Academic Press 2020
• Subjects: "Acipenser baerii larvae"; "gene expression"; "muscle development"; "stress"; "temperature"; Acipenser baerii; Siberian sturgeon
• Online Access: http://hdl.handle.net/11577/3348840; https://doi.org/10.1111/jfb.14280

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 tempera-tures (16, 19 and 22°C) throughout the endogenous feeding phase of the Siberian sturgeon Acipenser baerii. This was performed by assessing (a) larval survival and growth; (b) immunofluorescence localization and expression of genes involved in muscle development and growth – myog and Igf1; and (c) 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 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 at19 or 22°C. IGF-1 immunopositivity was particularly evident in red muscle at school-ing 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.