Temperature effects on gene expression and morphological development of European Eel, Anguilla anguilla larvae

• Published in: PLOS ONE
• Main Authors: Politis, Sebastian N., Mazurais, David, Servili, Arianna, Zambonino-Infante, Jose-Luis, Miest, Joanna J., Sørensen, Sune R., Tomkiewicz, Jonna, Butts, Ian A. E.
• Format: Article in Journal/Newspaper
• Language: English
• Published: Public Library of Science (PLoS) 2017
• Subjects: SH Aquaculture. Fisheries. Angling; Anguilla anguilla
• Online Access: http://gala.gre.ac.uk/id/eprint/17309/; http://gala.gre.ac.uk/id/eprint/17309/8/17309%20MIEST_Morphological_Development_of_European_Eel_%20%28OA%29_2017.pdf; https://doi.org/10.1371/journal.pone.0182726

Temperature is important for optimization of rearing conditions in aquaculture, especially during the “critical” early life history stages of fish. Here, we experimentally investigated the thermal tolerance range for early larval European eel, Anguilla anguilla. We assessed the impact of temperature (16, 18, 20, 22, and 24°C) on thermally induced phenotypic variability, from larval hatch to first-feeding, and the linked expression of targeted genes [heat shock proteins (hsp), growth hormone (gh) and insulin-like growth factors (igf)] associated to larval performance. Statistical models were applied to investigate temperature effects on larval morphology and gene expression throughout early larval development (0 to 18 days post-hatch) and at specific developmental stages (Stages 1-3). Stage 1 represents the day of hatch, Stage 2 represents the timing of jaw/teeth formation, and Stage 3 represents the first-feeding stage. Results showed that hatch success, yolk utilization efficiency, and survival decreased, while deformities, yolk utilization, and growth rates increased with increasing temperature (16-22°C). Increasing temperature accelerated larval development and in real-time, gene expression patterns were delayed when larvae were reared at cold temperatures (16°C) or accelerated when reared at warm temperatures (20-22°C). In developmental time, the expression of all targeted genes were affected by larval stage and expression of hsp90 and gh was furthermore affected by temperature. We conclude that 24°C is deleterious, while 16°C and 22°C (90% deformities) represent the lower and upper thermal tolerance limits. The combination of highest larval survival, lowest incidence of larval deformities at hatch, high yolk utilization efficiency, high gh and low hsp expression, suggest 18°C as the optimal temperature in larval culture of European eel. Furthermore, our results suggest that the still enigmatic early life history stages of European eel may inhabit the deeper layer of the Sargasso Sea and indicate ...