Seawater tolerance and gene expression in two strains of Atlantic salmon smolts

• Published in: Canadian journal of fisheries and aquatic sciences Vol. 59; no. 1; pp. 125 - 135
• Main Authors: Singer, Thomas D, Clements, Koreen M, Semple, Jeffrey W, Schulte, Patricia M, Bystriansky, Jason S, Finstad, Bengt, Fleming, Ian A, McKinley, R Scott
• Format: Journal Article
• Language: English
• Published: Ottawa, Canada NRC Research Press 01.01.2002; National Research Council of Canada; Canadian Science Publishing NRC Research Press
• Subjects: Agnatha. Pisces; Animal and plant ecology; Animal aquaculture; Animal productions; Animal, plant and microbial ecology; Animals; Autoecology; Biological and medical sciences; Brackish; Fish; Freshwater; Fundamental and applied biological sciences. Psychology; Genetics; Marine; Oceans; Pisciculture; Salmo salar; Salmon; Seawater; Vertebrata; Vertebrate aquaculture; Norway; Europe; Norway, Vest-Agder, Imsa R; Norway, Namsen R; Salmonidae; Enzyme; Salmo salar; Osmoregulation; Tolerance; Environmental factor; K; Gene expression; Aquatic environment; Vertebrata; Na; Messenger RNA; Enzymatic activity; Pisces; Pisciculture; Hydrolases; exchanging ATPase; Intraspecific comparison; Cystic fibrosis transmembrane conductance regulator; Seawater
• ISSN: 0706-652X; 1205-7533
• DOI: 10.1139/f01-205

The seawater tolerance of Atlantic salmon (Salmo salar) smolts reared under identical hatchery conditions was assessed in two Norwegian strains: AquaGen and Imsa. Plasma ion levels were disrupted in both strains following seawater exposure, but these disruptions were more profound in the AquaGen fish. To investigate the mechanisms underlying these differences, we measured gill Na + ,K + -adenosine triphosphatase (ATPase) activity and mRNA levels of Na + ,K + -ATPase α-subunit and two isoforms of the cystic fibrosis transmembrane conductance regulator (CFTR). Gill Na + ,K + -ATPase activity rose significantly in both strains following seawater exposure. Both Na + ,K + -ATPase α-subunit and CFTR I mRNA levels were significantly elevated for the entire 2-week period following seawater exposure, whereas CFTR II levels were transiently elevated during the first 24 h only. There were no differences in enzyme activity or gene expression between strains, with the exception of CFTR II, which was significantly lower in the Imsa strain 2 weeks following seawater exposure. This suggests that although changes in mRNA and protein expression for these genes are associated with seawater transfer, they are not the basis of observed physiological differences between strains.