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Variation in skin barrier function throughout smoltification in Atlantic salmon (Salmo salar)
Darragh Doyle1, Ana Silva Gomes2, Kristina Sundell1
1Department of Biological and Environmental Sciences, University of Gothenburg, Gothenburg, Sweden.
Frontiers in Physiology
|July 6, 2026
Summary
Atlantic salmon skin permeability increases during smoltification, with altered electrical properties observed across life stages. This highlights the need to manage skin health during this critical transition for aquaculture.
Area of Science:
- Aquaculture
- Fish Physiology
- Animal Science
Background:
- Smoltification is a complex developmental process in Atlantic salmon involving significant physiological and behavioral changes.
- Skin barrier function is crucial for osmoregulation and protection but remains understudied during smoltification.
Purpose of the Study:
- To functionally assess changes in Atlantic salmon skin barrier function during smoltification.
- To evaluate skin permeability and transport capacity across parr, smolt, and post-smolt stages.
Main Methods:
- Electrophysiological measurements (transepithelial resistance and short-circuit current) were used.
- Measurements were conducted under controlled Ringer's conditions and following freshwater/seawater exposure.
- mRNA expression of selected tight junction genes was analyzed.
Main Results:
- Parr skin exhibited higher permeability and lower electrical current compared to smolts.
- Seawater exposure increased transepithelial potential in post-smolts, while freshwater exposure increased current in smolts.
- No significant differences in tight junction gene expression correlated with skin permeability.
Conclusions:
- Functional changes in Atlantic salmon skin barrier during smoltification are not explained by the selected tight junction genes alone.
- Elevated skin permeability post-seawater exposure necessitates prioritizing skin health in aquaculture husbandry during and after smoltification.
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