Prolonged Cold Exposure Negatively Impacts Atlantic Salmon ( Salmo salar ) Liver Metabolism and Function

Large-scale mortality events have occurred during the winter in Atlantic salmon sea cages in Eastern Canada and Iceland. Thus, in salmon held at 3 °C that were apparently healthy (i.e., asymptomatic) and that had ‘early’ and ‘advanced’ symptoms of ‘winter syndrome’/’winter disease’ (WS/WD), we measu...

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Bibliographic Details
Published in:Biology
Main Authors: Isis Rojas, Albert Caballero-Solares, Émile Vadboncoeur, Rebeccah M. Sandrelli, Jennifer R. Hall, Kathy A. Clow, Christopher C. Parrish, Matthew L. Rise, Andrew K. Swanson, Anthony K. Gamperl
Format: Article in Journal/Newspaper
Language:English
Published: MDPI AG 2024
Subjects:
winter mortality
winter syndrome
lipid metabolism
fatty liver disease
salmon aquaculture
Biology (General)
QH301-705.5
Atlantic salmon
Iceland
Salmo salar
Online Access:https://doi.org/10.3390/biology13070494
https://doaj.org/article/cd88906ea5b844258dec22581e6953f3
Description
Summary:Large-scale mortality events have occurred during the winter in Atlantic salmon sea cages in Eastern Canada and Iceland. Thus, in salmon held at 3 °C that were apparently healthy (i.e., asymptomatic) and that had ‘early’ and ‘advanced’ symptoms of ‘winter syndrome’/’winter disease’ (WS/WD), we measured hepatic lipid classes and fatty acid levels, and the transcript expression of 34 molecular markers of fatty liver disease (FLD; a clinical sign of WS/WD). In addition, we correlated our results with previously reported characteristics associated with this disease’s progression in these same individuals. Total lipid and triacylglycerol (TAG) levels increased by ~50%, and the expression of 32 of the 34 genes was dysregulated, in fish with symptoms of FLD. TAG was positively correlated with markers of inflammation ( 5loxa , saa5 ), hepatosomatic index (HSI), and plasma aspartate aminotransferase levels, but negatively correlated with genes related to lipid metabolism ( elovl5b , fabp3a , cd36c ), oxidative stress ( catc ), and growth ( igf1 ). Multivariate analyses clearly showed that the three groups of fish were different, and that saa5 was the largest contributor to differences. Our results provide a number of biomarkers for FLD in salmon, and very strong evidence that prolonged cold exposure can trigger FLD in this ecologically and economically important species.

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