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Does the capacity for energy utilization affect the survival of post-smolt Atlantic salmon, Salmo salar L., during natural outbreaks of infectious pancreatic necrosis?


If osmotic stress and reduced seawater tolerance are predisposing factors for infectious pancreatic necrosis (IPN) outbreaks in farmed Atlantic salmon, increased survival by enhancing access to energy would be expected. The aim of the present study was, therefore, to increase energy access in 1-year old Atlantic salmon after sea transfer by increasing the level of dietary fat, by exchanging some of the dietary oil with more easily oxidized medium chain triacylglycerols, or by dietary supplementation of potentially energy enhancing additives such as clofibrate and tetradecylthioacetic acid (TTA). A natural outbreak of IPN occurred 8 weeks after sea transfer, and a significant dietary effect explaining 76% of the variation in mortality was observed. Relative percentage survival for the fish fed TTA in sea water was 70% when compared with the unsupplemented control, reducing mortality from 7.8 to 2.3%. Muscle fat content and plasma chloride were related to IPN mortality, suggesting that reduced hypoosmoregulatory capacity might be a predisposing factor to the onset of an IPN outbreak. Based on the observation of a threefold increase in white muscle mitochondrial fatty acid oxidizing activity by TTA, it is suggested that TTA has resulted in a re-allocation of dietary fatty acids from storage to energy producing oxidation.


Academic article




  • Magny Skinlo Thomassen
  • Kjell-Arne Rørvik
  • Henriette Alne
  • Mari Gaarder
  • Bente Ruyter
  • N.P. Måseide
  • Jan Vidar Jakobsen
  • Rolf Berge
  • Trygve Sigholt


  • Norges miljø- og biovitenskapelige universitet
  • Nofima, The Norwegian Institute of Food, Fisheries and Aquaculture Research
  • Intervet Norbio AS
  • Bergen
  • Unknown
  • University of Bergen
  • SINTEF Ocean



Published in

Journal of Fish Diseases




Blackwell Publishing




399 - 409

View this publication at Cristin