Aquaculture Europe 2023

September 18 - 21, 2023


Add To Calendar 21/09/2023 15:00:0021/09/2023 15:15:00Europe/ViennaAquaculture Europe 2023IMMUNOMODULATORY EFFECTS OF LAMINARIN FROM Laminaria hyperborea ON ATLANTIC SALMON LEUKOCYTES – FIRST STEPS TOWARDS NOVEL FUNCTIONAL FEED APPLICATION FOR SALMONSchubert 1The European Aquaculture Societywebmaster@aquaeas.orgfalseDD/MM/YYYYaaVZHLXMfzTRLzDrHmAi181982



R . Montero1*, V.F. Blihovde1 , L.J. Klau2 , J.M. Hooft1, B. Morales-Lange1 , O.A. Aarstad2 , F.L. Aachmann2, A. Tøndervik4, H. Sletta4, L.T. Mydland1, M. Øverland1

 1 Department of Animal and Aquaculture Sciences, Faculty of Biosciences, Norwegian University of Life Sciences, 1433 Ås, Norway.
2 Department of Biotechnology and Food Science, NTNU Norwegian University of Science and Technology, 7491 Trondheim, Norway.
3 Department of Biotechnology and Nanomedicine, SINTEF Industry, Trondheim, Norway.



Fish health and welfare are great concerns to the aquaculture industry. In this regard, the search for sustainable feed compounds  with bioactive properties,  which  contribute to maintaining fish health, is  highly  relevant.  Seaweeds are important natural resources for the food and feed industry worldwide and volumes of cultivated seaweeds a re increasing over the years. Seaweeds contain bioactive compounds such as laminarin and fucoidan which have shown antioxidant, immunostimulant and anti-bacterial properties in several mammalian and fish cells. Few studies have evaluated effects of laminarin in salmon cells , and so far, no  studies have been done to evaluate laminarin as a bioactive compound in diets for salmon  with the aim to improve/enhance immune responses.

 To assess whether laminarin has immune-modulating activity on salmon cells, and to  reduce the use of experimental animals, a “stepwise approach” was used. Step 1 involved an in vitro screening of  differentially processed laminarin on  the  viability  and on immune responses of salmon cells . Step 2 will involve  an in vivo  salmon  trial  evaluating  the effects of  different  dietary  inclusion  levels  of laminarin o n  growth performance and immune-related parameters.  Together,  this  work  will contribute to setting a basis for the inclusion of laminarin in salmon feed, with an overall aim to support and improve fish health and welfare.


Laminaria hyperborea biomass was processed by water extraction (50 oC, 4  h). A precipitate consisting of enriched laminarin was formed after storage of extract at 4 º C for several days. After extensive washing in 4 ºC ion-free water and in 50 % ethanol, three fractions were made by acid hydrolysis for further testing: L1, hydrolyzed 1 h, L2, hydrolyzed 3  h, and L3, control fraction without hydrolysis. To evaluate their  effects  in Atlantic salmon-isolated  leukocytes from  spleen and head kidney (HK) , viability and bioactivity assays were performed using the three  laminarin fractions. For the viability assay, 100, 250 and 500 µg mL-1 were used, and the cell viability  was measured after 6, 24, 48 and 72  h. For the bioactivity assay, spleen and HK cells were incubated with laminarin fractions at 250 µg mL-1 for 6 and 24 h, and a panel of immune-related biomarkers were measured by qPCR.

Results and discussion                      

None of the fractions exhibited a toxic effect on spleen and head kidney (HK) cells; L1 even  showed a positive effect on cell viability in cells from both organs at 250 µg mL-1 .  Regarding bioactive properties on salmon leukocytes , L1 elicited  an up-regulation of tnfa , il1b , inos , ifng, cath-2 , tgfb and sod in both organs,  which is similar to a mammalian macrophage type 1 profile (M1), evidencing a short-term inflammatory response  that decreased 24  h after the exposure to laminarin.  Moreover,  in HK,  L3 induced  an up-regulation of tgfb ,  while  no significant gene expression modulation was observed with L2. On the contrary, in spleen  L2 and L3 showed an up-regulation of ifng il1b, in os  and tgfb, suggesting a differential response between these two organs.


Results show that laminarin from L. hyperborea  has  immuno-modulating capacity on salmon leukocytes . Therefore, laminarin could be  a promising functional component  for  aquafeeds, especially when exposed to a low processing level such as  in  fraction L1. Further work is being carried out to elucidate whether laminarin may exert further immune effects on  other salmon cells. B ased on the promising results obtained in Step 1, Step 2 , which will focus on  including laminarin in salmon diets,  is now being planned ,  with a  future view to its application in novel functional feeds for the salmon aquaculture industry.

 Acknowledgements: This work was supported by The Norwegian Seaweed Biorenery Platform (The Research Council of Norway; grant number 294946) and Foods of Norway, a Center for Research-based Innovation (The Research Council of Norway; grant number 237841/030).