Aquaculture Europe 2023

September 18 - 21, 2023


Add To Calendar 20/09/2023 11:45:0020/09/2023 12:00:00Europe/ViennaAquaculture Europe 2023BEYOND NUTRITIONAL VALUE: MYCOPROTEIN Paecilomyces variotii IMPROVES GROWTH PERFORMANCE AND OVERALL HEALTH RESPONSES IN ATLANTIC SALMONStrauss 2The European Aquaculture Societywebmaster@aquaeas.orgfalseDD/MM/YYYYaaVZHLXMfzTRLzDrHmAi181982


 D. D. Mensah1*,  B. Morales-Lange1,  M. Øverland1 ,  K. Baruah2 ,  J. Kuivanen3 ,  L. T. Mydland1


1Department of Animal and Aquacultural Sciences, Faculty of Biosciences, Norwegian University of Life Sciences (NMBU ), Oluf Thesens vei 6-1430 , Aas (Norway).

2  Department of Animal Nutrition & Management, Faculty of Veterinary Medicine & Animal

Sciences, Swedish University of Agricultural Sciences 750 07 Uppsala, Sweden

3 EniferBio, Peuraniitty 5 B 25, 02750, Espoo, Finland




 Farmed  salmon will play a significant role in bridging the demand gap for high-quality food.  However, salmon farming is faced with several challenges including  access to high quality  feed resources,  and  multi-stressor conditions  such as suboptimal environmental conditions and diseases  leading to  mortalities and economic losses. Therefore ,  the need for sustainable novel feed resources to replace the conventional feed resources currently used in salmon feeds  has never been  more urgent. N ovel aquafeed  ingredients should  be sustainable  and  address  both nutritional and health related challenges in salmon farming. Microbial ingredients (MIs ) such as  yeast and  fungi  provide a viable alternative to address  both challenges due to their high nutritional value

  and bioactive components with proven health benefits

 . Paecilomyces variotii (PEKILO®) is a filamentous fungus with high crude protein content (60-70%)  and  it  contains  bioactive components such as β -glucans, mannans and nucleic acids w hich induce  health benefits for fish.  Considering this, our study  under the NordForsk -funded NordicFeed project  was designed  to  characterize the immuno modulating effects of P . variotii in Atlantic salmon ( Salmo salar )  using in vitro and in vivo  techniques.  We hypothesized that  the functional bioactive components in P . variotii  will improve  overall  health  and welfare in Atlantic salmon .

Materials and methods

 The immunomodulatory effect of P . variotii fermented on sulphite stillage as substrate was characterized using  adherent mononuclear leucocytes  isolated  from head kidney (HK) and spleen of Atlantic salmon (ca. 2 kg)  and incubated  for 6, 24 and 48 hours  with or without the presence of  heat inactivated Moritella viscosa (Figure 1, left panel).  For the in vivo assessment, vaccinated Atlantic salmon pre- smolts  were fed diets with P . variotii replacing  0, 5, 10, or 20%  of  crude protein  from fishmeal  and  soy protein concentrates for 4 weeks in freshwater . G rowth and  health parameters were analyzed (Figure 1, right panel).


 Results from the in vitro studies (Figure 1, left panel)  indicated that P . variotii  induces a strong immune response  in the HK of Atlantic salmon at all  time-points evaluated , but  most strongly after 6 h . Co-stimulation of the s pleen and HK leucocytes  with bo th P . variotii  and M . viscosa induces an even  stronger  immune response,  particularly in the HK. Upregulation of regulatory cytokine in the HK and downregulation  in the spleen  was observed when the bacteria alone  or a combination with P . variotii was added to cell cultures. In addition, P . variotii enhanced the antimicrobial activity of leucocytes with  higher transcript level s of β -glucan receptors, demonstrating recognition of this bioactive compound in the feed ingredient . Our results from the f eeding trial (Figure 1, right panel) indicates that all  inclusion  levels of P . variotii resulted in feed intake,  specific growth rate  like the control diet  and  a dose-dependent linear decrease in the feed conversion ratio with increasing inclusion of the mycoprotein . The i mmune responses induced by P . variotii were systemic.  Low and high doses of P . variotii modulated a strong T cell response, innate responses, and enhanced antimicrobial activity. Medium and high dosage also modulated a Th1 response as well as receptors and signaling molecules characteristic of β-glucan recognition (Fig ure  1). Further ,  inclusion of P . variotii  in diets for Atlantic salmon increased  specific  antibody titres against V . anguillarum.


P . variotii    can replace up to 20% of crude protein in the diet of Atlantic salmon  without compromising  growth performance of the fish.  In addition, P . variotii  has significant health benefits in Atlantic salmon beyond its nutritional value  including enhancing the natural killer cells, the complement system, antimicrobial activity of leucocytes, modulated type 1 and type 2 responses and  improved humoral responses.


1. Agboola, J.O., M. Øverland, A. Skrede, and J.Ø. Hansen, Yeast as major protein‐rich ingredient in aquafeeds: a review of the implications for aquaculture production. Reviews in Aquaculture, 2021. 13(2): p. 949-970.

2. Morales-Lange, B., B. Djordjevic, A. Gaudhaman, C.M. Press, J. Olson, L.T. Mydland, L. Mercado, M. Imarai, M. Castex, and M. Øverland, Dietary Inclusion of Hydrolyzed Debaryomyces hansenii Yeasts Modulates Physiological Responses in Plasma and Immune Organs of Atlantic Salmon (Salmo salar) Parr Exposed to Acute Hypoxia Stress. Frontiers in Physiology, 2022. 13.