Biotechnology processing of woody side streams from Norwegian spruce trees to produce high-quality microbial ingredients such as fungal single cell proteins can help address the protein deficit of the aquaculture industry, reduce environmental footprint, and improve fish health and welfare. PEKILO®, a β-glucan- and nucleotide-rich fungal single cell protein (mycoprotein), can serve as an alternative protein source in aquaculture feed. In the current study, PEKILO® was evaluated as a protein source in diets for Atlantic salmon at the Norwegian University of Life Sciences (NMBU, Norway). Four experimental diets were formulated to contain an increasing level of PEKILO®, replacing 0, 5, 10, or 20% of the crude protein (CP) content of the diet. The results showed that PEKILO® can successfully replace up to 20% of the CP content without significantly affecting growth rate or feed intake. Moreover, increasing dietary inclusion of PEKILO® resulted in a significant linear improvement in feed conversion ratio (Table 1).
Considering the composition of PEKILO®, its immunostimulant properties were evaluated in vitro using Atlantic salmon head kidney leucocytes. Gene expression data (Figure 1) indicated that PEKILO® and its fractions induce a strong immune response in Atlantic salmon by the upregulation of cytokines related to pro-inflammatory (IL-1β), chemoattractant (IL-8) and downregulated anti-inflammatory (IL-10) functions.
These findings suggest that PEKILO® is a high-quality novel protein source that also have potential to stimulate the immune response and improve health status of Atlantic salmon.