Nutrient digestibility and growth in Arctic charr fed microbial and mussel protein meal

The content of marine based feed sources must be decreased in feed for fish. New production has to be built on sustainable practices and technologies which include production of aquafeeds with other ingredients which are not suitable as food for humans.  We have investigated the nutrient digestibility and performed a short term growth study on Artic charr fed microbial biomass and blue mussel meal instead of fish meal. Analysis of feed show different amino acid profiles with very low methionine content in especially R. oryaze (RHO) and extracted Saccharomyces (ESC), whereas intact Saccharomyces (ISC) showed similar amino acid profile as fish meal but with slightly lower methionine content.

The apparent digestibility coefficients of dry matter, crude protein, total amino acid and energy were highest for ESC, mussel meal (MYE) and RHO. No difference in weight gain was observed between fish fed the reference diet, diet ISC and diet MYE. Fish fed diet RHO and ESC showed 16 and 13% lower weight gain compared with fish fed diet REF.

The conclusion of the results is that intact Saccharomyces and mussel meal are good alternatives as a protein source instead of marine fish meal for feeding Arctic charr. The results suggest that ISC togheter with MYE is the best choice for developing locally produced feed resources and closing the nutrient loop in the Baltic Sea region. The results will be followed up with further evaluation in long-term feeding experiments with Arctic charr.

Report: Nutrient digestibility and growth in Arctic charr fed microbial and mussel protein meal