Valorisation of Common Sea Star (Asterias rubens) Biomass as an Alternative Protein Source in Diets for Whiteleg Shrimp, Litopenaeus vannamei

Abstract Purpose Echinoderms, such as the common sea star ( Asterias rubens , Asteroidea), are a disregarded and underestimated source of high protein biomass. They form locally large densities, cause damage to natural mussel beds and shellfish aquaculture, and constitute a large proportion of bycatch in fisheries. Currently, captured or fished sea stars are dumped or used as fertilisers. This study investigates the valorisation of sea star meal (SM) as an alternative to fishmeal (FM) in aquaculture diets for Whiteleg shrimp ( Litopenaeus vannamei ). Methods Common sea stars were processed to meal and incorporated into four experimental diets with increasing levels of SM, replacing 0, 20, 50, and 80% of FM. The diets were fed to shrimp for 42 days in a recirculating aquaculture system. Survival, feed intake, growth, hepatosomatic index, haemolymph metabolic, and immune parameters as well as apparent digestibility and digestive enzyme activities were determined (Animal trial Vet Authority registration number/date: TA21-01/31.08.2021). Results All treatments showed equally high survival rates and feed intake. Shrimp showed maximum growth on the diet with the highest SM inclusion (80%), which significantly exceeded growth of shrimp in the 0% replacement diet. The feed conversion ratio was significantly lower for shrimp fed the 50% and 80% SM-diets than the 0%-diet. Protein and energy digestibility were significantly higher in the 80% SM-diet compared to the other diets. Metabolic and immune parameters were not affected by the different diets. Conclusion Sea star, A. rubens , biomass shows high potential as a “sustainable added-value material” for shrimp feed. Its use can reduce the dietary FM content to 5.4%. Therefore, the authors recommend application in novel value chains for aquaculture in Europe. Trial Registration The animal experiment was approved and registered by the local veterinary authority in Bremen, Germany (approval ID: TA21-01, date of approval: 31.08.2021). Graphical Abstract