MINERAL CARRYOVER FROM SHELLED MUSSEL MEAL IN THE SPOTTED WOLFFISH (ANARHICHAS MINOR). Potential of dietary mineral supplementation on growth, stress and health.

Abstract: The potential of Swedish aquaculture is currently not fulfilled as Sweden is still a net importer of fish with low production and narrow species diversity. In recent years, there has been increasing interest in expanding and diversifying Swedish aquaculture to make it more sustainable and competitive. Introducing new species and novel sustainable feeds can contribute to reducing the carbon footprint and the pressure on wild fish populations. A promising potential species for cold water aquaculture is the spotted wolffish. Commercial cultivation is compromised by the lack of an optimized diet, which may be related to health issues like nephrocalcinosis. Mussel meal is apromising protein source that can be produced locally in Sweden and contribute towards a new Swedish feed sector. Including shells in mussel meal can increase production efficiency, reduce waste, and may provide minerals. This project aimed to evaluate shelled mussel meal as a potentialfeed ingredient by assessing the effect of shell inclusion on growth, health, and stress in spotted wolffish. We measured osmolarity, ion- and acid-base balance in plasma, cortisol, glucose, lactate, hemoglobin and hematocrit, as well as insulin-like growth factor 1, free fatty acids and ghrelin. We also assessed specific growth rate, condition factor, weight gain and average weight and length. The results show that growth performance was not impaired by shell inclusion; the average final weight was 1162.72g ± 30.82 for fish fed shelled mussel meal, and 1145.17g ± 32.39 for fish fed musselmeal. The inclusion of shells did not impair the maintenance of the homeostasis, plasma stress biomarkers or growth biomarkers. This indicates that shelled mussel meal is a potentialsustainable ingredient in fish feed that does not impair the overall wellbeing of spotted wolffish.