ISSN: 2577-4050
Authors: Pan J, Wagner L, Trattner S, Brannas E, Bruheim I and Pickova J
Production of good quality fish muscle with reduced use of fish meal (FM) and oil (FO) is of great interest in aquaculture. This study tested 13 diets including (FM), krill meal (KM) or mussel meal (MM) and with rapeseed oil (RO) or RO+FO+KO (krill oil) (mixed oil, MO) or FO+KO (FKO) as the lipid source. These were fed to Arctic charr (Salvelinus alpinus) (initial weight 104.5±20.8 g, final weight 276.7±106.2, n=12) and their effects on FA profile, astaxanthin (AST) content and colour (a* value) of white muscle investigated. The FA profile of RO groups was characterised by monounsaturated fatty acids, α-linolenic acid and n-6 polyunsaturated fatty acids (PUFA), while FKO groups were mainly rich in saturated fatty acids (16:0, 14:0, 18:0), 16:1n-7 and n-3 PUFA, with a high n-3/n-6 ratio in the FA profile. Feeding KM, MM, KO gave positive effects on deposition of n-3 PUFA and AST. One group fed an AST-deficient diet showed comparable levels of arachidonic acid, eicosapentaenoic acid and docosahexaenoic acid to other groups, although the diet contained much lower levels of these FA. Another group fed a diet including the highest levels of KO (8.1%) and KM (29.4%) exhibited the highest n-3 PUFA level, n-3/n-6 ratio, AST content, a* value and thiobarbituric reactive substances (TBARS) value. In conclusion, KM, KO and MM could be used to improve the FA profile and colour properties of Arctic charr white muscle. AST not only affects colour properties, but also FA metabolism. Practical applications: It was found that the FA profile of muscle from Arctic charr fed high levels of MM, KO and KM were rich in n-3 PUFA and had a high n-3/n-6 ratio, high AST content and high a* value. These results indicate that KM, KO and MM can be used to improve lipid quality and colour property in fish fillet and can act as a potential substitute for FO and FM in salmonid aquaculture. The similar levels of n-3 PUFA in groups with and without sufficient AST in the diet fed group suggest that antioxidant deficiency may induce Arctic charr to use α-linolenic acid to form n-3 PUFA. This provides a possible avenue for low-cost accumulation of n-3 PUFA in fish fillet. All these results are beneficial information for improving the use of non-fish-based materials in salmonid farming.
Keywords: Krill; Blue mussel; Astaxanthin; Fatty acids; TBARS
