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Aquaculture Environment Interactions

    AEI prepress abstract   -  DOI:

    Production of polychaete Hediste diversicolor using side streams from aquaculture and biogas production and its potential as an aquaculture food source

    Haiqing Wang*, Andreas Hagemann, Kjell Inge Reitan, Jørgen Ejlertsson, Håvard Wollan, Aleksander Handå, Arne Malzahn

    *Corresponding author:

    ABSTRACT: We evaluated the potential of the marine bristleworm (polychaete) Hediste diversicolor to recycle side streams from aquaculture and biogas production. To assess the suitability of polychaetes produced on side streams as e.g. feed ingredients, we investigated effects of aquaculture and biogas side streams as feed on growth performance, survival, amino and fatty acid profiles of the worms. Polychaetes were fed along a gradient from pure aquaculture sludge (SS) to pure solid biogas digestate (SBD) in 33% steps and a positive control reared on fish feed (FF). Worms fed with FF showed the highest specific growth rate, while there were no significant differences in growth rates between pure SS, pure SBD and their mixtures. While the diets differed significantly in protein concentrations, the worm showed comparable protein concentrations at the end of the 30 d rearing period (42 to 47% of dry weight). The lipid content in the worms was positively correlated with that in the diets. The worms on mixtures of SS and SBD with different ratios showed similar amino acid profiles. Fatty acids of polychaetes changed with the diet they received, where increased fractions of SBD resulted in an increase in long-chain polyunsaturated fatty acids like arachidonic (ARA, C20:4 n-6) and eicosapentaenoic (EPA, C20:5 n-3) acids, and while increased ratio of SS can increase docosapentaenoic (DPA, C22:5 n-3) and docosahexaenoic (DHA, C22:6 n-3) acids. In conclusion, polychaetes can recycle organic nutrients from aquaculture and biogas side streams into high-quality proteins and lipids, which can potentially serve as ingredients for aquafeeds.