Valorisation and enhanced sustainability of Senegalese sole (Solea senegalensis) aquaculture by dietary use of ditch shrimp (Palaemonetes varians) meal

Abstract The European Blue Growth Strategy requires innovative proposals contributing to sustainable development of the aquaculture activity. Within this context, ditch shrimp (Palaemonetes varians) meal obtained from extensively managed aquaculture wetlands was assessed as a potential source to substitute dietary fishmeal (FM) in compound diets for Senegalese sole (Solea senegalensis) juveniles. Estuarine ditch shrimp biomass from an integrated aquaculture system was converted into a meal that contained 61.9% protein and 9.2% lipid on a dry matter (DM) basis. The n-3 highly unsaturated fatty acids (HUFA) constituted the main fraction of the polyunsaturated fatty acids (PUFA). Three isonitrogenous (55% DM), isolipidic (12% DM) and isoenergetic (17 kJ g−1 DM) diets containing three substitution levels of fishmeal by ditch shrimp meal (SM) were elaborated: 100% FM + 0% SM (SM0); 50% FM + 50% SM (SM50) and 0% FM + 100% SM (SM100). The experimental diets were tested on duplicate groups of sole juveniles (~4 g body weight) in an experiment that lasted 63 days. The substitution of dietary FM with SM did not influence growth and feed intake of the reared fish. Juveniles fed SM100 significantly decreased their muscle and skin lipid depositions in comparison with soles fed SM0. Moreover, muscle lipid analyses showed arachidonic acid (ARA) enrichment caused by the SM dietary use and a major presence of the n-3 over n-6 PUFA. Overall results demonstrate that dietary incorporation of P. varians meal in compound diets for Senegalese sole would add nutritional value to the harvested product with no impact on growth performance of reared fish. The dietary use of a low trophic level marine resource is an innovative practice that may contribute to a further sustainable development of aquaculture of carnivorous fish species.