Arachidonic acid enriched live prey induces albinism in Senegal sole (Solea senegalensis) larvae

We examined the effect of dietary arachidonic acid (20:4n-6, ARA) on growth, survival, pigmentation and fatty acid composition of Senegal sole larvae using a dose-response design. From 3 to 37 days post-hatch (dph), larvae were fed live food (rotifers from 3 to 9 dph, Artemia nauplii from −37 dph) that had been enriched using one of three experimental emulsions containing 3 graduated concentrations (1.3, 68 and 120.1 mg ARA g−1 dry weight) of ARA and constant docosahexaenoic acid (22:6n-3, DHA). A commercial enrichment product (DHA-Protein Selco, ARA content 7.8 mg g−1 dry weight) was used as a reference diet. Final concentration of ARA in Artemia nauplii ranged from 0.2 to 17.5 mg g−1 lipids. Growth and survival were independent of dietary levels of ARA tested. However, there was a correlation between dietary ARA and a significant reduction in pigmentation leading to increased albinism. Tissue fatty acid concentrations reflected the corresponding dietary composition. Eicosapentaenoic acid (20:5n-3, EPA) levels in all the tissues examined were inversely related to dietary ARA. There was almost a 100-fold increase in the proportion of docosapentaenoic acid (22:5n-3, DPA) in the tissues relative to the diet, which might indicate chain elongation from EPA as a result of inadequate dietary DHA. A negative, linear correlation was found between the pigmentation rate and the ARA content in the head, as well as with dietary ARA/EPA ratio.