| Summary: | A set of experiments was designed to understand the effect of standardized enrichment diets on the fatty acid composition and culture performance of turbot larvae reared using the food chain rotifers -freshly hatched Artemia nauplii- enriched Artemia . Rotifers were fed on experimental diets of similar total n-3 HUFA content (34-39 mg/g DW) but different DHA/EPA ratio (0.7, 2.6 and 5.5). DHA/EPA ratio in Artemia was manipulated by 24-h enrichment with an emulsion with either a high or low DHA/EPA ratio (respectively, 4.0 and 0.7). Results produced by three experiments showed that the n-3 HUFA composition of the rotifers (DHA/EPA 0.7-2.2) was a reflection of the diet composition, which in turn affected the fatty acid composition of the turbot larvae on day 7 (DHA/EPA 2.4-3.4). At day 13, however, when unenriched Artemia (containing EPA only) were fed to the larvae, the differences in the DHA/EPA ratio observed in the larvae where largely neutralized. The n-3 HUFA composition of the enriched Artemia (DHA/EPA 0.4 and 1.5, respectively) was again reflected in the fatty acid composition of the fish larvae at day 30. When the experiment was repeated with enriched Artemia nauplii , a range of different DHA/EPA ratios (0.9 till 4.2) could be obtained in the 16-day old turbot larvae. Although larval survival was low to allow conclusive results, high DPA/EPA ratios in rotifers and enriched Artemia seemed to be beneficial for normal pigmentation development and growth in turbot larvae.
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