Influence of the EPA/DHA ratio in rotifers on gilthead seabream (Sparus aurata) larval development

Abstract

A feeding experiment was carried out to investigate the influence of the eicosapentaenoic acid (EPA, 20:5n-3) to docosahexaenoic acid (DHA, 22:6n-3) ratio (EPA/DHA) on 17-day-old Sparus aurutu larval development. Larvae were fed rotifers (Bra&onus plicatilis) enriched with four different lipid emulsions containing the same amount of total n-3 highly unsaturated fatty acids (n-3 HUFA) but different EPA/DHA ratios. The different EPA/DHA ratios of the emulsions gave rise to different ratios in the enriched rotifers. Furthermore, increments of the EPA/DHA ratio in rotifers produced a decrease in larval growth performance, so that larvae fed rotifers containing the highest EPA/DHA ratio showed the poorest growth rate. The analysis of fatty acids from larvae showed that there was a significant linear relationship between EPA/DHA ratio in their total polar lipids (TPL) and larval growth. At the same time, when the EPA/DHA ratio increased in rotifers, there was an increase in total n-3 HUFA in larvae total neutral lipid (TNL), which was mainly due to the accumulation of EPA. Results obtained in the present study suggest that for the same level of total n-3 HUFA, larval growth performance can be improved by a decrease in EPA/DHA ratio in rotifers, indicating the importance of DHA during the first days of S. aurutu larval development.