Influence of the [formula omitted] 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, 20:5 n − 3) to docosahexaenoic acid (DHA, 22:6 n − 3) ratio ( EPA DHA ) on 17-day-old Sparus aurata larval development. Larvae were fed rotifers ( Brachionus 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. aurata larval development.