Essential fatty acid requirements of larval gilthead sea bream, Sparus aurata (L.)

Abstract

Abstract. Two experiments were carried out to study the effect of n-3 HUFA levels in rotifers on survival, growth, activity and fatty acid composition of gilthead bream, Sparus aurata (L.), larvae. From the third to the 15th day after hatching, gilthead bream larvae received one of the three kinds of rotifers containing different percentages of n–3 HUFA. Moisture, crude lipid, saponifiable matter and fatty acid composition of total lipids of rotifers and larvae were determined. A good correlation was found between larval growth and n–3 HUFA levels in rotifers. Larval survival was also significantly improved by the elevation of the n–3 HUFA levels in rotifers. A high occurrence of hydrops was registered in larvae fed with EFA-deficient rotifers. The n–3 HUFA levels in the larvae were increased by the elevation of n–3 HUFA contents in rotifers. However, n–9 fatty acids in the larvae remained almost constant, regardless of the different 18:1n–9 contents in rotifers. Therefore, the ratio of oleic acid to n–3 HUFA, known to be an indicator of the EFA deficiency in fish, was reduced by the elevation of the n–3 HUFA levels in rotifers.