The present work reviews the significance of lipids at different early
stages of marine fish larvae. Lipids in broodstock nutrition are cons
idered to be important for the quality of the larvae. Lipids affect th
e spawning and the egg quality of many fish species and a deficiency i
n (n - 3) highly unsaturated fatty acids (HUFA) in broodstock negative
ly affects fecundity, fertilization rate and hatching rate of the spec
ies studied. Lipids as a source of energy at the embryonic and larval
stage (before first-feeding) are evaluated in relation to other source
s of energy such as protein and carbohydrates. After hatching and prio
r to first-feeding, some marine species show a preference in cataboliz
ing phosphatidylcholine, whereas phosphatidylethanolamine tends to be
synthesized. The effect of long-term (LT) and short-term (ST) enrichme
nt techniques on the lipid composition of rotifers has been documented
using various marine oils/emulsions. The quantitative and qualitative
lipid class and fatty acid composition of diets influenced the lipid
and fatty acid composition of both LT- or ST-enriched rotifers. The nu
tritional improvement of Artemia is also important and may follow the
general methods used for rotifers. The functions of docosahexaenoic ac
id (DHA) and eicosapentaenoic acid (EPA) during early stages of marine
fish larvae are apparently different. High amounts of EPA in relation
to DHA may create an imbalance in the structural composition of the p
hospholipids, which could affect the normal growth and the quality of
the larvae. Turbot larvae tended to exhibit lower pigmentation success
with lower DHA:EPA ratio in the total lipid fraction of the larvae, e
specially when the absolute amounts of EPA were high compared to those
of DHA (in the total lipid and phospholipid fraction of the larvae).
Considerable research is necessary to clarify many aspects regarding t
he function of these fatty acids, especially how their content at the
egg stage can affect further requirements for normal growth and surviv
al. (C) 1997 Elsevier Science B.V.