Lipid composition and
vitamin content of wild female Litopenaeus vannamei in different
stages of sexual maturation
R.
Wouters, C. Molina, P. Lavens, J. Calderón-2001
Aquaculture,
198 (3-4): 307-323
Abstract:
Wild Litopenaeus vannamei females in
different stages of sexual maturation were sampled, including spent females
and their nauplii, for determination of the lipid content, lipid class (LC)
composition, fatty acid (FA) composition, vitamin C content and vitamin E
content. Free FA (FFA), triacylglycerol (TAG), phosphatidylcholine (PC) and
sterol esters (SE) were the dominant LC in the midgut gland. TAG and
phospholipids (PL), mainly PC and phosphatidylethanolamine (PE), were the
dominant ovarian LC. Neutral lipids (NL) prevailed over polar lipids (POL)
in midgut gland lipids, while ovarian lipids displayed an inverse
relationship. An increase in ovarian TL was observed from stage 0 (immature)
to stage 1 (early maturing). Later, from stage 1 to stage 2 (mid maturing),
a decrease in midgut gland TL was observed. TAG was most responsible for
these changes in TL. Lipids were preferentially transferred to the nauplii,
which contained relatively high TAG and PC levels. In both midgut gland and
ovaries, 16:00, 18:00, 16:1n-7, 18:1n-9, arachidonic acid (ARA;
20:4n-6), eicosapentaenoic acid (EPA; 20:5n-3) and
docosahexaenoic acid (DHA; 22:6n-3) were the principal FA. All
tissues and nauplii displayed n-3>n-6 and EPA>DHA
relationships, and contained high proportions of n-3 highly
unsaturated FA (n-3 HUFA). During sexual maturation, the sum of
poly-unsaturated FA (PUFA) decreased in the ovaries due to the decrease in n-6
PUFA such as ARA. The sum of mono-unsaturated FA (MUFA), on the other hand,
increased in the ovaries. AA levels were high in immature, maturing and
mature ovaries. They were low in the ovaries of spent females and nauplii.
Vitamin E levels were low in immature ovaries, increased substantially
during ovarian maturation, and then decreased again upon spawning. High
vitamin E levels were retained in the nauplii. The findings of this study,
combined with those reported in related studies, suggest the importance of n-3
HUFA for larval development, of vitamin C for egg development and hatching,
and of vitamin E for ovarian maturation and larval development. These
nutrients cannot be synthesised de novo by shrimp, and should be included at
high levels in the broodstock diet.
(CENAIM-ESPOL Foundation, P.O. Box 0901 4519,
Guayaquil, Ecuador, e-mail: r.wouters@inve.be)