Effect of an experimental
microparticulate diet on the growth, survival and fatty acid profile of
gilthead seabream (Sparus aurata L.) larvae
P. Pousão-Ferreira,
P. Santos, A.P. Carvalho, S. Morais, L. Narciso-2003
Aquaculture International, 11(5):
491-504
Abstract:
In recent years, a great deal of interest has emerged
in the development of microdiets as an economic alternative to live food, in
the larval culture of marine fish species. The ability to grow Sparus
aurata larvae on a prototype microparticulate diet was examined. To
achieve this objective, four feeding regimes differing in the time when the
microdiet was introduced (3, 7 or 12 days) and one based exclusively on an
inert diet were tested, during the first 22 days of larval life. Significant
differences in larval growth were found between the experimental feeding
regimes and their corresponding controls (enriched rotifers during the whole
experimental period); the larvae in the co-feeding regimes and with an
exclusive microparticulate diet were always significantly smaller than
larvae fed on rotifers alone. However, the difference was minimised by
introducing the inert diet at a later date. A lower survival was found in
larvae with a co-feeding regime, in comparison with the control treatments
and the survival was significantly lower in larvae fed exclusively on a
microparticulate diet. The fatty acid analysis revealed that the
experimental microencapsulated diet and the rotifers enriched with Protein
Selco® presented relatively similar fatty
acid content. In spite of the slightly higher (n-3)/(n-6)
and Docosahexaenoic acid (DHA)/Eicosapentaenoic acid (EPA) ratios and
somewhat lower highly unsaturated fatty acid (HUFA) content found in the
inert diet, the fatty acid composition of the diets cannot explain the
differences found in larval performance. The results revealed that the
complete replacement of live prey with the tested microparticulate diet is
still not possible in S. aurata larval rearing. Nevertheless,
better growth and survival results and a substantial reduction in the daily
supply of live food can be achieved with a combination of microdiet and live
prey.
(IPIMAR/CRIPSul
Av. 5 de Outubro s/n, 8700 Olhão,
Portugal, phone: +351 21 4869211; fax: +351 21 4869720, e-mail of L.
Narciso: lnarciso@fc.ul.pt)