Lipid Nutrition in marine fish larvae

M.S. Izquierdo, H. Fernández-Palacios, A. Valencia, C.M. Hernández-Cruz

Abstract:

Dietary lipids have been long recognized as a main factor affecting survival and growth of fish larvae. Studies on larval lipid nutrition have improved our knowledge on different aspects of lipid metabolism such as digestion, absorption, transport and metabolism. Lipid digestion, although occurring in larval lumen from first feeding, dramatically increases during the first two weeks of larval development, being affected by dietary fatty acid composition. Accordingly, capacity for lipid absorption by intestinal epithelium has been also observed at the onset of exogenous feeding, although specific location in the different digestive tract segments differ with species. But the increased lipid absorption capacity found in live prey fed larvae is delayed in larvae fed formulated diet. Increasing dietary phosphatidyl cholines levels enhanced lipid absorption regardless its soybean or marine origin, but the latter improved hepatic lipid utilization. Enzymatic, histological and biochemical evidences suggest that marine fish larvae are able to effectively digest and absorb n-3 HUFA rich triacylglycerols, but feeding n-3 HUFA rich phosphoacylglycerols improves digestion and specially lipid transport. Essentiality of eicosapentaenoic, arachidonic and docosahexaenoic acid is well documented in several fish larvae, but evidence for competitive iteractions among these essential fatty acids suggest the importance of determining optimum relative ratios among them.

(Grupo de Investigación en Acuicultura, ICCM & ULPGC, Ciencias Básicas, Tafira Baja, 35017 Las Palmas de Gran Canaria, Canary Islands, Spain, e-mail : marisoli@iccm.rcanaria.es)

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