Fatty acid profile of some crustacean eggs with commercial interest in Europe

L. Narciso, R. Calado

Abstract:

Larval nutrition studies have contributed to estimate the nutrient requirements of fish and crustacean larvae. It is not easy to estimate and quantify the larval nutritional requirements. however, it is generally accepted that the optimal formulations for first feeding larvae should simulate the egg composition, which somehow reflects the nutrient requirements and metabolic needs of pre-feeding larvae. The study of the fatty acid profile of eggs and newly hatched larvae can give us very important clues for a better understanding on the feeding of the first larval stages. We compared the fatty acid profile of eggs of different crustacean species in late development stage: shrimps (common prawn - Palaemon serratus (Ps), triple grooved shrimp -Penaeus kerathurus (Pk). golden shrimp - Plesionika martia (Pm)), lobsters (Norway lobster - Nephrops norvegicus (Nn). spiny lobster - Palinurus elephas (Pe). common lobster - Homarus gammarus (Hg)) and crabs (green crab - Carcinus maenas (Cm). spiny spider crab - Maja squinado (Ms)). When comparing the fatty acid profiles of the eggs of the different crustaceans it is clear that each species has specific lipidic demands. Seashore species such as P. serratus or C. maenas have small DHA amounts whereas pelagic or deeper species exhibit higher unsaturation degree and a DHA EPA ratio more than 1.

Lipids are one of the main sources of metabolic energy and are also essential materials for the formation of cell and tissue membranes, being the amount of lipids in the eggs generally correlated with the time interval between spawning and egg hatching or larval first feed. It is thus possible to make some correlations: a) larger eggs and larvae have longer incubation periods; b) longer incubation periods imply higher lipid content and c) lower water temperature and deeper species also have more lipids. When the larviculture of new crustacean species is increasing, is quite important to study the fatty acid profile of eggs and newly hatched larvae for a better understanding on the feeding of the first larval stages and the nutritional requirements of specific stages.

(Laboratorio Maritimo da Guia, Universidade de Lisboa. Estrada do Guincho P-2750 Cascais, Portugal, e-mail : lnarciso@fc.ul.pt)

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