Determination of essential requirements in fatty acids and vitamines (C and E) for broodstock of the oyster Crassostrea gigas. Bivalve broodstock nutrition is a critical step, that results in too much variability in egg quality with unacceptable overcosts for hatcheries and appears also a limiting factor for genetic selection. We have evidence for the importance of 20:4(n-6), 20:5(n-3), 22:6(n-3), cholesterol and vitamins for reproduction and quality of eggs. The supply of essential micronutrient from phytoplankton mixtures is too much variable to provide with security a good diet to broodstock. An artificial supplementation, using lipidic microparticles is definitely promising. The aim of this project is to produce a lipid rich emulsion for Crassostrea gigas oyster. a species of major economic importance in Europe. The different steps of the project will be successively focused on: selection of emulsion with different micronutrient compositions, quality control of essential micronutrients, experimental broodstock conditioning and related biological and biochemical analyses to determine the effects of the different compounds on egg quality and embryogenesis.