Marine microorganisms as source of DHA for use in first-feeding of cod (Gadus morhua) larvae

Most of the commercial hatcheries for marine fish utilise live feed for first-feeding of the larvae. The live feed however, needs to be produced and enriched with essential fatty acids Many reports coincide in the high requirement of DHA at early stages o f marine fish. In the recent years live feed enrichment diets based on microorganisms has appeared in the market. These products are rich in DHA and produced by fermentation technology. These products have shown in general good results for enrichment of live feed by inc reasing their levels of DHA. However there are some reports about the poor stability of the dried products under certain conditions. Most of these products are produced from Thraustochytrids. These organisms are eukaryotic, single cell organisms, which ar e widespread in marine coastal waters. They grow heterotrophically on simple carbon and nitrogen sources and accumulate triglycerides for reserve energy. Depending on the strains and growth conditions, their lipid content may account for nearly 80% of the cell dry. The aim of the project will be to develop an ingredient for first-feed of cod, with thraustochytrids from the Norwegian coast as source of DHA. The fermented biomass will be dried by heat pump drier technique.