Enrichment of Artemia nauplii in PUFA, phospholipids, and water-soluble nutrients using liposomes

Different liposome formulations, including several combinations of membrane composition, type of vesicle (multilamellar and large unilamellar vesicles), preparation method, and vehiculated nutrient, have been assayed as bioencapsulation products to enrich Artemia nauplii with nutrients for feeding fish larvae. The stability of the liposome preparations under conditions of use as enrichment product has been tested using water soluble fluorescent markers as leakage indicators. The content of the fatty acids and lipid classes bioencapsulated in Artemia nauplii with liposomes has been analyzed by gas and thin layer chromatography, respectively, and compared with other enrichment products. The effect of the liposome enriched Artemia nauplii used as food for fish larvae has been evaluated in sea bass cultures. Liposomes with high content in polyunsaturated fatty acids leak out more than 50% of their aqueous phase in less than 2 hours, unless they are stabilized with cholesterol and formed as large unilamellar vesicles. Such vesicles hold 70% of the encapsulated material for 8 hours. Liposome enriched nauplii in this study reflect the influence of the enrichment products, however, they are far from the commercial emulsion ( Super Selco) in terms of docosahexaenoic acid content, except for the nauplii enriched with liposomes made of pure krill phospholipid extract by the method of detergent solubilization. The liposome enriched nauplii show a higher amount of polar lipids in contrast to the feed enriched with emulsions. The larvae fed liposome enriched nauplii have only a slightly lower docosahexaenoic acid content than those fed emulsion enriched nauplii. The results obtained confirm the suitable potential use of liposomes as food supplement in larviculture. Problems and advantages are discussed.