Lutein enrichment of the rotifer Brachionus sp. using freeze-dried Muriellopsis sp. cells

Abstract

Rotifers, used in aquaculture as feed for early larval stages, are poor in carotenoids compared with cope- pods, the natural most common prey item of marine fish larvae. A minimal sufficient level of carotenoids in fish larvae may be essential for a correct develop- ment. The freshwater microalga Muriellopsis sp. has been identified as a potential source of the caroten- oid lutein with possible application in aquaculture. Lutein is a potent antioxidant, with potentially ben- eficial effects as a carotenoid for fish larvae. This study describes the lutein enrichment of the rotifer Brachionus sp. when incubated with homogeneously dispersed suspensions of freeze-dried, lutein-rich Muriellopsis sp. in seawater. A short enrichment time (2 or 2.5 h) resulted in a higher lutein content of the rotifers than a long enrichment time (13.5 or 24 h). Although the concentration of lutein in enriched rotifers, 0.06–0.16 mg (g dry weight) 1 was low compared with its content in Muriellopsis sp. [about 3 mg (g dry weight) 1], it was in the range reported for natural copepod populations. Therefore, we conclude that freeze-dried biomass of Muriellopsis sp. can be used to enrich rotifers with lutein, providing an adequate level of this caroten- oid for marine fish larvae.