Very-long-chain (C28) highly unsaturated fatty acids in marine dinoflagellates

Very-long-chain (C-28) highly unsaturated fatty acids (VLC-HUFA), octacosaheptaenoic acid (28:7(n-6)(4,7,10,13,16,19,22)) and octacosaoctaenoic acid (28:8(n-3)(4,7,10,13,16,19,22,25)) were identified in seven marine dinoflagellate species: Prorocentrum mexicanum, P. micans, Scrippsiella sp., Symbiodinium microadriaticum, Gymnodinium sp., G. sanguineum and Fragilidium sp. The proportion of these fatty acids accounted for less than 2.3% of the total fatty acids in these species. The main VLC-HUFA in S. microadriaticum was 28:7(n-6); in the other species it was 28:8(n-3), with Scrippsiella sp., Gymnodinium sp. and Fragilidium sp. containing only 28:8(n-3) and Gymnodinium sanguineum containing a small proportion of 28:7(n-6) in addition to 28:8(n-3). These findings show that some marine dinoflagellates have the ability to produce VLC-HUFA, but precursors of these VLC-HUFA with chain lengths between 22 and 28 carbon atoms were below the detection level. Both 28:7(n-6) and 28:7(n-3), as well as other VLC-HUFAs, have been detected previously in Baltic herring; our results suggest that they may have originated from microalgae. (C) 1998 Elsevier Science Ltd. All rights reserved.