Comparison of docosahexaenoic acid (22 : 6n-3) levels in various Artemia strains during enrichment and subsequent starvation

The aim of this study was to compare the levels of docosahexaenoic acid (DH A, 22:6n-3) in three different bisexual and one parthenogenetic strains of Artemia after enrichment. Freshly-hatched nauplii from A. franciscana (Grea t Salt Lake, USA), A. sinica (Yimeng, P. R. China), A. persimilis (Argentin a), and A. parthenogenetica (Tanggu, P. R. China) were enriched with a puri fied lipid emulsion containing 95% DHA ethyl eaters (% total fatty acids) a nd subsequently starved. All strains had very low initial DHA levels (< 0.3 mg/g dry weight). Initial eicosapentaenoic acid, 20:5n-3 (EPA) levels were high in A. parthenogenetica (18.2 mg/g dry weight) as compared to those in the other strains (4.6-8.5 mg/g dry weight). After 24-h enrichment, A. sin ica contained the highest DHA level (37.0 mg/g dry weight) as well as the h ighest DHA/ EPA ratio (3.7). The lowest DHA enrichment levels were found in A. franciscana and A. parthenogenetica (26.3 and 22.7 mg/g dry weight, res pectively). During the subsequent 24-h starvation period, the contents of D HA decreased rapidly in all strains, whereas EPA levels remained relatively stable. This indicates the high catabolism of DNA for energy production, t he relative conservation of EPA, and Possibly a partial bioconversion of DH A to EPA during the starvation period in each species.