Abstract
Lipid profiles were compared between Artemia nauplii enriched with fish oil triacylglycerols (TG) containing docosahexaenoic acid (DHA, 22:6n-3) in different positional distribution patterns. Four fish oils were selected on the basis of the positional distribution determined by a nonenzymatic analytical method, and directly given to Artemia nauplii in the form of oil emulsions. Time-courses of the lipid contents, lipid compositions, and fatty acid compositions were not so different between the nauplii enriched with tuna orbital and bonito head oil TG, in which 22:6n-3 (22.9-24.0%) was esterified in the sn-3>sn-1_??_sn-2 positions and the sn-3_??_sn-2=sn-1 positions, respectively. In both of the enrichments, the level of 22:6n-3 initially not detected reached a plateau (3.4-3.6% of totalfatty acids) after 12h and then decreased to 1.7% (48h). Slight differences were also observed between thelipids of nauplii fed on sardine (22:6n-3, 11.5%; sn-2_??_sn-3>sn-1) and seal (22:6n-3, 7.6%; sn-3>sn-1>sn-2) oil TG. The levels of 22:6n-3 after 24h enrichment were 0.4% of total fatty acids. Such similarities of the lipid profiles in Artemia nauplii indicate that the positional distribution of 22:6n-3 in dietary TG has practically no influence to enrichment of Artemia nauplii with this fatty acid. It is probable that any TG with different positional distribution patterns of 22:6n-3 can be used for enrichment of Artemia, when 22:6n-3 is concentrated in the TG at an adequate level.
