Enhanced absorption of docosahexaenoic acid (DHA, 22 : 6n-3) in Artemia nauplii using a dietary combination of DHA-rich phospholipids and DHA-sodium salts

The effects of surface-active agents such as phospholipids (PL) and salts o f long chain fatty acids in enrichment lipids on emulsification, and hence digestion and absorption of essential fatty acids (EFA) were studied. The a dvantages obtained by using a mixture of docosahexaenoic acid (DHA, 22:6n-3 )-rich phospholipids (DHA-PL) and DHA-salts in the process of live feed enr ichment are reported on. Enrichment diets at equal levels of DHA, but with varying proportions of DHA-rich triacylglycerols (DHA-TAG), DHA-PL and DHA- sodium salt (DHA-Na) isolated from heterotrophicaly grown Crypthecodinium s p. algae were fed to instar-II stage Artemia nauplii. Artemia nauplii survi val and lipid content after 16 h of enrichment were 74.0 +/- 7.8% and 24.3 +/- 0.6% (dry weight) respectively, and not significantly affected (P > 0.0 5) with increasing dietary quantities of PL and DHA-salts (up to 40 and 30% , respectively). Artemia lipid class composition was independent of dietary phospholipid level. However, higher proportions of polar lipid fraction wa s evident in Artemia lipids with the addition of DHA-Na. Dietary inclusion of 20% PL or a mixture of 10% PL and 10%;, DHA-Na resulted in maximal (P < 0.05) absorption of dietary DHA by the Artemia (27.5 +/- 2.6 mg/g dry weigh t) with a DHA to eicosapentaenoic acid (EPA, 20:5n-3) ratio greater than 3. Furthermore, PL was the most efficient dietary fraction to deliver DHA to Artemia nauplii as compared to TAG or unesterified delivery forms. (C) 1999 Elsevier Science Inc. All rights reserved.