Fatty acid composition of Heterorhabditis sp during storage

The fatty acid composition of three North West European isolates of Heteror habditis sp. from different geographical origins, UK211 (England), HF85 (Th e Netherlands) and EU17 (Estonia) was assessed directly after harvest and, for UK211 and HF85, after 5 weeks storage in water at 20 degrees C. Lipid r epresented 34-43% of the dry weight of fresh nematodes. Of this, neutral li pid (NL) comprised from 70% (HF85) to over 90% (UK211, EU17). The fatty aci d patterns were similar between the three isolates. Oleic (C18:1n-9), palmi tic (C16:0), and linoleic (C18:2n-6) acid predominated with 51, 13 and 12%, respectively in the total lipid (TL) of fresh nematodes (average for the t hree isolates). Levels of unsaturation (U.I.) of fresh nematodes were on av erage 110, 112, 113 and 152 for the TL, NL, phospholipid and free fatty aci d fractions, respectively. EU17 had a slightly lower U.I than the other two strains, despite its more northern origin. Changes in fatty acid compositi on due to storage were most significant in the NL fraction. The U.I. for th e NL fraction increased during storage, suggesting a preferential use of sa turated fatty acids. (C) 1999 Elsevier Science Inc. All rights reserved.