Journal of Lipid Research, Vol 34, 1423-1434, Copyright © 1993 by Lipid Research, Inc.
Modification of spleen phospholipid fatty acid composition by dietary fish oil and by n-3 fatty acid ethyl esters
DR Robinson, LL Xu, CT Knoell, S Tateno and W Olesiak
Arthritis Unit, Massachusetts General Hospital, Boston.
We have compared the effects of diets containing purified ethyl esters of
either eicosapentaenoic acid, docosahexaenoic acid, or a mixture of both of
these compounds, with diets containing either purified fish oil or beef
tallow on spleen phospholipid fatty acid composition. Autoimmune mice, the
(NZB x NZW)F1 strain, were fed with experimental diets for 14 weeks, after
which spleen phospholipids were extracted and separated into classes by
HPLC, and the alkenylacyl, alkylacyl, and diacyl subclasses of
glycerylphosphatidylethanolamine and glycerylphosphatidylcholine were
resolved as their benzoyl esters by HPLC. Fatty acids were analyzed by
capillary gas-liquid chromatography of their methyl esters. Each of the
marine lipid diets suppressed n-6 fatty acids and elevated n-3 fatty acids
in all phospholipids. The eicosapentaenoic acid ethyl ester diets led to
high levels of eicosapentaenoic acid and docosapentaenoic acid (C22:5n-3),
but little or no increase in docosahexaenoic acid. The docosahexaenoic acid
ethyl ester diets elevated docosahexaenoic acid, docosapentaenoic acid, and
eicosapentaenoic acid in all phospholipids, indicating that extensive
retroconversion of 22 carbon n-3 fatty acids had occurred. These results
document changes in the fatty acid composition of mammalian phospholipids
that are induced by dietary fish oil triglycerides and by dietary long
chain n-3 fatty acid ethyl esters.