Artificial rearing with docosahexaenoic acid and n-6 docosapentaenoic acid alters rat tissue fatty acid composition

Ken D. Stark^*, Sun-Young Lim and Norman Salem, Jr.¹^,

^* Laboratory of Nutritional and Nutraceutical Research, Department of Kinesiology, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada
Division of Marine Environment and Bioscience, Korea Maritime University, Busan 606-791, Korea
Laboratory of Membrane Biochemistry and Biophysics, Division of Intramural Clinical and Biological Research, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Bethesda, MD 20892

The online version of this article (available at http://www.jlr.org)contains supplementary data in the form of 9 tables.

Published, JLR Papers in Press, August 16, 2007.

^¹ To whom correspondence should be addressed. e-mail: nsalem{at}niaaa.nih.gov

Docosahexaenoic acid (DHA; 22:6n-3) and n-6 docosapentaenoicacid (DPAn-6; 22:5n-6) are components of enriched animal feedand oil derived from Schizochytrium species microalgae. A onegeneration, artificial rearing model from day 2 after birthonward (AR) and a dam-reared control group (DAM) were used toexamine DPAn-6 feeding on the fatty acid composition of variousrat tissues at 15 weeks of age. Four AR diets were based onan n-3 fatty acid-deficient, 18:2n-6-based artificial milk with22:6n-3 and/or 22:5n-6 added: AR-LA, AR-DHA, AR-DPAn-6, andAR-DHA+DPAn-6. The 22:6n-3 levels for the DAM, AR-DHA, and AR-DHA+DPAn-6groups tended to be similar and higher than in the AR-LA andAR-DPAn-6 groups. The levels of 22:5n-6 tended to be higheronly in the absence of dietary 22:6n-3. Adipose levels of 22:5n-6was the only exception, as 22:5n-6 was significantly higherin AR-DHA+DPAn-6 than was observed in either the DAM or theAR-DHA group. There were no differences in 20:4n-6 levels withinthe tissues examined. In conclusion, 22:5n-6 replaces 22:6n-3in the absence of 22:6n-3 only and does not appear to competewith 22:6n-3 in the presence of dietary 22:6n-3, suggestingthat oils containing 22:5n-6 and 22:6n-3 may be a good dietarysource of 22:6n-3.

Supplementary key words brain • heart • plasma • erythrocytes • liver • adipose • kidney • muscle • testes • gas chromatography

Abbreviations: AR, artificially reared; DAM, dam-reared; DHA, docosahexaenoic acid; DPAn-6, n-6 docosapentaenoic acid; HUFA, highly unsaturated fatty acid; LA, linoleic acid

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