BRAIN AND HEART MEMBRANE FATTY-ACID COMPOSITION IN MINIATURE SWINE FED DIETS CONTAINING CORN AND MENHADEN OILS

Thirty-six female minipigs, from 4.7-10.6 years old, were fed corn oil (CO) and/or menhaden oil (MO) in diets containing 0, 0.75, or 15% MO and sufficient CO to provide 15% total oil for 6 months. Half the anim als were made hypercholesterolemic by feeding them a 13% lard, 2% chol esterol diet for 2 months prior to the experimental feeding period. Sa mples were taken from the same location in each animal from forebrain, caudate nucleus, cerebellum, and heart to isolate brain synaptosomes and heart plasma membranes. Pretreatment of the minipigs with choleste rol had no effect on the fatty acid composition of the fractions isola ted and their membrane fluidity. Despite MO feeding, the long chain n- 3 fatty acids were low in the heart plasma membranes compared to heart tissue homogenates from the same animals. Minipigs fed 15% MO showed significant increases in synaptosomal eicosapentaenoate (EPA) and doco sapentaenoate (DPA). Docosahexaenoate (DHA) was incorporated into syna ptosomes in animals fed 0.75% MO, at concentrations significantly high er than in the CO-fed pigs. Rigs fed 15% MO showed significantly lower brain DHA than those fed CO. The synaptosomal data for the pigs fed t he various diets suggest that metabolic synthesis from linolenate, 18: 3(n-3), may be a more important source bf brain DHA than diet, but tha t dietary n-6/n-3 ratios and levels of 18:3(n-3), EPA, DPA and DHA may require careful attention. The fatty acid changes did not affect flui dity determined by fluorescence anisotropy of diphenylhexatriene or it s polar derivatives. Published by Elsevier Science Inc.