Rapid incorporation of docosahexaenoic acid from dietary sources into brain microsomal, synaptosomal and mitochondrial membranes in adult mice

This study examined the incorporation of docosahexaenoic acid (DHA) from several dietary sources into the brain tissue and intracellular organelles in mice,which had been fed a 5% palm oil (low n-3 fatty acid level) diet for 8 or 11 weeks. The percentages of DHA in the tissues of mice fed 5% representative oils for 30 days or 5% purified n-3 fatty acid diets for 6 days were analysed using gas chromatography. The percentage of DHA in the brain was ranked in the following order: the salmon oil diet group > the sardine oil diet group much greater than the perilla oil diet group much greater than the lard and palm oil diet groups for the 30 day feeding trial; and the DHA diet group much greater than the eicosapentaenoic acid and alpha-linolenic acid diet groups for the 6 day feeding trial. The percentage of arachidonic acid showed a more dramatic decrease than that of docosapentaenoic acid. These results reflected the plasma fatty acid concentrations, but rt ere not as pronounced as the changes observed in the plasma, The majority of the DHA incorporated into the brain was recovered in microsomal, synaptosomal and mitochondrial fractions separated by density gradient centrifugation. These membrane fractions took up DHA within several days. These results suggest that the intake of DHA itself increases the DHA level of brain membranes more rapidly than intake of the precursors in animals fed a low n-3 fatty acid level diet.