Fatty acid tissue composition in mice fed diets containing varying levels of Omega-3 fatty acids.

This study compares varying levels of dietary α-linolenic acid (ALA) as well as eicosapentaenoic acid (EPA) plus docosahexaenoic acid (DHA) on the fatty acid composition of multiple tissues. Two-day pregnant, C57Bl6 mice were fed through gestation and lactation with four custom made diets and the offspring were weaned to the corresponding diet: n-3 deficient (ALA, 0.07wt % of dietary fatty acids), Low ALA (0.4wt %), High ALA (5wt %), and a Low ALA enriched with DHA (2wt %) plus EPA (2wt %). The fatty acid profiles in nine tissues/organs were determined at 12 wk of age by gas chromatography. In the brain, dietary DHA+ EPA supplementation produced a slight increase in DHA but produced no effect on retina in comparison to the High ALA diet. This contrasted with liver, heart, plasma, thigh muscle where the EPA+DHA diet produced higher levels of tissue EPA and DHA compared with the ALA diets. The proportion of arachidonic acid (AA) was depressed at the DHA+ EPA intake in retina, but not brain when compared to the High ALA diet. Tissue incorporation of EPA appeared maximal for the DHA+ EPA supplementation diet, with more than a 3-fold increase in the heart when compared to the High ALA diet. The highest level of DHA was found in heart (32 %), followed by retina (27 %) in the DHA+EPA supplemented diet. These results suggest that even high levels of ALA generally cannot support the higher tissue levels of EPA or DHA found when preformed long chain n-3 PUFA are supplied in the diet.