The metabolic syndrome of ω3-depleted rats. V. Intestinal phospholipid ω6 fatty acids

This study aims mainly at investigating the effects of a dietary deprivation and replenishment of ω3 PUFA upon the phospholipid pattern of ω6 PUFA in the duodenum, jejunum, caecum and colon of rats exposed for 3-7 months to an ω3-depleted diet and then eventually exposed for 2-4 weeks to an ω3-rich diet. In control rats, the relative weight content of all ω6 fatty acids differed in the proximal and distal intestinal segments. In the ω3-depleted rats the C18:2ω6, C20:2ω6 and C20:3ω6 content was decreased whilst that of C20:4ω6 and C22:4ω6 was increased. Significant correlations were found in the caecum or colon between the C18:2ω6 or C20:4ω6 content of intestinal phospholipids and their C22:6ω3 content, an increase in the latter content coinciding with an increase in C18:2ω6 and decrease of C20:4ω6. Such was also the case for C20:4ω6, but not C18:2ω6, in the duodenum and jejunum. At these proximal intestinal levels, exposure of the ω3-depleted rats to a flaxseed oil-enriched diet indeed decreased the C18:2ω6 phospholipid content, an effect possibly attributable to the much lower content of C18:2ω6 in the latter diet, as distinct from the sunflower diet offered to the ω3-depleted rats during the first 7 months. However, at more distal intestinal levels, and like in the liver, a deficiency in ω3 fatty acids apparently favours the stepwise conversion of C18:2ω6 to C20:4ω6 and C22:4ω6.