ESSENTIAL FATTY ACID DEFICIENCY DIFFERENTLY AFFECTS THE FATTY ACID COMPOSITION OF THE RAT INTESTINAL AND COLONIC MUCOSA.

Abstract

223 The gastro-intestinal tract is involved in the first stage of fatty acid(FA) consumption, as well as in immunological reactions such as development of tolerance or allergy. We analysed the FA patterns in the mucosa of the intestine and colon in two groups of rats: 1) Sprague Dawley female rats were fed a reference diet: 2) similar rats received an essential fatty acid deficient (EFAD) diet during 6 weeks. We analysed the relative FA composition in phospholipids (PLs) by gas-liquid chromatography in serum, erthrocyte (RBC) membranes and intestinal mucosa of jejunum, ileum and colon. We found changes in arachidonic acid (AA, 20:4, n-6) levels in RBC membrane PLs and serum PLs following EFAD diet (p<0.005).TableTable: The molar percentage of EFA in PLs of normal and EFAD rats (%)We revealed more pronounced changes of the AA in serum PLs than in RBC membrane PLs. At the same time the FA 20:3 portion in serum PLs became significantly more elevated than in RBC PLs (p<0.005). We assume that the composition of FAs in membrane PLs is more stable. Membrane PLs might be one of the main sources of EFA during a prolonged deficient state. We found for normal rats that the FA composition was almost the same for ileal and colonic mucosa, but differed drastically for jejunal mucosa. The portion of AA in jejunal mucosa was lower than in ileal mucosa, but the level of linoleic acid(LA, 18:2, n-6) was significantly higher (p<0.005). The EFAD diet induced a profound fall of LA in rat jejunal mucosa (p<0.005), whereas the relative proportion of AA remained normal. Morphological signs of EFA deficiency were more expressed in the ileal mucosa that the jejunal mucosa. At the same time, both AA and LA were strikingly decreased in ileal mucosa of EFAD rats(p<0.005). Simultaneously, the relative levels of 20:3 (n-9) and 18:1 (n-9) were increased. Similar changes were found in the ileal and colonic mucosa. EFAD diet seemed to cause more significance disturbances in the ileal and colonic mucosa than in the jejunal mucosa.