KINETICS OF INCORPORATION OF N-3 TRANS FATTY-ACID IN RAT RETINA

Geometrical isomers of essential fatty acids are formed during heat treatment of vegetable oils. They are subsequently present in human diet. They have been reported to be elongated, desaturated and incorporated in many rat tissues. The aim of the present study was to consider the incorporation of trans (n-3) fatty acids in the rat retina, which is a docosahexaenoic acid (DHA)-rich tissue and often described as a protected structure against xenobiotics. Rats were fed for up to 8 weeks with a heated linseed oil, which is rich in geometrical isomers ct linolenic acid. Isomers of linolenic acid, but also of eicosapentaenoic acid (EPA) and DHA were found in the retina. The incorporation of the latter is time-dependent, whereas the Delta 17 trans isomer of EPA increased strongly after 8 weeks of diet while it remained almost constant until 8 weeks. The percentage of incorporation of the trans isomer of DHA is almost the same than in the liver after 8 weeks of diet. It suggests that the retina may not be much more protected than the liver against long chain trans fatty acid incorporation.