INCREASING DIETARY LINOLEIC-ACID IN YOUNG-RATS INCREASES AND THEN DECREASES DOCOSAHEXAENOIC ACID IN RETINA BUT NOT IN BRAIN

The accumulation of fatty acids in retina, brain, liver, and plasma of 30-day-old rat pups consuming various levels of linoleic acid (LA, 18 :2n-6) and constant alpha-linolenic acid (ALA, 18:3n-3) is reported. D ams were fed graded levels of LA during gestation and lactation, and t he pup were maintained on the diet of their dams until the end of. the brain growth spurt at 30 d of life. Milk, and pup brain, retina, live r, and plasma were analyzed quantitatively for fatty acid profile. The percentage of docosahexaenoic acid (DHA, 22:6n-3) in retina increased from an LA-deficient dietary level, peaked at the 9:1 (LA/ALA) level, then fell for the 41:1 and 69:1 levels. In contrast, the brain DHA pe rcentage was unaffected by dietary LA levels. Retinal unsaturated fatt y acid levels paralleled liver and plasma levels. The milk fatty acid composition mirrored the diets. These data show that the. retinal fatt y acid composition responds sensitively to dietary fatty acid composit ion, similar to liver and plasma, while the brain unsaturate compositi on is nearly independent of dietary composition.