Dietary oleic acid not used during brain development and in adult in rat, in contrast with sciatic nerve

In order to determine exactly the effect on the nervous system of concentration of dietary oleic acid on the fatty acid composition of different part of the nervous system, triglycerides were synthesized using chemical and enzymological methods. The dose-effect was determined using an experimental protocol with seven groups of rats who received a diet in which the oleic acid level varied from 0 to 6000 mg per 100 g diet, but the other ingredients were identical (in particular the essential fatty acids, linoleic and alpha-linolenic acid). Rats were fed the diets from two weeks before mating, and their pups were sacrificed aged either 21 or 60 days. When the level of oleic acid in the diet was increased, the main modifications observed in 21-day-old deficient animals were as follows. (i) For 18:1(n-9), in liver, plateau was reached at about 4 g oleic acid per 100 g diet. Below this level, the higher the dose the greater the response. In whole brain, brain myelin, and nerve endings (but not sciatic nerve) the oleic acid level remained optimal and constant whatever the level of oleic acid in the diet. (ii) 16:1(n-7) concentration decreased in liver and in sciatic nerve, but not in nervous tissue. (iii) In 60-day-old animals, results were generally similar to those in 21-day-old animals.