Lipid alterations and their reversion in the central nervous system of growing rats deficient in essential fatty acids

Essential fatty acid (EFA) deficiency modifies several biological parameters, i.e., growth, metabolic rate and water balance and induces functional changes in liver, kidney and lung tissues. The brain fatty acid changes reported in the literature are generally smaller than those observed in other tissues. However, EFA deficiency initiated in rats prior to birth and continued for a prolonged period of time results in decreased brain weight, brain lipid and phospholipid content and in considerable changes in polyunsaturated fatty acid distribution, especially in the ethanolamine phosphoglyceride fraction. The unsaturation level of this phospholipid is maintained at a constant level in spite of the fatty acid distribution changes. Brain lipid analyses, carried out at various time intervals in EFA deficient animals, indicate that brain weights are already reduced in 10‐day‐old deficient rats, that brain phospholipids decrease, especially in the males after three months, and that fatty acid distribution changes begin rather early. The latter consist of a decrease of tetraenes and increase of trienes and of the triene‐tetraene ratios as early as at 10 days, a decrease of hexaenes after six months, and after six months, an increase of pentaenes, which are elevated at birth but usually disappear after three months of age. Similar changes are observed in myelin. The induced changes are not completely reversed upon return to normal diet.