Fatty acid profiles of brain phospholipid subclasses of rats fed n - 3 polyunsaturated fatty acids of marine or vegetable origin. A two generation study.

The effects of dietary n - 3 polyunsaturated fatty acids (PUFA) on fatty acid profiles of rat brain phospholipid subclasses as well as on heart phosphatidylethanolamine through two generations were examined: Three groups of rats were fed 20 weight% fat diets in which approx. 30% of the fatty acids were polyunsaturated, either 17% linoleic acid + 13% C20(-) + C22 polyunsaturates from fish oil or 17% linoleic + 13% alpha-linolenic acid from linseed oil or 30% linoleic acid. The rats of the two generations were killed as adults at 18 weeks of age. The results demonstrated that fish oil was a better source than alpha-linolenic acid for incorporation of n - 3 PUFA into the examined phospholipids. This was seen both in brain and heart tissue and in both generations of rats. In the brain phosphatidylethanolamine (PE) and phosphatidylserine (PS) similar fatty acid profiles were found in 1st and 2nd generation, but fish oil was more efficient than 18:3(n - 3) in increasing the levels of 22:6(n - 3), 20:5(n - 3), 22:5(n - 3) and reducing 20:4(n - 6) and 22:5(n - 6). Fatty acid profiles of phosphatidylinositol (PI), phosphatidylinositol-4-phosphate (PIP) and phosphatidylinositol-4,5-bisphosphate (PIP2) were affected by dietary fats. In PIP and PIP2 of 2nd generation rats 20:4(n - 6) was reduced from 36 to 29% following fish oil intake, whereas alpha-linolenic acid had no effects. The cholesterol/phospholipid ratio was not affected in the brain, neither was the degree of unsaturation of the phospholipids. In heart PE the highest levels of 20:5(n - 3)(2%) and 22:6(n - 3) (36%) were observed following fish oil intake. However, in rats fed alpha-linolenic acid a considerable increase in the level of 22:6(n - 3) was observed from the 1st (21%) to the 2nd generation (26%).