Effects of dietary polyunsaturated fatty acids on rat brain plasma membrane fatty acid composition

The effects of four different diets on phospholipid fatty acid composition of rat brain plasma membranes were evaluated. Rats were given a semisynthetic diet in which lipids were supplied by 5% peanut oil (n-3 PUFA deficient diet), cod liver oil (n-6 PUFA deficient diet), partially hydrogenated palm oil (total PUFA deficient diet) or a mixture of peanut and rapeseed oil (control group). Animals fed the total PUFA deficient diet had significantly lower body and brain weights than the control group (p < 0.05). Lower brain cholesterol and phospholipids also were observed in animals fed the total PUFA deficient diet, whereas the brain of animals fed the n-6 PUFA deficient diet had higher levels of these lipid components than the control group (p < 0.05). Phosphatidylcholine and phosphatidylethanolamine were mutually replaced in animals fed the n-6 and n-3 PUFA deficient diets, so that the sum of these two membrane constituents was maintained around 77% of total phospholipids. Brain phospholipid fatty acid composition was significantly modified by the diets studied. Thus, despite being a highly protected organ, the fatty acid composition of the brain can be extensively modulated by dietary lipids.