Effect of dietary docosahexaenoic acid connecting phospholipids on the lipid peroxidation of the brain in mice.

The effect of dietary docosahexaenoic acid (DHA, C22:6n-3) with two lipid types on lipid peroxidation of the brain was investigated in streptozotocin (STZ)-induced diabetic mice. Each group of female Balb/c mice was fed a diet containing DHA-connecting phospholipids (DHA-PL) or DHA-connecting triacylglycerols (DHA-TG) for 5 wk. Safflower oil was fed as the control. The lipid peroxide level of the brain was significantly lower in the mice fed the DHA-PL diet when compared to those fed the DHA-TG and safflower oil diets, while the alpha-tocopherol level was significantly higher in the mice fed the DHA-PL diet than in those fed the DHA-TG and safflower oil diets. The DHA level of phosphatidylethanolamine in the brain was significantly higher in the mice fed the DHA-PL diet than in those fed the safflower oil diet. The dimethylacetal levels were significantly higher in the mice fed the DHA-PL diet than in those fed the safflower oil and DHA-TG diets. These results suggest that the dietary DHA-connecting phospholipids have an antioxidant activity on the brain lipids in mice, and the effect may be related to the brain plasmalogen.

Lipid and fatty acids of three edible myctophids, Diaphus watasei, Diaphus suborbitalis, and Benthosema pterotum: high levels of icosapentaenoic and docosahexaenoic acids.

The fatty acid compositions of the total lipids of three edible deep-sea fishes, Diaphus watasei, Diaphus suborbitalis, and Benthosema pterotum, were compared with those of a highly migratory fish, Katsuwonus pelamis, to clarify their lipid characteristics and nutritional value as seafood. The mean lipid contents in the three myctophids were markedly higher than was that of K. pelamis. All three myctophids had medium levels of 20:5n-3 (icosapentaenoic acid, EPA) and 22:6n-3 (docosahexaenoic acid, DHA) in their lipids, similar to those in surface pelagic fishes. The actual EPA and DHA amounts of the three myctophid fishes were higher than were those of K. pelamis. Therefore, the nutritional values of the myctophids as source for EPA and DHA are better than that of K. pelamis, and this finding may introduce a new resource of healthy marine food from these under-utilized deep-sea fish species.

Effects of dietary sialic acid in n-3 fatty acid-deficient dams during pregnancy and lactation on the learning abilities of their pups after weaning.

The effects of dietary sialic acid in dams on the learning abilities of their pups after weaning were investigated using rats deficient in n-3 fatty acids. Nine-week-old female Wistar rats were fed an n-3 fatty acid-deficient diet for 3 wk and were mated at 12 wk of age. During pregnancy and lactation, the female rats were fed the n-3 fatty acid-deficient diet, and were given water or water containing 1% N-acetylneuraminic acid (NANA) ad libitum. After weaning, the learning abilities of the pups were evaluated using a novel object recognition test. The recognition index of pups nursed by dams fed on water containing 1% NANA (NANA-intake dams) was significantly higher than that of pups nursed by dams fed only on water (NANA non-intake dams). There were no significant differences in the total sialic acid or docosahexaenoic acid contents in the cerebral cortex or hippocampus of pups nursed by dams fed on either type of water. The total dimethylacetal (DMA, from plasmalogen) level in the cerebral cortex of pups nursed by NANA-intake dams was significantly higher than that of pups nursed by NANA non-intake dams. These results suggest that dietary sialic acid in dams during pregnancy and lactation might be beneficial for the learning abilities of pups after weaning, which may be related to the plasmalogen level in the brain of pups.

Effects of dietary docosahexaenoic acid connecting phospholipids on the learning ability and fatty acid composition of the brain.

The effects of dietary docosahexaenoic acid (DHA, C22:6n-3) connecting phospholipids on the learning ability and fatty acid composition of the brain were investigated in hypercholesterolemic mice. ICR mice were subjected to a very low level of n-3 fatty acids through two generations. At 4 wk of age, the F(1) generation, n-3 fatty acid deficient male mice were provided with an experimental diet containing four kinds of lipids (safflower oil: Saf, DHA connecting triacylglycerols: DHA-TG, DHA connecting phospholipids: DHA-PL, soybean phospholipids: Soy-PL) for 5 wk. Another group of ICR mice were obtained and fed a commercial diet (CE-2, CLEA Japan, Inc.) as a control. The learning and memory abilities of the mice were evaluated by the modified avoidance procedure. The learning and memory ability level was significantly higher in mice fed the DHA-PL diet than in those fed the Saf and Soy-PL diets, and was the same level as the control. The DHA levels of phosphatidylethanolamine in the brain were significantly higher in the mice fed the two types of DHA-containing diets than in those fed the Saf and Soy-PL diets and was not significantly different between DHA-TG and DHA-PL. The dimethylacetal levels in the brain were significantly higher in the mice fed the DHA-PL diet than in those fed the Saf and DHA-TG diets. These results suggest that the dietary DHA connecting phospholipids have the effect of improving memory learning, and may be related to the both the DHA and plasmalogen levels in the brain.