Krill-derived Phospholipids Rich in n-3 Fatty Acid Improve Spatial Memory in Adult Rats

Abstract

We indicated previously that dietary supplementation of the ethyl ester form of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) improves spatial cognition through an increase in DHA levels in the hippocampus and cerebral cortex. In the present study, we investigated the effects of peroral administration of krill-derived phospholipids (KPL) on the spatial learning ability and the fatty acid composition of the plasma and brain tissues. Both parameters of the radial arm maze task, the reference-and working memory errors, significantly decreased after KPL administration. The plasma and brain levels of n-3 PUFAs significantly increased, and the levels of arachidonic acid were significantly decreased after KPL administration. Lipid peroxidation in the plasma and in brain tissues was depressed, and cell generation in the dentate gyrus was enhanced in KPL-administered rats. All these effects are similar to those induced by the ethyl ester forms of EPA and DHA.

Enhanced cognitive function and antidepressant-like effects after krill oil supplementation in rats

“…Moreover, in these rats, DHA levels were shown to be significantly increased in the cerebral cortex, as well as in the hippocampus [30]. The KO used in the present study was previously shown to similarly increase brain DHA levels in Zucker rats [38].…”

“…Improved reference and spatial memory was recently reported in the radial maze test for rats that had received a diet supplemented with isolated phospholipids from KO [30]. Moreover, in these rats, DHA levels were shown to be significantly increased in the cerebral cortex, as well as in the hippocampus [30].…”

“…As the different structure of krill fatty acids may affect their incorporation into neuronal cell membranes, krill products may be particularly effective in modulating neuronal membrane function and signalling, including processes of synaptic transmission and plasticity. At present there is only one animal study addressing the effect of krill-derived phospholipids on brain function in rats [30]. The authors observed that spatial learning ability (for the radial arm maze task) and cell generation in the dentate gyrus was enhanced after KO administration.…”

Marine Omega-3 Phospholipids: Metabolism and Biological Activities

“…There was also a significantly higher presence of DHA in the brain after KO supplementation to the diet as compared to FO supplementation [45]. This finding was supported by a recent study with KO demonstrating increased DHA amount in the brain and beneficial effect on memory function in rats [46]. Moreover, it has been demonstrated that DHA in the form of lyso-PC, and more specifically, when DHA is located in the sn -1 position, is efficiently taken up in the developing rat brain [47].…”

“…Moreover, increased endocannabinoid levels, as metabolic parameters of metabolic syndrome and obesity [136], have been found to be ameliorated in obese rats, mice and humans after KO supplementation [44,45,57,69]. Other recent studies have demonstrated that KO improves memory function, protects against heart failure and attenuates inflammation in ulcerative colitis in rats [46,65,74]. …”