Effect of fish oils containing different amounts of EPA, DHA, and antioxidants on plasma and brain fatty acids and brain nitric oxide synthase activity in rats

Abstract

BackgroundThe interest in n-3 polyunsaturated fatty acids (PUFAs) has expanded significantly in the last few years, due to their many positive effects described. Consequently, the interest in fish oil supplementation has also increased, and many different types of fish oil supplements can be found on the market. Also, it is well known that these types of fatty acids are very easily oxidized, and that stability among supplements varies greatly.Aims of the studyIn this pilot study we investigated the effects of two different types of natural fish oils containing different amounts of the n-3 PUFAs eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) and antioxidants on plasma and brain fatty acids, blood lipids, vitamin E, and in vivo lipid peroxidation, as well as brain nitric oxide synthase (NOS) activity, an enzyme which has been shown to be important for memory and learning ability.MethodsSprague-Dawley rats were divided into four groups and fed regular rat chow pellets enriched with 5% (w/w) of butter (control group), a natural fish oil (17.4% EPA and 11.7% DHA, referred to as EPA-rich), and a natural fish oil rich in DHA (7.7% EPA and 28.0% DHA, referred to as DHA-rich). Both of the fish oils were stabilized by a commercial antioxidant protection system (Pufanox®) at production. The fourth group received the same DHA-rich oil, but without Pufanox® stabilization (referred to as unstable). As an index of stability of the oils, their peroxide values were repeatedly measured during 9 weeks. The dietary treatments continued until sacrifice, after 10 days.ResultsStability of the oils varied greatly. It took the two stabilized oils 9 weeks to reach the same peroxide value as the unstable oil reached after only a few days. Both the stabilized EPA- and DHA-rich diets lowered the triacylglycerols and total cholesterol compared to control (-45%, P < 0.05 and -54%, P < 0.001; -31%, P < 0.05 and -25%, P < 0.01) and so did the unstable oil, but less efficiently. Only the unstable oil increased in vivo lipid peroxidation significantly compared to control (+40%, P < 0.001). Most of the fatty acids in the plasma phospholipids were significantly affected by both the EPA- and DHA-rich diets compared to control, reflecting their specific fatty acid pattern. The unstable oil diet resulted in smaller changes, especially in n-3 PUFAs. In the brain phospholipids the changes were less pronounced, and only the diet enriched with the stabilized DHA-rich oil resulted in a significantly greater incorporation of DHA (+13%, P < 0.01), as well as total n-3 PUFAs (+13%, P < 0.01) compared to control. Only the stabilized DHA-rich oil increased the brain NOS activity (+33%, P < 0.01).ConclusionsBoth the EPA- and DHA-rich diets affected the blood lipids in a similarly positive manner, and they both had a large impact on plasma phospholipid fatty acids. It was only the unstable oil that increased in vivo lipid peroxidation. However, the intake of DHA was more important than that of EPA for brain phospholipid DHA enrichment and brain NOS act...

Vitamin E content in fish oil emulsion does not prevent lipoperoxidative effects on human colorectal tumors

“…This observation is consistent with a clinical study having shown that the presence of vitamin E in FO capsules did not prevent the increased formation of plasma lipid peroxides after 3 mo of oral supplementation [25]. Because EPA, DHA, and antioxidant contents can vary greatly among natural and commercially available FO supplements [26], further investigations are needed to optimize the ratio of vitamin E to u-3 PUFAs in emulsions dedicated to treatment. For example, g-tocopherol could be used as vitamin E in lipid emulsion because it has been reported, in contrast to a-tocopherol, to induce growth reduction and apoptosis in different colorectal cancer cell lines, including HT-29 cells [27].…”

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

“…The levels of LPO and ROS in the cerebral cortex and the hippocampus in both the HD and LD groups were also significantly decreased compared to the control, but significant differences between the HD and LD groups were not observed (Fig 2). Engström et al suggested that the plasma levels of LPO remains unaltered in rats fed a diet supplemented with EPA-or DHA-rich fish oil in comparison with standard diet-fed rats (Engström et al, 2009). Moreover, in our present study, administration of the ethyl ester form of EPA and DHA significantly decreased the LPO levels in either the cerebral cortex or the hippocampus in aged (100 weeks old) rats (Gamoh et al, 2001), but in young-adult rats (Hashimoto et al, 2009, Hashimoto et al, 2005.…”

Combined oral supplementation of chromium picolinate, docosahexaenoic acid, and boron enhances neuroprotection in rats fed a high-fat diet

“…The findings of glucose and lipid metabolism parameters could have been not only due to Cr picolinate but also DHA, PS, and B effects as well. Feeding SpragueDawley rats a DHA-rich diet for 9 weeks resulted in a decrease in blood triacylglycerols and total cholesterol concentrations and the intake of DHA is important for brain phospholipid DHA enrichment and brain NOS activity (37). Phosphatidylserine, a phospholipid component of cell membranes, functions in memory and cognition and has important roles in sports nutrition including hormone balance for athletes (38).…”