Dietary fatty acids effects on sucrose-induced cardiovascular syndrome in rats.

Cardiovascular disease is one of the leading causes of morbidity and mortality in Mexico. We investigated the effects of omega-3 (n-3) and omega-6 (n-6) polyunsaturated fatty acids on the metabolic syndrome associated with cardiovascular disease in a high-sucrose-fed rat model. The metabolic syndrome-induced rats showed a significant increase in systolic blood pressure, serum insulin, nonfasting serum triglyceride and serum cholesterol levels. Experimental high-sucrose-fed animals received either a n-3 or n-6 enriched diet or a control diet during 6 weeks. Animals fed the n-3 enriched diet had a significant reduction in blood pressure and serum insulin and triglyceride levels. Serum triglyceride levels were also significantly reduced in the n-6-rich diet animals.

The effect of low light flux and nitrogen deficiency on the chemical composition of Spirulina sp. (Arthrospira) grown on digested pig waste.

Evaluation of the effect of low light flux and nitrogen deficiency on growth and chemical composition of Spirulina sp. (straight filaments strain, SF) in batch cultures utilizing a complex medium containing sea-water supplemented with anaerobic effluents from digested pig waste, was undertaken. Cultivation was carried out either at a light flux of 66 (lower) or 144 micromol photon m(-2) s(-1) (higher), utilizing bench raceways. Biomass concentration (as dry weight) after 12 days of cultivation in the complex medium was similar (P < 0.05) to the one observed in a chemically defined medium (Zarrouk), regardless of the light intensity. Protein content of the biomass in the complex medium was significantly lower (P < 0.05), compared to the Zarrouk medium, regardless of the light flux. However, biomass from the complex medium was enriched in total lipids (28.6%), when cultures were exposed to the lower light flux. On the other hand, the palmitoleic acid percentage of total fatty acids was significantly higher (P < 0.05) at a higher light intensity and a high level of gamma linolenic acid (GLA) as a percentage of total fatty acids was observed (28.13%) in the biomass harvested from the complex medium at the lower light intensity. Finally, polysaccharide content was significantly higher (P < 0.05) at the high light intensity and a very high content of total polysaccharides (28.41%) was observed in the complex medium.

Seasonal variation in the fatty acid composition and quality of sardine oil from Sardinops sagax caeruleus of the Gulf of California.

One of the few sources of long-chain n-3 polyunsaturated fatty acids is fish oil, but considerable variation may exist according to species and season. In this study, the fatty acid profiles of sardine oils from Sardinops sagax caeruleus of the Gulf of California, Mexico, were evaluated in three seasonal catch periods. Oil quality was also evaluated by peroxide and free acid values. The most abundant fatty acids found in the oils were palmitic acid (19.3%), oleic acid (14.3%), eicosapentaenoic acid (EPA, 20.4%), and docosahexaenoic acid (DHA, 12.2%). There was no significant difference in the composition and quality among the six reduction plants where the samples were obtained. However, a significant difference in the proportion of EPA and DHA in one of the catch seasons analyzed was observed.

Effects of dietary polyunsaturated fatty acids on adenylate cyclase, 5'nucleotidase and Na+K(+)-ATPase activities in rat brain-plasma membrane.

The incidence of polyunsaturated fatty acids (PUFA) in human nutrition is now generally accepted. As essential membrane components, PUFA may act as enzyme activity modulators. In this study, four different diets, in which PUFA type was the only modifying factor, were evaluated on 5'nucleotidase, adenylate cyclase and Na+/K+ATPase activities in rat brain plasma membranes. Animals fed the total PUFA deficient diet exhibited significant lower body weight and lower brain weight than did the control group. The specific activities of 5'nucleotidase and Na+/K+ATPase in brain plasma membrane were slightly modified by dietary PUFA. The catalytic unit of adenylate cyclase in total PUFA deficient animals presented augmented enzyme activity and animals receiving diets deficient in n-6 PUFA showed reduced activity in relation to the control animals. Our results showed that the epinephrine receptors, in the case of adenylate cyclase are not modified by dietary PUFA, but rather the catalytic unit seems to be altered by dietary PUFA. These results can be partially explained by the fluidity that PUFA confers to membranes facilitating the proximity of enzyme-substrate. The physiological consequences of dietary PUFA incidence on enzyme activity needs further study.

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.