Selenium

About: Selenium is a research topic. Over the lifetime, 21192 publications have been published within this topic receiving 429715 citations. The topic is also known as: Se & selen.

Determination of nitrogen in organic substances

Abstract: A modified oxidation-reduction titration method for the determination of nitrogen in organic matter after Kjeldahl digestion is described The catalysts including copper, selenium or mercury, which often interfere with the end point of oxidation-reduction titration, were removed by addition of zinc granules

Quantification and speciation of mercury and selenium in fish samples of high consumption in Spain and Portugal

Abstract: Mercury (Hg) and selenium (Se) determinations were carried out to evaluate human exposure to those elements through fish consumption in Spain and Portugal. Atomic fluorescence spectroscopy (AFS) was applied in a cold vapor mode for total mercury quantification and was also hyphenated to gas chromatography (GC) to achieve the speciation of organomercurial species in fish samples. The results obtained show the highest concentration of Hg in swordfish and tuna (0.47±0.02 and 0.31±0.01 μg g−1, respectively), and a much lower concentration in sardine, mackerel shad, and octopus (0.048±0.002, 0.033±0.001, and 0.024±0.001 μg g−1, respectively), The determination of alkyl mercury compounds revealed that 93–98% of mercury in the fish samples was in the organic form. Methylmercury (MeHg) was the only species found in the three fish species with higher mercury content. Total selenium concentraton was high in sardine, swordfish, and tuna (0.43±0.02, 0.47±0.02, and 0.92±0.01 μg g−1, respectively), but low in mackeral shad and octopus (0.26±0.01 and 0.13±0.01 μg g−1, respectively). Speciation of selenium compounds was done by high-performance liquid chromatography in conjunction with inductively coupled plasma mass spectrometry (LC-ICP-MS). Selenomethionine (SeMet) was the only selenium compound identified in the fish samples with higher selenium content. Among the fish species studied, sardine had the most favourable Se:Hg and SeMet:MeHg molar ratios; therefore, its consumption seems to be preferable.

Effect of dietary selenium and omega-3 fatty acids on muscle composition and quality in broilers

Abstract: Human health may be improved if dietary intakes of selenium and omega-3 fatty acids are increased. Consumption of broiler meat is increasing, and the meat content of selenium and omega-3 fatty acids are affected by the composition of broiler feed. A two-way analyses of variance was used to study the effect of feed containing omega-3 rich plant oils and selenium enriched yeast on broiler meat composition, antioxidation- and sensory parameters. Four different wheat-based dietary treatments supplemented with 5% rapeseed oil or 4% rapeseed oil plus 1% linseed oil, and either 0.50 mg selenium or 0.84 mg selenium (organic form) per kg diet was fed to newly hatched broilers for 22 days. The different dietary treatments gave distinct different concentrations of selenium and fatty acids in thigh muscle; one percent linseed oil in the diet increased the concentration of the omega-3 fatty acids 18:3, 20:5 and 22:5, and 0.84 mg selenium per kg diet gave muscle selenium concentration at the same level as is in fish muscle (0.39 mg/kg muscle). The high selenium intake also resulted in increased concentration of the long-chain omega-3 fatty acids EPA (20:5), DPA (22:5) and DHA (22:6), thus it may be speculated if high dietary selenium might have a role in increasing the concentration of EPA, DPA and DHA in tissues after intake of plant oils contning omega-3 fatty acids. Moderate modifications of broiler feed may give a healthier broiler meat, having increased content of selenium and omega-3 fatty acids. High intakes of selenium (organic form) may increase the concentration of very long-chain omega-3 fatty acids in muscle.

Selenium and cardiovascular disease.

Abstract: For humans, ecological and epidemiological results are reported that show a relationship between the serum selenium concentration and cardiovascular disease in populations where low serum selenium concentrations are found, e.g., in Eastern Finland. From clinical studies done in Germany (FRG and GDR), Finland, and Sweden, subnormal serum selenium and partially whole blood selenium concentrations are reported in patients with acute myocardial infarction. For patients with coronary arteriosclerosis, subnormal serum selenium concentrations are reported from the USA and Germany and subnormal whole blood selenium concentrations from Germany. Subnormal serum and subnormal whole blood selenium concentrations of patients with cardiomyopathy are reported from non Keshan disease affected areas in Germany, France, and China. In selenium deficiency, an accumulation of lipid peroxides in the heart may occur, especially under ischemic conditions and if ischemic tissue is reperfused. Lipid peroxides in the heart may damage the cell membrane and may lead to an impaired calcium transport with an uncontrolled calcium accumulation in the cell. This may result in an activation of phospholipids, and, in consequence, to an enhanced formation of arachidonic acid. An increased concentration of lipid peroxides owing to selenium deficiency may shift the prostaglandin synthesis from prostacyclin to thromboxane, causing enhanced blood pressure and platelet aggregability. From animal experiments, it is known that selenium protects against cardiotoxic elements, cardiotoxic xenobiotics, and viral infections that affect the heart. Selenium deficiency may also be a secondary factor in the causation of hypertension and myocardial ischemia.