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Background Selenium is an essential trace element for life. It plays an irreplaceable role in delaying human aging, improving immunity, preventing cardiovascular diseases and treating Keshan disease. There are inorganic selenium and organic selenium in nature. Selenopolysaccharide plays an important role in the selection of selenium supplements, but the selenium content of selenopolysaccharide is generally low, so there are some regional limitations in obtaining selenopolysaccharide. Scope and approach In order to improve the biological activity of selenium polysaccharides, organic selenium polysaccharides with high selenium content have become one of the hot spots of research and development. Selenium polysaccharide has a variety of biological activities, such as anti-tumor, anti-virus, improving immunity and so on. Key findings and conclusions The research status of selenium polysaccharide at home and abroad in recent years was reviewed, including the source, preparation and biological activity of selenium polysaccharide. The future development and utilization of selenium polysaccharides in the field of health care or medicine is of great significance.

The present experiment aimed to compare toxic effects of dietary organic or inorganic selenium (Se) and to predict of Se intake and tissue Se concentrations in broiler chickens based on feather Se concentrations. A total of four hundred twenty 7-day-old Ross 308 male broiler chicks were allotted to 1 of 7 dietary treatments in a completely randomized design. Each treatment had 6 replicates with 10 birds per replicate. Organic Se (selenium yeast) or inorganic Se (sodium selenite) was added to the basal diet at the levels of 5, 10, or 15 mg/kg Se. All experimental diets were fed to birds on an ad libitum basis for 28 d. Results indicated that a significant interaction (P

The ability of several plants to accumulate and transform inorganic selenium forms into its bioactive organic compounds has important implications for human nutrition and health. Selenium in plant food can be found in several chemical forms, which have huge difference in function and bioavailability. Therefore, it is very important to analyze them to ensure food quality and to evaluate their impact on health. Liquid chromatography operating in different modes (size exclusion, reverse phase, ion exchange or hydrophilic interaction) and coupled to sensitive inductively coupled plasma mass spectrometry detection is the most frequently used technique for selenium speciation analysis. The main purpose of this review is to provide an update on the recent literature concerning the strategies for selenium speciation in plant materials. This survey will attempt to cover the state of-the art since 2010.

The Allium genus vegetables are of special interest since being potentially sources for selenium. In this study, the metabolization of selenite and selenate fortification at low and high levels in hydroponically cultivated Allium porrum (Leek) was investigated. The total Se analysis of nutritional solutions which was used in cultivation medium revealed that leeks had potential to accumulate Se above over 1000 mg/kg without any growth disturbance which was proved by comparing dry masses of control group with the ones fortified by Se species. Speciation analyses performed in edible parts which are leaves and stems showed that approximately 90% of total selenium was biotransformed into organo-selenium species in which MeSeCys and SeMet were found to be the most dominant in Se(IV) fortified leeks. However, selenate was found to be the most abundant species in edible parts of selenate fortified leeks especially at high levels. Although bioavailability rate of total selenium in selenate fortified leeks was found to be higher, lower amount of inorganic selenium and higher amount of MeSeCys were found to be bioavailable in Se(IV) fortified.

SUMMARY The present study was planned to explore the effects of different selenium-supplemented diets on production performance in 4 varieties of Aseel chicken, including Lakha (LK), Mushki (MS), Peshawari (PW), and Mianwali (MW). The selenium (Se) from Se-enriched yeast (SY) and sodium selenite (SS) was supplemented into a corn-soybean meal basal diet at 0.3 mg/kg, whereas control diet had no supplemental Se. In total, 84 adult molted Aseel hens (50 wk old), 21 from each variety, were randomly assigned to 12 treatment groups in a 3 × 4 factorial arrangement of 3 Se diets (organic, inorganic, and control) and 4 Aseel varieties (LK, MS, PW, and MW), under a randomized complete block design (RCBD). Each treatment had 7 replicates with individual hens per replicate. Feed intake (FI), body weight (BW), egg production (EP), egg weight (EW), egg mass (EM), FCR/dozen eggs, and FCR/kg egg mass parameters were evaluated. The results indicated that the hens fed organic Se-supplemented diet showed greater (P

Anthropogenic activities such as mining, industrialization and subsequent emission of industrial waste, and agricultural practices have led to an increase in the accumulation of metal(loid)s in agricultural soils and crops, which threatens the health of people; the risk is more pronounced for individuals whose survival depends on food sources from several contaminated regions. Selenium (Se) is an element essential for the normal functioning of the human body and is a beneficial element for plants. Se deficiency in the diet is a common issue in many countries around the world, such as China and Egypt. >40 diseases are associated with Se deficiency. In practice, Se compounds have been applied through foliar sprays or via base application of fertilizers to increase Se concentration in the edible parts of crops and to satisfy the daily Se intake. Moreover, Se at low concentrations has been used to mitigate the toxicity of many metal(loid)s. In this review, we present an overview of the latest knowledge and practices with regards to the utilization of Se to reduce the uptake/toxicity of metal(loid)s in plants. We have focused on the following issues: 1) the current status of understanding the mechanisms of detoxification and uptake restriction of metal(loid)s regulated by Se; 2) the optimal dose and speciation of Se, and stage of plant growth that is optimal for application; 3) the differences in the efficiency of different application methods of Se including seed priming, base application, and foliar spray of Se fertilizers; 4) the possibility of using Se along with other methods to reduce multiple metal(loid) accumulation in crops; and 5) potential risks when Se is used to reduce metal(loid) accumulation in crops.

Selenium, a metalloid, commonly known for its essentiality has emerged out as a water pollutant of concern for environmentalist due to its presence in natural water resources above the permissible limit. The high level of selenium in the environment poses severe health and ecosystem threats, therefore, its monitoring in water is of paramount concern. The present contribution summarizes and critically analyzes the field promising techniques, in particular, voltammetry and optical approach, for selenium quantification in water. The role of sensor material (organic fluorophores, colorimetric dyes and quantum dots), electrode surface modifiers (Hg, Bi, polymers, nanomaterials, etc.), chelators, etc., to overcome various challenges and achieve better sensor performance in terms of detection limit, range, reproducibility, stability, selectivity, sensitivity, and so forth are critically discussed. To end with, the possible future developments are discussed towards the realization of a cost-effective & field deployable monitoring device for on-site selenium analysis.

Selenium is an essential trace element that is involved in the synthesis of various selenoproteins in higher animals including humans. Twenty five selenoproteins have been identified in humans. These selenoproteins have various physiological functions. Organic selenium is safer than inorganic selenium and can be used as a nutritional supplement for people who live in selenium-deficient areas. Supera-nutritional intake of selenium has been claimed to prevent cancer, however, consistent clinical results are lacking. At this time, the use of selenium-rich foods by those in selenium-deficient areas might be the safest and best recommendation. This is a brief overview of the requirements for selenium, the selenium enrichment process in plants and animals, and the preparation of typical selenium-rich foods so as to provide some help for the application and development of selenium fortified products.

The aim of this study was to investigate the effects of dietary organic and inorganic selenium (Se) on the growth, Se concentration and meat quality of juvenile grouper, Epinephelus malabaricus. Organic Se (selenomethionine, SeMet) and inorganic Se (sodium selenite, Na2SeO3) were each added to the basal diet of juvenile grouper at 0.3, 0.7, 1.0 and 1.5 mg Se/kg-diet. The basal diet, without Se supplementation, was used as a control. There was a total of 9 experimental diets, and each was fed in triplicate to groups of fish (initial wt: 24.45 ± 0.73 g) in a seawater recirculating system for 8 weeks. Weight gain was significantly (P

Selenium (Se) is shown to be an essential element for poultry nutrition and a great deal of information has been accumulated for the last 20 years indicating that dietary form of Se is a major determinant of its efficiency. Generally speaking, there are two major Se sources for poultry, namely inorganic selenium (mainly selenite or selenate) and organic selenium in the form of selenomethionine (SeMet; mainly as Se-Yeast or SeMet preparations). In this review two main areas are considered in relation to the Se nutrition of breeders. Firstly, it is Se important roles in the maintenance of semen quality and optimal Se status of poultry males and Se is considered to be an important factor in ensuring the fertility of breeding stock. Secondly, Se status of the eggs from breeding birds is of great importance for the maintenance of the antioxidant system of the developing embryo. It is generally accepted that the hatching process is an oxidative stress and improvement in antioxidant defences of the embryo can increase hatchability. It is quite clear that the roles of Se in poultry nutrition and reproduction need new consideration in light of our recent knowledge on the molecular mechanisms of Se action at the cellular and sub-cellular levels. In particular, the discovery and characterisation of a range of new selenoproteins and a better understanding of the relationships between different antioxidants, as important parts of integrated antioxidant system with possibilities for antioxidant recycling in vivo, have yielded new insights in this area. In particular, it should be mentioned that increased levels of Se supplementation are not always beneficial, since selenoprotein synthesis is under the gene control and it reflects the need in these active molecules to deal with various stresses. However, to give a body a chance to affectively respond to environmental challenges by modulating selenoprotein synthesis there should be enough Se reserves available and this an ability of building Se reserves in the body is considered to be the main point in advantages of organic selenium in poultry and farm animal nutrition. A comprehensive analysis of the effects of various forms of dietary Se on its egg concentration, its transfer to the embryonic tissues and physiological consequences of the improved Se status of the progeny chicks are considered.

The present study aims to determine the effect of dietary Se supplement on Merghoz goats at the last stage of gestation on serum Se, Cu, Zn and Fe status of goats and their kids. Thirty Merghoz does (30 ± 3 kg) were fed the same basal diet containing 0.11 mg Se kg −1 DM and randomly assigned to one of three dietary treatments in a randomized complete block design. Three weeks before the expected kidding, the basal diet was supplemented with 0 (control) or 0.3 mg Se head −1 d −1 in the form of l -selenomethionin (Se-Met) and 0.3 mg Se head −1 d −1 in the form of sodium selenite (SS). Blood samples were collected from the does three weeks before the expected kidding and on the kidding day. Blood samples of newborn kids were also taken from the jugular vein at birth and 7 days of age. The results indicated that the serum concentration of Se increased in supplemented does compared with the control ones. The selenium concentration was also significantly increased in colostrum of treated does ( P P

Two cruises were undertaken to study the selenium species and arsenic, and their relationship with marine production in the Zhujiang (Pearl River) Estuary, covering both wet (July, 1999) and dry (January, 2000) seasons. Concentrations of dissolved Se (IV), Se (VI) and arsenic in the Zhujiang River are generally within the range of Chinese rivers and other large systems, like the Rhone River and Panama River. In January 2000, the concentration of selenium was lower than that in the July 1999. Total dissolved inorganic selenium averaged 2.77 nmol L−1 in the winter and 4.15 nmol L−1 in the summer, with Se (VI) accounting for 55% and 58%, respectively. Total dissolved inorganic arsenic averaged 25.8 nmol L−1 in the winter and 22.3 nmol L−1 in the summer. The data indicated that dissolved arsenic and selenium did not behave conservatively in the estuary. An important mobilization of dissolved selenium and arsenic was observed from the river up to halfway in the estuary. Both input flux (from river to estuary) and output flux (from estuary to coastal zone) of dissolved selenium and arsenic were calculated from statistical interpretations of the salinity profiles.

Two cruises of “R/V Dong Fang Hong 2” were carried out in September 1998 and May 1999, respectively, to understand the behavior of selenium in the Bohai Sea. Selenium species (dissolved inorganic selenium, selenite) are determined by HG-AFS for 30 grid stations. Selenium concentrations display short-term variability and seasonal change in the Bohai Sea, with higher levels in shallow coastal waters than in the Central Bohai Sea. The influence of riverine discharge on selenium levels can be seen from salinity isopleths, selenium distribution and species ratios. Near-bottom waters have similar selenium concentrations as to the surface waters in the Central Bohai Sea, whereas stratification takes place in the Bohai Strait and North Yellow sea. Based on the data of this study, a preliminary estimate of selenium budgets via riverine input is established. The seasonal variation of Se (IV)/Se (VI) ratio is maximum in Bohai Sea. The predominant species of selenium was selenate in autumn 1998. However, selenite became the dominant species in spring 1999. A simple box model was used to estimate the water-mass balance and selenium budgets for the Bohai Sea. Selenium budgets demonstrated that net sink of selenium can be mainly from the water column into bottom sediments and/or by transformation to other forms of selenium.

This experiment evaluated the maximum tolerable level of inorganic Se fed to growing wether lambs for 1 year. Sodium selenite was added to provide 0.2, 2, 4, 6, 8, and 10 ppm Se to a basal diet. Thirty-nine crossbred wether lambs initially weighing 22.8 ± 3.3 kg were randomly allotted to one of six treatments. Blood samples were collected and liveweight gain determined at 28-day intervals and tissue samples were collected at experiment termination. Serum, whole blood, wool, hooves, bile and five tissues were analyzed for Se concentrations. Five tissues at experiment termination were microscopically evaluated for tissue breakdown due to Se toxicosis. Also, five enzyme activities and albumin were determined. Lamb BW were not influenced by dietary Se concentrations ( P > 0.15). Both serum and whole blood Se concentrations increased at each collection period as dietary Se level increased ( P P r = 0.92) between serum and whole blood Se concentration. At termination of the study, all tissues and wool, hoof, and bile Se concentrations increased as dietary Se level increased ( P P > 0.15) among treatments, and enzymes were within their respective normal ranges. These results suggest that ≤10 ppm dietary Se as selenite is not toxic to wether lambs when fed for 1 year. It seems plausible, therefore, to consider the maximum tolerable level of Se as selenite for sheep to be considerably higher than 2 ppm as previously suggested.

The importance of inorganic selenium and chromium speciation at low concentration levels is well established. Thus, society demands that accurate analytical methods be implemented in routine laboratories. In this context, the European Commission, through the Standards, Measurements and Testing Programme, has contributed significantly to improving the quality control of the speciation of inorganic selenium, as Se(IV) and Se(VI), and chromium, as Cr(III) and Cr(VI), by organising interlaboratory studies followed by the preparation of candidate reference materials. In this article are outlined the performance of the methods used by the participating laboratories and the main sources of errors detected.

Selenium in the form of selenocysteine plays an essential role in a number of proteins, but its role in non-enzymatic biochemistry is also important. In this short review we discuss the interactions between inorganic selenium, arsenic and mercury under physiological conditions, especially in the presence of glutathione. This chemistry is obviously important in making the arsenic and mercury unavailable for more toxic interactions, but in the process it suggests that a side-effect of chronic arsenic and/or mercury exposure is likely to be functional selenium deficiency.

The selenate (VI) and selenite (IV) forms of selenium were found to be acutely toxic to the freshwater green alga Selenastrum capricornutum Printz. The concentrations causing 50% growth inhibition (EC50) in 24 hr were 61.5 mg Se/l for selenate and 143 mg Se/l for selenite. Subsequent EC50 values for selenite were; 100 mg Se/l at 2 days; 96 mg Se/l at 4 days; and 65 mg Se/l at 6 days. Selenate was more toxic, producing 88% growth inhibition in 6 days at 40 mg Se/l compared to 18% for selenite at the same concentration. The relationship between growth inhibition and selenium concentration was found to be linear over the range of concentrations tested for both the selenate and selenite forms.

The stability of inorganic selenium(IV) and selenium(VI) species at levels of 1 and 10μg l -1 has been studied under various conditions of pH, type of water and type of container. Polyethylene containers and adjustment to pH 1.5 provide optimum conditions of preservation for both distilled and natural water samples up to 125 days. Algal growth is detrimental to solution stability at natural pH values of 5.4–7.2, but adjustment to pH 1.5 with sulfuric acid successfully avoids this effect. Container size and temperature are also discussed. Storage of samples at 4°C gives satisfactory stability but is less practicable. The essential nature of preservation techniques applicable to interlaboratory quality control studies is emphasized.

An experiment was conducted with 192 day-old male Cobb chicks to study tissue uptake of Se as an estimate of the bioavailability of supplemental inorganic Se sources fed at high dietary concentrations. A basal corn-soybean meal diet (.18 mg Se/kg diet, dry matter basis) was supplemented with 0, 3, 6, or 9 mg Se/kg diet (as-fed basis) as either reagent grade Na2 SeO3, CaSeO3, or Na2 SeO3 plus fumed amorphous carrier or 6 mg Se/kg diet as either Na2 SeO4 or Se metal, and fed for 1 wk. No toxic effects were noted as expressed by mortality; however, there was a reduction (P Multiple regression slope ratios were used to estimate relative bioavailability values of 100, 103, 99, 112, and 83 for Na2 SeO3, CaSeO3, Na2 SeO3 + carrier, Na2 SeO4, and Se metal, respectively. When these ratios were corrected for the analyzed dietary Se concentration, relative values were 100, 96, 94, 109, and 81 for the above sources, respectively.

A longitudinal dietary Se supplementation study on lactating mothers was performed to determine the possibilities of improving the Se status of exclusively breast-fed infants. A total of 200 mothers randomized into three groups received either no Se supplements, 100 micrograms of selenite, or 100 micrograms of yeast-Se daily. Maternal and infant serum Se concentrations showed a linear correlation during exclusive breast-feeding. Yeast-Se in the dose administered was safe and more effective than selenite in increasing the Se concentrations of maternal serum and milk, and infant serum. The mean estimated daily Se intakes of the infants were 7.7 +/- 2.2, 8.9 +/- 2.2, and 11.5 +/- 4 micrograms, in the control, selenite, and yeast-Se groups respectively. Though the infant Se intakes of the unsupplemented and selenite-supplemented mothers were below the lower limit of the safe and adequate range as set by the US National Research Council, their serum Se concentrations increased steadily over the 6-mo study period. As maternal serum Se also increased by over 50% during the same period the results suggest that a maternal daily intake of 50-75 micrograms is adequate during lactation.

In a study designed to examine the long-term effects of inorganic selenium (IV) on early life stages of rainbow trout (Salmo gairdneri), survival was significantly reduced at selenium concentrations of 47 and 100 μg l−1 after 90 days of exposure. Length and weight were significantly reduced after 90 days of exposure to 100 μg l−1. Whole-body residues of selenium increased with increasing exposure concentrations but appeared to decline between 30 and 90 days of exposure. Analyses of trout backbone indicated little change in bone development with exposure to selenium (IV) with one exception; calcium concentrations were significantly decreased in fish exposed to ⩾ 12 μg l−1 of selenium. Results of our study indicates that a recommended safe level of 10 μg l−1 for inorganic selenium would not significantly affect growth and survival of rainbow trout; however, concentrations of selenium near this level can reduce the levels of calcium in the backbones of trout.

A 75Se tracer technique is used to show that Sb, Cd, Mn, Mo, Ni, KI, KIO3, Ag, Th, Tl, Zn and Zr quantitatively stabilize inorganic selenium. Only Mo, Ni and Ag were effective for organoselenium compounds in urine, and only molybdenum was partially successful for blood samples.

The effects of selenite and selenate treatment by air cell injection on mortality and growth of 14-day chick embryos during a 64–68 hour period were studied. The LD50 for selenite-Se was about 0.5 ppm, based on weight of the egg contents, and that for selenate-Se about 1.8–2.0 ppm. Growth depression was evident from these treatments, but other gross effects were not prominent. The treatment of embryos with selenite and sulfate together caused a greater mortality than treatment with selenite alone.

Quantitative chemical analyses and biological potency testing of stored premixes of selenite or selenate salts with a variety of carriers was performed. The results suggest that the selenium was quite stable in glucose monohydrate, wheat bran, corn, linseed meal, soybean meal or soybean protein premixes kept reasonably dry and stored at temperatures below 40°C.

INVESTIGATIONS of the toxic effects of seleniferous grains on hatchability were first reposted by Franke and Tully (1935). Subesquent studies have shown that the feeding of inorganic selenium salts in the laying ration or the injection of small amounts of inorganic selenium into the air cells of fertile eggs, Franke et al 1936, as well as the feeding of seleniferous grains, will as the feeding of seleniferous grains, will produce deformed embryos. Other angles of the effects of seleniferous grains on poultry have also been investigated, Tully and Franke (1936) and Poley et al (1937). In connection with investigations of the “alkali disease” the selenium content of the organs and tissues from several selenzied laboratory animals had been determined by Moxon (1937). The selenium content of the selenized animals indicated that it would be important to investigate the selenium content of eggs and meat from hens fed seleniferous grains. EXPERIMENTAL . . .

A series of experiments was conducted in which practical use levels of Tower and Candle rapeseed meals were included in diets for broiler chickens, laying hens and growing-finishing pigs to determine the efficacy of these products in providing selenium to the animals. Organic selenium from rapeseed was better utilized than the inorganic selenium from sodium selenite. At use levels of 15-20% rapeseed meal in corn, soybean type diets for broiler chickens, laying hens or growing-finishing pigs no inorganic selenium need be added to prevent Se deficiency, and the meat and eggs produced would appear to be at desirable levels of Se for human consumption.

IT HAS been shown that the inclusion of seleniferous grain in the rations of laying hens will reduce hatchability of fertile eggs and cause deformed embryos (Franke and Tully, 1935). Similar results have been produced by injecting small amounts of inorganic selenium salts into fertile eggs (Franke et al., 1936). More recently it has been found that arsenic will counteract the toxic action of selenium in rats (Moxon, 1938; Moxon and DuBois, 1939; and DuBois, Moxon, and Olson, 1940), in hogs (Moxon, 1941a), in dogs (Rhian and Moxon, 1943), and in cattle. 1 Arsenic has also been found to be quite effective in counteracting the toxicity of selenium in the diet of growing chicks (Moxon, 1941b). In connection with studies on the mechanism of selenium-arsenic antagonism it was desirable to determine whether arsenic would prevent the reduction in hatchability of chickens eggs when selenium was included in the ration of laying . . .

The biochemical association and chemical form of selenium in the muscle tissues of four marine animals has been examined. Selenium was predominantly associated with soluble proteins (72–80%), and not present as characterizable inorganic selenium species (SeO 3 2− , SeO 4 2− ).