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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.

Inorganic selenium, the most common form of harmful selenium in the environment, can be determined using electrochemical sensors, which are compact, fast, reliable and easy-to-operate devices. Despite progress in this area, there is still significant room for developing high-performance selenium electrochemical sensors. To achieve this, one should take into account (i) the electrochemical process that selenium undergoes on the electrode; (ii) the valence state of selenium species in the sample and (iii) modification of the sensor surface by a material with high affinity to selenium. The goal of this review is to provide a knowledge base for these issues. After the Introduction section, mechanisms and principles of the electrochemical reduction of selenium are introduced, followed by a section introducing the modification of electrodes with materials interacting with selenium and a section dedicated to speciation methods, including the reduction of non-detectable Se(VI) to detectable Se(IV). In the following sections, the main types of materials (metallic, polymers, hybrid (nano)materials…) interacting with inorganic selenium (mostly absorbents) are reviewed to show the diversity of properties that may be endowed to sensors if the materials were to be used for the modification of electrodes. These features for the main material categories are outlined in the conclusion section, where it is stated that the engineered polymers may be the most promising modifiers.

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 total selenium content of selenium-enriched agricultural products was determined by inductively coupled plasma mass spectrometry after microwave digestion. The total selenium content in the tes...

Aims Most crops are supplemented with selenium (Se) through the exogenous addition of inorganic selenium fertilizer. There is a lack of in-depth research on organic selenium fertilizers. Meanwhile, the dosage range between human selenium deficiency and selenium toxicity is narrow, so the selenium content of agricultural products needs to be controlled within a reasonable interval. Methods W e analyzed and compared the Se accumulation and speciation in rice during three different growth stages (late tillering stage, initiate heading stage, and full heading stage) using three selenium fertilizers, selenite, fermented Se, and potassium Selenocyanoacetate (Se-AAF) via the foliar application. Results The selenium content in rice sprayed with organic selenium fertilizer was controlled in the relatively safe range and met the human selenium supplement requirement compared to the sprayed sodium selenite, which was too high of a dose. The percentage of organic Se and protein Se in brown rice was found to be similar in all three Se fertilizers. The highest organic selenium content of 91.57% was found in the grain of rice at the full heading stage by spraying Se-AAF. The main Se species in the grain was selenomethionine (SeMet), which reached 80% of the total selenium. Se-methyl selenocysteine(SeMeCys) was found only in Se-AAF. The grain quality showed that all three Se fertilizers increased the consistency of gelatinization. Conclusions Appropriately delaying the spraying time and selecting organic Se fertilizer as the Se source can help to produce green and safe selenium-rich rice.

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.

This chapter is devoted to selenium and its role in organism. Selenium has been proved as an essential element for animals and humans. Perception of its role changed from the toxic toward essential element as in the last decade its importance has been described through its biochemical functions. Selenium can be found in the environmental components such as air, water, soil, as well as in living organisms. Plants have crucial role especially in transformation of inorganic selenium forms into organically bound. The natural source of selenium for plants is usually soil, and from the soil solution, selenium is absorbed and metabolized into organic compounds such as seleno-amino acids which can be used as a building materials for the higher structures, especially selenoproteins. Selenium enrichment of crops has been briefly described with the examples from the practice across the world.

Ninety-six male goslings were allocated and assigned to treatment using a completely randomized design. Dietary treatments included a basal diet consisting of corn, wheat, and soybean meal with either no additional selenium (CON), 0.3 mg/kg of inorganic selenium (I-Se, sodium selenite), or 0.3 mg/kg of organic selenium (O-Se, selenium-enriched yeast). After a 56-day feeding period, geese were slaughtered on a common ending day and two geese per pen (n = 24) were used for the analyses conducted in this study. Meat (equal portions of the breast and thigh meat) and liver were collected and evaluated for proximate composition, fatty acid profile, pH, phenolic content, thiobarbituric acid reactive substances (TBARS), and total volatile basic nitrogen (TVB-N) over a 9-day storage period at 4 &deg, C. The meat and liver samples from geese supplemented I-Se or O-Se had greater (p &lt, 0.01) lipid content compared with geese not supplemented with additional selenium. At the conclusion of the 9-day storage period, meat and liver samples from geese supplemented I-Se or O-Se had lower (p &lt, 0.05) pH values, greater (p &lt, 0.05) phenolic content, lower (p &lt, 0.05) TBARS values, and lower (p &lt, 0.05) TVB-N compared with geese not supplemented with additional selenium (CON).

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.

A fit for purpose analytical protocol was designed towards searching for low molecular weight seleno-compounds in sprouts. Complementary analytical techniques were used to collect information enabling the characterization of selenium speciation. Conceiving the overall characterization of the behavior of selenium, inductively plasma optical mass spectrometry (ICP-MS) was used to determine the total selenium content in entire sprouts as well as in selected extracts or chromatographic fractions. Then, high-performance liquid chromatography combined with ICP-MS (HPLC-ICP-MS) was used to evaluate the presence of inorganic and organic seleno-compounds, with the advantages of being very sensitive towards selenium, but limited by available selenium standard compounds. Finally, ultra-high performance liquid chromatography electrospray ionization triple quadrupole mass spectrometry (UHPLC-ESI-QqQ-MS/MS) and UHPLC-ESI-Orbitrap-MS/MS were used for the confirmation of the identity of selected compounds and identification of several unknown compounds of selenium in vegetable sprouts (sunflower, onion, radish), respectively. Cultivation of plants was designed to supplement sprouts with selenium by using solutions of selenium (IV) at the concentration of 10, 20, 40, and 60 mg/L. The applied methodology allowed to justify that vegetable sprouts metabolize inorganic selenium to a number of organic derivatives, such as seleno-methylselenocysteine (SeMetSeCys), selenomethionine (SeMet), 5&prime, seleno-adenosine, 2,3-DHP-selenolanthionine, Se-S conjugate of cysteine-selenoglutathione, 2,3-DHP-selenocysteine-cysteine, 2,3-DHP-selenocysteine-cysteinealanine, glutathione-2,3-DHP-selenocysteine, gamma-Glu-MetSeCys or glutamyl-glycinyl-N-2,3-DHP-selenocysteine.

Selenium nanostructures are characterized with high activity and antibacterial properties. Selenium nanoparticles, received by the biotechnological method using microorganisms are not toxic and free from admixtures of other toxic elements. For getting selenium nanostructures, there was set a problem of development of the biotransfrormation technology of inorganic selenium by the culture Lactobacillus acdophilus, strain 412/307 from the museum of the Department of Biochemistry, Microbiology and Physiology of Nutrition Odessa National Academy of Food Technologies (Ukraine). Selenium nanostructures are the side product in the process of selenocysteine formation. There was realized the study of the influence of the sodium selenite concentration on the growth speed and generation duration of lactobacteria on MRS medium for determining the main technological parameters. There was determined the quantitative content of accumulated selenium at different initial concentrations of sodium selenite in the medium. The important part of the elaborated technology is destruction of cellular walls of microorganisms for removal selenium nanoparticles. There was studied the influence of different physical-chemical factors of cells’ destruction. There was offered to use the combined influence of saline acid, freezing and microwave field for destructing cellular walls of lactobacteria biomasses. There is presented the scheme of the technology of getting “Nanoselenium” and given physical-chemical parameters of the received product.

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 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.

Selenium is a trace element essential for human health that has received considerable attention due to its nutritional value. Selenium’s bioactivity and toxicity are closely related to its chemical form, and several studies have suggested that the organic form of selenium (i.e., selenomethionine) is more bioavailable and less toxic than its inorganic form (i.e., sodium selenite). Probiotics, especially Bifidobacteriium and Lactobacillus spp., have received increasing attention in recent years, due to their intestinal microbial balancing effects and nutraceutical benefits. Recently, the bioconversion (a.k.a biotransformation) of various bioactive molecules (e.g., minerals, primary and secondary metabolites) using probiotics has been investigated to improve substrate biofunctional properties. However, there have been few reports of inorganic selenium conversion into its organic form using Bifidobacterium and Lactobacillus spp. Here we report that the biosynthesis of organic selenium was accomplished using the whole cell bioconversion of sodium selenite under controlled Bifidobacterium bifidum BGN4 culture conditions. The total amount of organic and inorganic selenium was quantified using an inductively coupled plasma-atomic emission spectrometer (ICP-AES). The selenium species were separated via anion-exchange chromatography and analyzed with inductively coupled plasma-mass spectrometry (ICP-MS). Our findings indicated that the maximum level of organic selenium was 207.5 µg/g in selenium-enriched B. bifidum BGN4. Selenomethionine was the main organic selenium in selenium-enriched B. bifidum BGN4 (169.6 µg/g). Considering that B. bifidum BGN4 is a commercial probiotic strain used in the functional food industry with clinically proven beneficial effects, selenium-enriched B. bifidum BGN4 has the potential to provide dual healthy functions as a daily supplement of selenium and regulator of intestinal bacteria. This is the first report on the production of organic selenium using B. bifidum spp.

OBJECTIVE This study was conducted with the objectives to examine the impacts of inorganic selenium (Se) and different types and levels of organic selenium on the serum and tissues Se status and antioxidant capacity in broiler breeders. METHODS Five hundred and forty 48-wk-old Lingnan Yellow broiler breeders were randomly assigned to 6 dietary treatments, provided same basal diet (0.04 mg/kg of Se) with 0.15 mg/kg, or 0.30 mg/kg of Se from sodium selenite (SS) or from selenium-enriched yeast (SY) or from selenomethionine (SM). The broiler breeders were slaughtered after an 8-wk experiment. RESULTS The results showed that SM was better than SY and SS, 0.30 mg/kg level was better than 0.15 mg/kg level in Se deposition (p

Selenium is one of the most prominent essential trace elements for humans. Generally, the major supply of selenium results from the regular nutrition. In the regular diet almost all selenium exists in the form of organic compounds, e.g. as selenomethionine and other selenoamino acids. In contrast, special exposure by functional food, environmental contamination or occupational exposure may occur partly or mainly in the form of inorganic selenium compounds and elemental selenium, which differ in absorption, distribution, metabolism and elimination compared to the organic compounds.

This study evaluated the effect of dietary organic and inorganic selenium supplementation on chemical, mineral and fatty acid composition of ostrich meat. Forty ostriches were raised in two groups (OSe and IOSe, diets supplemented with an organic form and an inorganic form of selenium, respectively). The form of selenium had no influence on chemical composition of ostrich muscle. Although, there were no significant differences in total content of SFA, MUFA and PUFA, the content of LA and EPA was higher in the muscles of ostriches which were put on a diet supplemented with an organic form of selenium, what resulted in lower n-6/n-3 fatty acids ratio in OSe group (9.99) in comparison to IOSe group (11.70). The results of the study indicate that dietary organic selenium supplementation improves the quality of the ostrich meat as related to the health promoting properties (LA, EPA and selenium content) of meat.

Selenium compounds, in both inorganic and organic forms have been explored for development as radioprotectors, agents used to minimize the deleterious effects of radiation. Most of the research in this direction has been focused on inorganic selenium, including several clinical studies where selenium supplementation yielded useful outcomes in cancer patients undergoing radiotherapy. Since organic selenium is less toxic than inorganic selenium, researchers are now focusing on the development of organoselenium compounds for radioprotection. Both natural and synthetic organoselenium compounds are being examined and one such water-soluble selenium compound, 3,3′-diselenodipropionic acid (DSePA) developed by our group, showed promising activity at pre-clinical stages. These results, along with the current status and future scope of research, are discussed in this chapter.

The aim of the study was to examine the assimilability of organic and inorganic selenium supplied as an additive to pig feed. The influence of both selenium forms on pig slaughter value as well as on the physicochemical and sensory characteristics of meat was also examined (experiment I). An attempt to establish the distribution of selenium in the body of experimental fatteners was made (experiment II). Experiment I was performed on 20 carcasses of crossbred pigs of (Polish Large White × Polish Landrace) × Duroc genotype and experiment II was carried out on 45 samples of longissimus and semimembranosus muscles taken from fatteners of the same genotype (PLW × PL × Duroc). The results obtained indicated that selenium supplementation in the diet had no impact on slaughter performance, meat quality and most physicochemical and sensory characteristics of meat. Selenium was found to have no significant effect on meat colour. The meat water holding capacity (WHC) was lower in the group of pigs fed organic selenium. The highest selenium concentration was found in the semimembranosus muscle of fatteners receiving the inorganic selenium additive.

Effect of selenium(+4) as selenite (Se32−) on two Azospirillum brasilense strains, which occupy different ecological niches (an epiphyte Sp7 and a facultative endophyte Sp245), was studied. The cultures grown in the medium with sodium selenite exhibited intense red coloration. Transmission electron microscopy and X-ray fluorescence analysis revealed accumulation of elementary selenium within the cells of both strains as nanoparticles 50–400 nm in diameter. The ability to reduce inorganic selenium(+4) to elementary selenium (as nanoparticles) has not been previously reported for azospirilla. Our results indicate the possibility to apply Azospirillum strains as microsymbionts for phytoremediation of, and cereal cultivation on, selenium-contaminated soils. The ability of azospirilla to synthesize selenium nanoparticles may be of interest for nanobiotechnology.

An overview highlighting the anti-cancer potential of (bio-essential) selenium- and tellurium-containing species, with an emphasis on biological targets and mechanisms of action, is presented. Studies thus far have focused on selenium(II) compounds (along with – to a lesser extent – inorganic selenium and selenium nanoparticles) which often successfully exploit the inherent anti-oxidizing ability of selenium. Significantly less work has been conducted in developing anti-cancer tellurium compounds, yet two tellurium(IV) species are proven, clinically, as anti-cancer agents. Given the prevalence of the disease and the accumulated insights into mechanisms of action, the continued development of selenium- and tellurium-containing molecules is an area deserving greater attention. Copyright © 2012 John Wiley & Sons, Ltd.

Selenium was believed to be toxic to animals, however, in 1957, selenium was reported as a dietary vital nutrient. Selenium is available in inorganic and organic forms. In 1974, the Food and Drug Administration (FDA) regulated the supplementation of selenium in poultry diets. In 1994, the National Research Council recognized selenium as a dietary essential nutrient for laying hens. The maximum allowed selenium addition level is 0.30 mg/kg. One of the most common supplements used is sodium selenite (SS), the inorganic selenium source. However, in 2000, the FDA approved the use of the organic source of selenium, Se-enriched yeast (SY) in poultry diets. Selenium has valuable effects on animal immune status, growth parameters, production and reproduction. Experimentally, it has been indicated that SY benefits more than that of SS due to its more bioavailability. Selenium inclusion in food-animal diets has an extra nutritional advantage to human consumers of Se-enriched food-animal products.

Selenium is an essential trace element in the diets which is required for maintenance of health, growth and biochemical-physiological functions. The area covered in this review has been rapidly unfolding in recent years and has already acquired a vast spread. This study presents a concise introductory overview of the effect of organic and inorganic selenium on growth performance, carcass traits, daily egg production, egg quality, Se uptake in various tissues and plasma and plasma glutathione peroxidase activity in animals.

Selenium has been recognized as an important element from the perspective of human health and environmental geochemistry because it is either essential or toxic depending on its concentration and c...

The biochemistry, pharmacology and epidemiology of selenium and selenium-containing compounds continue to be subjects of considerable interest from the viewpoint of public health. Selenium has a long history of association with human health and disease, and we now recognize that this element is an essential nutrient that is critical to key cellular processes. We now know that the selenoproteins constituting the human selenoproteome are encoded by 25 genes in the human genome, and much progress is being made in our understanding of selenium metabolism and the health effects of selenium metabolites in normal and disease states. The idea that selenium-containing dietary supplements might be effective in preventing disease has gone through both optimistic and pessimistic phases in recent years, and the future prospects for such a nutritional approach are unclear at the present time. In contrast, a significant number of promising efforts are underway that are aimed at designing and developing pharmaceutical agents that are selenium-based or that target specific aspects of selenium metabolism. This chapter focuses on some of these efforts to develop new selenium-based anticancer, antioxidant, antihypertensive, antiviral, immunosuppressive, and antimicrobial agents. While most of the efforts that entail designed organoselenium compounds – as opposed to inorganic selenium metabolites – are still at the preclinical stage, evidence is emerging that selenium-based compounds can operate via several beneficial biochemical and pharmacological mechanisms. Since our understanding of the biology, biochemistry and pharmacology of selenium and selenoproteins is rapidly expanding, we can anticipate that the coming years will bring further development of new selenium-based pharmaceutical agents with therapeutic potential against human diseases.

For studying geochemical behavior of selenium, a marine investigation was conducted in September 1998 cruise in the Bohai Sea. Horizontal and vertical distributions of inorganic selenium and selenite were studied. The inorganic selenium varied from 0.73 to 2.41 nmol/L, with an average of 1.31 nmol/L; while selenite varied from 0.18 to 0.72 nmol/L with an average of 0.47 nmol/L. The average ratio of selenite to selenate was 0.68, and selenate was the predominant species of inorganic selenium in the most study area. Concentrations of inorganic selenium and selenite decreased with distance from the coast. No apparent variations of the concentration between surface and bottom was shown. There were two water masses in the area, one from the Huanghe (Yellow) River and other from the Yellow Sea. Of the two, Huanghe River was the major source of inorganic selenium.

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.

1. Selenium (Se) is an essential part of numerous selenoproteins, most of which are involved in the antioxidant system of the body. It is also required by poultry for the maintenance of optimal health and meat quality. This paper reports data from a study examining the effect of dietary source and concentration of selenium on broiler performance and meat quality. 2. Increased dietary selenium content markedly reduced feed conversion ratio (FCR) as a result of significantly lower feed intakes of birds while maintaining the same weight gains. 3. Selenium supplementation increased feathering, with organic selenium (selenised yeast) being superior to inorganic selenium (sodium selenite). 4. Birds receiving organic selenium in their diets had improved eviscerated weight, breast yield and reduced drip loss. 5. There were significant concentration x source interactions on yields of breasts and marylands (thigh plus drumstick), with elevated levels of organic selenium increasing the yields, whereas the opposite was true for the inorganic selenium.

Using a flow-through photochemical reactor and a low pressure mercury lamp as a UV source, alkyl selenium species are formed from inorganic selenium(IV) in the presence of low molecular weight organic acids (LMW acids). The volatile alkyl Se species were cryogenically trapped and identified by GC-MS and GC-ICP-MS. In the presence of formic, acetic, propionic and malonic acids, inorganic selenium(IV) is converted by UV irradiation to volatile selenium hydride and carbonyl, dimethylselenide and diethylselenide, respectively. Se(IV) was successfully removed from contaminated agricultural drainage waters (California, U.S.A.) using a batch photoreactor system Se. Photochemical alkylation may thus offer a promising means of converting toxic selenium salts, present in contaminated water, to less toxic dimethylselenide. The LMW acids and photochemical alkylation process may also be key to understanding the source of atmospheric selenium and are likely involved in its mobility in the natural anaerobic environment.

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 toxicity and essential nature of selenium in the environment depend on its concentration and on the chemical forms in which it is present. Dissolved inorganic selenium can be found in natural waters as selenides (Se-II), colloidal elemental selenium (Se0), selenite (SeIV) as well as selenate (SeVI). Organic forms of selenium that may be found in organisms, air or in the aqueous environment are volatile methylselenides, trimethylselenonium ion and selenoamino acids. This review article intends to show some general ideas in speciation analysis of selenium and to highlight some important procedures.

Inorganic selenium species were determined in several parts of a freshwater fish of the speciesTilapia nilotica found breeding in disused tin-mining pools. The inorganic selenium species in the monazite-rich ores can enter the human food chain through the consumption of the fish. The Se(IV) and Se(VI) species were preconcentrated by solvent extraction with APCDT-CHCl3 before irradiation in a TRIGA Mk.II reactor. Total inorganic selenium species separation was done using Chelex-100 chelating resin. Quantitative interpretations of the distribution of inorganic selenium species in the fish are discussed with particular reference to the Se(IV)/Se(VI) ratio.

Selenium (Se) is an essential trace element for humans and animals. To consumption of selenium could be good sources the vegetables. Many of them are able to convert the inorganic selenium forms to organic forms, which are more effective for health. To enrich onion with selenium is known however some unclear points are remained. A closed fortification system was conducted to compare the difference of selenium tolerance in two onion cultivars in greenhouse environment. This system was well controlled, eliminating a lot of disturbing factors. The comparative analysis of Makói bronz and Makói lila spring onoins showed that there is difference in selenium tolerance and accumulation not only between plant species but inside it between the different cultivars, too. The Makói bronz seemed to more sensitive to the selenate treatment than Makói lila.

The advance in the area of synthesis and reactivity of organoselenium, as well as the discovery that selenium was the cause of severe intoxication episodes of livestock in the 1930s and the subsequent determination that selenium was an essential trace element in the diet for mammals, has motivated intense studies of the biological properties of both organic and inorganic selenium compounds. In this review, we shall cover a wide range of toxicological and pharmacological effects, in which organoselenium compounds are involved but the effects of inorganic compounds were not discussed in detail here. The molecular toxicity of inorganic selenium was described in relation to its interaction with endogenous –SH groups to allow a comparison with that of synthetic organoselenium compounds. Furthermore, in view of the recent points of epidemiological evidence that overexposure to selenium can facilitate the appearance of chronic degenerative diseases, we also briefly revised the history of selenium toxicity and physiology and how environmental selenium can reach inside the mammalian cells. The biological narrative of the element selenium, in the last century, has been marked by a contrast between its toxic and its beneficial effects. Thus, the potential therapeutic use of simple organoselenium compounds has not yet been sufficiently explored and, consequently, we cannot discard this class of compounds as promising pharmaceutical agents. In effect, the future of the organochalcogens as pharmacological agents will depend on more detailed toxicological studies in the oncoming years.

salman, Mustafa/0000-0003-0828-5998 WOS: 000267681600006 PubMed: 19537046 The aim of this study was to compare the effects of inorganic and organic selenium compounds supplementations to diets containing adequate selenium in broilers on performance, carcass traits, plasma and tissue glutathione peroxidase activity. A total of 150 one-day old broilers were randomized into one control and two treatment groups each containing 50 birds; each group was then divided into 3 replicate groups. The experiment lasted 42 days. All groups were fed with broiler starter diet from day 1 to 21 and finisher diet from day 22 to 42. The basal diet for control group included adequate selenium due to vitamin-mineral premix and feeds. The basal diet was supplemented with 0.2 mg/kg organic selenium (selenomethionine, treatment group 1) and 0.2 mg/kg inorganic selenium (sodium selenite, treatment group 2). Although no significant differences were determined between treatment group I and the control group for mean body weights, the differences between the group given inorganic selenium and the other groups were statistically significant (p < 0.01). There was no significant difference between control and treatment groups with regard to mean feed intake and feed efficiency. The dressing percentages of the second treatment group were found to be lower than the first treatment group. Treatment groups were observed to have increased levels of glutathione peroxidase in plasma (p < 0.01), kidney (p < 0.05), femoral muscle (p < 0.05), heart (p < 0.01) and liver tissue (p < 0.01) compared with the control group. Results of this study indicated that the supplementation of organic selenium to diets containing adequate selenium increased plasma, liver, femoral muscle, kidney and heart tissue glutathione peroxidase activity in broilers. Ondokuz Mayis University Research FundOndokuz Mayis University [Vet-019] This study was supported by Ondokuz Mayis University Research Fund (Project number: Vet-019).

Background Selenium is part of the antioxidant defence system in animals and humans. The available selenium concentration in soil is low in many regions of the world. The purpose of this study was to evaluate the effect of organic versus inorganic selenium supplementation on selenium status of ewes, their lambs, and slaughter lambs. Methods Ewes on four organic farms were allocated five or six to 18 pens. The ewes were given either 20 mg/kg inorganic selenium as sodium selenite or organic selenium as selenized nonviable yeast supplementation for the two last months of pregnancy. Stipulated selenium concentrations in the rations were below 0.40 mg/kg dry matter. In addition 20 male lambs were given supplements from November until they were slaughtered in March. Silage, hay, concentrates, and individual ewe blood samples were taken before and after the mineral supplementation period, and blood samples were taken from the newborn lambs. Blood samples from ewes and lambs in the same pens were pooled. Muscle samples were taken from slaughter lambs in March. Selenium concentrations were determined by atomic absorption spectrometry with a hydride generator system. In the ANOVA model, selenium concentration was the continuous response variable, and selenium source and farm were the nominal effect variables. Two-sample t-test was used to compare selenium concentrations in muscle samples from the slaughtered lambs that received either organic or inorganic selenium supplements. Results In all ewe pens the whole blood selenium concentrations increased during the experimental period. In addition, ewe pens that received organic selenium had significantly higher whole blood selenium concentrations (mean 0.28 μg/g) than ewe pens that received inorganic selenium (mean 0.24 μg/g). Most prominent, however, was the difference in their lambs; whole blood mean selenium concentration in lambs from mothers that received organic selenium (mean 0.27 μg/g) was 30% higher than in lambs from mothers that received inorganic selenium (mean 0.21 μg/g). Slaughter lambs that received organic selenium had 50% higher meat selenium concentrations (mean 0.12 mg/kg wet weight) than lambs that received inorganic selenium (mean 0.08 mg/kg wet weight). Conclusion Organic selenium supplementation gave higher selenium concentration in ewe and newborn lamb blood and slaughter lamb meat than inorganic selenium supplementation.

International audience; The objectives of this study were to determine the effect of the chemical form of selenium (Se) fed to sows (1) on production and immune quality of colostrum and (2) on piglet response to a deterioration of sanitary conditions after weaning. Twenty-two pregnant sows were assigned to receive a diet supplemented with 0.3ppm Se from either sodium selenite (inorganic Se) or Se-enriched yeast (organic Se as Sel-Plex (R); Alltech Inc., Nicholasville, KY, USA). Dietary treatments were applied during the last month of pregnancy and lactation. Blood samples were collected on sows before dietary treatment, on the day of weaning and 6 weeks later, and on three to five piglets within litters at birth, at weaning and 6 weeks post weaning. Whole blood was analysed for Se concentration. Colostrum samples were collected at 0, 3, 6 and 24 h post partum and milk samples on days 14 and 27 of lactation. Colostrum and milk were analysed for Se and immunoglobulin G (IgG) concentrations. At weaning, 40 pairs of littermate piglets were moved to rooms where sanitary conditions were good or purposely deteriorated. Piglets were reared individually and fed ad libitum. After 15 days, piglets and feed refusals were weighed and a blood sample was collected to measure plasma haptoglobin concentration. When sows were fed organic Se, Se concentrations were increased by 33% in colostrum (P < 0.05), 89% in milk (P < 0.001) and by 28% in whole blood of piglets at weaning (P < 0,001). Colostrum production during the 24 h after the onset of farrowing and IgG concentrations in colostrum and milk did not significantly differ between the two groups of sows. Weaned piglets reared in good sanitary conditions grew faster (P < 0.001) than piglets housed in poor conditions. Sanitary conditions did not influence mean plasma haptoglobin concentrations of piglets (P > 0.1). The source of Se fed to the dams did not influence piglet performance or haptoglobin concentrations after weaning. These findings confirm that, compared with inorganic Se, organic Se fed to the dam is better transferred to colostrum and milk, and consequently to piglets. They indicate that the Se source influences neither colostrum production nor IgG concentrations in colostrum, and that the higher Se contents of piglets does not limit the reduction of growth performance when weaning occurs in experimentally deteriorated sanitary conditions.

A selenium-dependent bacterium, Bacillus sp., failed to grow on selenium-free media. However, it is able to grow at high concentrations of sodium selenite containing media up to 3% (w/v). It accumulated extraordinary high quantities of selenium, 432 ppm/mL. The bacterium generated the transformation of inorganic selenium into volatile selenium form(s) into the atmosphere. The biological release of volatile selenium basically depended on several factors: incubation temperature, pH, incubation periods, and substrate concentration. Maximal quantity of the volatile selenium form was obtained at 30 degrees C, pH 7, and 1% (w/v) sodium selenite.

Objective—To evaluate the respiratory excretion and elimination kinetics of organic and inorganic selenium after oral administration in sheep. Animals—38 crossbred sheep. Procedures—Selenium was administered PO to sheep as a single dose of 0, 1, 2, 3, or 4 mg/kg as sodium selenite or selenomethionine. Expired air was collected and analyzed from all sheep at 4, 8, and 16 hours after administration. Results—Clinical signs consistent with selenium intoxication were seen in treatment groups given sodium selenite but not in treatment groups given the equivalent amount of selenium as selenomethionine. However, a distinct garlic-like odor was evident in the breath of all sheep receiving 2 to 4 mg of selenium/kg. The intensity of odor in the breath did not correlate with clinical signs in affected animals receiving sodium selenite treatment. Conclusions and Clinical Relevance—The concentration of selenium in expired air was greater in sheep receiving selenium as selenomethionine than sodium selenite. The concentration of selenium in expired air from sheep receiving high doses of selenium (3 and 4 mg of selenium/kg) was larger and selenium was expired for a longer duration than the concentration of selenium in expired air from sheep receiving low doses of selenium (1 and 2 mg of selenium/kg). (Am J Vet Res 2005;66:2142–2148)

cited By 22; International audience; Experiments were performed in the laboratory on synthetic seawater spiked with different selenium species at trace levels to study the formation of volatile selenium compounds under dark or controlled simulated sunlight conditions. Spiking the reaction media with inorganic and organic selenium compounds demonstrated that several volatile selenium species could be formed under these simulated conditions. Selenoamino acids react to produce significant amounts of volatile selenium species in both light and dark conditions. Products formed include dimethyl selenide (DMSe), dimethyl selenyl sulphide (DMSeS) and dimethyl diselenide (DMDSe). Inorganic selenium oxyanions added to the synthetic reaction media did not form volatile species via abiotic reactions despite the presence of strong methylating agents. These results suggest that the formation of stable volatile species from bio-organic selenium compounds can occur via abiotic reactions in the marine photic zone. Copyright (C) 2000 John Wiley And Sons, Ltd.

The concentrating of essential minerals, vitamins, and bioactive phytochemicals into human foodstuffs is of vital importance in our rapidly expanding world. Selenium is an essential micronutrient which is currently receiving much publicity for its anticarcinogenic potentials. Unfortunately, this mineral is deficient in most soils worldwide, and as a result most geographical food chains contain highly inadequate amounts of selenium. Scientific evidence in now available which shows that common vegetable members of the allium genus, especially garlic, are seleniferous in that they readily uptake inorganic selenium from the soil and incorporate it into bioactive organic chemicals. The brassicas have also been found to be highly seleniferous in nature and to produce various seleno amino acids and potentially bioactive organic selenium-containing phytochemicals. Upon consumption by humans, these selenium phytochemicals, derived from both plant genus, show anticarcinogenic potentials. Due to the high concentrations of natural phytochemicals, and the additional assimilation of selenium, the commercial or small scale production of selenium-enriched brassicas and garlic is an excellent way of introducing anticarcinogenic phytochemicals into the human diet.

The selenium status of 57 elderly people (or = 65 years) has been investigated on the basis of selenium concentration in serum, whole blood and erythrocytes and on the basis of the activity of the selenium-dependent enzyme glutathione peroxidase (GSH-px) in erythrocytes and plasma. Thirty-six elderly subjects participated in a 4-month trial of supplementation: 12 subjects were supplemented with 125 micrograms organic selenium, 12 subjects were supplemented with 125 micrograms inorganic selenium and 12 subjects participated as controls. The results showed that the selenium status of the elderly people was not significantly lower than that of younger people (p0.05). The effect of organic and inorganic selenium on the activity of GSH-px in plasma and erythrocytes showed a nearly identical increase (25-35%) during the period of supplementation. The effect of inorganic selenium supplementation caused a 30% increase in selenium concentration in plasma and erythrocytes which stabilized after 4 weeks. The effect of organic selenium supplementation on selenium concentration in plasma and erythrocytes showed an increase of up to 100% and 120% during the period of supplementation.

An experiment was carried out with 36 growing pigs in order to compare their responses to organic selenium and inorganic selenium. No significant differences were found in daily gain, feed/gain ratio or carcass quality of growing pigs fed with 0.1 mg inorganic Se or the same amount of Se bound in yeast. Neither were there significant differences in the content of Se in the liver and serum between these Se sources. The amount of 0.4 mg yeast selenium in the feed increased the Se level in the serum and liver significantly as compared to a lower level ofsupplementation (0.1 mg) (p, Kasvavien sikojen rehuun lisättiin seleeniä 0.1 mg/kg joko epäorgaanisena, seleenidioksidina = I vertailuryhmä, tai orgaanisena, seleenihiivana = II ryhmä. Seleenihiivaa lisättiin myös 0.4 mg/kg rehua = III ryhmä. Seleenihiiva oli Alko Ltd:n tuottama Alkosel niminen hiiva. Se on kehitetty tavallisesta leipomohiivasta korvaamalla osa hiivan rikistä seleenillä. Seleenihiivassa on seleeniä 10000 kertaa enemmän kuin tavallisessa hiivassa eli 500 mg/kg ka. Seleenihiivan seleeni on 80 %:sti orgaanisesti sitoutunutta, pääasiassa selenometioniinia. Eri määrillä tai eri lähteistä peräisin olevalla seleenillä ei ollut vaikutusta sikojen kasvuun, rehun hyväksikäyttöön tai teurastuloksiin. Seleenihiivalla, varsinkin korkeammalla tasolla, sikojen seerumin ja maksan seleenipitoisuudet olivat korkeammat kuin seleenidioksiidilla. Seleenihiivan todettiin olevan seleenidioksiidin kanssa samanarvoisen sikojen lisäseleenilähteenä.

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.

The toxicity of selenomethionine and sodium selenite to mallard ducklings (Anas platyrhynchos) was measured by feeding each form from hatching to six weeks of age at dietary concentrations of 0, 10, 20, 40, and 80 ppm selenium. At 80 ppm selenium, sodium selenite caused 97.5% mortality by six weeks and selenomethionine caused 100% mortality. At 40 ppm, these two forms of selenium caused 25 and 12.5% mortality. No mortality occurred at 10 or 20 ppm. Diets containing 20, 40, or 80 ppm selenium in both forms caused decreases in food consumption and growth. The only statistically significant effect of 10 ppm selenium was with sodium selenite, which resulted in larger livers than controls. Selenomethionine was more readily stored in the liver than sodium selenite at levels above 10 ppm selenium in the diet. Based on comparisons of residues of selenium in livers of surviving and dead ducklings, concentrations in the liver were not diagnostic of death due to selenium poisoning. Because both forms of selenium resulted in severe reductions in food consumption, selenium-induced starvation may have been related to duckling mortality. It was not clear whether either form of selenium at 10 ppm in the diet resulted in a leveling off of selenium concentrations in the liver within six weeks.

Chemical forms of selenium were studied in a solution extracted from soil with water or sodium sulfate solution by means of gel chromatography. When the soil extracts were chromatographed on a Sephadex G-25 column, the selenium in the extracts was separated into high and low molecular-weight fractions. A large proportion of the selenium in both fractions occurred in an organically-bound form and a small amount of inorganic selenium was found in the low molecular-weight fraction. The distribution of selenium on the chromatogram agreed well with that of fluorescamine-reactive substances. It was considered that the selenium in the soil extracts was mainly contained in proteins, peptides or amino acids. In addition, the high molecular-weight fraction containing selenium extracted from an Andosol was found to be a polypeptide with a molecular-weight of about 3,200 and was assumed to be composed of about 29 amino acids.

In the electrically-heated carbon-furnace atomic-absorption spectrometry of selenium and mercury, interelemental interference is present between the two elements. Mercury has no effect on selenium sensitivity in a simple inorganic selenium solution. When, however, the solution contains organic materials such as 0.5% albumin, the selenium sensitivity is decreased. The presence of mercury in addition to the organic material further decreases the sensitivity to about a half of that of a solution containing only selenium and albumin. The addition of 0.94 mmol dm−3 palladium ion completely removes the negative interferences due to organic materials and mercury. On the other hand, in mercury determination the presence of organic materials also decreases the mercury sensitivity. The addition of palladium, in contrast to selenium determination, enhances the mercury sensitivity about 50 times, independent of whether or not the solution contains organic materials.

The excretion of selenium in milk was investigated in twelve ewes. Four of these were injected 12–29 days before, and four immediately after delivery, with Se(75)-sodium selenite. One month after delivery two ewes were injected with Se(75)-selenomethionine, and two with Se(75)-sodium selenite. The Se(75)-concentration was measured in the milk and its various fractions as well as in the plasma, whole blood and organs of three lambs. The excretion of Se(75) into the milk was markedly higher when Se(75)-selenomethionine was administered than when Se(75)-sodium selenite was given. The amount of Se(75) in the various milk fractions was, to a great extent, proportional to the amount of protein in the fractions; this applied to the administration of organic as well as inorganic selenium. The highest Se(75)-concentration in the milk was obtained already within 24 hours after injection. Selenium administered before delivery gave the highest concentration in samples taken less than six hours after delivery. The lambs which received Se(75) via the milk had a higher content of Se(75) than those who received it during the fetal period.

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 . . .

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 . . .