Source Of Dietary Selenium Research Articles

Selenium uptake and distribution in chicory (Cichorium intybus L.) grown in an aeroponic system

Cultivated plants generally are a poor source of dietary selenium (< 0.1 mg/kg wet weight). In this work the influence of sodium selenate on selenium distribution in the chicory (Cichorium intybus L.) cultivars ‘Anivip’ and ‘Monivip’ was studied in an aeroponic system in a greenhouse. The plants roots were moistened every fifteen minutes with a Resh nutrient solution with added selenium (10 mg L-1) in the form of sodium selenate. The content of total selenium in chicory roots and leaves was studied after different periods of time and different temperatures of exposure to the selenium enriched nutrient solution. In two separate experiments chicory was treated with selenium enriched nutrient solution for 40 days at 10 ºC in the slow growing phase, and for 5, 7 and 10 days at 20 ºC in the developmental phase at the beginning of formation of the flower stem. The concentration in leaves increased with time during plant growth, and in Se treated groups was 370 and 139 mg kg-1 in ‘Anivip’ and 460 and 205 mg kg-1 in ‘Monivip’ leaves after 40 and 10 days of exposure, respectively. A smaller increase in selenium content was obtained in roots, namely to 73 and 46 mg kg-1 in ‘Anivip’ roots and to 87 and 46 mg kg-1 in ‘Monivip’ roots after 40 and 10 days of exposure, respectively. All results are expressed on a lyophilised matter basis. In long and short term treatment, the selenium content in ‘Monivip’ cultivar was higher than in ‘Anivip’. No visible toxic effects on the chicory plants were observed.

Catalytic activity of selenomethionine in removing amino acid, peptide, and protein hydroperoxides

Selenium is a critical trace element, with deficiency associated with numerous diseases including cardiovascular disease, diabetes, and cancer. Selenomethionine (SeMet; a selenium analogue of the amino acid methionine, Met) is a major form of organic selenium and an important dietary source of selenium for selenoprotein synthesis in vivo. As selenium compounds can be readily oxidized and reduced, and selenocysteine residues play a critical role in the catalytic activity of the key protective enzymes glutathione peroxidase and thioredoxin reductase, we investigated the ability of SeMet (and its sulfur analogue, Met) to scavenge hydroperoxides present on amino acids, peptides, and proteins, which are key intermediates in protein oxidation. We show that SeMet, but not Met, can remove these species both stoichiometrically and catalytically in the presence of glutathione (GSH) or a thioredoxin reductase (TrxR)/thioredoxin (Trx)/NADPH system. Reaction of the hydroperoxide with SeMet results in selenoxide formation as detected by HPLC. Recycling of the selenoxide back to SeMet occurs rapidly with GSH, TrxR/NADPH, or a complete TrxR/Trx/NADPH reducing system, with this resulting in an enhanced rate of peroxide removal. In the complete TrxR/Trx/NADPH system loss of peroxide is essentially stoichiometric with NADPH consumption, indicative of a highly efficient system. Similar reactions do not occur with Met under these conditions. Studies using murine macrophage-like J774A.1 cells demonstrate a greater peroxide-removing capacity in cells supplemented with SeMet, compared to nonsupplemented controls. Overall, these findings demonstrate that SeMet may play an important role in the catalytic removal of damaging peptide and protein oxidation products.

Metabolic and hematological profiles in heat stressed lactating dairy cows fed diets supplemented with different selenium sources and doses

This study was conducted to determine the effects of either dietary selenium (Se) source or dose on a range of dairy cow metabolic and hematological profiles and their subsequent relationship with oxidative status and environmental temperature. Forty lactating cows, offered the same basal diet, were blocked by days in milk, milk yield and parity and then randomly allocated to 1 of 5 dietary treatments: negative control (CTRL; 0.098mgSekg−1 DM), two levels of Se yeast (SY) supplementation (0.31 and 0.50mg total Sekg−1 DM), and two levels of sodium selenite (SS) supplementation (0.31 and 0.50mg total Sekg−1 DM). Whole blood samples were taken from all animals at the start of the study (23 March) and after 28, 56, 84, 112, 126, and 140d. Whole blood samples were analyzed for total Se, glutathione peroxidase (GPX-1) and a range of hematological parameters. Plasma was analyzed for total Se, glutathione peroxidase (GPX-3), metabolites related to energy and protein metabolism, concentration of minerals, enzyme activities, acute phase proteins and oxidative status markers. Glutathione peroxidase activity and total Se in whole blood and plasma were greater (P<0.001) in Se supplemented cows than CTRL. The temperature humidity index (THI) values indicate that during the trial cows experienced a slight–mild heat stress. A negative effect of THI on plasma glucose, non-esterified fatty acids (NEFA), thiol groups, plasma Na and K, and leukocyte count was observed. Conversely, a positive effect of THI on aspartate aminotransferase (AST) activity and GPX-3 activity was observed. Lower values (P<0.05) of thiobarbituric acid reactive substances (TBARS) during the hotter period were observed in SY supplemented animals when compared with CTRL and SS. Furthermore, plasma total antioxidants were lower (P<0.05) in SY supplemented animals when compared with SS during the hotter period. Plasma reactive oxygen metabolites were also numerically lower in SY when compared to SS. These results could be interpreted as an improvement in the preventive antioxidant systems of cows fed Se yeast.

Selenium in Seafood Materials

Research interests in studying the biochemical nature of selenium have increased and the importance of this element as an essential micronutrient in many organisms has been well recognized. Selenium occurs in proteins in the form of the 21st amino acid, selenocysteine (SeCys or Sec). In this review, we describe the speciation analysis of the fish-specific selenoproteins and non-proteinous selenium compounds, and the nutritional bioavailability of selenium from seafood materials. Selenium is essential to fish and shellfish. The selenoproteomes (sets of SeCys-containing proteins) of fish are greater in number than those of mammals (25 selenoproteins in humans); at 30-37 selenoproteins, the selenoproteomes of fish are among the largest known. The same core selenoprotein families are found in mammals and fish. In addition, fish have several species-specific selenoproteins [fish 15 kDa selenoprotein-like protein (Fep 15), selenoprotein J and selenoprotein L] that are missing in mammals. Actually, not only proteinous selenium species like selenomethionine (SeMet) and SeCys derivatives, but also many non-proteinous organic ones were detected in fish and shellfish samples. Although the selenium contents in seafood are higher than in terrestrial foodstuffs, little is known about the chemical forms of organoselenium species in seafood. The nutritional bioavailability of selenium from seafood appears to be dependent on the fish and shellfish species and/or place where they are produced; some seafood gives rise to a high bioavailability of selenium, which is comparable to that of wheat and beef. Fish and shellfish materials are major dietary sources of selenium for the Japanese population (∼60% of daily intake). Seafood materials appear to contain nutritionally effective organoselenium compounds that have not yet been chemically identified.

Selenium uptake and distribution in chicory (Cichorium intybus L.) grown in an aeroponic system

Cultivated plants generally are a poor source of dietary selenium (< 0.1 mg/kg wet weight). In this work the influence of sodium selenate on selenium distribution in the chicory (Cichorium intybus L.) cultivars ‘Anivip’ and ‘Monivip’ was studied in an aeroponic system in a greenhouse. The plants roots were moistened every fifteen minutes with a Resh nutrient solution with added selenium (10 mg L -1 ) in the form of sodium selenate. The content of total selenium in chicory roots and leaves was studied after different periods of time and different temperatures of exposure to the selenium enriched nutrient solution. In two separate experiments chicory was treated with selenium enriched nutrient solution for 40 days at 10 oC in the slow growing phase, and for 5, 7 and 10 days at 20 oC in the developmental phase at the beginning of formation of the flower stem. The concentration in leaves increased with time during plant growth, and in Se treated groups was 370 and 139 mg kg -1 in ‘Anivip’ and 460 and 205 mg kg -1 in ‘Monivip’ leaves after 40 and 10 days of exposure, respectively. A smaller increase in selenium content was obtained in roots, namely to 73 and 46 mg kg -1 in ‘Anivip’ roots and to 87 and 46 mg kg -1 in ‘Monivip’ roots after 40 and 10 days of exposure, respectively. All results are expressed on a lyophilised matter basis. In long and short term treatment, the selenium content in ‘Monivip’ cultivar was higher than in ‘Anivip’. No visible toxic effects on the chicory plants were observed.

The effect of dietary selenium sources and levels on performance, selenium content in muscle and glutathione peroxidase activity in broiler chickens

The study examined the effect of dietary supplements of sodium selenite (SS), selenium-enriched yeast (Sel-Plex&amp;reg;, SP) and selenium-enriched alga Chlorella (SCH) on growth traits, carcass analysis, selenium content in breast meat, glutathione peroxidase (GSH-Px) activity in breast and thigh meat and liver of chickens. The experiment was realized with seven hundred thirty-five cockerels Ross 308 randomly divided into 7 dietary treatments with 3 replications in each treatment. Chickens were fed a diet supplemented with 0 (control), 0.15 or 0.30 mg of selenium/kg in the form of sodium selenite (SS), Sel-Plex&amp;reg; (SP) and selenium-enriched alga Chlorella (SCH). Selenium addition influenced body weight at 21 (P &amp;le; 0.001) and 35 (P &amp;le; 0.05) days of age. Significantly higher body weight at 35 days of age was determined in chickens receiving 0.15 mg of selenium from SP (2 122 g) and 0.3 mg of selenium from SCH (2 116 g) contrary to dietary treatment with a lower level of selenium from SCH (2 010 g) per kg of feed. The selenium content in breast muscle was increased (P &amp;le; 0.001) by both the lower and higher selenium concentration in the form of SP (0.6 and 0.85 mg/kg dry matter) and SCH (0.6 and 0.82 mg/kg dry matter) in comparison with the control (0.31 mg/kg dry matter). A significant increase (P &amp;le; 0.001) was ascertained even in SS treatments, but no significant differences were found between both levels. The selenium source and level, including SS, significantly (P &amp;le; 0.001) influenced the GSH-Px activity in breast and thigh meat. &amp;nbsp;

Effects of Dietary Selenium Source, Storage Time, and Temperature on the Quality of Quail Eggs

We report the effects of time of storage, temperature, and supplementation with sodium selenite- and selenium-enriched yeast on the quality of quail eggs. For this study, 90 10-week-old female Japanese quails (Coturnix coturnix japonica) with similar body size were caged individually and randomly divided into five groups of 18 quails each. One group was fed a normal diet and served as control. A second group was supplemented with 0.2mg/kg sodium selenite (In-Se) and three groups supplemented with 0.1, 0.2, and 0.3mg/kg of a commercially available selenium-enriched yeast (O-Se1, O-Se2, and O-Se3, respectively). The eggs were collected at third and fourth weeks of the experiment and were stored at 4°C and 20°C for 0, 15, 30, and 45days. Extension of the storage time to 45days at 20°C resulted in significant deterioration of egg quality. The albumen Haugh unit (HU), pH, albumen index, yolk index, and egg weight loss were the most important parameters influenced by the nature of the selenium sources, storage time, and temperature. Storage time and temperature were also significant for egg weight loss, HU, and albumen and yolk indexes. The results show that supplementation with selenium yeast significantly affected shell weight, shell thickness, HU, albumen index, yolk index, and pH. The HU decreased with increased storage time and temperature. Higher levels of Se-yeast administration resulted in greater HU compared to the selenite and control groups.

A Balanced Diet?: Selenium May Offset the Effects of Methylmercury on Cataract Development

Dietary exposure to mercury from fish has been posited as a risk factor for cataracts because some reports have suggested methylmercury accumulates in the lens of the eye. But selenium from other dietary sources may offset that damage, according to a study of communities in the Amazon basin [EHP 118(11):1584–1589; Lemire et al.]. The findings, while preliminary, hint at potential public health measures in areas where methylmercury-contaminated fish are a significant part of people’s diets. With old age comes cataracts, particularly in latitudes like the Amazon, where higher ultraviolet radiation exposure and other environmental factors contribute to the clouding of the lenses in human eyes. And while surgical fixes exist for cataracts, people in isolated regions may not always have access to those options. Cataracts therefore are a major cause of blindness among older people in the Amazon. The current study involved communities that eat fish from the Tapajos River, a tributary of the Amazon. People here have among the highest reported exposures to mercury in the world. Deforestation in the region leads to the release of natural inorganic mercury from soils into surface waters, where it is methylated and eventually ends up in fish. Several hundred people voluntarily participated in the study, which entailed taking an overnight boat trip to a nearby city where participants gave blood samples and were examined by optometrists. In the end, 211 people over age 40 were included in the analysis. A third of them had age-related cataracts. Low plasma selenium and high blood mercury each were associated with a higher prevalence of cataracts (over 2 and 4 times higher, respectively). The team calculated that the people with both low plasma selenium and high blood mercury were 16 times more likely to develop cataracts than the “optimum situation” group, which had both high plasma selenium and low blood mercury. This is the first study known to associate high levels of methylmercury from fish consumption with increased occurrence of cataracts. The authors emphasize that other factors—such as differences in dietary intakes of antioxidants and vitamins—could confound their findings. Still, if the observed associations hold true in broader studies, public health interventions to alleviate cataracts in this Amazonian population must consider both the health benefits of fish consumption and the risks of the main source of dietary selenium in the region: brazil nuts, which also contain barium and strontium, heavy metals with their own hazards.

Natural enrichment of selenium in Saskatchewan field peas (Pisum sativum L.).

Pulses are important dietary sources of selenium (Se). Supplying needed Se through widely used foods such as pulses and cereals could increase dietary Se intake. We analyzed the total Se concentration of 17 field pea (Pisum sativum L.) cultivars grown at six locations for 2 yr in Saskatchewan. A significant effect of location was identified, with the highest Se concentration in pea seeds grown in the Saskatoon region and the lowest concentration in the Melfort region. The effect of crop year was not significant. Significant genotypic differences in total Se concentration among the 17 field pea cultivars were not observed in the combined analysis. Total Se concentrations over six locations × 2 yr ranged from 373 to 519 µg kg-1, corresponding to 68-94% of the recommended daily allowance (RDA) for adults based on a 100 g serving of dry field peas. Saskatchewan soils are derived from marine shale and are rich in Se, and pulses grown in Saskatchewan have the potential to provide an excellent natural source of this element. Key words: Selenium, field pea, biofortification

Involvement of Silicon Influx Transporter OsNIP2;1 in Selenite Uptake in Rice

Rice (Oryza sativa) as a staple food, provides a major source of dietary selenium (Se) for humans, which essentially requires Se, however, the molecular mechanism for Se uptake is still poorly understood. Herein, we show evidence that the uptake of selenite, a main bioavailable form of Se in paddy soils, is mediated by a silicon (Si) influx transporter Lsi1 (OsNIP2;1) in rice. Defect of OsNIP2;1 resulted in a significant decrease in the Se concentration of the shoots and xylem sap when selenite was given. However, there was no difference in the Se concentration between the wild-type rice and mutant of OsNIP2;1 when selenate was supplied. A short-term uptake experiment showed that selenite uptake greatly increased with decreasing pH in the external solution. Si as silicic acid did not inhibit the Se uptake from selenite in both rice and yeast (Saccharomyces cerevisiae) at low pHs. Expression of OsNIP2;1 in yeast enhanced the selenite uptake at pH 3.5 and 5.5 but not at pH 7.5. On the other hand, defect of Si efflux transporter Lsi2 did not affect the uptake of Se either from selenite or selenate. Taken together, our results indicate that Si influx transporter OsNIP2;1 is permeable to selenite.

Effects of selenium source on blood selenium content, blood cell counts and peripheral blood mononuclear cell mRNA profiles in maturing beef heifers

To determine if source of dietary selenium (Se) supplementation affects blood Se content and expression of biomarkers of immune status in blood cells of growing cattle, Angus heifers were assigned (n = 10) to 4 Se treatments (TRT) for 126 d. The basal diet contained 0.08 mg Se/d, whereas the mineral supplements provided no (control, C), or 3 mg Se/d as inorganic (sodium selenite, SS), organic (Sel‐Plex®, SP), or a 50/50 mix (SS/SP). Jugular blood was collected for blood cell counts, Se analysis and peripheral blood mononuclear cell (PBMC) isolation. Whole blood (WB), plasma, and red blood cell (RBC) Se content was greater (P &lt; 0.01) for all TRT versus C. SS/SP and SP heifers had greater (P &lt; 0.01) WB and RBC Se content than SS, while plasma Se tended (P = 0.06) to be higher in SS/SP heifers than SS. PBMC count was negatively correlated (P &lt; 0.05) to plasma and WB Se content in SP heifers, and tended (P = 0.06) to be negatively correlated to WB Se in SS/SP heifers. Se TRT did not affect interleukins 1β, 8, and receptor 2α mRNA levels in PBMC, while selenoprotein S (SelS) mRNA content was decreased (P &lt; 0.05) in SS/SP and SP versus C heifers. Because SelS plays an important role in the regulation of the inflammatory cytokine response, decreased SelS mRNA levels indicate supplementing with 3 mg/d SP or SS/SP may result in cattle with a less challenged immune state. This work is supported by the Alltech‐University of KY Animal Nutrigenomics Alliance.

Antioxidant enzymes and somatic cell count in dairy cows fed with organic source of zinc, copper and selenium

The objectives of this study were to evaluate the effects of dietary organic sources of zinc (Zn), copper (Cu) and selenium (Se) for dairy cows on somatic cell count (SCC), occurrence of subclinical mastitis, number of clinical mastitis cases and concentration of superoxide dismutase (CuZnSOD), glutathione peroxidase (GSH-Px) and ceruloplasmin (CP). Nineteen dairy cows, with confirmed pregnancy, were selected by body weight, body condition score (BCS), number of lactation, and milk yield in previous lactation, and randomly distributed among two groups, one to receive organic ( n = 9) and the other the inorganic ( n = 10) source of Zn, Cu and Se. Diets were formulated to meet the nutritional requirements of animals from 60 days before the expected date of calving up to 80 days of lactation. Blood samples were collected at − 60, − 21, 1, 21, 40 and 80 days in relation to the expected date of calving for analysis of CuZnSOD, GSH-Px and CP concentration. Milk samples for SCC determination were collected weekly after 15 days of lactation, also at day 1 and 7 and when a clinical case was diagnosed for microbiological culture. The number of new and total cases of subclinical mastitis was lower for the group of cows fed with organic sources of Zn, Cu and Se compared to animals receiving inorganic sources. Average SCC during the first 80 days of lactation tended to be lower for the group fed with organic Zn, Cu and Se. Feeding organic Zn, Cu and Se did not alter the concentration of CuZnSOD, GSH-Px and CP.

Enrichment of the African catfish Clarias gariepinus (Burchell) with functional selenium originating from garlic: effect of enrichment period and depuration on total selenium level and sensory properties

We wanted to optimize the procedure for the selenium enrichment of farmed African catfish, using garlic as dietary selenium source. In the first experiment we established the relation between the length of the selenium enrichment period and the resulting total selenium level in the fillet of the fish. It was found that at a dietary level of 11.7 mg kg−1 Se, a total selenium level in the fillet of 0.7 mg kg−1 was reached in a relatively short enrichment period of 10 days before harvest. In the second experiment we studied the effect of depuration on the selenium level in the fillet and the sensory properties of selenium-enriched African catfish. It was found that total selenium levels in the fillet were not affected during a 7-day depuration period, while garlic odours and flavours in the raw and cooked fillets were significantly reduced after 2 days of depuration. We concluded that selenium enrichment of farmed African catfish can be obtained by selenium-enriched finishing diets, while garlic odours and flavours resulting from dietary garlic can be effectively reduced in the fillet during a short depuration period without negatively affecting fillet levels of total selenium.

The effects of dietary oxidized fat and selenium source on performance, glutathione peroxidase, and glutathione reductase activity in broiler chickens

Normal or elevated selenium status of broilers, which is influenced by dietary selenium sources, improves the bird’s ability to overcome the adverse effects of reactive oxygen metabolites. The objective of this study was to evaluate the effects of feeding graded levels of peroxidized poultry fat on blood and hepatic glutathione peroxidase (GSH-Px), and hepatic glutathione reductase activity in broiler chickens fed either inorganic sodium selenite (SEL) or organic selenium enriched in the organic selenium yeast product Sel-Plex (SP). Nine starter diets, varying in levels of oxidized fat (0, 3, and 6 mEq/kg) and dietary selenium sources, were fed to 360 male chicks from hatch to 21 d of age. Sel-Plex or SEL was added to the basal diet to provide either 0 or 0.2 ppm of supplemental selenium in the diets. Blood and hepatic samples were obtained for each treatment group at 21 d of age. Neither peroxidized fat nor selenium source significantly altered the activity of hepatic glutathione reductase (P ≤ 0.05). Blood GSH-Px was influenced significantly by both fat and selenium source (P ≤ 0.05), but the fat × selenium source interaction was not significant (P ≥ 0.3). A selenium source effect on the hepatic GSH-Px activity (P ≤ 0.05) was evidenced by higher GSH-Px activity, even in the basal diet with no added peroxidized fat. An increase in GSH-Px activity was seen in the erythrocyte and hepatic samples in both the SEL and SP treatments when peroxidized fat was given at 3 mEq/kg, but in the erythrocytes and in the hepatic tissues from SEL-supplemented birds, there was an apparent inhibition of GSH-Px activity. This inhibition was not seen in the hepatic tissue samples from SP-fed birds. Because elevated GSH-Px activity is indicative of oxidative stress, it was concluded that dietary SP supplementation resulted in better selenium and redox status in broilers than did SEL. These results indicate that the dietary selenium supplied in an organic form (selenium yeast as SP) improved the selenium and redox status in broilers, leading to greater resistance to oxidative stress than when the inorganic form of selenium (SEL) was fed.

The Effect of Dietary Selenium Source and Level on Hen Production and Egg Selenium Concentration

A 16-week experiment was conducted to compare effects of various levels of sodium selenite (SS) and Se-enriched yeast (SY), on the whole-egg Se content and hen's productivity. One hundred Shaver 579 hens, 27 weeks old, were placed on one of five experimental treatments. Each treatment was replicated four times with five hens per cage. Treatments consisted of feeding a low Se diet without supplementation (basal diet) or basal diet with one of two levels of supplemented Se (0.4 or 0.8 mg/kg) supplied by SS or SY. All supplemented treatments had significantly higher whole-egg Se concentration from basal diet (P < 0.05). On the same supplemented level, hens fed on SY had higher egg Se content from hens feed on SS (P < 0.001). No effects of dietary treatments on egg weight, percentages of dirty and cracked egg, and feed intake and conversion of feed were observed throughout the trial (P < 0.05). In the first 8 weeks, there was no significant difference (P < 0.05) in hen-day egg production among treatments. From the ninth week on to the end of the trial, supplementation of SY to hen's diet resulted in a higher egg production than SS (P < 0.01).

Effects of different dietary selenium sources (selenium nanoparticle and selenomethionine) on growth performance, muscle composition and glutathione peroxidase enzyme activity of crucian carp ( Carassius auratus gibelio)

An experiment was conducted to compare the effects of selenium nanoparticle (T-1) and selenomethionine (T-2) on crucian carp, Carassius auratus gibelio. There were significant differences ( P < 0.05) in relative gain rate and final weight of T-1 and T-2 compared with the control. Survival rate and feed conversion ratio (FCR) were not affected by the dietary treatments. Fish fed the basal diet (control) showed lower ( P < 0.05) selenium content in muscle (6.10 ± 0.78 μg g − 1 ) compared to T-1 and T-2 (16.42 ± 1.07 μg g − 1 and 13.52 ± 1.31 μg g − 1 , respectively). Furthermore, the highest value ( P < 0.05) of selenium content in muscle was observed in T-1. Glutathione peroxidase (GSH-Px) activities in carps plasma and liver of T-1 and T-2 were significantly different ( P < 0.05) with that of the control. However, no significant differences were observed in GSH-Px activities both in plasma and liver between T-1 and T-2.

Characteristics of Se-Enriched Mycelia by Stropharia rugoso-annulata and its Antioxidant Activities in vivo

Selenium (Se) is an essential trace element for humans and animals. Stropharia rugoso-annulata is a nutritional and functional mushroom containing many kinds of bioactive ingredients. The aims of this study were to investigate the Se-enrichment characteristics of S. rugoso-annulata in submerged culture and evaluate the antioxidant activities of Se-enriched mycelia in vivo in terms of the values of glutathione peroxidase (GSH-Px), superoxide dismutase (SOD), and malondialdehyde (MDA). The optimum parameters of Se-enrichment under the optimal Se concentration (150 microg/mL) in media were as follows: biomass 8.11 +/- 0.25 g/L, Se content in mycelia 4,727.68 +/- 13 microg/g, Se-accumulated rate 24.68 +/- 1.67%, and percentage of organic Se 96.27 +/- 3.26%. The mainly subsistent forms of selenium in Se-enriched mycelia were selenoprotein and selenium-polysaccharide. The contents of total amino acids (TAA) and essential amino acids (EAA) in Se-enriched mycelia were increased by 13.5 +/- 1.09% and 12.8 +/- 0.89%, respectively. It was efficient for Se-enriched mycelia to elevate GSH-Px and SOD activities and decrease MDA content. These results indicated that Se-enriched mycelia of S. rugoso-annulata represent a novel dietary source of bioavailable supplemental selenium.

Effects of Dietary Selenium Source and Storage on Internal Quality of Eggs

A 4-week experiment was carried out on 360 laying hens of the Hy Line Brown hybrid. Laying hens were divided into three groups (C, E1 and E2) with 120 hens in each group and kept in 24 cages. Hens were fed layer diets containing 18% of crude protein and 11.60 MJ ME. Hens in the control group C were fed diets that contained 0.2 mg/kg of inorganic selenium (sodium selenite). Experimental groups E1 and E2 were given diets with increased concentrations of selenium as follows: E1 = 0.4 mg/kg of selenium (sodium selenite), E2 = 0.4 mg/kg of organic selenium (Sel-Plex). Selenium concentration in diets affected significantly the content of selenium in albumen (P &lt; 0.001) and yolk (P &lt; 0.05). The highest concentration of selenium was determined in albumen and yolk of eggs produced in group E2 (345 ng/g and 783 ng/g, respectively), then in eggs of group E1 (230 ng/g and 757 ng/g, respectively), and group C had the lowest concentration of selenium in albumen and yolk (181 ng/g and 573 ng/g, respectively). After 28 days of storage at 4 °C, the eggs containing organic selenium had more freshness (VN: C = 32.9, E1 = 2.60, E2 = 2.11). It was concluded that higher concentration of organic selenium in eggs was a limiting factor in metabolic processes, which positively affected the indicators of egg freshness.

Selenium-Enriched Garlic and Cabbage as a Dietary Selenium Source for Broilers

This study determined the selenium (Se) bioavailability from Se-enriched garlic and cabbage using broiler chickens. Se-enriched garlic (18.5 mg of Se/kg) and cabbage (101.5 mg of Se/kg) were produced by soil enrichment using selenate. Conventional and Se-enriched garlic and cabbage were dried, ground, and added to broiler chick diets. Ninety-six broiler chickens at 1 day of age were assigned to four dietary treatments: NC (cabbage + garlic), PC (cabbage + garlic + selenomethionine, 0.5 mg of Se/kg of diet), GS (cabbage + Se-enriched garlic, 0.5 mg of Se/kg of diet), and CS (garlic + Se-enriched cabbage, 0.5 mg of Se/kg of diet), with six replicates per treatment and four birds per cage. Birds were fed the experimental diets for 4 weeks and slaughtered to obtain blood and tissues: white (breast) muscle, dark (thigh) muscle, liver, and feathers. All excreta were collected weekly, dried, and ground for Se analysis. Bird weight gain and feed intake were measured weekly. Total Se content and glutathione peroxidase (GPX) activity in liver and plasma were measured. Total liver Se content of the PC birds (0.876 mg of Se/kg) was the highest (P < .05). The CS (0.693 mg of Se/kg) and GS (0.627 mg of Se/kg) birds had higher (P < .05) total liver Se than the NC birds (0.514 mg of Se/kg). Plasma GPX activity of the PC birds was highest (P < .05), and that of CS and GS birds was higher (P < .05) than the NC birds. Liver GPX activity of the PC birds was higher (P < .05) than all other treatments. Bioavailability of Se to broiler chickens was not different (P > .05) among PC (65.2%), CS (61.2%), and GS (70.7%) birds. This study indicates that the Se from Se-enriched garlic and cabbage is highly bioavailable and can potentially be beneficial in enhancing Se status and GPX activity.

Selenium in Edible Mushrooms

Selenium is vital to human health. This article is a compendium of virtually all the published data on total selenium concentrations, its distribution in fruitbody, bioconcentration factors, and chemical forms in wild-grown, cultivated, and selenium-enriched mushrooms worldwide. Of the 190 species reviewed (belonging to 21 families and 56 genera), most are considered edible, and a few selected data relate to inedible mushrooms. Most of edible mushroom species examined until now are selenium-poor (< 1 μ g Se/g dry weight). The fruitbody of some species of wild-grown edible mushrooms is naturally rich in selenium; their occurrence data are reviewed, along with information on their suitability as a dietary source of selenium for humans, the impact of cooking and possible leaching out, the significance of traditional mushroom dishes, and the element's absorption rates and co-occurrence with some potentially problematic elements. The Goat's Foot (Albatrellus pes-caprae) with ∼ 200 μ g Se/g dw on average (maximum up to 370 μ g/g dw) is the richest one in this element among the species surveyed. Several other representatives of the genus Albatrellus are also abundant in selenium. Of the most popular edible wild-grown mushrooms, the King Bolete (Boletus edulis) is considered abundant in selenium as well; on average, it contains ∼ 20 μ g Se/g dw (maximum up to 70 μ g/g dw). Some species of the genus Boletus, such as B. pinicola, B. aereus, B. aestivalis, B. erythropus, and B. appendiculus, can also accumulate considerable amounts of selenium. Some other relatively rich sources of selenium include the European Pine Cone Lepidella (Amanita strobiliformis), which contains, on average, ∼ 20 μ g Se/g dw (up to 37 μ g/g dw); the Macrolepiota spp., with an average range of ∼ 5 to < 10 μ g/g dw (an exception is M. rhacodes with < 10 μ g/g dw); and the Lycoperdon spp., with an average of ∼ 5 μ g Se/g dw. For several wild-grown species of the genus Agaricus, the selenium content (∼ 5 μ g/g dw) is much greater than that from cultivated Champignon Mushroom; these include A. bisporus, A. bitorquis, A. campestris, A. cesarea, A. campestris, A. edulis, A. macrosporus, and A. silvaticus. A particularly rich source of selenium could be obtained from selenium-enriched mushrooms that are cultivated on a substrate fortified with selenium (as inorganic salt or selenized-yeast). The Se-enriched Champignon Mushroom could contain up to 30 or 110 μ g Se/g dw, while the Varnished Polypore (Ganoderma lucidum) could contain up to 72 μ g Se/g dw. An increasingly growing database on chemical forms of selenium of mushrooms indicates that the seleno-compounds identified in carpophore include selenocysteine, selenomethionine, Se-methylselenocysteine, selenite, and several unidentified seleno-compounds; their proportions vary widely. Some aspects of environmental selenium occurrence and human body pharmacokinetics and nutritional needs will also be briefly discussed in this review.