Dietary Se Supplementation Research Articles

Effects of different dietary selenium sources (sodium selenite, selenomethionine and nanoselenium) on growth performance, muscle composition, blood enzymes and antioxidant status of common carp (Cyprinus carpio)

This experiment was conducted to compare the effects of different sources of selenium (Se) on growth, muscle Se concentration, muscle proximate composition, blood enzymes and antioxidant status of common carp, Cyprinus carpio. Organic Se (selenomethionine, SeMet), inorganic Se (sodium selenite, Na2SeO3), or nanoselenium were each added to the basal diet at 0.7 mg Se kg−1 diet. Four groups of fish with an average weight of 9.69 ± 0.12 g were fed one of the experimental diets for 8 weeks. Nano-Se diet resulted in better growth performance (P < 0.05). Fish fed with Se-supplemented diets showed a higher (P < 0.05) Se content in the muscle and liver tissues. Fish fed nano-Se had the highest liver glutathione peroxidase, superoxide dismutase and catalase activities (P < 0.05). Liver malondialdehyde level was significantly (P < 0.05) lower in fish fed on SeMet and nano-Se diets as compared to control. The carp fed on nano-Se diet had the lowest values of aspartate transaminase and alanine transaminase. Lactate dehydrogenase activity was significantly lower in fish fed on SeMet and nano-Se diets. This study shows that nano-Se acts more efficiently on growth performance and antioxidant defence system of common carp than organic and inorganic sources of Se.

Digital Gene Expression (DGE) Analysis of Nutritional Pancreatic Atrophy of Chicks Induced by the Se/Vitamin E Deficiencies

Nutritional pancreatic atrophy (NPA) is a classical Se/vitamin E deficiency disease of chicks. We previously determined responses of mRNA abundances of 25 selenoprotein genes in various tissues of chicks to the deficiencies of these two nutrients. The present DGE analysis was performed to reveal effects of dietary Se/vitamin E deficiencies on the pancreatic transcriptome of chicks and to identify global gene association with the NPA. We fed 4 groups of day‐old broiler chicks (n = 40/group) with a corn‐soy basal diet (BD: 10 μg Se/kg, no vitamin E added), the BD plus all‐rac‐a‐tocopheryl acetate at 50 mg/kg, Se (as sodium selenite) at 0.3 mg/kg, or both of these nutrients for 6 wk. High incidences of NPA (70%) and mortality (35%) of chicks were induced by BD, starting at wk 3. Both NPA incidences and mortality were prevented by dietary Se supplementation. On day 18, chicks were killed to collect pancreases for the DGE analysis. Pancreatic RNA samples were pooled from five individual chicks into each of the four dietary groups, respectively. Dietary Se deficiency altered expression of 884 unigenes, with 360 unigenes up‐regulated and 524 unigenes down‐regulated. Of the differentially expressed genes, 530 unigenes were annotated and 65 were classified into metabolism pathways. Real‐time PCR analyses of selected four unigenes related to selenocompound metabolic and apoptotic pathways showed consistent results with those obtained from the DGE analysis, which confirms the quality of the sequencing data for further gene expression characterization. In conclusion, our pancreatic transcriptiom data of the chicks fed the four experimental diets will facilliate mechanistic investigation on the pathogenesis of NPA induced by the dietary Se/vitamin E deficiencies.Support or Funding Information(This research is supported in part by a NSFC grant #31320103920).

Evaluation of the toxicity of selenium from hydroponically produced selenium-enriched kale sprout in laying hens

Hydroponically produced Se-enriched kale sprouts (HPSeKS) are studied for their use as an alternative dietary Se supplement for poultry. The study experimented with different levels and sources of Se to determine toxicity and how the toxicity may affect productive performance, Se concentration in egg and tissues, and physiological responses of laying hens. One-hundred and twenty hens, 59 weeks of age, were divided into 5 groups. Each group consisted of 4 replicates and each replicate had 6 birds according to a 2×2+1 Augmented Factorial Experiment in a Completely Randomized Design. The experiment was conducted over a 4 week period, and 5 dietary treatments (T) were used: T1 basal diet, T2 and T3 basal diet plus 5 and 10mg Se/kg from sodium selenite (SS), T4 and T5 basal diet plus 5 and 10mg Se/kg from HPSeKS, respectively. The results make clear that Se from HPSeKS, at 5–10mg/kg, did not affect (P>0.05) feed intake and egg production; however, Se bioavailability decreased (P<0.05). Egg, tissue and plasma Se concentrations, and GSH-Px activity in red blood cells increased (P<0.05) compared to those in T1. Final body weight, feed intake, Se bioavailability, concentration of Se in breast muscle and plasma of hens fed Se from SS were lower (P<0.05) than those of hens fed Se from HPSeKS. The findings demonstrate that dietary Se from HPSeKS at 5–10mg/kg is not considered a toxic level for laying hens. The toxicity of Se from HPSeKS was less than the toxicity of Se from SS.

Metabolic syndrome and selenium during gestation and lactation.

Selenium (Se) has a dual role in metabolic syndrome (MS) development as it has an antioxidant action against both "good" and "bad" reactive oxygen species. This study evaluates Se body profile in dams which present MS during gestation and lactation, in order to elucidate a normal dietary Se's implication in this pathology. Rats were randomized into control (C) and fructose (F) groups. The rich fructose diet (65%) during gestation and lactation periods induced MS in dams. Se body distribution was determined by atomic absorption spectrophotometry, and the hepatic activity of the four antioxidant enzymes and the bimolecular oxidation were determined by spectrophotometry. The cardiac activity was monitored using the indirect tail occlusion method. Lipid and glucidic profile was also analyzed. Despite the fact that the diet supplied has 0.1ppm of Se, the minimal dietary requirement for rats, F dams ate less amount of food, and therefore, they had lower Se retention. However, they had normal levels of Se in serum and milk. Dams with MS had Se depletion in heart and muscle joint to hypertension and a lower heart rate, and Se repletion in liver and kidney. Despite the increase in hepatic glutathione peroxidase (GPx) and catalase activity found, lipid oxidation occurred-probably because superoxide dismutase activity was diminished. In heart, the activity and expression of the selenoprotein GPx1 were decreased. With these results, it is not possible to elucidate whether a dietary Se supplementation or a Se-restricted diet are good for MS; because despite the fact that GPx activity is increased in liver, it is also found, for the first time, that heart Se deposits are significantly decreased during MS.

Selenium Biochemistry and Bioavailability: Implications for Animal Agriculture

Selenium (Se) is an essential trace mineral required for growth, development, immune function, and metabolism. Selenium exerts its biological effects as an integral component of selenoproteins (SePs). Deficiency or low Se status leads to marked changes in many biochemical pathways and a range of pathologies and disorders which are associated with SeP function. Animals, and presumably humans, are able to efficiently utilize nutritionally adequate levels of Se in both organic and inorganic forms. It is now clear that the bioavailability of Se varies depending on the source and chemical form of the Se supplement. There are a range of products available for dietary Se supplementation, however, organic sources have been shown to be assimilated more efficiently than inorganic compounds and are considered to be less toxic and more appropriate as a feed supplement. Yeast enriched with Selenohomoalanthionine (SeHLan) has recently become commercially available, and initial research suggests that it may be an efficacious source for the production of Se enriched animal products.

Effects of different dl‐selenomethionine and sodium selenite levels on growth performance, immune functions and serum thyroid hormones concentrations in broilers

This trial was conducted in a 2×3+1 factorial arrangement based on a completely randomized design to evaluate the effects of different dl-selenomethionine (dl-Se-Met) and sodium selenite (SS) levels on growth performance, immune functions and serum thyroid hormones concentrations in broilers. A total of 840 Ross 308 broilers (7days old) were allocated by body weight to seven treatments (three replicates of 40 birds each treatment) including (1) basal diet (containing 0.04mg of selenium (Se)/kg; control) without supplementary Se; (2, 3 and 4) basal diet+0.05, 0.15 or 0.25mg/kg Se as SS; (5, 6 and 7) basal diet+0.05, 0.15 or 0.25mg/kg Se as dl-Se-Met. The experiment lasted 42days. The results revealed that dietary Se supplementation improved (p<0.05) average daily gain, feed efficiency, immune organ index, serum immunoglobulin A (IgA), immunoglobulin G (IgG), immunoglobulin M (IgM) and triiodothyronine (T3 ) concentrations and decreased (p<0.01) thyroxine (T4 )/T3 ratio in serum compared with the control. Broilers receiving the dl-Se-Met-supplemented diets had higher (p<0.05) feed efficiency, thymus index, the amounts of IgA, IgG, IgM and T3 as well as lower (p<0.05) serum T4 concentrations and T4 /T3 ratio than those consuming the SS-supplemented diets. Serum IgA and IgM levels of broilers fed 0.15mg Se/kg were significantly higher (p<0.05) than those of broilers fed 0.05 or 0.25mg Se/kg. In summary, we concluded that dl-Se-Met is more effective than SS in increasing immunity and promoting conversion of T4 to T3 , thus providing an effective way to improve the growth performance of broilers. Besides, based on a consideration of all experiment indices, 0.15mg Se/kg was suggested to be the optimal level of Se supplementation under the conditions of this study.

2-Hydroxy-4-Methylselenobutanoic Acid as New Organic Selenium Dietary Supplement to Produce Selenium-Enriched Eggs.

Food-based strategies need to be developed to improve the selenium (Se) status of individuals. The aim of this study was to evaluate the effects of a new organic Se [2-hydroxy-4-methylselenobutanoic acid (HMSeBA)] on selected performance criteria and Se deposition in egg of laying hens. Isa Brown laying hens, 18weeks of age were randomly allocated to two dietary treatments and fed for 10weeks. The hens were fed two corn-soybean meal-based diets comprising a control basal diet without Se supplementation and a test diet supplemented with Se at 0.2mg/kg from HMSeBA. No difference was observed among dietary treatments on feed intake, egg weight and laying rate, whereas egg yolk fatty acid profile and vitamin E content were positively influenced by HMSeBA supplementation. Hens fed Se-supplemented diet exhibited greater (P<0.001) egg yolk total Se contents, which averaged 21.2mg/100g dry matter (DM) compared to control diet (11.7mg/100g DM). Our results suggested that HMSeBA as Se supplement influences positively egg yolk quality without affecting hens' productive traits. Moreover, HMSeBA offers an efficient alternative to fortify eggs with Se, which can consequently lead to greater supply of Se for humans.

Selenium Deficiency Influences the mRNA Expression of Selenoproteins and Cytokines in Chicken Erythrocytes.

Selenium (Se) deficiency induces hemolysis in chickens, but the molecular mechanism for this effect remains unclear. Se primarily elicits its function through the activity of selenoproteins, which contain the unique amino acid selenocysteine (Sec). In this study, we aimed to investigate the effect of Se deficiency on the expression of 24 selenoproteins and 10 cytokines. One hundred eighty chickens were randomly divided into 2 groups (90 chickens per group). During the entire experimental period, chickens were allowed ad libitum consumption of feed and water. The chickens were fed either a Se-deficient diet (0.008mgSe/kg; produced in the Se-deficient area of Heilongjiang, China) or a Se-supplemented diet (as sodium selenite) at 0.2mg/kg for 35days. At the 35th day, the messenger RNA (mRNA) levels of 24 selenoproteins and 10 cytokines were examined in erythrocytes of 5 chickens per group, and the correlation was analyzed. The results showed that the expression of 24 selenoproteins and 7 cytokines (IL-2, IL-4, IL-8, IL-10, IL-12β, TGF-β4, and IFN-γ) decreased (P<0.05), and the expression of 3 cytokines (IL-1γ, IL-6 and IL-7) was higher in the Se-deficient group. In both groups, glutathione peroxidase (GPX), thioredoxin 1 (Txnrd1), selenoprotein P1 (SELP), and selenoprotein synthetase (SPS2) were highly expressed compared to the other selenoproteins in chicken erythrocytes (P<0.05). These data suggest that GPXs, Txnrd1, SELP, and SPS2 possibly play a more important role than the other selenoproteins. The increase of pro-inflammatory cytokines (IL-1γ, IL-6, and IL-7) suggested that the immune system of chickens was damaged by the Se deficiency. Correlation analysis suggested that although the expression of 24 selenoproteins and 7 cytokines decreased and that of 3 cytokines increased, there was a close correlation between their expression levels and a Se diet. These results suggested that Se deficiency influenced the expressions of 24 selenoproteins and 10 cytokines in chicken erythrocytes, revealing a relationship between Se and the chicken immune system. This study offers information regarding the mechanism of Se deficiency-induced hemolysis.

Selenium Health Benefit Values: Updated Criteria for Mercury Risk Assessments.

Selenium (Se)-dependent enzymes (selenoenzymes) protect brain tissues against oxidative damage and perform other vital functions, but their synthesis requires a steady supply of Se. High methylmercury (CH3Hg) exposures can severely diminish Se transport across the placenta and irreversibly inhibit fetal brain selenoenzymes. However, supplemental dietary Se preserves their activities and thus prevents pathological consequences. The modified Se health benefit value (HBVSe) is a risk assessment criterion based on the molar concentrations of CH3Hg and Se present in a fish or seafood. It was developed to reflect the contrasting effects of maternal CH3Hg and Se intakes on fetal brain selenoenzyme activities. However, the original equation was prone to divide-by-zero-type errors whereby the calculated values increased exponentially in samples with low CH3Hg contents. The equation was refined to provide an improved index to better reflect the risks of CH3Hg exposures and the benefits provided by dietary Se. The HBVSe provides a biochemically based perspective that confirms and supports the FDA/EPA advice for pregnant and breast-feeding women regarding seafoods that should be avoided vs. those that are beneficial to consume. Since Se can be highly variable between watersheds, further evaluation of freshwater fish is needed to identify locations where fish with negative HBVSe may arise and be consumed by vulnerable subpopulation groups.

Effect of selenium supplementation on performance, cost economics, and biochemical profile of Nellore ram lambs.

Aim:Present experiment was conducted to investigate the effect of selenium (Se) supplementation on performance, carcass characteristics, meat composition, shelflife of meat and biochemical profile in Nellore ram lambs.Materials and Methods:24 male Nellore ram lambs (15.75±0.47 kg) were randomly divided into four dietary groups with six lambs in each and reared under uniform management conditions for 120 days. Basal diet was not supplemented with Se and consisted of green fodder (Se 0.09 mg/kg dry matter [DM]), dry roughage (Se 0.11 mg/kg DM) and concentrate mixture (Se 0.019 mg/kg DM) and fed individually. Dietary treatments were prepared by adding graded levels Se (0, 0.45, 0.9, and 1.8 ppm) to concentrate mixture (1% body weight [BW]) from sodium selenite. Feed offered and refusal measured daily; and BWs were measured at fortnight interval to find out average daily gain (g), feed conversion ratio (FCR), cost economics and plane of nutrition. Serum biochemical profile (concentration of glucose, total protein, albumin, globulin, cholesterol, and hemoglobin) was assessed on 0, 60th, and 120th day. At the end of experiment, the carcass characteristics (dressing percentage, cut-up parts, meat to bone ratio) and meat chemical composition were evaluated. Meat keeping (thiobarbituric acid reactive substances) quality from different groups was evaluated on day 0, 3, and 6 post-slaughter.Results:Dietary Se supplementation did not show any effect on weight gain, FCR, cost economics, plane of nutrition, and serum biochemical profile in Nellore ram lambs. However, Se supplemented lambs had numerically higher weight gain than the unsupplemented lambs. Similarly, carcass characteristics and keeping quality were comparable among the four treatments. However, numerical increase in post-slaughter keeping quality with increasing Se supplementation was observed.Conclusion:It can be concluded that supplementation of Se in the form of sodium selenite (inorganic source) at different levels did not influence animal performance in growing Nellore ram lambs had no effect on lamb performance, cost economics, carcass characteristics, and serum biochemical profile.

Effects of Se on the Diversity of SelT Synthesis and Distribution in Different Smooth Muscle Tissues in Rats.

Selenium (Se) is a nutritionally essential trace element associated with health and disease, including many muscle diseases. Selenoprotein T (SelT) has been identified as a member of the redoxin protein family that includes selenocysteine, localizing to the endoplasmic reticulum. The synthesis of selenoprotein is influenced by Se. However, there is currently no data concerning the pattern of SelT expression in smooth muscle tissues. To investigate the effects of dietary Se on the expression of SelT, 90 rats were randomly allocated into three groups: LG, NG, and HG. The LG group was fed a basal diet deficient in Se (containing 0.023 mg/kg Se); the NG and HG groups were fed Se-supplemented diets containing either 0.3 or 1.5 mg/kg Se, respectively, for 90 days. The smooth muscle of the esophagus, trachea, stomach, intestine, and blood vessels was collected when the rats were 90 days old. The Se content in the blood and tissues was examined. The messenger RNA (mRNA) of selenocysteine-tRNA([Ser]Sec) synthase (SecS), selenophosphate synthetase 1 (SPS1), selenophosphate synthetase 2 (SPS2), and SelT were examined using qPCR, and SelT protein was detected by Western blotting. The results indicated that Se had an effect on the mRNA levels of SecS, with little effect on those of SPS1 in smooth muscle tissues. SelT was expressed in the smooth muscle tissues of blood vessels, esophagus, bronchus, stomach, and intestine, and the transcription of the SelT was very sensitive to dietary Se. Thus, SelT may play a major role in the mechanisms underlying the biological activity of Se in smooth muscle tissues.

Do selenium hyperaccumulators affect selenium speciation in neighboring plants and soil? An X-Ray Microprobe Analysis

Neighbors of Se hyperaccumulators Stanleya pinnata and Astragalus bisulcatus were found earlier to have elevated Se levels. Here we investigate whether Se hyperaccumulators affect Se localization and speciation in surrounding soil and neighboring plants. X-ray fluorescence mapping and X-ray absorption near-edge structure spectroscopy were used to analyze Se localization and speciation in leaves of Artemisia ludoviciana, Symphyotrichum ericoides and Chenopodium album growing next to Se hyperaccumulators or non-accumulators at a seleniferous site. Regardless of neighbors, A. ludoviciana, S. ericoides and C. album accumulated predominantly (73–92%) reduced selenocompounds with XANES spectra similar to the C-Se-C compounds selenomethionine and methyl-selenocysteine. Preliminary data indicate that the largest Se fraction (65–75%), both in soil next to hyperaccumulator S. pinnata and next to nonaccumulator species was reduced Se with spectra similar to C-Se-C standards. These same C-Se-C forms are found in hyperaccumulators. Thus, hyperaccumulator litter may be a source of organic soil Se, but soil microorganisms may also contribute. These findings are relevant for phytoremediation and biofortification since organic Se is more readily accumulated by plants, and more effective for dietary Se supplementation.

Comparative study of DL-selenomethionine vs sodium selenite and seleno-yeast on antioxidant activity and selenium status in laying hens

The aim of this study was to compare the effect of DL-selenomethionine (SM) with 2 routinely used Se sources, sodium selenite (SS) and seleno-yeast (SY), on relative bioavailability based on antioxidant activity and tissue Se content. Six hundred thirty 131-day-old brown laying hens were randomly assigned to 7 treatments for 168 d (24 wks) with 6 replicates of 15 hens per replicate. The SS and SY animals were supplemented a cornmeal and soybean diet that supplied a total Se 0.3 mg/kg whereas SM was added at 4 different levels to the total Se at 0.1, 0.3, 0.5 and 0.7 mg/kg. All hens fed the Se-supplemented diet showed higher glutathione peroxidase (GSH–Px) activity (P < 0.01), higher superoxide dismutase (SOD) activity (P < 0.05), lower malondialdehyde (MDA) content (P < 0.05) in plasma, and greater Se contents in egg yolks, albumen, leg muscle, breast muscle, liver, and plasma compared with those fed the control diet (P < 0.01). The organic sources (SY and SM) exhibited a greater ability to increase the GSH–Px activity (P < 0.01) and Se content in albumen (P < 0.01), leg, and breast muscles (P = 0.0099 and P = 0.0014, respectively) than the SS that was added at 0.3 mg Se/kg. The higher SM added levels increased the GSH–Px activity until the dose of 0.5mg Se/kg (P < 0.01).The greater Se concentrations in albumen, muscle and liver appeared in the higher SM-added level, as well as above the dose of 0.1 mg Se/kg (P < 0.01). In addition, hens fed the diet with SM accumulated more Se in albumen, leg, and breast muscle than those fed diets with SY (P < 0.05). These results confirmed the higher ability of organic Se sources to increase the antioxidant activity and Se deposition in egg albumen, leg, and breast muscles compared with SS, and demonstrated a significantly better efficiency of SM compared with SY for albumen and muscle Se enrichment.

Efficacy of selenium from hydroponically produced selenium-enriched kale sprout (Brassica oleracea var. alboglabra L.) in broilers.

An experiment was conducted to determine the efficacy of Se from hydroponically produced Se-enriched kale sprout (HPSeKS) on performance, carcass characteristics, tissue Se concentration, and physiological responses of broilers in comparison to that of Se from Se-enriched yeast and sodium selenite. Three hundred and sixty male broilers, 10 days of age, were assigned to 6 groups, 4 replicates of 15 broilers each, according to the completely randomized design. The dietary treatments were the following: T1: control diet; T2: control diet plus 0.3 mg Se/kg from sodium selenite; T3: control diet plus 0.3 mg Se/kg from Se-enriched yeast; and T4, T5, and T6: control diet plus 0.3, 1.0, and 2.0 mg Se/kg from HPSeKS, respectively. The results found that dietary Se supplementation did not (p > 0.05) alter performance and carcass characteristics of broilers. Se supplementation increased (p < 0.05) Se concentrations in the liver and kidney of broilers. Heart tissue Se concentration of broilers fed Se from sodium selenite was lower (p < 0.05) than that of broilers fed Se from HPSeKS and Se-enriched yeast. Selenium from HPSeKS increased higher (p < 0.05) GSH-Px activity when compared to Se from sodium selenite and Se-enriched yeast. The results indicated that the efficacy of Se from HPSeKS was comparable in increasing tissue Se concentration, but higher in improving GSH-Px activity in Rbc when compared to those of Se from Se-enriched yeast.

Estimation of dietary selenium requirement for Chinese egg-laying ducks

The purpose of this study was to estimate the selenium (Se) requirement of egg-laying ducks based on daily egg production and the selenoprotein glutathione peroxidase (Gpx). Five-hundred and forty laying ducks were divided into six treatments, each containing six replicates of 15 ducks. The birds were caged individually and received a Se-deficient basal diet (0.04 mg/kg) or diets supplemented with 0.08, 0.16, 0.24, 0.32, 0.40 mg/kg Se (as sodium selenite) for 6 months. The experiment consisted of two periods: an early-laying period of 2 months and the peak-laying period of 4 months. Egg production and feed intake were recorded daily. At the end of the experiment, blood samples were drawn for determination of Gpx activity in plasma (Gpx3) and in erythrocytes (Gpx1). Hepatic Gpx1 activity and relative expression of Gpx1 mRNA were also determined. Eggs (n = 6) were sampled for quality determination and Se content at the end of the experiment. The activities of plasma Gpx3, erythrocyte Gpx1 and liver Gpx1 increased in a quadratic manner (P &lt; 0.001) with increasing supplemental Se. The mRNA abundance of hepatic Gpx1 increased linearly (P &lt; 0.001) with dietary Se supplementation. Egg shell thickness was significantly reduced in the ducks fed 0.44 mg Se/kg (P &lt; 0.05), indicating that higher dietary Se tends to compromise egg shell quality. Yolk and albumen contents of Se increased linearly (P &lt; 0.0001) with dietary Se supplementation. Using quadratic broken line models, the Se requirement for daily egg production was 0.18 mg/kg for early-laying ducks and 0.24 mg/kg for peak-laying ducks; for optimal function of Gpx (peak-laying ducks), it was 0.37 mg Se/kg.

Dietary selenium protect against redox-mediated immune suppression induced by methylmercury exposure

The antagonism between selenium (Se) and mercury (Hg) has been widely recognized, however, the protective role of Se against methylmercury (MeHg) induced immunotoxicity and the underlying mechanism is still unclear. In the current study, MeHg exposure (0.01mM via drinking water) significantly inhibited the lymphoproliferation and NK cells functions of the female Balb/c mice, while dietary Se supplementation (as Se-rich yeast) partly or fully recovered the observed immunotoxicity, indicating the protective role of Se against MeHg-induced immune suppression in mice. Besides, MeHg exposure promoted the generation of the reactive oxygen species (ROS), reduced the levels of nonenzymic and enzymic antioxidants in target organs, while dietary Se administration significantly diminished the MeHg-induced oxidative stress and subsequent cellular dysfunctions (lipid peroxidation and protein oxidation). Two possible mechanisms of Se’s protective effects were further revealed. Firstly, the reduction of mercury concentrations (less than 25%, modulated by Se supplementation) in the target organs might contribute, but not fully explain the alleviated immune suppression. Secondly and more importantly, Se could help to maintain/or elevate the activities of several key antioxidants, therefore protect the immune cells against MeHg-induced oxidative damage.

Hepatic transcriptome profiles differ among maturing beef heifers supplemented with inorganic, organic, or mixed (50% inorganic:50% organic) forms of dietary selenium.

Selenium (Se) is an important trace mineral that, due to deficiencies in the soil in many parts of the USA, must be supplemented directly to the diet of foraging cattle. Both organic and inorganic forms of dietary Se supplements are available and commonly used, and it is known that Se form affects tissue assimilation, bioavailability, and physiological responses. However, little is known about the effects of form of dietary Se supplements on gene expression profiles, which ostensibly account for Se form-dependent physiological processes. To determine if hepatic transcriptomes of growing beef (Angus-cross) heifers (0.5 kg gain/day) was altered by form of dietary supplemental Se, none (Control), or 3 mg Se/day as inorganic Se (ISe, sodium selenite), organic (OSe, Sel-Plex®), or a blend of ISe and OSe (1.5 mg:1.5 mg, Mix) Se was fed for 168 days, and the RNA expression profiles from biopsied liver tissues was compared by microarray analysis. The relative abundance of 139 RNA transcripts was affected by Se treatment, with 86 of these with complete gene annotations. Statistical and bioinformatic analysis of the annotated RNA transcripts revealed clear differences among the four Se treatment groups in their hepatic expression profiles, including (1) solely and commonly affected transcripts; (2) Control and OSe profiles being more similar than Mix and ISe treatments; (3) distinct OSe-, Mix-, and ISe-Se treatment-induced "phenotypes" that possessed both common and unique predicted physiological capacities; and (4) expression of three microRNAs were uniquely sensitive to OSe, ISe, or Mix treatments, including increased capacity for redox potential induced by OSe and Mix Se treatments resulting from decreased expression of MiR2300b messenger RNA. These findings indicate that the form of supplemental dietary Se consumed by cattle will affect the composition of liver transcriptomes resulting, presumably, in different physiological capacities.

Fatty Acid Profiles of Supraspinatus, Longissimus lumborum and Semitendinosus Muscles and Serum in Kacang Goats Supplemented with Inorganic Selenium and Iodine.

Fat and fatty acids in muscle and adipose tissues are among the major factors influencing meat quality particularly nutritional value and palatability. The present study was carried out to examine the effects of supplementing inorganic selenium (Se), iodine (I) and a combination of both on fatty acid compositions in serum, and supraspinatus (SS), longissimus lumborum (LL), and semitendinosus (ST) muscles in goats. Twenty-four, 7 to 8 months old, Kacang male goats with a mean live weight of 22.00±1.17 kg were individually and randomly assigned into four groups of six animals each for 100 d of feeding prior to slaughter. The animals were offered the same concentrate (basal) diet as 1% of body weight with ad libitum amount of fresh guinea grass. The four groups were as follows: T1 (control) - basal diet without supplementation; T2 - basal diet with 0.6 mg Se/kg DM; T3 - basal diet with 0.6 mg I/kg DM; T4 - basal diet with combination of 0.6 mg Se/kg DM and 0.6 mg I/kg DM. The major fatty acids (FAs) detected in the serum were palmitic (C16:0), stearic (C18:0), oleic (C18:1n9) and linoleic (C18:2n-6), while the major FAs in the selected muscles were C16:0, C18:0 and C18:1n9 acids. The main polyunsaturated fatty acids (PUFA) detected in muscles and serum were (CI8:2n-6), linolenic acid (C18:3n-3), and arachidonic acid (C20:4n-6). No significant differences (p>0.05) were observed in the concentration of total saturated fatty acids (SFA) among the four groups. PUFA concentrations in the goats supplemented with Se (T2) were significantly higher (p<0.05) than the goats of the control group (T1). The PUFA: SFA ratio was significantly higher in the animals supplemented with dietary Se (T2) than those of control ones (T1). It is concluded that dietary supplementation of inorganic Se increased the unsaturated fatty acids in muscle. The supplementation of iodine with or without Se had negligible effects on muscle fatty acid content of Kacang crossbred male goats.

Selenium and Selenoproteins in Inflammatory Bowel Diseases and Experimental Colitis

Inadequate dietary intake of the essential trace element selenium (Se) is thought to be a risk factor for several chronic diseases associated with oxidative stress and inflammation. Biological actions of Se occur through low-molecular weight metabolites and through selenoproteins. Several key selenoproteins including glutathione peroxidases; selenoproteins M, P, and S; and selenium-binding protein 1 have been detected in the intestine. Interestingly, Se and antioxidant selenoproteins are known to modulate differentiation and function of immune cells and contribute to avoid excessive immune responses. This review discusses the role of Se and intestinal selenoproteins in inflammatory bowel diseases, based on data from human, animal, and in vitro studies. In humans, Se deficiency is commonly observed in patients with Crohn's disease. In animal models of experimental colitis, the Se status was negatively correlated with the severity of the disease. While the cause-effect relationship of these observations remains to be clarified, the beneficial outcome of dietary Se supplementation and an optimization of selenoprotein biosynthesis in murine inflammatory bowel disease models have led to investigations of targets and actions of Se in the gastrointestinal tract. The Se status affects gene expression, signaling pathways, and cellular functions in the small and large intestine as well as the gut microbiome composition. This data, particularly from animal experiments, hold promise that adequate dietary Se supply may counteract chronic intestinal inflammation in humans.

Selenium status affects selenoprotein expression, reproduction, and F1 generation locomotor activity in zebrafish (Danio rerio)

Se is an essential trace element, and is incorporated into selenoproteins which play important roles in human health. Mammalian selenoprotein-coding genes are often present as paralogues in teleost fish, and it is unclear whether the expression patterns or functions of these fish paralogues reflect their mammalian orthologues. Using the model species zebrafish (Danio rerio; ZF), we aimed to assess how dietary Se affects key parameters in Se metabolism and utilisation including glutathione peroxidase (GPX) activity, the mRNA expression of key Se-dependent proteins (gpx1a, gpx1b, sepp1a and sepp1b), oxidative status, reproductive success and F1 generation locomotor activity. From 27 d until 254 d post-fertilisation, ZF were fed diets with graded levels of Se ranging from deficient ( < 0·10 mg/kg) to toxic (30 mg/kg). The mRNA expression of gpx1a and gpx1b and GPX activity responded in a similar manner to changes in Se status. GPX activity and mRNA levels were lowest when dietary Se levels (0·3 mg/kg) resulted in the maximum growth of ZF, and a proposed bimodal mechanism in response to Se status below and above this dietary Se level was identified. The expression of the sepp1 paralogues differed, with only sepp1a responding to Se status. High dietary Se supplementation (30 mg/kg) decreased reproductive success, while the offspring of ZF fed above 0·3 mg Se/kg diet had lower locomotor activity than the other groups. Overall, the novel finding of low selenoprotein expression and activity coinciding with maximum body growth suggests that even small Se-induced variations in redox status may influence cellular growth rates.