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This study aimed to compare the effects of various dietary selenium (Se) sources (0.5 mg/kg) on performance, meat quality, and antioxidant capacity in broilers as well as essential trace elements concentrations in their blood and tissues. A total of 360 one-day-old male yellow-feathered chickens (37.00 ± 0.17 g) were randomly allocated to 5 diet treatments: the basal diet (CON) and 4 diets supplemented with sodium selenite (SS), selenomethionine (SM), selenium-enriched yeast (SY), and nano-selenium (NS) for 56 d, respectively, with 6 replicates per treatment and 12 chickens per replicate. Dietary Se supplementation did not affect growth performance and carcass characteristics in broilers (P > 0.05). Supplemental SM enhanced the redness in the pectoral muscle compared to CON and NS (P < 0.05). Supplementation of SY and NS improved the concentrations of Se, copper, manganese, and zinc in the serum (P < 0.05). Supplemental SS also elevated the zinc content in the serum (P < 0.05). Broilers fed the SY diet showed increased Se content in the liver and pectoral muscle compared to those fed CON, SM, and NS diets (P < 0.05). Also, SY improved the pectoral muscle Se concentration compared to SS (P < 0.05). Besides, dietary Se supplementation increased the Se content in the thigh muscle (P < 0.05), with SY showing highest Se deposition. Dietary supplementation with SS, SM, and NS improved the activities of total superoxide dismutase and total antioxidant capacity (T-AOC) in the serum (P < 0.05). Supplemental SY also elevated the T-AOC in the serum (P < 0.05). Additionally, SS and SM enhanced the T-AOC in the liver (P < 0.05). In conclusion, supplemental SM affected meat color. Supplementing diets with various Se sources increased antioxidant capacity and Se content in the thigh muscle of broilers, with SY showing a more pronounced deposition efficiency. Besides, diets supplemented with different Se sources had variable effects on the concentrations of essential trace elements in the serum and tissues of broilers., Competing Interests: DISCLOSURES The authors declare that they have no competing interests., (Copyright © 2024 The Authors. Published by Elsevier Inc. All rights reserved.)

Selenium (Se) is a mineral with natural antioxidant properties that constitutes a number of enzymes with a fundamental role in the immunity and antioxidant systems and may confer a protective role against oxidative stress in fish following exposure to physical stressors. Adopting an integrated approach, this study investigated simultaneously the role of hydroxy-selenomethionine (OH-SeMet) supplementation in performance, hematological parameters, innate immune, antioxidant capacity and tissue Se retention of tambaqui (Colossoma macropomum) and the possible protective role of dietary selenium when fish are exposed to a physical stressor (transport). Juvenile specimens (15.71 ± 1.90 g) were fed one of five diets: a basal unsupplemented diet (0.0 mg kg -1 Se) or diets supplemented with OH-SeMet to provide 0.3, 0.6, 0.9 and 1.2 mg kg -1 Se of diet for 75 days prior to subjection of fish to transport stress. Dietary supplementation with Se in the form of OH-SeMet for 75 days did not affect the production performance of juvenile tambaqui, but increased innate immunity parameters (oxidative burst) from the Se inclusion level of 0.6 mg kg -1 and induced the activation of the antioxidant defense system (GPX, GSH and GST) especially at the Se inclusion level of 0.9 mg kg -1 . In addition, the Se content in the fillet rose significantly, as the OH-SeMet contents in the diet were increased. The stress caused by transport resulted in alterations in hematological parameters, blood protein profile and immune and enzymatic responses in the species. However, Se supplementation at 0.9 mg kg -1  had a positive effect, increasing innate immunity and activating antioxidant defenses (CAT and GPx, especially) after this physical stressor was applied. These results demonstrate that, when submitted to transport stress, juvenile tambaqui use Se stored in the muscle and dietary supplementation with OH-SeMet at 0.9 mg kg -1 improves the innate immunity and antioxidant system parameters of fish after transport. These findings reinforce the need for supplementing hydroxy-selenomethionine in commercial diets for tambaqui to ensure tissue Se reserves as a contingency in cases of stress., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

Exercise overproduces oxygen reactive species (ROS) and eventually exceeds the body's antioxidant capacity to neutralize them. The ROS produce damaging effects on the cell membrane and contribute to skeletal muscle damage. Selenium (Se), a natural mineral trace element, is an essential component of selenoproteins that plays an important role in antioxidant defense. The activity of the enzyme glutathione peroxidase (GPx), a highly-efficient antioxidant enzyme, is closely dependent on the presence of Se. These properties of Se may be potentially applicable to improve athletic performance and training recovery. We systematically searched for published studies to evaluate the effectiveness of Se supplementation on antioxidant defense system, muscle performance, hormone response, and athletic performance among physically active individuals. We used the Preferred Reporting Elements for Systematic Reviews and Meta-Analysis (PRISMA) guidelines and searched in SCOPUS, Web of Science (WOS), and PubMed databases to identify published studies until March 2020. The systematic review incorporated original studies with randomized controlled crossover or parallel design in which intake of Se administered once a day was compared with the same placebo conditions. No exclusions were applied for the type of physical exercise performed, the sex, nor the age of the participants. Among 150 articles identified in the search, 6 met the criteria and were included in the systematic review. The methodological quality of the studies was evaluated using the McMaster Critical Review Form. Oral Se supplementation with 180 µg/day or 240 µg/day (selenomethionine) and 200 µg/day (Sodium Selenite), significantly decreased lipid hydroperoxide levels and increased GPx in plasma, erythrocyte, and muscle. No significant effects were observed on athletic performance, testosterone hormone levels, creatine kinase activity, and exercise training-induced adaptations on oxidative enzyme activities or on muscle fiber type myosin heavy chain expression. In addition, Se supplementation showed to have a dampening effect on the mitochondria changes in chronic and acute exercise. In summary, the use of Se supplementation has no benefits on aerobic or anaerobic athletic performance but it may prevent Se deficiencies among athletes with high-intensity and high-volume training. Optimal Se plasma levels may be important to minimize chronic exercise-induced oxidative effects and modulate the exercise effect on mitochondrial changes.

This study was conducted to assess the effects of the hydroxy-analogue of selenomethionine (HMSeBA) on growth performance, selenium (Se) deposition and antioxidant status of piglets. In a 28-d experiment, 252 piglets were assigned into seven treatments. These treatments were a negative control (Con-, basal diet without supplement Se), a positive control (Con+, basal diet + 0.3 mg Se from sodium selenite per kg), and five HMSeBA groups (basal diet + 0.1, 0.2, 0.3, 0.4 and 0.5 mg Se/kg from HMSeBA, respectively). Results showed that dietary HMSeBA supplementation did not affect growth performance of piglets. However, HMSeBA supplementation increased the Se concentrations in serum, liver, kidney and muscle compared with groups Con- and Con+ ( p < 0.05). Compared with group Con-, supplementation with 0.2 and 0.4 mg Se from HMSeBA increased serum total antioxidant capability (T-AOC) and addition of 0.4 and 0.5 mg Se from HMSeBA increased serum glutathione peroxidase (GSH-Px) activities ( p < 0.05). Compared with group Con-, the addition of 0.1, 0.2, 0.4, 0.5 mg Se from HMSeBA increased GSH-Px activities and decreased malondialdehyde (MDA) contents in the liver, and 0.3 mg Se from HMSeBA increased T-AOC and GSH-Px activities in the liver ( p < 0.05). Compared with group Con+, 0.3 mg Se from HMSeBA increased serum superoxide dismutase (SOD) and hepatic T-AOC activities, and decreased the serum MDA level ( p < 0.05). In general, dietary HMSeBA supplementation could improve Se deposition in serum and tissue and antioxidant capacity of piglets, suggesting that HMSeBA could be an effective Se source for piglets.

A total of 200 healthy 28-day-old male Jiangnan White geese were used to investigate the free radical scavenging ability, reduced glutathione (GSH) and thioredoxin systems, and the concentrations of reactive oxygen metabolites (ROM), malondialdehyde (MDA), and protein carbonyl (PC) in geese fed diets with organic selenium (Se) (Selenomethionine, SeMet) and inorganic Se (sodium selenite, SS). All geese were randomly allotted into 4 groups with 5 replicates of 10 geese each, and received basal diet supplemented with 0.3 mg Se/kg SS, 0.2, 0.3 and 0.4 mg Se/kg SeMet until 70 D of age, respectively. Geese in the SS and SeMet groups exhibited similar growth performance. Diet with SeMet increased the scavenging abilities of 2,2-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt free radical (ABTS•+, P < 0.001) and superoxide radical (O2-•, P = 0.002) in the serum of geese, as well as the scavenging abilities of ABTS•+ (P = 0.023), hydroxyl radical (P = 0.009) and O2-• (P = 0.019) in the liver of geese. Compared to the SS group, SeMet increased hepatic GSH concentration (P = 0.002), the activities of glutathione peroxidase (P = 0.031), γ-glutamate cysteine ligase (P < 0.001), and thioredoxin reductase (P < 0.001), and decreased the concentrations of ROM, MDA, and PC in the serum and liver of geese (P < 0.05). In conclusion, dietary SeMet inclusion would be more effective than SS in increasing the antioxidant capacity of geese, possibly by improving GSH and thioredoxin systems, and 0.2 mg Se/kg SeMet in goose diet is recommended., (© 2019 Poultry Science Association Inc.)

This study was conducted to investigate the effects of different selenomethionine (SM) forms and levels on productive performance and antioxidant status of broiler breeders and its offspring. Four hundred eighty 48-week-old Lingnan Yellow broiler breeders were randomly divided into four groups, provided basal diet with 0.15 or 0.30 mg/kg Se coming from two SM forms of DL-SM and L-SM. The experiment included a 4-week pretreatment period and an 8-week trial period. During the trial period, eggs were incubated once a week under standard conditions. The broiler breeders were slaughtered after the trial period. At the same time, 15 1-day-old chicks were selected at random per replicate and killed. The results showed that different SM forms and levels had no significant differences in average egg weight, feed intake, and feed-to-egg ration. The DL-SM group in contrast to the L-SM group induced a notable elevation of glutathione peroxidase (GPx) activity in serum (P < 0.01) and liver (P < 0.05), and the 0.15 mg/kg group had higher GPx activity than 0.30 mg/kg in serum (P < 0.01) and pancreas (P < 0.05). Different SM forms showed no significant differences in total antioxidant capability (T-AOC). Diets with 0.15 mg/kg Se exhibited a higher level of T-AOC in serum (P < 0.01) and some tissues. Besides, malondialdehyde (MDA) concentrations in serum, liver, and kidney significantly decreased due to the supplementation of DL-SM. Supplemental 0.15 mg/kg Se reduced MDA concentrations in kidney and muscle. The offspring of broiler breeders fed on DL-SM had higher GPx activity in liver and kidney than L-SM treatment. Supplemental 0.15 mg/kg Se also improved GPx activity in kidney and muscle and T-AOC in kidney of 1-day-old chicks. In summary, our study demonstrated that compared with L-SM, DL-SM was more effective for enhancing the antioxidant status of broiler breeders and its offspring. Moreover, the recommended level of Se supplementation was 0.15 mg/kg Se in Lingnan Yellow broiler breeder diets.

This study aimed to evaluate the effect of hydroxy-selenomethionine (HMSeBA), a novel organic selenium (Se) source, on milk performance, antioxidative status, and Se concentrations in the milk and plasma of mid-lactation dairy cows compared with that of sodium selenite (SS). Fifty mid-lactation dairy cows with similar days in milk, milk yield, and parity received the same basal diet containing 0.06 mg of Se/kg of DM. They were assigned to 1 of 5 treatments according to a randomized complete block design: negative control (without Se supplementation), SS supplementation (0.3 mg of Se/kg of DM; SS-0.3) or HMSeBA supplementation (0.1, 0.3, or 0.5 mg of Se/kg of DM: SO-0.1, SO-0.3, and SO-0.5, respectively). The experiment lasted for 10 wk, including a pretrial period of 2 wk. The results indicated that neither Se supplementation nor Se source affected dry matter intake, milk yield, milk composition, or blood biochemical parameters, except for milk fat percentage. Simultaneously, milk fat percentage and milk fat yield increased linearly as the quantity of HMSeBA supplementation was increased. Production of 4% FCM and ECM was elevated linearly as dietary HMSeBA increased. The SO-0.3 group showed higher serum activity of glutathione peroxidase, total antioxidant capacity, and superoxide dismutase than the SS-0.3 group, but malondialdehyde content was not affected by Se source. Furthermore, HMSeBA supplementation linearly increased the activities of serum glutathione peroxidase and superoxide dismutase, but decreased malondialdehyde content. Compared with the SS-0.3 group, the SO-0.3 group showed augmented concentrations of total Se in milk and plasma, and total Se milk-to-plasma concentration ratio. In addition, increasing doses of HMSeBA linearly increased the concentrations of total Se in the milk and plasma. This study demonstrates that HMSeBA improves antioxidant status and increases milk and plasma Se concentrations more effectively than SS, indicating that HMSeBA could replace SS as an effective organic Se source for lactating dairy cows., (Copyright © 2017 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.)

Aim: To evaluate molecular mechanisms of tissue-protective effects of antioxidants selenomethionine (SeMet) and D-pantethine (D-Pt) applied in combination with doxorubicin (Dx) in B16 melanoma-bearing-mice., Methods: Impact of the chemotherapy scheme on a survival of tumor-bearing animals, general nephro- and hepatotoxicity, blood cell profile in vivo, and ROS content in B16 melanoma cells in vitro was compared with the action of Dx applied alone. Nephrotoxicity of the drugs was evaluated by measuring creatinine indicator assay, hepatotoxicity was studied by measuring the activity of ALT/AST enzymes, and myelotoxicity was assessed by light microscopic analysis of blood smears. Changes in ROS content in B16 melanoma cells under Dx, SeMet, and D-Pt action in vitro were measured by incubation with fluorescent dyes dihydrodichlorofluoresceindiacetate (DCFDA, H2O2-specific) and dihydroethidium (DHE, O2--specific), and further analysis at FL1 (DCFDA) or FL2 channels (DHE) of FACScan flow cytometer. The impact of aforementioned compounds on functional status of mitochondria was measured by Rhodamine 123 assay and further analysis at FL1 channel of FACScan flow cytometer., Results: Selenomethionine (1200 µg/kg) and D-pantethine (500 mg/kg) in combination with Dx (10 mg/kg) significantly reduced tumor-induced neutrophilia, lymphocytopenia, and leukocytosis in comparison to Dx treatment alone. Moreover, SeMet and D-Pt decreased several side effects of Dx, namely an elevated creatinine level in blood and monocytosis, thus normalizing health conditions of B16 melanoma-bearing animals., Conclusions: Our results showed that antioxidants selenomethionine and D-pantethine possess significant nephroprotective and myeloprotective activity toward Dx action on murine B16 melanoma in vivo, but fail to boost a survival of B16 melanoma-bearing animals. The observed cytoprotective effects of studied antioxidants are not directly connected with their ROS scavenging.

Selenium and vitamin E micronutrients have been advocated for the prevention of colorectal cancer. Colorectal adenoma occurrence was used as a surrogate for colorectal cancer in an ancillary study to the Selenium and Vitamin E Cancer Prevention Trial (SELECT) for prostate cancer prevention. The primary objective was to measure the effect of selenium (as selenomethionine) on colorectal adenomas occurrence, with the effect of vitamin E (as α-tocopherol) supplementation on colorectal adenoma occurrence considered as a secondary objective. Participants who underwent lower endoscopy while in SELECT were identified from a subgroup of the 35,533 men randomized in the trial. Adenoma occurrence was ascertained from the endoscopy and pathology reports for these procedures. Relative Risk (RR) estimates and 95% confidence intervals (CI) of adenoma occurrence were generated comparing those randomized to selenium versus placebo and to vitamin E versus placebo based on the full factorial design. Evaluable endoscopy information was obtained for 6,546 participants, of whom 2,286 had 1+ adenomas. Apart from 21 flexible sigmoidoscopies, all the procedures yielding adenomas were colonoscopies. Adenomas occurred in 34.2% and 35.7%, respectively, of participants whose intervention included or did not include selenium. Compared with placebo, the RR for adenoma occurrence in participants randomized to selenium was 0.96 (95% CI, 0.90-1.02; P = 0.194). Vitamin E did not affect adenoma occurrence compared with placebo (RR = 1.03; 95% CI, 0.96-1.10; P = 0.38). Neither selenium nor vitamin E supplementation can be recommended for colorectal adenoma prevention. Cancer Prev Res; 10(1); 45-54. ©2016 AACR., (©2016 American Association for Cancer Research.)

Aim: To investigate the potential tissue-protective effects of antioxidants selenomethionine and D-pantethine applied together with doxorubicin (Dx) on NK/Ly lymphoma-bearing mice. The impact of this chemotherapy scheme on animal survival, blood cell profile, hepatotoxicity, glutathione level, and activity of glutathione-converting enzymes in the liver was compared with the action of Dx applied alone.., Methods: The hematological profile of animals was studied by the analysis of blood smears under light microscopy. Hepatotoxicity of studied drugs was evaluated measuring the activity of alanine aminotransferase (ALT) and aspartate aminotransferase (AST) enzymes, De Ritis ratio, and coenzyme A fractions by McDougal assay. Glutathione level in animal tissues was measured with Ellman reagent, and the activity of glutathione reductase, transferase, and peroxidase was measured using standard biochemical assays., Results: D-pantethine (500 mg/kg) and, to a lower extent, selenomethionine (600 µg/kg) partially reduced the negative side effects (leukocytopenia and erythropenia) of Dx (5 mg/kg) in NK/Ly lymphoma bearing animals on the 14th day of their treatment. This increased animal survival time from 47-48 to 60+ days and improved the quality of their life. This ability of D-pantethine and selenomethionine was realized via hepatoprotective and immunomodulating activities. D-pantethine also restored the levels of acid-soluble and free CoA in the liver of tumor-bearing animals, while selenomethionine caused the recovery of glutathione peroxidase levels in the liver, which was significantly diminished under Dx treatment. Both compounds decreased glutathione level in the liver, which was considerably induced by Dx., Conclusions: Antioxidants selenomethionine and D-pantethine partially reversed the negative side effects of Dx in NK/Ly lymphoma-bearing mice and significantly increased the therapeutic efficiency of this drug in tumor treatment.

Importance: Observational studies suggest a role for dietary nutrients such as vitamin E and selenium in cataract prevention. However, the results of randomized clinical trials of vitamin E supplements and cataract have been disappointing and are not yet available for selenium., Objective: To test whether long-term supplementation with selenium and vitamin E affects the incidence of cataract in a large cohort of men., Design, Setting, and Participants: The Selenium and Vitamin E Cancer Prevention Trial (SELECT) Eye Endpoints Study was an ancillary study of the Southwest Oncology Group-coordinated SELECT, a randomized placebo-controlled 4-arm trial of selenium and vitamin E conducted among 35,533 men, 50 years and older for African American participants and 55 years and older for all other men, at 427 participating sites in the United States, Canada, and Puerto Rico. A total of 11,267 SELECT participants from 128 SELECT sites participated in the SELECT Eye Endpoints ancillary study., Interventions: Individual supplements of selenium (200 μg per day from L-selenomethionine) and vitamin E (400 IU per day of all rac-α-tocopheryl acetate)., Main Outcomes and Measures: Incident cataract was defined as a lens opacity, age related in origin, and responsible for a reduction in best-corrected visual acuity to 20/30 or worse based on self-reports confirmed by medical record review. Cataract extraction was defined as the surgical removal of an incident cataract., Results: During a mean (SD) of 5.6 (1.2) years of treatment and follow-up, 389 cases of cataract were documented. There were 185 cataracts in the selenium group and 204 in the no selenium group (hazard ratio, 0.91; 95 % CI, 0.75-1.11; P = .37). For vitamin E, there were 197 cases in the treated group and 192 in the placebo group (hazard ratio, 1.02; 95 % CI, 0.84-1.25; P = .81). Similar results were observed for cataract extraction., Conclusions and Relevance: These data from a large cohort of apparently healthy men indicate that long-term daily supplementation with selenium and/or vitamin E is unlikely to have a large beneficial effect on age-related cataract., Trial Registration: ClinicalTrials.gov Identifier: NCT00784225.

This study was conducted to investigate the effects of different sources of dietary selenium (Se) supplementation on growth performance, meat quality, Se deposition, and antioxidant property in broilers. A total of 600 one-day-old Ross 308 broilers with an average body weight (BW) of 44.30 ± 0.49 g were randomly allotted to three treatments, each of which included five replicates of 40 birds. These three groups received the same basal diet containing 0.04 mg Se/kg, supplemented with 0.15 mg Se/kg from sodium selenite (SS) or from L-selenomethionine (L-Se-methionine (Met)) or from D-selenomethionine (D-Se-Met). The experiment lasted 42 days. Both Se source and time significantly influenced (p < 0.01) drip loss of breast muscle. Supplementation with L-Se-Met and D-Se-Met were more effective (p < 0.05) in decreasing drip loss than SS. Besides, the pH value of breast muscle was also significantly influenced (p < 0.05) by time. The SS-supplemented diet increased more (p < 0.05) liver, kidney, and pancreas glutathione peroxidase (GSH-Px) activities than the D-Se-Met-supplemented diet. In addition, L-Se-Met increased more (p < 0.01) liver and pancreas GSH-Px activities than D-Se-Met. The antioxidant status was greatly improved in broilers of L-Se-Met-treated group in comparison with the SS-treated group and was illuminated by the increased glutathione (GSH) concentration in serum, liver, and breast muscle (p < 0.05); superoxide dismutase (SOD) activity in liver (p < 0.01); total antioxidant capability (T-AOC) in kidney, pancreas, and breast muscle (p < 0.05) and decreased malondialdehyde (MDA) concentration in kidney and breast muscle (p < 0.05) of broilers. Besides, supplementation with D-Se-Met was more effective (p < 0.01) in increasing serum GSH concentration and decreasing breast muscle MDA concentration than SS. L-Selenomethionine supplementation significantly increased GSH concentration in liver and breast muscle (p < 0.05); SOD activity in liver (p < 0.01); and T-AOC in liver, pancreas, and breast muscle (p < 0.05) of broilers, compared with broilers fed D-Se-Met diet. The addition of L-Se-Met and D-Se-Met increased (p < 0.01) Se concentration in serum and different organs studied of broilers in comparision with broilers fed SS diet. Therefore, dietary L-Se-Met and D-Se-Met supplementation could improve antioxidant capability and Se deposition in serum and tissues and reduce drip loss of breast muscle in broilers compared with SS. Besides, L-Se-Met is more effective than D-Se-Met in improving antioxidant status in broilers.

Previous epidemiologic observational and experimental studies investigated the potential of antioxidant micronutrients to modulate cancer risk, but these studies produced inconsistent results. In this pilot, randomized, double-blind, placebo-controlled clinical trial (n = 47), we assessed the effects of an antioxidant micronutrient combination (800 mg dl-alpha-tocopherol acetate, 24 mg beta-carotene, 1.0 g vitamin C, 200 microg l-selenomethionine, 7.2 mg riboflavin, 80 mg niacin, 60 mg zinc, 5 mg manganese) given daily over 4 months on oxidative and inflammatory biomarkers in patients with a history of sporadic colorectal adenoma. Plasma tumor necrosis factor-alpha (TNF-alpha), interleukin-6, and F2-isoprostane concentrations were measured using ELISAs, and cystine (CySS) was measured using high-performance liquid chromatography. Plasma TNF-alpha concentration decreased in the active treatment group by 37% relative to the placebo group (P = 0.002), and CySS decreased by 19% (P = 0.03); however, interleukin-6 and F2-isoprostane concentrations decreased in antioxidant-treated nonsmokers but increased in smokers, although these findings were not statistically significant. The decreases of TNF-alpha and CySS were more pronounced in nonsmokers. These data suggest that (a) an antioxidant micronutrient cocktail can modulate biomarkers of oxidative stress and inflammation in humans and (b) the effects of antioxidant micronutrient supplementation on biomarkers of inflammation and oxidative stress may differ according to smoking status.

This study was conducted to investigate the effects of dietary selenomethionine (Se-Met) supplementation on growth performance, meat quality and antioxidant property in male broilers. A total of 800 43-day-old Lingnan yellow male broilers were randomly allotted to 5 dietary treatments with four replicates of 40 birds for a period of 3 weeks ad libitum. Final BW and weight gain of birds significantly increased by Se-Met supplementation at the 0.225 mg/kg level (P < 0.05). The addition of Se-Met significantly decreased drip loss, lightness value, and elevated pH value of meat (p < 0.05). Adding sodium selenite (SS) only increased pH value of meat (p < 0.05). In plasma, supplemental Se-Met at 0.225 mg/kg level increased total antioxidant capability (T-AOC), glutathione peroxidase (GPX), total superoxide dismutase (T-SOD), catalase (CAT) activities, glutathione (GSH) concentration (p < 0.05), and decreased malondialdehyde production (p < 0.05), compared with the control and broilers fed SS diet. In breast muscle, the addition of Se-Met significantly elevated T-AOC, GPX, T-SOD, CAT activities, contents of metallothionein and GSH (p < 0.05), and reduced carbonyl protein content (p < 0.05). While compared with broilers fed SS diet, supplemental 0.225 mg/kg Se-Met increased T-AOC, GPX, CAT activities, and GSH content (p < 0.05). Therefore, dietary Se-Met supplementation could improve growth performance and meat quality by enhancing antioxidative capacity in broilers compared with SS.

Background: Selenium is a central determinant of antioxidative glutathione peroxidase 1 (GPx-1) expression and activity. The relevance of selenium supplementation on GPx-1 in coronary artery disease (CAD) needs to be established. We assessed the effect of selenium supplementation on GPx-1 in cell culture and on endothelial function in a prospective clinical trial., Methods: Human coronary artery endothelial cells were incubated with 5.78 to 578 nmol/L sodium selenite, Se-methyl-selenocysteine hydrochloride, or seleno-l-methionine. Glutathione peroxidase 1 mRNA and protein expression and activity were measured. Coronary artery disease patients (n = 465) with impaired endothelial function (flow-mediated dilation [FMD] <8%) were randomly assigned to receive 200 or 500 microg sodium selenite daily or matching placebo during a 12-week period. We tested the effect on red blood cell GPx-1 activity and brachial artery FMD. Furthermore, differences in biomarkers of oxidative stress and inflammation were measured., Results: Sodium selenite and Se-methyl-selenocysteine hydrochloride increased GPx-1 protein and activity in a dose-dependent manner (P < .0001). The intention-to-treat groups comprised 433 CAD patients. Glutathione peroxidase 1 activity increased from 37.0 U/gHb (31.3-41.7) to 41.1 U/gHb (35.2-48.4) (P < .0001) in the 200 microg and from 38.1 U/gHb (33.2-43.8) to 42.6 U/gHb (35.0-49.1) (P < .0001) in the 500 microg sodium selenite group treated for 12-weeks. No relevant changes were observed for FMD or biomarkers of oxidative stress and inflammation., Conclusions: Sodium selenite supplementation increases GPx-1 activity in endothelial cells and in CAD patients. Future studies have to demonstrate whether long-term CAD outcome can be improved.

Many studies evaluating the effects of selenium (Se) status on immunity utilize inorganic Se, although selenomethionine (Se-Met) has been suggested to be more bioavailable and less toxic. In the current study, we investigated the effects of dietary Se-Met on immune system function and cellular redox status in C57BL/6N female mice fed with low (0.02 ppm), sufficient (0.2 ppm, control group), or excess Se-Met (2 ppm) in the diet for 50 days. Low Se-Met intake reduced glutathione peroxidase (GPx) activity and glutathione concentration without modifying lipoperoxidation. While low Se-Met intake also reduced the number of B cells in the spleen, it increased mitogen-induced proliferation, IL-4 and IL-12 secretion when compared to the sufficient Se-Met intake group. In comparison to controls, excess Se-Met intake increased splenocyte proliferation and reduced B cell numbers, IL-4, and IL-12 secretion without affecting oxidative stress markers. These data suggest that Se-Met supplementation should be carefully evaluated as it many influence immune function.

The molecular basis and downstream targets of oral selenium supplementation in individuals with elevated risk of cancer due to chronic exposure from environmental carcinogens has been largely unexplored. In this study, we investigated genome-wide differential gene expression in peripheral blood mononuclear cells (PBMC) from individuals with pre-malignant arsenic (As)-induced skin lesions before and after 6 months daily oral supplementation of 200 microg L-selenomethionine. The Affymetrix GeneChip Human 133A 2.0 array, containing probes for 22,277 gene transcripts, was used to assess gene expression. Three different normalization methods, RMA (robust multi-chip analysis), GC-RMA and PLIER (Probe logarithmic intensity error), were applied to explore differentially expressed genes. We identified a list of 28 biologically meaningful, significantly differentially expressed genes. Genes up-regulated by selenium supplementation included TNF, IL1B, IL8, SOD2, CXCL2 and several other immunological and oxidative stress-related genes. When mapped to a biological association network, many of the differentially expressed genes were found to regulate functional classes such as fibroblast growth factor, collagenase, matrix metalloproteinase and stromelysin-1, and thus, considered to affect cellular processes like apoptosis, proliferation and others. Many of the significantly up-regulated genes following selenium-supplementation were previously found by us to be down-regulated in a different set of individuals with As-induced skin lesions compared to those without. In conclusion, findings from this study may elucidate the biological effect of selenium supplementation in humans. Additionally, this study suggests that long-term selenium supplementation may revert some of the gene expression changes presumably induced by chronic As exposure in individuals with pre-malignant skin lesions.

The aim of this study was to investigate the effect of combined therapy of vitamin E and selenomethionine to pro/antioxidant status in experimental hypercholesterolemia. Thirty male rabbits were included in the study and randomized into five groups consisting of the control group (standard diet) and four experimental groups staying on a diet rich in cholesterol (0.5 g/100 g diet): cholesterol group and groups supplemented cholesterol with selenomethionine (12.5 microg/kg body mass/24 h) or vitamin E (10 mg of DL-alpha-tocopherol/kg body mass/24 h) or combination of the above antioxidants for 3 mo. The activity of superoxide dismutase (SOD), glutathione peroxidase (GPX), and catalase (CAT) as well as the concentration of malondialdehyde (MDA) was estimated in the blood during every month of experiment. Increased activity of SOD and GPX with a decreased concentration of MDA in comparison to the cholesterol diet was found mainly in the combination of study antioxidants. The supplementation of the cholesterol diet with combined doses of vitamin E and selenomethionine appears to prevent the lesions induced by experimental hypercholesterolemia much more efficiently than single doses of the above.

Background: Oxidative stress, as measured by 8-iso-prostaglandin F(2)(alpha) (8-iso-PGF(2)(alpha)), and depleted antioxidant defenses were shown in stable cystic fibrosis (CF) patients. The plasma fatty acid status of CF patients was linked to oxidative stress after respiratory exacerbations., Objective: We examined changes in plasma 8-iso-PGF(2)(alpha), antioxidant defenses, plasma fatty acid status, and clinical markers resulting from short-term antioxidant supplementation., Design: Forty-six CF patients were randomly assigned to either group A [low dose of supplement (10 mg vitamin E and 500 micro g vitamin A)] or group B [high dose of supplement (200 mg vitamin E, 300 mg vitamin C, 25 mg beta-carotene, 90 micro g Se, and 500 micro g vitamin A)]. Plasma concentrations of 8-iso-PGF(2)(alpha), vitamins E and C, beta-carotene, zinc, selenium, and copper; plasma fatty acid composition; erythrocyte glutathione peroxidase (EC 1.11.1.9) and superoxide dismutase (EC 1.15.1.1) activities; lung function; and dietary intake were measured before and after 8 wk of supplementation., Results: Antioxidant defenses in group B improved, whereas those in group A did not: in groups B and A, the mean (+/- SEM) changes (Delta) in vitamin E were 10.6 +/- 1.5 and -1.9 +/- 0.9 micro mol/L, respectively (P < 0.001), (Delta)beta-carotene were 0.1 +/- 0.04 and -0.01 +/- 0.02 micro mol/L, respectively (P = 0.007), (Delta)selenium were 0.51 +/- 0.10 and -0.09 +/- 0.04 micro mol/L, respectively (P < 0.001), and (Delta)glutathione peroxidase activity were 1.3 +/- 0.3 and -0.3 +/- 0.6 U/g hemoglobin, respectively (P = 0.016). There were no significant differences between the groups in Delta8-iso-PGF(2)(alpha), (Delta)vitamin C, (Delta)fatty acid composition, (Delta)superoxide dismutase activity, (Delta)lung function, or (Delta)white cell count. Within group B, (Delta)beta-carotene correlated with (Delta)percentage of forced vital capacity (r = 0.586, P = 0.005), (Delta)selenium correlated with (Delta)percentage of forced expiratory volume in 1 s (r = 0.440, P = 0.046), and (Delta)plasma fatty acid concentrations correlated with (Delta)percentage of forced expiratory volume in 1 s (r = 0.583, P = 0.006) and Delta8-iso-PGF(2)(alpha) (r = 0.538, P = 0.010)., Conclusions: Whereas increased beta-carotene, selenium, and fatty acid concentrations are linked to improved lung function, increased plasma fatty acid concentrations are linked to oxidative stress. If oxidative stress is deemed to be important to the clinical outcome of CF patients, means of reducing oxidative stress while maintaining a high-fat, high-energy diet must be investigated.

Adverse effects of selenium (Se) in wild aquatic birds have been documented as a consequence of pollution of the aquatic environment by subsurface agricultural drainwater and other sources. These effects include mortality, impaired reproduction with teratogenesis, reduced growth, histopathological lesions and alterations in hepatic glutathione metabolism. A review is provided, relating adverse biological effects of Se in aquatic birds to altered glutathione metabolism and oxidative stress. Laboratory studies, mainly with an organic form of Se, selenomethionine, have revealed oxidative stress in different stages of the mallard (Anas platyrhynchos) life cycle. As dietary and tissue concentrations of Se increase, increases in plasma and hepatic GSH peroxidase activities occur, followed by dose-dependent increases in the ratio of hepatic oxidized to reduced glutathione (GSSG:GSH) and ultimately hepatic lipid peroxidation measured as an increase in thiobarbituric acid reactive substances (TBARS). One or more of these oxidative effects were associated with teratogenesis (4.6 ppm wet weight Se in eggs), reduced growth in ducklings (15 ppm Se in liver), diminished immune function (5 ppm Se in liver) and histopathological lesions (29 ppm Se in liver) in adults. Manifestations of Se-related effects on glutathione metabolism were also apparent in field studies in seven species of aquatic birds. Reduced growth and possibly immune function but increased liver:body weight and hepatic GSSG:GSH ratios were apparent in american avocet (Recurvirostra americana) hatchlings from eggs containing 9 ppm Se. In black-necked stilts (Himantopus mexicanus), which contained somewhat lower Se concentrations, a decrease in hepatic GSH was apparent with few other effects. In adult American coots (Fulica americana), signs of Se toxicosis included emaciation, abnormal feather loss and histopathological lesions. Mean liver concentrations of 28 ppm Se (ww) in the coots were associated with elevated hepatic GSH peroxidase, depletion of hepatic protein bound thiols and total thiols, but a small increase in GSH. Diving ducks in the San Francisco Bay area exhibited a positive correlation between hepatic Se concentration and GSH peroxidase activity (r=0.63, P<0.05), but a negative correlation between hepatic Se and GSH concentration (r=-0.740, P<0.05). In willets (Catoptrophorus semipalmatus) from the San Diego area, positive correlations occurred between hepatic Se concentration and GSSG (r=0.70, P<0.001), GSSG:GSH ratio, and TBARS. In emperor geese (Chen canagica) from western Alaska, blood levels of up to 9.4 ppm occurred and were associated with increased plasma GSH peroxidase activity (r=0.62, P<0.001), but with decreased plasma GSSG reductase activity. When evaluating Se toxicity, interactive nutritional factors, including other elements and dietary protein, should also be taken into consideration. Further studies are needed to examine the relationship between different forms of environmentally occurring selenium, arsenic and mercury on reproduction, hepatotoxicity and immune function of aquatic birds. Further selenium nutritional interaction studies may also help to illucidate the mechanism of selenium induced teratogenesis, by optimizing GSH and other antioxidant defense mechanisms in a manner that would stabilize or raise the cell's threshold for susceptibility to toxic attack from excess selenium. It is concluded that Se-related manifestations of oxidative stress may serve as useful bioindicators of Se exposure and toxicity in wild aquatic birds.

Effectiveness of selenium in different forms like sodium selenite, selenocysteine and selenomethionine has been compared in four different doses, namely 4, 6, 8 and 10 ppm of each, in terms of their bioavailability and prolongation of survival of Dalton's lymphoma (DL) bearing mice. Selenomethionine, at a dose of 8 ppm, was found to be the most bioavailable and least-cytotoxic form that was capable of increasing the life span of the tumour bearing hosts maximally (almost two-fold). Beneficiality of selenomethionine has also been studied by observing continuous changes brought about by this compound on the glutathione (GSH) level, glutathione peroxidase (GPx) activity and extent of lipid peroxidation in the hepatic tissue of the tumour bearing hosts, which are indispensable for a cell to function normally and are found to exhibit significantly altered behaviour in neoplastic cells. Selenomethionine caused the maintenance of high steady state GSH level and a normal GPx activity during the fist phase of tumour growth. It also controlled lipid peroxidation during the first 15-20 days following tumour transplantation. These conditions helped in the maintenance of intracellular redox balance, cellular integrity and metabolic rhythms of cells in DL bearing mice receiving selenomethionine.