Effects of hydroxy-selenomethionine on performance, innate immune system and antioxidant defense of tambaqui (Colossoma macropomum) exposed to a physical stressor.

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.

Selenium Modulates the Allergic Response to Whey Protein in a Mouse Model for Cow's Milk Allergy.

Cow's milk allergy is a common food allergy in infants, and is associated with an increased risk of developing other allergic diseases. Dietary selenium (Se), one of the essential micronutrients for humans and animals, is an important bioelement which can influence both innate and adaptive immune responses. However, the effects of Se on food allergy are still largely unknown. In the current study it was investigated whether dietary Se supplementation can inhibit whey-induced food allergy in an animal research model. Three-week-old female C3H/HeOuJ mice were intragastrically sensitized with whey protein and cholera toxin and randomly assigned to receive a control, low, medium or high Se diet. Acute allergic symptoms, allergen specific immunoglobulin (Ig) E levels and mast cell degranulation were determined upon whey challenge. Body temperature was significantly higher in mice that received the medium Se diet 60 min after the oral challenge with whey compared to the positive control group, which is indicative of impaired anaphylaxis. This was accompanied by reductions in antigen-specific immunoglobulins and reduced levels of mouse mast cell protease-1 (mMCP-1). This study demonstrates that oral Se supplementation may modulate allergic responses to whey by decreasing specific antibody responses and mMCP-1 release.

Selenium Kinetics in Humans Change Following 2 Years of Supplementation With Selenomethionine.

Background: Selenium (Se) is a nutritionally essential trace element and health may be improved by increased Se intake. Previous kinetic studies have shown differences in metabolism of organic vs. inorganic forms of Se [e.g., higher absorption of selenomethionine (SeMet) than selenite (Sel), and more recycling of Se from SeMet than Sel]. However, the effects on Se metabolism after prolonged Se supplementation are not known. Objective: To determine how the metabolism and transport of Se changes in the whole-body in response to Se-supplementation by measuring Se kinetics before and after 2 years of Se supplementation with SeMet. Methods: We compared Se kinetics in humans [n = 31, aged 40 ± 3 y (mean ± SEM)] studied twice after oral tracer administration; initially (PK1), then after supplementation for 2 y with 200 µg/d of Se as selenomethionine (SeMet) (PK2). On each occasion, we administered two stable isotope tracers of Se orally: SeMet, the predominant food form, and selenite (Na276SeO3, or Sel), an inorganic form. Plasma and RBC were sampled for 4 mo; urine and feces were collected for the initial 12 d of each period. Samples were analyzed for tracers and total Se by isotope dilution GC-MS. Data were analyzed using a compartmental model, we published previously, to estimate fractional transfer between pools and pool masses in PK2. Results: We report that fractional absorption of SeMet or Sel do not change with SeMet supplementation and the amount of Se absorbed increased. The amount of Se excreted in urine increases but does not account for all the Se absorbed. As a result, there is a net incorporation of SeMet into various body pools. Nine of the 11 plasma pools doubled in PK2; two did not change. Differences in metabolism were observed for SeMet and Sel; RBC uptake increased 247% for SeMet, urinary excretion increased from two plasma pools for Sel and from two different pools for SeMet, and recycling to liver/tissues increased from one plasma pool for Sel and from two others for SeMet. One plasma pool increased more in males than females in PK2. Conclusions: Of 11 Se pools identified kinetically in human plasma, two did not increase in size after SeMet supplementation. These pools may be regulated and important during low Se intake.

Protective effect of selenomethionine on T-2 toxin-induced liver injury in New Zealand rabbits.

BACKGROUND: T-2 toxin is a mycotoxin produced by Fusarium species that is highly toxic to animals. Recent studies have indicated that Selenomethionine (SeMet) have protective effect against mycotoxins-induced toxicity. The aim of the present study was to investigate the protective effect of SeMet on T-2-toxin-induced liver injury in rabbit and explore its molecular mechanism. Fifty rabbits (30 d, 0.5 ± 0.1 kg) were randomly divided into 5 groups: control group, T-2 toxin group, low, medium and high dose SeMet treatment group. The SeMet-treated group was orally pretreated with SeMet (containing selenium 0.2 mg/kg, 0.4 mg/kg and 0.6 mg/kg) for 21 days. On the 17th day, T-2 toxin group and SeMet-treated group were orally administered with T-2 toxin (0.4 mg/kg body weight) for 5 consecutive days. RESULTS: The results showed that low-dose SeMet significantly improved T-2 toxin-induced liver injury. We found that low-dose SeMet can reduce the level of oxidative stress and the number of hepatocyte apoptosis. Moreover, the levels of Bax, caspase-3 and caspase-9 were significantly reduced and the levels of Bcl-2 were increased. CONCLUSIONS: Therefore, we confirmed that low-dose SeMet may protect rabbit hepatocytes from T-2 toxin by inhibiting the mitochondrial-caspase apoptosis pathway.

Selenomethionine administration decreases the oxidative stress induced by post mortem ischemia in the heart, liver and kidneys of rats.

Selenium is an essential element in human and animal metabolism integrated into the catalytic site of glutathione peroxidase (GPX1), an antioxidant enzyme that protects cells from damage caused by reactive oxygen species (ROS). Oxidative stress refers the imbalance between ROS and antioxidant defense systems. It generates alterations of DNA, proteins and lipid peroxidation. The imbalance occurs particularly during ischemia and lack of postmortem perfusion. This mechanism is of relevance in transplant organs, affecting their survival. The aim of this research is to evaluate the effect of seleno-methionine (SeMet) as a protective agent against postmortem ischemia injury in transplant organs. Wistar rats were orally administered with SeMet. After sacrifice, liver, heart and kidney samples were collected at different postmortem intervals (PMIs). SeMet administration produced a significant increase of Se concentration in the liver (65%, p < 0.001), heart (40%, p < 0.01) and kidneys (45%, p < 0.05). Levels of the oxidative stress marker malondialdehyde (MDA) decreased significantly compared to control in the heart (0.21 ± 0.04 vs. 0.12 ± 0.02 mmol g-1) and kidneys (0.41 ± 0.02 vs. 0.24 ± 0.03 mmol g-1) in a PMI of 1-12 h (p < 0.01). After SeMet administration for 21 days, a significant increase in GPX1 activity was observed in the liver (80%, p < 0.001), kidneys (74%, p < 0.01) and heart (35%, p < 0.05). SeMet administration to rats significantly decreased the oxidative stress in the heart, liver and kidneys of rats generated by postmortem ischemia.

Selenium supplementation inhibits IGF-1 signaling and confers methionine restriction-like healthspan benefits to mice.

Methionine restriction (MR) dramatically extends the healthspan of several organisms. Methionine-restricted rodents have less age-related pathology and increased longevity as compared with controls, and recent studies suggest that humans might benefit similarly. Mechanistically, it is likely that the decreased IGF-1 signaling that results from MR underlies the benefits of this regimen. Thus, we hypothesized that interventions that decrease IGF-1 signaling would also produce MR-like healthspan benefits. Selenium supplementation inhibits IGF-1 signaling in rats and has been studied for its putative healthspan benefits. Indeed, we show that feeding mice a diet supplemented with sodium selenite results in an MR-like phenotype, marked by protection against diet-induced obesity, as well as altered plasma levels of IGF-1, FGF-21, adiponectin, and leptin. Selenomethionine supplementation results in a similar, albeit less robust response, and also extends budding yeast lifespan. Our results indicate that selenium supplementation is sufficient to produce MR-like healthspan benefits for yeast and mammals.

The mixed application of organic and inorganic selenium shows better effects on incubation and progeny parameters.

This experiment aims to study the effects of dietary selenium (Se) sources on the production performance, reproductive performance, and maternal effect of breeder laying hens. A total of 2,112 Hyline brown breeder laying hens of 42 wk of age were selected and randomly divided into 3 groups, with 8 repeats in each group and 88 chickens per repeat. The sources of dietary Se were sodium selenite (SS, added at 0.3 mg/kg), L-selenomethionine (L-SM, added at 0.2 mg/kg), and combination of SS and L-SM (SS 0.15 mg/kg + L-SM 0.15 mg/kg). The pretest period was 7 d, and the breeding period was 49 d. Compared with 0.3 mg/kg SS, the addition of 0.2 mg/kg L-SM in the diet significantly increased the hatchability (P < 0.05) and the Se content (P < 0.05) in egg yolk and chicken embryo tissues and improved the activity of yolk glutathione peroxidase (GSH-px) effectively (P < 0.05). Treatment with 0.2 mg/kg L-SM also reduced the content of yolk malondialdehyde (P < 0.05) and significantly improved the antioxidant performance of 1-day-old chicks, as manifested by increased activity of antioxidant enzymes (GSH-px, total antioxidant capacity and the ability to inhibit hydroxyl radicals) in serum, pectoral, heart, and liver (P < 0.05). This treatment decreased the malondialdehyde content (P < 0.05) and increased the expression of liver glutathione peroxidase 4 and deiodinase 1 mRNA (P < 0.05). Adding L-SM to the diets of chickens increased the hatchability of breeder eggs as well as the amount of Se deposited and antioxidant enzyme activity in breeder eggs and embryos. Compared with SS, L-SM was more effectively transferred from the mother to the embryo and offspring, showing efficient maternal nutrition. For breeder diets, the combination of organic and inorganic Se (0.15 mg/kg SS + 0.15 mg/kg L-SM) is an effective nutrient supplementation technology program for effectively improving the breeding performance of breeders and the antioxidant performance and health level of offspring chicks.

NLRP3 Inflammasome: A New Pharmacological Target for Reducing Testicular Damage Associated with Varicocele.

Many bioactive natural compounds are being increasingly used for therapeutics and nutraceutical applications to counteract male infertility, particularly varicocele. The roles of selenium and Polydeoxyribonucleotide (PDRN) were investigated in an experimental model of varicocele, with particular regard to the role of NLRP3 inflammasome. Male rats underwent sham operation and were daily administered with vehicle, seleno-L-methionine (Se), PDRN, and with the association Se-PDRN. Another group of rats were operated for varicocele. After twenty-eight days, sham and varicocele rats were sacrificed and both testes were weighted and analyzed. All the other rats were challenged for one month with the same compounds. In varicocele animals, lower testosterone levels, testes weight, NLRP3 inflammasome, IL-1ß and caspase-1 increased gene expression were demonstrated. TUNEL assay showed an increased number of apoptotic cells. Structural and ultrastructural damage to testes was also shown. PDRN alone significantly improved all considered parameters more than Se. The Se-PDRN association significantly improved all morphological parameters, significantly increased testosterone levels, and reduced NLRP3 inflammasome, caspase-1 and IL-1ß expression and TUNEL-positive cell numbers. Our results suggest that NLRP3 inflammasome can be considered an interesting target in varicocele and that Se-PDRN may be a new medical approach in support to surgery.

Protective effect of selenomethionine on intestinal injury induced by T- 2 toxin.

T-2 toxin is the most toxic as a type A trichothecenes, which could contaminate grains, especially in wheat and corn. It can cause immune suppression, neurotoxicity, the apoptosis of cells and even induce tumorigenesis. Recent studies have indicated that selenium (Se) have protective effect against mycotoxins-induced toxicity. The present studies was designed to investigate the protective role of Selenomethionine (SeMet) on T-2 toxin-induced toxicity in rabbit's jejunum. 50 New Zealand rabbits were divided into five group (Control group, T-2 group, low-dose Se + T-2 group, medium-dose + T-2 group and high-dose Se + T-2 group). New Zealand rabbits were orally administered with SeMet (0.2, 0.4 and 0.6 mg/kg, Adding diet) for 21 days. On 17th days, each group began to take 0.4 mg/kg of T-2 toxin orally every day for 5 days. We found that rabbit exposed to T-2 toxin could increase the levels of ROS, and decrease activities of antioxidant enzymes and the expression of Occludin and ZO-1. In addition, T-2 toxin could trigger jejunal inflammatory response and enhance the expression of IL-1ß, IL-6 and TNF-α. After SeMet pretreatment, our results indicated that Se attenuated the T-2 toxin-induced oxidative stress, decreasing the level of ROS, MDA and enhancing the activity of SOD and GSH-Px. Moreover, SeMet can alleviate jejunal inflammatory response, and protect the integrity of the intestinal barrier through up-regulating the expression of ZO-1 and Occludin. In the present research, supplementation of 0.2 mg/kg SeMet in the diet could effectively alleviate the T-2 toxin poisoning in rabbits.

Hyperprolactinaemia attenuates the inhibitory effect of vitamin D/selenomethionine combination therapy on thyroid autoimmunity in euthyroid women with Hashimoto's thyroiditis: A pilot study.

WHAT IS KNOWN AND OBJECTIVE: Vitamin D administered together with selenomethionine has been reported to markedly reduce thyroid antibody titres in patients with autoimmune thyroiditis. Hyperprolactinaemia exerts a complex pro-inflammatory effect. This study was aimed at investigating whether prolactin excess determines the effect of vitamin D/selenomethionine combination therapy on thyroid autoimmunity. METHODS: The study included two age-, body mass index-, hormone- and thyroid antibody-matched groups of young euthyroid women with Hashimoto's thyroiditis: 19 women with mild-to-moderate hyperprolactinaemia and 19 individuals with prolactin levels within the reference range. All participants were then treated with vitamin D (4000 IU daily) and selenomethionine (200 µg daily). Serum titres of thyroid peroxidase and thyroglobulin (TgAb) antibodies, serum levels of thyrotropin, free thyroxine, free triiodothyronine, prolactin and 25-hydroxyvitamin D, as well as the calculated parameters of thyroid homeostasis, were determined at baseline and 6 months later. RESULTS AND DISCUSSION: All women completed the study. With the exception of prolactin and 25-hydroxyvitamin D levels, there were no differences between the study groups in the investigated parameters. In both study groups, vitamin D/selenomethionine combination therapy reduced thyroid peroxidase and TgAb antibody titres, decreased the free thyroxine:free triiodothyronine ratio and increased 25-hydroxyvitamin D levels and SPINA-GD. The decrease in antibody titres, as well as the improvement in vitamin D status, was more pronounced in subjects with prolactin levels within the reference range than in subjects with hyperprolactinaemia and was inversely correlated with prolactin levels. Moreover, only in normoprolactinaemic women, the treatment reduced thyrotropin levels and increased SPINA-GT. WHAT IS NEW AND CONCLUSION: The obtained results suggest that hyperprolactinaemia attenuates the impact of vitamin D/selenomethionine combination on thyroid autoimmunity.

The Role of Selenium Mineral Trace Element in Exercise: Antioxidant Defense System, Muscle Performance, Hormone Response, and Athletic Performance. A Systematic Review.

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.

Targeted Metabolomics Analysis Reveals that Dietary Supranutritional Selenium Regulates Sugar and Acylcarnitine Metabolism Homeostasis in Pig Liver.

BACKGROUND: The association between high selenium (Se) intake and metabolic disorders such as type 2 diabetes has raised great concern, but the underlying mechanism remains unclear. OBJECTIVE: Through targeted metabolomics analysis, we examined the liver sugar and acylcarnitine metabolism responses to supranutritional selenomethionine (SeMet) supplementation in pigs. METHODS: Thirty-six castrated male pigs (Duroc-Landrace-Yorkshire, 62.0 ± 3.3 kg) were fed SeMet adequate (Se-A, 0.25 mg Se/kg) or SeMet supranutritional (Se-S, 2.5 mg Se/kg) diets for 60 d. The Se concentration, biochemical, gene expression, enzyme activity, and energy-targeted metabolite profiles were analyzed. RESULTS: The Se-S group had greater fasting serum concentrations of glucose (1.9-fold), insulin (1.4-fold), and free fatty acids (FFAs,1.3-fold) relative to the Se-A group (P < 0.05). The liver total Se concentration was 4.2-fold that of the Se-A group in the Se-S group (P < 0.05), but expression of most selenoprotein genes and selenoenzyme activity did not differ between the 2 groups. Seven of 27 targeted sugar metabolites and 4 of 21 acylcarnitine metabolites significantly changed in response to high SeMet (P < 0.05). High SeMet supplementation significantly upregulated phosphoenolpyruvate carboxy kinase (PEPCK) activity by 64.4% and decreased hexokinase and succinate dehydrogenase (SDH) activity by 46.5-56.7% (P < 0.05). The relative contents of glucose, dihydroxyacetone phosphate, α-ketoglutarate, fumarate, malate, erythrose-4-phosphate, and sedoheptulose-7-phosphate in the Se-S group were 21.1-360% greater than those in the Se-A group (P < 0.05). The expression of fatty acid synthase (FASN) and the relative contents of carnitine, hexanoyl-carnitine, decanoyl-carnitine, and tetradecanoyl-carnitine in the Se-S group were 35-97% higher than those in the Se-A group (P < 0.05). CONCLUSIONS: Dietary high SeMet-induced hyperglycemia and hyperinsulinemia were associated with suppression of sugar metabolism and elevation of lipid synthesis in pig livers. Our research provides novel insights into high SeMet intake-induced type 2 diabetes.

Ameliorative Effect of Selenomethionine on Cadmium-Induced Hepatocyte Apoptosis via Regulating PI3K/AKT Pathway in Chickens.

Selenium (Se) is a trace element for human and animal health. Cadmium (Cd) is a known human carcinogen. The effects of Cd on the environment and humans are well known. Because chickens are at the top of the food chain, it is a good experimental animal model for assessing heavy metal toxicity and its potential threat to humans. Selenomethionine (Se-met) is a suitable form for nutritional Se supplementation. Therefore, the toxicity of Cd to the chicken liver and the antagonistic effects of Se-met on Cd were examined at the molecular level in the present study. The results showed that oxidative stress indicators (apoptosis-related genes, P13K/AKT pathway-related genes, and heat shock proteins (HSPs)-related genes) in the Cd group have changed significantly, indicating Cd induced hepatocyte stress and apoptosis. Interestingly, the changes in oxidative stress indicators (apoptosis-related genes, P13K/AKT pathway-related genes, and HSPs-related genes) in the Cd-Se-met group were mitigated compared with the control group. Our results indicated that Cd can induce hepatocyte apoptosis and stress in the chickens. Se-met has an ameliorative effect on Cd-induced apoptosis of chicken hepatocyte by regulating PI3K/AKT pathway. Our findings will provide a new insight for better understanding of the detoxification function of Se-met to heavy metals.

Selenium supplementation in patients with subclinical hypothyroidism affected by autoimmune thyroiditis: Results of the SETI study.

OBJECTIVE: The purpose of this prospective study was to assess the effects of selenium supplementation on TSH and interferon-γ inducible chemokines (CXCL9, CXCL10 and CXCL11) levels in patients with subclinical hypothyroidism due to Hashimoto's thyroiditis. PATIENTS AND METHODS: Patients with subclinical hypothyroidism due to Hashimoto thyroiditis were prospectively enrolled in the SETI study. They received 83mcg of selenomethionine/day orally in a soft gel capsule for 4 months with water after a meal. No further treatment was given. All patients were measured thyroid hormone, TPOAb, CXCL9, CXCL10, CXCL11, iodine, and selenium levels at baseline and at study end. RESULTS: 50 patients (43/7 female/male, median age 43.9±11.8 years) were enrolled, of which five withdrew from the study. At the end of the study, euthyroidism was restored in 22/45 (48.9%) participants (responders), while 23 patients remained hypothyroid (non-responders). There were no significant changes in TPOAb, CXCL9, CXCL10, CXCL11, and iodine levels from baseline to the end of the study in both responders and non-responders. TSH levels were re-tested six months after selenomethionine withdrawal: 83.3% of responding patients remained euthyroid, while only 14.2% of non-responders became euthyroid. CONCLUSIONS: The SETI study shows that short-course supplementation with selenomethionine is associated to a normalization of serum TSH levels which is maintained 6 months after selenium withdrawal in 50% of patients with subclinical hypothyroidism due to chronic autoimmune thyroiditis. This TSH-lowering effect of selenium supplementation is unlikely to be related to changes in humoral markers of autoimmunity and/or circulating CXCL9.

Injectable organic and inorganic selenium in dairy cows - Effects on milk, blood and somatic cell count levels.

Mastitis is the most costly disease of dairy cows. A pro-active approach includes insuring adequate levels of selective trace minerals. The aim of this study was to determine the effect of two different commercially available, injectable selenium products, (sodium) Na-selenite (inorganic) and (selenium) Se-methionine (organic), on milk composition and on serum and milk selenium concentrations in high-yielding Holstein cows on total mix ration. Sixty multiparous cows were randomly selected into three groups of 20, one control group and two groups supplemented with injectable trace minerals. Blood and milk samples were collected over a period of 60 days. No specific change was indicated in milk yield, lactose, milk urea nitrogen (MUN) and milk pH levels compared with baseline values. The Se-methionine supplemented group showed a numerical increase in total milk protein percentage. In the group injected with Se-methionine, a negative correlation was present for the initial 72 hours between serum selenium concentration and somatic cell count (SCC) and a highly significant (p 0.001) increase in milk selenium concentration for the initial 24 hours. Serum selenium concentration of Se-methionine-supplemented cows was however not significantly changed. Injection of Na-selenite led to a 60-day initial increase in serum selenium concentration above baseline levels and a significant milk selenium concentration on day 1 but to a negative correlation between serum selenium concentration and SCC. Differences in serum and milk selenium concentrations followed with the use of organic and inorganic selenium injectables. Injectable Na-selenite, as selenium, can be of important value for cattle farmers if supplemented on strategically physiological periods to improve production, reproduction and immunity.

In ovo exposure of fathead minnow (Pimephales promelas) to selenomethionine via maternal transfer and embryo microinjection: A comparative study.

Selenium (Se) is an essential trace element of concern that is known to contaminate aquatic ecosystems as a consequence of releases from anthropogenic activities. Selenium is of particular toxicological concern for egg-laying vertebrates as they bioaccumulate Se through the diet and deposit excess Se to embryo-offspring via maternal transfer, a process which has been shown to result in significant teratogenic effects. The purpose of the present study was to determine and compare the in ovo effects of Se exposure on early development of a laboratory model fish species native to North American freshwater systems, the fathead minnow (Pimephales promelas), through two different exposure routes, maternal transfer and microinjection. For maternal transfer studies, fathead minnow breeding groups (3 females: 2 males) were exposed to diets containing Se-background levels (1.21 µg Se/g food, dry mass [dm]) or environmentally relevant concentrations of selenomethionine (SeMet; 3.88, 8.75 and 26.5 µg Se/g food dm) and bred for 28 days. Embryos were collected at different time points throughout the study to measure Se concentrations and to assess teratogenicity in embryos. While exposure to dietary Se did not negatively affect fecundity among treatment groups, the lowest treatment group (3.88 µg Se/g food dm) produced on average the most embryos per day, per female. The maternal transfer of excess Se occurred rapidly upon onset of exposure, reaching steady-state after approximately 14 days, and embryo Se concentrations increased in a dose-dependent manner. The greatest concentrations of maternally transferred Se significantly increased the total proportion of deformed embryo-larval fathead minnows but did not impact hatchability or survival. In a second study, fathead minnow embryos were injected with SeMet at concentrations of 0.00 (vehicle control), 9.73, 13.5 and 18.9 µg Se/g embryo dm. Microinjection of SeMet did not affect hatchability but significantly increased the proportion of deformed embryo-larval fish in a dose-dependent manner. There was a greater proportion of deformed fathead minnows at embryo Se concentrations of 18.9 µg Se/g embryo dm when exposed via microinjection versus maternal transfer at concentrations of 28.4 µg Se/g embryo dm. However, the findings suggest that both exposure routes induced analogous developmental toxicities in early life stage fish at Se concentrations between 9.73 and 13.5 µg Se/g embryo dm. Overall, this study demonstrated that microinjection has utility for studying the effects of Se in embryo-larval fish and is a promising method for the study of early life stage Se exposure in egg-laying vertebrates.

Varied doses and chemical forms of selenium supplementation differentially affect mouse intestinal physiology.

In this study, the effects of three doses (diets containing <0.01, 0.15, 0.40 mg kg-1 Se) and two forms (sodium selenite and selenomethionine) of dietary Se supplementation on the intestinal physiology of untreated, dextran sodium sulfate-treated, and Salmonella typhimurium-infected mice were evaluated. The underlying modes of action of the varied doses and forms of Se supplementation were analyzed using fecal metabolomic and jejunal proteomic approaches. Compared with adequate Se (0.15 mg kg-1 Se) supplementation, Se-deficiency supplementation adversely affected the gut barrier and intestinal immune responses of the untreated mice and increased their susceptibility to experimental colitis and pathogen infection. In contrast, supranutritional Se (0.40 mg kg-1 Se) supplementation improved mouse intestinal physiology compared with adequate Se supplementation. Varied doses of Se supplementation differentially perturbed the fecal metabolic profiles of and jejunal protein expression in mice. Further, both forms of dietary Se supplementation, i.e., sodium selenite and selenomethionine, showed similar effects on the gut barrier and intestinal immune homeostasis but differentially affected fecal metabolites, such as neurosubstances and immunomodulators, and induced significant proteomic variations in various pathways, including the xenobiotic detoxification pathway and glutathione metabolism. Our results indicate that the doses and chemical forms of Se should be considered when developing dietary nutritional supplements for gut health.

Feed-to-Fillet Transfer of Selenite and Selenomethionine Additives to Plant-Based Feeds to Farmed Atlantic Salmon Fillet.

This study investigated the transfer kinetics of dietary selenite and selenomethionine (SeMet) to the fillet of farmed Atlantic salmon (Salmo salar). The uptake and elimination rate constants of the two selenium (Se) forms were determined in Atlantic salmon fed either selenite- or SeMet-supplemented diets followed by a depuration period. The fillet half-life of selenite and SeMet was 779 ± 188 and 339 ± 103 days, respectively. The elimination and uptake rates were used in a simple one-compartmental kinetic model to predict levels in fillet based on long-term (whole production cycle) feeding with given dietary Se levels. Model predictions for Atlantic salmon fed plant-based feeds low in natural Se and supplemented with either 0.2 mg of selenite or SeMet kg-1 gave a predicted fillet level of 0.042 and 0.058 mg Se kg-1 wet weight, respectively. Based on these predictions and the European Food Safety Authority risk assessment of Se feed supplementation for food-producing terrestrial farm animals, the supplementation with 0.2 mg of selenite kg-1 would likely be safe for the most sensitive group of consumers (toddlers). However, supplementing feed to farm animals, including salmon, with 0.2 mg of SeMet kg-1 would give a higher (114%) Se intake than the safe upper intake limit for toddlers.

Selenomethionine as a dietary supplement for laying hens: Impacts on lipid peroxidation and antioxidant capacity in fresh and stored eggs.

The objective of this study was to determine whether supplementing the diets of laying hens with selenomethionine (SM, 1% selenium) improves performance and egg quality. We supplemented diets with SM as follows: T0 control (without SM); T5, T10, T15, and T20 were supplemented with 5, 10, 15, and 20 mg of SM/kg of feed, respectively (equal to 0.05, 0.10, 0.15, and 0.20 mg selenium/kg of feed). T5 and T10 hens showed better feed conversion per kg of egg, percentage of laying, higher daily feed intake, and higher average egg weight. The eggs of hens supplemented with SM had lower levels of lipoperoxidation (LPO) in fresh (T15 and T20) and stored eggs (T20). Glutathione peroxidase (GPx) and superoxide dismutase (SOD) activities, as well as total antioxidant capacity were greater in egg yolks after storage (T10; T15; T20 compared to T0). Hens supplemented with SM had elevated GPx and SOD activities and decreased oxidative reactions. PRACTICAL APPLICATIONS: Selenium has several nutraceutical properties, with beneficial effects on the health of the animal and the food produced from them (eggs, in this case). Selenomethionine supplementation in the diet of laying hens improves productive efficiency, stimulates the antioxidant system and reduces lipid peroxidation in the egg yolk. Egg-laying hens that received selenomethionine showed minimized lipid peroxidation in stored eggs, possibly improving shelf life of the eggs.

Effects of different levels of dietary hydroxy-analogue of selenomethionine on growth performance, selenium deposition and antioxidant status of weaned piglets.

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.