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Se is an essential trace element associated with animal growth and antioxidant and metabolic processes. However, whether Se, especially organic Se with higher bioavailability, can alleviate the adverse effects of low salinity stress on marine economic crustacean species has not been investigated. Accordingly, juvenile Pacific white shrimp (Litopenaeus vannamei) were reared in two culture conditions (low and standard salinity) fed diets supplemented with increasing levels of l-selenomethionine (0·41, 0·84 and 1·14 mg/kg Se) for 56 d, resulting in four treatments: 0·41 mg/kg under standard seawater (salinity 31) and 0·41, 0·84 and 1·14 mg/kg Se under low salinity (salinity 3). The diet containing 0·84 mg/kg Se significantly improved the survival and weight gain of shrimp under low salinity stress and enhanced the antioxidant capacity of the hepatopancreas. The increased numbers of B and R cells may be a passive change in hepatopancreas histology in the 1·14 mg/kg Se group. Transcriptomic analysis found that l-selenomethionine was involved in the regulatory pathways of energy metabolism, retinol metabolism and steroid hormones. In conclusion, dietary supplementation with 0·84 mg/kg Se (twice the recommended level) effectively alleviated the effects of low salinity stress on L. vannamei by regulating antioxidant capacity, hormone regulation and energy metabolism. [ABSTRACT FROM AUTHOR]

Ammonia is a significant pollutant in the livestock houses and the atmospheric environment, and excessive ammonia would harm the health of livestock and breeders. Previous studies have shown that ammonia exposure could damage the tissue structure of the nervous system, but the molecular mechanism of ammonia-induced hypothalamus damage was still unclear. The purpose of this study was to determine the role of excessive ammonia in abnormal autophagy of pig hypothalamus and whether selenomethionine would have a mitigating effect on ammonia toxicity. Twenty-four 18-week pigs were randomly divided into four groups: the control group (C group), the selenium group (Se group), the ammonia + selenium group (A + Se group), and the ammonia group (A group). In our study, the expression levels of NF-κB, IL-1β, iNOS, TNF-α, IKK-α, p-IKK-α, Nrf2, ATG5, ATG 10, ATG 12, LC3 I/II, HSP60, HSP70, and HSP90 were increased after ammonia exposure; meanwhile, IFN-γ, IKB-α, p-IKB-α, Keap1, P62, mTOR, AKT, p-AKT, PI3K, SQSTM, and Beclin1 showed decreasing trends. The results indicated that excessive ammonia inhalation inhibited the AKT/mTOR pathway to acclerated autophagy through oxidative stress-mediated inflammation in the porcine hypothalamus. L-selenomethionine could alleviate hypothalamus injury induced by ammonia exposure. [ABSTRACT FROM AUTHOR]

Ammonia (NH3) is a harmful gas in livestock houses. So far, many researchers have demonstrated that NH3 is detrimental to animal and human organs. Selenium (Se) is one of the essential trace elements in the body and has a good antioxidant effect. However, there was little conclusive evidence that Se alleviated NH3 poisoning. To investigate the toxic mechanism of NH3 on pig spleen and the antagonistic effect of L-selenomethionine, a porcine NH3-poisoning model and an L-selenomethionine intervention model were established in this study. Our results showed that NH3 exposure increased the apoptosis rate, while L-selenomethionine supplementation alleviated the process of excessive apoptosis. Immunofluorescence staining, real-time quantitative polymerase chain reaction (qRT-PCR), and western blot results confirmed that exposure to NH3 changed the expression levels of interleukin family factors, apoptosis, death receptor, and oxidative stress factors. Our study further confirmed that excessive NH3 induced inflammatory response and mediated necroptosis leading to cell apoptosis by activating the Nrf2 signaling pathway. Excessive NH3 could mediate spleen injury through oxidative stress-induced mitochondrial dynamics disorder. L-Selenomethionine could alleviate inflammation and abnormal apoptosis by inhibiting the IL-17/TNF-α/FADD axis. Our study would pave the way for comparative medicine and environmental toxicology. [ABSTRACT FROM AUTHOR]

Ammonia has been reported to have a variety of toxicity to aquatic animals, farm animals and humans. However, its potential toxicity on the intestines remains unknown. L-selenomethionine is one of the important organic selenium sources. However, the mitigating effect of L-selenomethionine on ammonia exposure toxicity is still lacking. Therefore, in this study, the mechanism of toxic action of ammonia on intestinal tract and the detoxification effect of L-selenomethionine were examined. We evaluated the intestinal toxicity of ammonia and the alleviating effect of L-selenomethionine in an in vivo model, and then verified it in vitro model by a variety of cutting-edge experimental techniques. Our results showed that ammonia exposure causes oxidative stress, necroptosis, Th1/Th2 imbalance and inflammation in the intestinal tissue and the intestinal cells, and L-selenomethionine had a significant mitigation effect on the changes of these indexes induced by ammonia. In conclusion, ammonia exposure caused oxidative stress and Th1/Th2 imbalance in the porcine small intestine and IPEC-J2 cells, and that excessive ROS accumulation-mediated necroptosis targeted inflammatory responses, resulting in the destruction of tight connections of intestinal cells, thereby causing intestinal barrier dysfunction. L-selenomethionine could effectively reduce the intestinal injury caused by ammonia exposure and antagonize the toxic effect of ammonia.

L-Selenomethionine is one of the important organic selenium sources. The supplementation of L-selenomethionine in diets is significant to improve the health of pigs. Ammonia is a major pollutant in the atmosphere and piggery, posing a threat to human and animal health. Although ammonia exposure can damage the heart, the mechanism of cardiac toxicity by ammonia is still unknown. In this study, we investigated the mechanism of cardiac injury induced by ammonia exposure in pigs and the protective effect of L-selenomethionine on its cardiotoxicity. The results showed that the blood ammonia content of pig increased significantly in ammonia group, the expressions of energy metabolism-related genes (LDHA, PDK4, HK2, and CPTIB) and the oxidative stress indexes were significantly changed (P < 0.05), the AMPK/PPAR-γ/NF-κB signaling pathways were activated, the chromatin edge aggregation and nuclear pyknosis were observed in ultrastructure, the apoptotic cells were significantly increased (P < 0.05), and the mRNA and protein expressions of apoptosis-related genes (Bcl-2, Bax, Cyt-c, caspase-3, and caspase-9) were significantly affected (P < 0.05). The above changes were significantly alleviated in ammonia + L-selenomethionine group, but there were still significant differences compared with the C group (P < 0.05). Our results indicated that ammonia exposure could cause energy metabolism disorder and oxidative stress and induce apoptosis of cardiomyocytes through AMPK/PPAR-γ/NF-κB pathways, which could lead to cardiac injury and affect cardiac function. L-Selenomethionine could effectively alleviate the cardiac damage caused by ammonia and antagonize the cardiotoxicity of ammonia. [ABSTRACT FROM AUTHOR]

Ammonia (NH3) is a common air pollutant, which poses a serious threat to farm animals. L-selenomethionine is organic selenium (Se), which can inhibit intracellular ROS generation, block ROS-dependent autophagy, promote mitochondrial energy metabolism, and enhance the body's immunity. Lung, as an important organ of the respiratory system, is highly susceptible to the toxic effects of NH3. However, there were few studies on the mechanism of toxic effects of NH3 on lung tissues. The aim of this study was to investigate the effect of NH3 on the lungs in pigs and the alleviating effect of L-selenomethionine. Twenty-four Large White*Duroc*Min pigs were randomly assigned to 4 groups: control group, NH3 group, Se group, and NH3 +Se group. The results showed that exposure to NH3 caused damage and inflammation in lung tissues and significantly increased blood NH3 concentration. NH3 induced changes of oxidative stress indexes (GSH, GSH-Px, SOD, MDA, Keap1, Nrf2, and HO-1) and expressions of energy metabolism related genes (HK1, HK2, PFK, PK, LDHA, and HIF-1α). Ultrastructure showed that mitochondrial damage and autophagosome increased significantly, and the expression levels of autophagy related genes (Beclin1, ATG5, ATG7, ATG10, and p62) changed. However, the addition of L-selenomethionine alleviated the above changes, but there was still a significant difference compared with the control group (P

Ammonia (NH3) is a hazardous substance to human and animal health. Selenium (Se) is an essential micronutrient with multiple health benefits. The present study aimed to verify whether and how Se supplementation has a protective role against NH3 mediated-nephrotoxicity in pigs. A Se-NH3 interaction model was established in pigs and the kidney samples were collected after a 30-day treatment period. The results showed that NH3 exposure inhibited the PI3K/AKT/mTOR pathway and enhanced the secretion of inflammatory cytokines to induce autophagy and inflammation. Se can regulate the PI3K/AKT/mTOR pathway and attenuate the secretion of inflammatory cytokines altered by NH3 to reduce autophagy and inflammation. In addition, Se co-treatment inhibited ROS production, elevated the activities of antioxidant systems, and increased the expression of 13 selenoproteins in pig kidneys caused by NH3 exposure. These results implied that L-selenomethionine can moderate NH3-induced nephrotoxicity in pigs. Our study gives new ideas for the specific mechanism of NH3 nephrotoxicity and provides a reference for comparative medicine and clinical medication.

Selenium is an essential trace element for humans and other vertebrates, playing an important role in antioxidant defense, neurobiology and reproduction. However, the toxicity of excessive selenium has not been thoroughly evaluated, especially for the visual system of vertebrates. In this study, fertilized zebrafish embryos were treated with 0.5 µM L-selenomethionine to investigate how excessive selenium alters zebrafish eye development. Selenium-stressed zebrafish embryos showed microphthalmia and altered expression of genes required for retinal neurogenesis. Moreover, ectopic proliferation, disrupted mitochondrial morphology, elevated ROS-induced oxidative stress, apoptosis and ferroptosis were observed in selenium-stressed embryos. Two antioxidants—reduced glutathione (GSH) and N-acetylcysteine (NAC)—and the ferroptosis inhibitor ferrostatin (Fer-1) were unable to rescue selenium-induced eye defects, but the ferroptosis and apoptosis activator cisplatin (CDDP) was able to improve microphthalmia and the expression of retina-specific genes in selenium-stressed embryos. In summary, our results reveal that ferroptosis and apoptosis might play a key role in selenium-induced defects of embryonic eye development. The findings not only provide new insights into selenium-induced cellular damage and death, but also important implications for studying the association between excessive selenium and ocular diseases in the future. [ABSTRACT FROM AUTHOR]

Ammonia (NH3) is a major pollutant in livestock houses and atmospheric environment. It has been demonstrated that NH3 can cause a series of damage to animals and human. However, toxicity evaluation of NH3 on farm animals was rarely reported, especially in the intestinal microflora. Therefore, in this study, twenty-four 125-day-old fattening pigs were randomly divided into 4 groups: control group, NH3 group (88.2 mg m−3

Selenium deficiency is associated with many physiological disorders including the high risk of cancer. The rehabilitation of selenium with different selenium supplements, however, fails due to their low therapeutic index. Therefore, it is advantageous to have a less toxic form of selenium for supplementation with potentially high anticancer activity. Here we show Bacillus licheniformis derived biogenic selenium nanoparticles at a minimal concentration of 2 μg Se/ml induce necroptosis in LNCaP-FGC cells, without affecting the RBC integrity. Real-time gene expression analysis indicated the overexpression of tumor necrotic factor (TNF) and interferon regulatory factor (IRF1) and decreased expression of androgen receptor (AR) and prostate-specific antigen (PSA). Furthermore, histopathological analysis showed the subsequent oral administrations of 10 times higher concentration of these endotoxin free selenium nanoparticles in C3H/HeJ mice (50 mg Se/kg of body weight), induce significantly lower toxicity compared to the L-selenomethionine (5 mg Se/kg). Our study suggested that the biogenic SeNP could emerge as the safest form of selenium supplementation with potent anticancer activity. [ABSTRACT FROM AUTHOR]

Purpose: Selenium is frequently in nutraceuticals for pregnancy, given its role on fertility and thyroid metabolism. However, most evidence rise from non-controlled studies. We aimed to evaluate the protective effect of selenium against thyroid autoimmunity during and after pregnancy. Methods: A multicenter, randomized, double-blind, placebo-controlled trial was performed and promoted by the Young Italian Endocrinologists Group (EnGioI)—Italian Society of Endocrinology. Forty-five women with thyroiditis in pregnancy were enrolled and randomly assigned to L-selenomethionine (L-Se-Met) 83 mcg/day or placebo (PLB) and evaluated at 10 ± 2 (T1), 36 ± 2 weeks of gestation (T2) and 6 months after delivery (postpartum, PP). Results: We measured a significant reduction of autoantibodies after pregnancy in L-Se-Met group [at PP: TgAb 19.86 (11.59–52.60), p < 0.01; TPOAb 255.00 (79.00–292.00), p < 0.01], and an antibodies titer's rebound in PLB group (TgAb 151.03 ± 182.9, p < 0.01; TPOAb 441.28 ± 512.18, p < 0.01). A significant increase in selenemia was measured in L-Se-Met group at T2 (91.33 ± 25.49; p < 0.01) and PP (93.55 ± 23.53; p = 0.02). Two miscarriage occurred in PLB. No differences were found in thyroid volume, echogenicity, quality of life, maternal/fetal complications. Conclusions: SERENA study demonstrated a beneficial effect of L-Se-Met supplementation on autoantibody titer during pregnancy and on postpartum thyroiditis recurrence. [ABSTRACT FROM AUTHOR]

The effect of selenium (Se) on the reproductive system has been investigated in both humans and vertebrates, but few studies of female fertility and reproduction in invertebrate have been reported. This study is aimed to investigate the effect of SeMet on growth performance and reproductive system after crayfish were fed with graded levels of dietary SeMet (0, 1.49, 3.29, 10.02, 30.27 or 59.8 μg Se/g dry weight) for 60 days. Crayfish treated with the high levels of SeMet (10.02, 30.27 and 59.76 μg Se/g) exhibited decreasing FW and CL in both male and female. Interestingly, Se accumulation was higher in ovary than in other tissues, suggesting that ovary may serve as a target organ for Se accumulation. We found that dietary Se concentration of 10.02 μg Se/g significantly improved the spawning rate, promoted the synchronized spawning, and up-regulated the expressions of mRNA of cdc2 and vitellogenin , with significantly increased E2 and VTG concentrations in hemolymph of female crayfish. However, a marked decrease of the E2 contents and spawning rate was observed in the groups treated with 30.27 and 59.76 μg Se/g diets. In conclusion, the results of this study indicated that the Se had maximum accumulation in ovary, affecting the reproductive capacity by intervening the expression of cdc2 and vitellogenin in the reproductive system. The LOAEL to induce FW was observed in crayfish fed with 10.02 μg Se/g diet, and its value can cause toxicity within the range of natural concentration, so the addition of Se in the feed should be within 10.02 μg Se/g. Image 1 • Se accumulation was higher in ovary than in other tissues. • The LOAEL to induce FW was 10.02 μg Se/g diet. • Se intervened the expression of some key genes in the reproductive system. • High concentration of Se produced reproductive toxicity on female crayfish. The LOAEL to induce FW was observed in crayfish fed with 10.02 μg Se/g diet, and its value can cause toxicity within the range of natural concentration, so the addition of Se in the feed should be within 10.02 μg Se/g. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Abstract A field study in periparturient sows fed different dietary concentrations of either sodium selenite or L-selenomethionine (SeMet) was conducted to evaluate feed intake, haematological and biochemical parameters as well as to describe some key selenium (Se) species, namely selenoprotein P (SelP), selenoalbumin (SeAlb) and selenomethionine (SeMet) as well as total Se in plasma, colostrum and milk. Thirty-two sows were allotted to four treatments from 30 days (d) prepartum throughout on average a 32 d lactation period. Sodium selenite supplemented diets contained 0.40 and 0.60 mg Se/kg feed, while SeMet supplemented feed contained 0.26 and 0.43 mg Se/kg feed. Concentrations of sodium selenite and SeMet in complete feed exceeded the upper limits for total dietary Se and added organic Se, respectively, according to the European Union legislation. Blood samples were collected at initiation of the study, at farrowing and at weaning. Colostrum samples were collected at farrowing and milk samples at weaning. Se species were subjected to liquid chromatography, and total Se and Se species were determined using inductively coupled plasma mass spectrometry. The SeMet supplemented diets resulted in higher feed intake and in higher levels of total Se, SelP, SeAlb and SeMet in colostrum compared with sows fed sodium selenite. Similar results were obtained for levels of total Se and SeMet in milk at weaning. The higher dietary sodium selenite concentration in sows' feed did not increase the Se transfer into colostrum or milk when compared with those receiving the lower level of sodium selenite. However, the increase in serum-Zn from initiation until farrowing, observed in sows fed SeMet as well as the higher glutamate dehydrogenase activity in sodium selenite supplemented sows in this period might indicate a higher requirement of antioxidant defence in sodium selenite-supplemented sows. To our knowledge, the present data on Se species in plasma, colostrum and milk of sows represent the most complete investigation of Se in sows conducted to date. A higher amount of the above-mentioned Se species in the colostrum of sows supplemented with SeMet might strengthen the piglets' antioxidative system and passive immunity as well as improve their average daily weight gain. The higher feed intake in sows fed diets supplemented with SeMet is an interesting finding that warrants further investigation. [ABSTRACT FROM AUTHOR]

Summary: What is known and objective: Although a beneficial effect of selenium (Se) administration has been proposed in adults with autoimmune thyroiditis (AT), there is a paucity of similar data in children and adolescents. The purpose of the study was to investigate whether administration of a high dose of organic Se (200 μg daily as l‐selenomethionine) has an effect on antithyroid antibody titres in children and adolescents with AT. Methods: Seventy‐one (71) children and adolescents, with a mean age of 11.3 ± 0.3 years (range 4.5‐17.8), diagnosed with AT (antibodies against thyroid peroxidase [anti‐TPO] and/or thyroglobulin [anti‐Tg] ≥60 IU/mL, euthyroidism or treated hypothyroidism and goitre in thyroid gland ultrasonography) were randomized to receive 200 μg l‐selenomethionine or placebo daily for 6 months. Blood samples were drawn for measurement of serum fT4, TSH, anti‐TPO and anti‐Tg levels, and thyroid gland ultrasonography was performed at the entry to the study and after 6 months of treatment. Results and discussion: At the end of the study, a statistically significantly higher reduction in anti‐Tg levels was observed in the Se group compared to the placebo group (Δ: −70.9 ± 22.1 vs −6.7 ± 60.6 IU/mL, P = 0.021). Although anti‐TPO levels were also decreased in the Se group, this change was not statistically different from that of the control group (Δ: −116.2 ± 68.4 vs +262.8 ± 255.5 IU/mL, P = 0.219). No significant difference in thyroid gland volume was observed between the two study groups (P > 0.05). What is new and conclusion: In this original study, organic Se supplementation appears to reduce anti‐Tg levels in children and adolescents with AT. Seventy‐one children and adolescents with autoimmune thyroiditis (AT) were randomized to receive 200 μg L‐selenomethionine (N = 38) or placebo (N = 33) daily for 6 months. Organic Se supplementation appears to reduce anti‐Tg levels in children and adolescents with AT. [ABSTRACT FROM AUTHOR]

Abstract The study was conducted to compare effects of different dietary Se sources (sodium selenite [NaSe], Se-enriched yeast [Se yeast] or L-selenomethionine [SeMet]) and one Se-deficient control diet on the expression of selected genes, hematological and clinical biochemical parameters, and muscle morphology in two parallel trials with finisher pigs. Se concentrations in blood plasma and tissues were also monitored. From the pigs in one of the parallel groups, muscle samples obtained from Musculus longissimus dorsi (LD) before and during the trial were examined. The pigs in the other parallel group were challenged once with lipopolysaccharide (LPS) intravenously. Transcriptional analyses of LD showed that selenogenes SelenoW and H were higher expressed in pigs fed Se-supplemented diets compared with control. Furthermore, the expression of interferon gamma and cyclooxygenase 2 was lower in the Se-supplemented pigs versus control. In whole blood samples prior to LPS, SelenoN, SelenoS and thioredoxin reductase 1 were higher expressed in pigs fed NaSe supplemented feed compared with the other groups, possibly indicating a higher level of oxidative stress. After LPS exposure glutathione peroxidase 1 and SelenoN were more reduced in pigs fed NaSe compared with pigs fed organic Se. Products of most above-mentioned genes are intertwined with the oxidant-antioxidant system. No significant effects of Se-source were found on hematologic parameters or microscopic anatomy. The Se-concentrations in various skeletal muscles and heart muscle were significantly different between the groups, with highest concentrations in pigs fed SeMet, followed by those fed Se yeast, NaSe, and control diet. Consistent with previous reports our results indicate that dietary Se at adequate levels can support the body's antioxidant system. Our results indicate that muscle fibers of pigs fed organic Se are less vulnerable to oxidative stress compared with the other groups. [ABSTRACT FROM AUTHOR]

Effects of different forms of dietary selenium (Se) supplementation on gene expression of cytoplasmic thioredoxin reductase (TrxR1), selenoprotein P (SelP), and selenoprotein W (SelW) in broilers were investigated. A total of six hundred Ross 308 broilers (1-day-old) with similar body weight were randomly divided into three groups, each of which included 5 replicates of 40 birds. These three treatments received the same basal diet with only background Se level of 0.04 mg Se/kg, supplemented with 0.15 mg Se/kg as sodium selenite (SS) or l-selenomethionine (l-Se-Met) or d-selenomethionine (d-Se-Met) for 42 days. The SS supplemented diet increased TrxR1 activity in liver (P < 0.01) and kidney (P < 0.01) as well as SelP concentration in serum (P < 0.05) and liver (P < 0.01) more than the d-Se-Met supplemented diet. The addition of SS also highly increased liver (P < 0.01) and kidney (P < 0.01) TrxR1 activities of broilers in comparison with broilers fed l-Se-Met diet. In addition, liver TrxR1 activity in l-Se-Met group was higher than that in d-Se-Met group (P < 0.05). Liver and kidney mRNA levels of TrxR1 and SelP as well as breast muscle SelW mRNA level were significantly increased by l- and d-Se-Met supplementation in comparison with SS supplementation (P < 0.01), while the d-Se-Met group showed more effective (P < 0.01) than the l-Se-Met group in increasing the mRNA levels of TrxR1 and SelP in liver and kidney. Therefore, dietary l-Se-Met and d-Se-Met supplementation could improve mRNA levels of different selenoproteins studied and reduce amounts of TrxR1 and SelP in broilers compared with SS. Besides, l-Se-Met is more effective than d-Se-Met in raising TrxR1 activity and decreasing mRNA abundance of TrxR1 and SelP in broilers.

Aflow-electrolytic cell that consists of a bare goldwire or of different thiol-compound-modified gold electrodes (such as 2,4-thiazolidinedione, 2-mercapto-5-thiazoline, 2-mercaptothiazoline, L-cysteine, thioglycolic acid) was designed to be used in a voltammetric detector to identify L-selenomethionine and Se-methylseleno-L-cysteine using high-performance liquid chromatography. Both L-selenomethionine and Se-methylseleno-L-cysteine are more efficiently electrochemically oxidized on a thiol/gold than on a bare gold electrode. For the DC mode, and for measurements with suitable experimental parameters, a linear concentration from 10 to 1600 ng·mL-1 was found. The limits of quantification for L-selenomethionine and Se-methylseleno-L-cysteine were below 10 ng·mL-1. The method can be applied to the quantitative determination of L-selenomethionine and Se-methylseleno-L-cysteine in commercial selenium-containing supplement products. Findings using high-performance liquid chromatography with a flow-through voltammetric detector and ultraviolet detector are comparable. [ABSTRACT FROM AUTHOR]

Ammonia has been reported to have a variety of toxicity to aquatic animals, farm animals and humans. However, its potential toxicity on the intestines remains unknown. L -selenomethionine is one of the important organic selenium sources. However, the mitigating effect of L -selenomethionine on ammonia exposure toxicity is still lacking. Therefore, in this study, the mechanism of toxic action of ammonia on intestinal tract and the detoxification effect of L -selenomethionine were examined. We evaluated the intestinal toxicity of ammonia and the alleviating effect of L -selenomethionine in an in vivo model, and then verified it in vitro model by a variety of cutting-edge experimental techniques. Our results showed that ammonia exposure causes oxidative stress, necroptosis, Th1/Th2 imbalance and inflammation in the intestinal tissue and the intestinal cells, and L -selenomethionine had a significant mitigation effect on the changes of these indexes induced by ammonia. In conclusion, ammonia exposure caused oxidative stress and Th1/Th2 imbalance in the porcine small intestine and IPEC-J2 cells, and that excessive ROS accumulation-mediated necroptosis targeted inflammatory responses, resulting in the destruction of tight connections of intestinal cells, thereby causing intestinal barrier dysfunction. L -selenomethionine could effectively reduce the intestinal injury caused by ammonia exposure and antagonize the toxic effect of ammonia. [Display omitted] • Ammonia is a toxic pollutant, which has a strong toxic effect on intestinal tract. • Ammonia exposure causes oxidative stress and Th1/Th2 imbalance in intestinal cells. • Excessive ROS accumulation-mediated necroptosis targeted inflammatory responses. • L -selenomethionine can mitigate the toxic effect of ammonia on intestinal tract. [ABSTRACT FROM AUTHOR]

Ammonia (NH 3) is a common air pollutant, which poses a serious threat to farm animals. L-selenomethionine is organic selenium (Se), which can inhibit intracellular ROS generation, block ROS-dependent autophagy, promote mitochondrial energy metabolism, and enhance the body's immunity. Lung, as an important organ of the respiratory system, is highly susceptible to the toxic effects of NH 3. However, there were few studies on the mechanism of toxic effects of NH 3 on lung tissues. The aim of this study was to investigate the effect of NH 3 on the lungs in pigs and the alleviating effect of L-selenomethionine. Twenty-four Large White*Duroc*Min pigs were randomly assigned to 4 groups: control group, NH 3 group, Se group, and NH 3 +Se group. The results showed that exposure to NH 3 caused damage and inflammation in lung tissues and significantly increased blood NH 3 concentration. NH 3 induced changes of oxidative stress indexes (GSH, GSH-Px, SOD, MDA, Keap1, Nrf2, and HO-1) and expressions of energy metabolism related genes (HK1, HK2, PFK, PK, LDHA, and HIF-1α). Ultrastructure showed that mitochondrial damage and autophagosome increased significantly, and the expression levels of autophagy related genes (Beclin1, ATG5, ATG7, ATG10, and p62) changed. However, the addition of L -selenomethionine alleviated the above changes, but there was still a significant difference compared with the control group (P < 0.05). This finding can provide a new evidence for mitigation of NH 3 toxicity. [Display omitted] • Ammonia is a typical air pollutant, which has a strong toxic effect on respiratory system. • Ammonia exposure causes lung damage by oxidative stress and energy metabolism disorder. • ROS-mediated excessive autophagy is important mechanisms of ammonia toxicity. • L -selenomethionine can mitigate the toxic effect of ammonia exposure on lungs. [ABSTRACT FROM AUTHOR]

Ammonia (NH 3) is a hazardous substance to human and animal health. Selenium (Se) is an essential micronutrient with multiple health benefits. The present study aimed to verify whether and how Se supplementation has a protective role against NH 3 mediated-nephrotoxicity in pigs. A Se-NH 3 interaction model was established in pigs and the kidney samples were collected after a 30-day treatment period. The results showed that NH 3 exposure inhibited the PI3K/AKT/mTOR pathway and enhanced the secretion of inflammatory cytokines to induce autophagy and inflammation. Se can regulate the PI3K/AKT/mTOR pathway and attenuate the secretion of inflammatory cytokines altered by NH 3 to reduce autophagy and inflammation. In addition, Se co-treatment inhibited ROS production, elevated the activities of antioxidant systems, and increased the expression of 13 selenoproteins in pig kidneys caused by NH 3 exposure. These results implied that L -selenomethionine can moderate NH 3 -induced nephrotoxicity in pigs. Our study gives new ideas for the specific mechanism of NH 3 nephrotoxicity and provides a reference for comparative medicine and clinical medication. [Display omitted] • Excess NH 3 induced inflammatory damage in pig kidneys. • NH 3 led to autophagy through inhibition of PI3K/AKT/mTOR pathway. • 0.50 mg/kg of Se showed a nephroprotective effect against NH 3. • Selenoproteins contributed to the detoxification of NH 3 by Se. [ABSTRACT FROM AUTHOR]

Selenium is a trace element that is essential for vertebrates and involved in series of vital metabolic functions. Considering the purity of the L-selenomethionine (L-SeMet) under application and the metabolic pathways of SeMet, the FEEDAP Panel considers the use of L-SeMet as safe for all animal species, provided that the maximum total selenium level authorised in feed is respected. The use of in animal nutrition is expected to result in a similar increase in selenium deposition in animal tissues/products as that resulting from other sources of SeMet. To ensure consumer safety from consumption of food originating from animals fed L-SeMet, the FEEDAP Panel concludes that dietary selenium supplementation from the additive should not exceed a maximum of 0.2 mg Se/kg complete feed. In the absence of specific data, the additive should be considered as an irritant to skin and eyes, as a skin sensitiser and as potentially harmful by inhalation. The FEEDAP Panel considers that the use of L-SeMet in feed does not pose an additional risk to the environment, compared with other sources of selenium for which it will substitute, as long as the maximum authorised content in feedingstuffs is not exceeded. L-SeMet is an efficient source of selenium for all species. This conclusion is derived from studies with laying hens and pigs for fattening and, in the case of ruminants, from literature describing the microbial incorporation of selenium from organic sources in the rumen. The FEEDAP Panel made some recommendations concerning (i) the specification, (ii) the use of the compound in premixtures, (iii) the use in water for drinking and (iv) risk reduction when handling the additive.

Selenium is a trace element that is essential for vertebrates and involved in series of vital metabolic functions. Considering the purity of the L-selenomethionine (L-SeMet) under application and the metabolic pathways of SeMet, the FEEDAP Panel considers the use of L-SeMet as safe for all animal species, provided that the maximum total selenium level authorised in feed is respected. The use of in animal nutrition is expected to result in a similar increase in selenium deposition in animal tissues/products as that resulting from other sources of SeMet. To ensure consumer safety from consumption of food originating from animals fed L-SeMet, the FEEDAP Panel concludes that dietary selenium supplementation from the additive should not exceed a maximum of 0.2 mg Se/kg complete feed. In the absence of specific data, the additive should be considered as an irritant to skin and eyes, as a skin sensitiser and as potentially harmful by inhalation. The FEEDAP Panel considers that the use of L-SeMet in feed does not pose an additional risk to the environment, compared with other sources of selenium for which it will substitute, as long as the maximum authorised content in feedingstuffs is not exceeded. L-SeMet is an efficient source of selenium for all species. This conclusion is derived from studies with laying hens and pigs for fattening and, in the case of ruminants, from literature describing the microbial incorporation of selenium from organic sources in the rumen. The FEEDAP Panel made some recommendations concerning (i) the specification, (ii) the use of the compound in premixtures, (iii) the use in water for drinking and (iv) risk reduction when handling the additive. [ABSTRACT FROM AUTHOR]

Since selenium supplements have been shown to undergo biotransformation in the gut, probiotic treatment in combination with selenium supplements may change selenium disposition. We investigated the metabolism of l-selenomethionine (SeMet) and selenite by probiotic bacteria in vitro and the disposition of selenium after probiotic treatment followed by oral dosing with SeMet and selenite in rats. When SeMet was incubated anaerobically with individual antibiotic-resistant probiotic strains ( Streptococcus salivarius K12, Lactobacillus rhamnosus 67B, Lactobacillus acidophilus L10, and Bifidobacterium lactis LAFTI® B94) at 37°C for 24 h, 11-18% was metabolized with 44-80% of SeMet lost being converted to dimethyldiselenide (DMDSe) and dimethylselenide (DMSe). In similar incubations with selenite, metabolism was more extensive (26-100%) particularly by the lactobacilli with 0-4.8% of selenite lost being converted to DMSe and DMDSe accompanied by the formation of elemental selenium. Four groups of rats ( n = 5/group) received a single oral dose of either SeMet or selenite (2 mg selenium/kg) at the time of the last dose of a probiotic mixture or its vehicle (lyoprotectant mixture used to maintain cell viability) administered every 12 h for 3 days. Another three groups of rats ( n = 3/group) received a single oral dose of saline or SeMet or selenite at the same dose (untreated rats). Serum selenium concentrations over the subsequent 24 h were not significantly different between probiotic and vehicle treated rats but appeared to be more sustained (SeMet) or higher (selenite) than in the corresponding groups of untreated rats. Probiotic treated rats given SeMet also had selenium concentrations at 24 h that were significantly higher in liver and lower in kidney than untreated rats given SeMet. Thus, treatment with probiotics followed by SeMet significantly affects tissue levels of selenium. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Previous studies on the chemopreventive mechanisms of dietary selenium have focused on its incorporation into antioxidative selenoproteins, such as glutathione peroxidase and thioredoxin reductase. Several studies, however, have revealed that dietary selenium in the form of l-selenomethionine and the 21st amino acid, selenocysteine, also have intrinsic anti-cancer properties. Biochemical mechanisms previously investigated to contribute to their anticancer effects involve β- and γ-lyase reactions. Some pyridoxal 5′-phosphate (PLP)-containing enzymes can catalyze a β-lyase reaction with Se-methyl- l-selenocysteine (MSC) generating pyruvate and ammonia. Other PLP-enzymes can catalyze a γ-lyase reaction with l-selenomethionine (SM) generating α-ketobutyrate and ammonia. In both cases, a purported third product is methylselenol (CHSeH). Although not directly quantifiable, as a result of its extreme hydrophobicity and high vapor pressure, CHSeH has been indirectly observed to act through the alteration of protein-sulfhydryl moieties on redox-responsive signal and transcription factors, thereby maintaining a non-proliferative intracellular environment. We have considered the possibility that α-keto acid analogues of MSC (i.e., methylselenopyruvate; MSP) and SM (i.e., α-keto-γ-methylselenobutyrate; KMSB), generated via a transamination and/or l-amino acid oxidase reaction may also be chemoprotective. Indeed, these compounds were shown to increase the level of histone-H3 acetylation in human prostate and colon cancer cells. MSP and KMSB structurally resemble butyrate, an inhibitor of several histone deacetylases. Thus, the seleno α-keto acid metabolites of MSC and SM, along with CHSeH derived from β- and γ-lyase reactions, may be potential direct-acting metabolites of organoselenium that lead to de-repression of silenced tumor suppressor proteins and/or regulation of genes and signaling molecules. [ABSTRACT FROM AUTHOR]

l-Selenomethionine (SeMet) and sodium selenite are widely used selenium nutritional supplements with potential benefit in preventing cancer. However, supplementation is not without risks of toxicity if intake is too high. The aim of the present study was to investigate SeMet and selenite metabolism in the gastrointestinal tract with particular focus on the formation of the volatile selenium excretion products, dimethylselenide (DMSe) and dimethyldiselenide (DMDSe). Adult male Wistar rats ( n = 5) were euthanized, their intestinal tracts removed and the contents of jejunum, ileum, caecum and colon used to prepare 10% suspensions in saline. SeMet and selenite (0.5-0.6 mM) were then incubated with these suspensions at 37°C for 3 h. Caecum and colon contents were the most metabolically active towards SeMet with 30% and 15% metabolized over 3 h. DMDSe was the only volatile selenium metabolite detected accounting for 8.7 ± 1.3% of the selenium lost in caecum contents. Selenite was completely metabolized by caecum contents and 73% by colon contents under the same conditions forming DMSe (5.7 ± 0.9% of the selenium lost in caecum) and a precipitate of red amorphous elemental selenium. Based on previous literature and these results, we conclude that the gut microbiota contributes to the excretion of excess selenium through the production of methylated selenium compounds and elemental selenium. [ABSTRACT FROM AUTHOR]

Selenium is an important trace element with anti-cancer properties. In the present study, the apoptosis-inducing effects of organic selenium derivatives, namely methyl-l-selenocysteine and selenomethionine, were evaluated in vitro on human tumour-derived cell lines from breast, liver, colon, brain, skin and a non-tumorigenic line of epithelial origin. Apoptosis was assessed by cell-death detection immunoassay on cytoplasmic cell lysates. Breast carcinoma cells were highly sensitive to the organic selenium compounds, manifesting apoptosis at concentrations as low as 0·113 μm (0·0205 μg/ml) selenium. By contrast, non-tumorigenic mammary epithelial cells displayed poor sensitivity to selenium, requiring a substantially high concentration of the trace element of 87·9 μm (16·0 μg/ml). The cell lines derived from hepatoma and neuroblastoma showed intermediate sensitivity, with colon carcinoma cells manifesting the lowest sensitivity to the trace element. These results indicate intrinsic differences in the sensitivity of human tumour derivatives to selenium-mediated apoptosis, providing experimental support for the development of organic selenium compounds as anti-neoplastic agents against solid tumours displaying selective apoptotic sensitivity to these compounds. [ABSTRACT FROM PUBLISHER]

Variable Temperature 77Se Cross Polarization Magic Angle Spinning (CP/MAS) NMR experiment was used to study of structure and dynamics of L-selenomethionine (L-SeMet) in the solid state. The 77Se principal elements of chemical shift tensor δii and shielding parameters were calculated employing SIMPSON fitting procedure. Correlation between experimental and computed 77Se δii parameters and molecular geometry of L-SeMet in the crystal lattice is discussed. [ABSTRACT FROM AUTHOR]

Abstract: Selenomethionine (SeMet) adsorbs irreversibly from an aqueous solution to the gold surface. The resulting surface layer has a composite character and consists of SeMet and selenohomocysteine (SeHcy), which forms by the hydrolytic cleavage of the first one. The occurrence of these compounds was demonstrated by cyclic voltammetry and EQCM investigations. An anodic scan results in two poorly separated peaks corresponding to the oxidative desorption processes (E 1/2 about 0.70V and E p about 0.92V vs. the Ag|AgCl (3M KCl) electrode, respectively). The first one corresponds to the oxidation of SeHcy to RSeO2H (where R stands for HO2CCH(NH2)(CH2)2−) whereas the second results from the anodic conversion of SeMet to RSeO3H with RSeO2H as a possible intermediate. SeMet oxidation may continue in the region of gold oxide formation if not completed in the pre-oxide region. Partial decomposition of RSeO2H gives rise to H2SeO3 which was evidenced by its reduction reaction to Se(0) at about 0.25V. In turn, Se(0) can be oxidized back to H2SeO3 at about 0.83V. Surface Se(0) inhibits the electron transfer reaction of the redox couple. Ionization of the amino acid functions in the adsorbed state was investigated by capacitance vs. pH determinations. It was thus found that the carboxyl ionization constant (pK a1) shifts from 2.19 in the aqueous solution to 5.1 in the adsorbed state whereas the adsorption has almost no effect on the ionization constant of the amino group (pK a2 =9.05 in the adsorbed state vs. 9.15 in the solution form). Adsorption effect on the ionization constants was accounted for by the interplay of the effect of the surface charge on the local activity of the hydrogen ion, on one had, and intramolecular hydrogen bonding, on the other hand. A SeMet modified electrode can bind reversibly the copper(II) ion in the same way as cysteine and homocysteine proving that the amino acid functions are not involved in surface interactions. Selenium head group forms therefore the link between the adsorbate and the gold surface. [Copyright &y& Elsevier]

In a supplementation study in which organic selenium as l-selenomethionine was administered in low doses during 1 yr, alterations in the concentrations of metal ions in the erythrocytes and the neutrophil granulocytes were observed. In the erythrocytes, altered concentrations of zinc were parallel with selenium. The concentrations of magnesium, calcium, manganese, copper, and sulfur were not significantly altered. However, altered concentrations of iron and zinc were observed in the neutrophils. The concentrations of magnesium, calcium, manganese, copper, and sulfur were not significantly altered. The accumulation of selenium in individual blood cells was different from that obtained with supplementation of inorganic selenium. When organic selenium was supplemented, the thrombocytes accumulated more selenium than the erythrocytes and the neutrophil granulocytes. The observations indicate that selenium interacts with metal ions at the cellular level when supplemented in low doses. The chemical form of selenium might be important in nutrition and therapy in view of the interaction and distribution pattern at the cellular level. [ABSTRACT FROM AUTHOR]

Selenium precipitates were demonstrated histochemically by silver amplification at light and electron microscopic levels in the anterior pituitary of rats exposed to L-selenomethionine (SeMeth). By electron microscopy (EM), the silver amplified selenium complexes were identified in somatotrophs, corticotrophs and gonadotrophs. Precipitates were observed mainly in the secretory granules and to a lesser extent in the lysosomes. The staining intensity increased with increasing amounts of SeMeth. Following a single injection of 3.7 mg Se/kg a substantial increase in staining was observed during the first 48 h after injection and precipitates could still be observed in the anterior pituitary after 2 weeks. During a long-term study where the rats were exposed to selenium contained in the drinking water (3.0 mg Se/1 drinking water for 1, 2 or 4 weeks) an increasing amount of precipitates were observed during the first 2 weeks followed by a small decrease in staining intensity. Organic selenium, or rather a metabolite, is suggested to form bands with endogenous metal, primarily zinc, as has been suggested in the brain and anterior pituitary after exposure to sodium selenite. [ABSTRACT FROM AUTHOR]

Ammonia (NH 3) is a major pollutant in livestock houses and atmospheric environment. It has been demonstrated that NH 3 can cause a series of damage to animals and human. However, toxicity evaluation of NH 3 on farm animals was rarely reported, especially in the intestinal microflora. Therefore, in this study, twenty-four 125-day-old fattening pigs were randomly divided into 4 groups: control group, NH 3 group (88.2 mg m−3 < NH 3 concentration < 90.4 mg m−3), Se group (Se content: 0.5 mg kg−1), and NH 3 + Se group (88.2 mg m−3 < NH 3 concentration < 90.4 mg m−3, Se content: 0.5 mg kg−1), and the effects of NH 3 and L -Selenomethionine on the microbiota composition in the jejunum and the levels of inflammatory markers in feces of fattening pigs were examined by 16S rDNA and ELISA, respectively. Our results showed that the content of Matrix metalloproteinase-9 (MMP-9), Myeloperoxidase (MPO), Lactoferrin (LTF) and Calprotectin in the ammonia group (A group) were significantly elevated compared to the control group, and the content of MMP-9, MPO, LTF and Calprotectin in the A + Se group were significantly reduced. A significant difference in microbiota composition in the phylum, class, family and genus levels was found in the A group and the NH 3 + Se group. There was a negative correlation between Streptococcus and Calprotectin. Our results indicated that excessive NH 3 inhalation could cause changes in inflammatory markers and beta diversity of intestinal microflora in fattening pigs. We found there was a positive correlation between MPO and Pseudomonas. In addition, we first proposed that L -Selenomethionine could improve the imbalance of microbial flora and the inflammatory injury caused by NH 3. Changes in intestinal microflora and inflammatory markers can be used as important indicators to evaluate NH 3 toxicity, and studying changes in intestinal microflora is also an important mechanism to reveal NH 3 toxicity. ga1 • Ammonia is a typical pollutant in atmospheric environment and livestock production. • Excessive ammonia exposure can cause the changes in inflammatory markers. • Excessive ammonia exposure can cause the imbalance of intestinal microflora. • L -selenomethionine can improve the imbalance of intestinal flora caused by ammonia. • Intestinal flora is involved in the toxic mechanism of ammonia. [ABSTRACT FROM AUTHOR]