Alleviation of cadmium toxicity in soybean (Glycine max L.): Up-regulating antioxidant capacity and enzyme gene expressions and down-regulating cadmium uptake by organic or inorganic selenium.

Although much interest has been focused on the role of selenium (Se) in plant nutrition over the last 20 years, the influences of organic selenium (selenomethionine; Se-Met) and inorganic selenium (potassium selenite; Se-K) on the growth and physiological characters of cadmium (Cd)-stressed Glycine max L.) seedlings have not yet been studied. In this study, the impacts of Se-Met or Se-K on the growth, water physiological parameters (gaseous exchange and leaf water content), photosynthetic and antioxidant capacities, and hormonal balance of G. max seedlings grown under 1.0 mM Cd stress were studied. The results showed that 30 µM Se-K up-regulates water physiological parameters, photosynthetic indices, antioxidant systems, enzymatic gene expression, total antioxidant activity (TAA), and hormonal balance. In addition, it down-regulates levels of reactive oxygen species (ROS; superoxide free radicals and hydrogen peroxide), oxidative damage (malondialdehyde content as an indicator of lipid peroxidation and electrolyte leakage), Cd translocation factor, and Cd content of Cd-stressed G. max seedlings. These positive findings were in favor of seedling growth and development under Cd stress. However, 50 µM Se-Met was more efficient than 30 µM Se-K in promoting the above-mentioned parameters of Cd-stressed G. max seedlings. From the current results, we conclude Se-Met could represent a promising strategy to contribute to the development and sustainability of crop production on soils contaminated with Cd at a concentration of up to 1.0 mM. However, further work is warranted to better understand the precise mechanisms of Se-Met action under Cd stress conditions.

Selenomethionine supplementation mitigates fluoride-induced liver apoptosis and inflammatory reactions by blocking Parkin-mediated mitophagy in mice.

As an environmental pollutant, fluoride-induced liver damage is directly linked to mitochondrial alteration and oxidative stress. Selenium's antioxidant capacity has been shown to alleviate liver damage. Emerging research proves that E3 ubiquitin ligase Park2 (Parkin)-mediated mitophagy may be a therapeutic target for fluorosis. The current study explored the effect of diverse selenium sources on fluoride-caused liver injury and the role of Parkin-mediated mitophagy in this intervention process. Therefore, this study established a fluoride-different selenium sources co-intervention wild-type (WT) mouse model and a fluoride-optimum selenium sources co-intervention Parkin gene knockout (Parkin-/-) mouse model. Our results show that selenomethionine (SeMet) is the optimum selenium supplementation form for mice suffering from fluorosis when compared to sodium selenite and chitosan nano­selenium because mice from the F-SeMet group showed more closely normal growth and development levels of liver function, antioxidant capacity, and anti-inflammatory ability. Explicitly, SeMet ameliorated liver inflammation and cell apoptosis in fluoride-toxic mice, accomplished through downregulating the mRNA and protein expression levels associated with mitochondrial fusion and fission, mitophagy, apoptosis, inflammatory signalling pathway of nuclear factor-kappa B (NF-κB), reducing the protein expression levels of PARKIN, PTEN-induced putative kinase1 (PINK1), SQSTM1/p62 (P62), microtubule-associated protein light chain 3 (LC3), cysteinyl aspartate specific proteinase 3 (CASPAS3), as well as restraining the content of interleukin-1ß (IL-1ß), interleukin-6 (IL-6), tumor necrosis factor α (TNF-α), and interferon-γ (IFN-γ). The Parkin-/- showed comparable positive effects to the SeMet in the liver of fluorosis mice. The structure of the mitochondria, mRNA, protein expression levels, and the content of proinflammatory factors in mice from the FParkin-/- and F + SeMetParkin-/- groups closely resembled those in the F + SeMetWT group. Overall, the above results indicated that SeMet could alleviate fluoride-triggered inflammation and apoptosis in mice liver via blocking Parkin-mediated mitophagy.

Selenomethionine Promotes Milk Protein and Fat Synthesis and Proliferation of Mammary Epithelial Cells through the GPR37-mTOR-S6K1 Signaling.

Selenomethionine (SeMet) is an important nutrient, but its role in milk synthesis and the GPCR related to SeMet sensing is still largely unknown. Here, we determined the dose-dependent role of SeMet on milk protein and fat synthesis and proliferation of mammary epithelial cells (MECs), and we also uncovered the GPCR-mediating SeMet function. At 24 h postdelivery, lactating mother mice were fed a maintenance diet supplemented with 0, 5, 10, 20, 40, and 80 mg/kg SeMet, and the feeding process lasted for 18 days. The 10 mg/kg group had the best increase in milk production, weight gain of offspring mice, and mammary gland weight and acinar size, whereas a higher concentration of SeMet gradually decreased the weight gain of the offspring mice and showed toxic effects. Transcriptome sequencing was performed to find the differentially expressed genes (DEGs) between the mammary gland tissues of mother mice in the 10 mg/kg SeMet treatment group and the control group. A total of 258 DEGs were screened out, including 82 highly expressed genes including GPR37 and 176 lowly expressed genes. SeMet increased milk protein and fat synthesis in HC11 cells and cell proliferation, mTOR and S6K1 phosphorylation, and expression of GPR37 in a dose-dependent manner. GPR37 knockdown decreased milk protein and fat synthesis in HC11 cells and cell proliferation and blocked SeMet stimulation on mTOR and S6K1 phosphorylation. Taken together, our data demonstrate that SeMet can promote milk protein and fat synthesis and proliferation of MECs and functions through the GPR37-mTOR-S6K1 signaling pathway.

p38MAPK/HSPB1 is involved in the regulatory effects of selenomethionine on the apoptosis, viability and testosterone secretion of sheep Leydig cells exposed to heat.

Testosterone derived from testicular Leydig cells (LCs) is important for male sheep, and the testis is susceptible to external temperature. The present study aimed to explore the alleviating effect of selenomethionine (Se-Met) on heat-induced injury in Hu sheep LCs. Isolated LCs were exposed to heat (41.5°C, heat exposure, HE) or not (37°C, nonheat exposure, NE), and cells in NE and HE were treated with 0 (C) or 8 µmol/L (S) Se-Met for 6 h. Cell viability, testosterone level, and the expression of GPX1, HSD3B, apoptosis-related genes and p38 mitogen-activated protein kinase (p38MAPK)/heat shock protein beta-1 (HSPB1) pathway were examined. The results showed that Se-Met increased GPX1 expression (NE-S vs. NE-C: 2.28-fold; HE-S vs. HE-C: 2.36-fold, p < 0.05) and alleviated heat-induced decrease in cell viability (HE-S vs. HE-C: 1.41-fold; HE-C vs. NE-C: 0.61-fold, p < 0.01), although the viability was still lower than that in the NE-C cells (HE-S vs. NE-C: 0.85-fold) and Se-Met-treated cells (HE-S vs. NE-S: 0.81-fold). Se-Met relieved heat-induced decrease in testosterone level (HE-S vs. HE-C: 1.84-fold, p < 0.05) and HSD3B expression (HE-S vs. HE-C: 1.67-fold, p < 0.05). Se-Met alleviated heat-induced increase in Bcl2-associated protein X (BAX) expression (HE-C vs. HE-S: 2.4-fold, p < 0.05), and decrease in B-cell lymphoma-2 (BCL2) expression (HE-S vs. HE-C: 2.62-fold, p < 0.05), resulting in increased BCL2/BAX ratio in the HE-S cells (HE-S vs. HE-C: 5.24-fold, p < 0.05). Furthermore, Se-Met alleviated heat-induced activation of p-p38MAPK/p38MAPK (HE-C vs. HE-S: 1.79-fold, p < 0.05) and p-HSPB1/HSPB1 (HE-C vs. HE-S: 2.72-fold, p < 0.05). In conclusion, p38MAPK/HSPB1 might be involved in Se-Met-mediated alleviation of heat-induced cell apoptosis, cell viability and testosterone secretion impairments in sheep LCs.

Comparative effects of various dietary selenium sources on growth performance, meat quality, essential trace elements content, and antioxidant capacity in broilers.

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.

Extraction recovery and speciation of selenium in Se-enriched yeast.

The complete characterization of selenium-enriched yeast in terms of selenium species has been the goal of extensive research for the last three decades. This contribution addresses the two outstanding questions: the mass balance of the identified and reported selenium species and the possible presence of inorganic selenium. For this purpose, four procedures have been designed combining, in diverse order, the principal steps of selenium speciation analysis in Se-rich yeast: extraction of the Se-metabolome, derivatization of cysteine and Se-cysteine (SeCys) residues, proteolysis, and definitive Se recovery using SDS extraction, followed by mineralization. The recovery of selenium in each step and its speciation were controlled by ICP MS and by reversed-phase HPLC-ICP MS, respectively. The study, carried out for the SELM-1 reference material, demonstrated the presence of about 10% of inorganic selenium and a serious risk of losses of SeCys during derivatization and proteolysis. As result of our work, we postulate the following values for SELM-1: Se-metabolome fraction (SeMF) 14.8 ± 0.7%; total selenomethionine (SeMet) 66.2 ± 2.7% (including ca. 1.5% SeMet present in the SeMF); total SeCys 12.5 ± 1.5% (including 2% of SeCys present in the Se-MF); total inorganic selenium 9.7 ± 1.7%, accounting for > 99.8% of the selenium.

Effect of exogenous selenium on physicochemical, structural, functional, thermal, and gel rheological properties of mung bean (Vigna radiate L.) protein.

Selenium (Se) biofortification during the growth process of mung bean is an effective method to improve the Se content and quality. However, the effect of Se biofortification on the physicochemical properties of mung bean protein is unclear. The objective of this study was to clarify the changes in the composition, Se forms, particle structure, functional properties, thermal stability, and gel properties of mung bean protein at four Se application levels. The results showed that the Se content of mung bean protein increased in a dose-dependent manner, with 7.96-fold (P1) and 8.52-fold (P2) enhancement at the highest concentration. Exogenous Se application promotes the conversion of inorganic Se to organic Se. Among them, selenomethionine (SeMet) and methyl selenocysteine (MeSeCys) replaced Met and Cys through the S metabolic pathway and became the dominant organic Se forms in Se-enriched mung bean protein, accounting for more than 80 % of the total Se content. Exogenous Se at 30 g/hm2 significantly up-regulated protein content and promoted the synthesis of sulfur-containing protein components and hydrophobic amino acids in the presence of increased levels of SeMet and MeSeCys. Meanwhile, Cys and Met substitution altered the sulfhydryl groups (SH), ß-sheets, and ß-turns of protein. The particle size and microstructural characteristics depend on the protein itself and were not affected by exogenous Se. The Se-induced increase in the content of hydrophobic amino acids and ß-sheets synergistically increases the thermal stability of the protein. Moderate Se application altered the functional properties of mung bean protein, which was mainly reflected in the significant increase in oil holding capacity (OHC) and foaming capacity (FC). In addition, the increase in SH and ß-sheets induced by exogenous Se could alter the protein intermolecular network, contributing to the increase in storage modulus (G') and loss modulus (G″), which resulted in the formation of more highly elastic gels. This study further promotes the application of mung bean protein in the field of food processing and provides a theoretical basis for the extensive development of Se-enriched mung bean protein.

The effect of hydroxy-selenomethionine on the productive and reproductive performance of old broiler breeders.

BACKGROUND: Selenium (Se) is a rare essential element that plays a vital role in the health and performance of animals. By interfering in the production of antioxidant enzymes such as glutathione peroxidase, thioredoxin reductase and methionine sulfoxide, Se plays a role in reducing the effects of oxidative stress and animal performance. OBJECTIVES: This study aimed to investigate the effect of hydroxy-selenomethionine (OH-SeMet) in the diet of broiler breeder and old broiler breeder roosters on productive performance, reproduction and sperm quality parameters. METHODS: For this purpose, 260 broiler breeders of the Ross 308 strain were used in a completely randomized design with four treatments and five replications (13 hens and one rooster in each replication). Experimental treatments included: (1) a basal diet without OH-SeMet (T1:control), (2) a broiler breeder diet without OH-SeMet and a rooster diet containing 0.1 mg/kg OH-SeMet (T2), (3) broiler breeder diet containing 0.1 mg/kg OH-SeMet and rooster diet without OH-SeMet (T3) and (4) broiler breeder and rooster diet contained 0.1 mg/kg OH-SeMet (T4). RESULTS: The results showed that T3 and T4 treatments improved egg production, egg weight, egg mass and feed conversion ratio (FCR) compared to the control treatment (p < 0.05). The fertility and hatchability percentages of T4 and T2 treatments increased compared to T1 and T3 treatments (p < 0.05). The rate of embryonic losses in T1 was higher than in other treatments. However, grade one chickens were higher in T4 than in other treatments (p < 0.05). Total motility and viability of sperms were significantly higher in T2 and T4 treatments than in T1 and T3 treatments. The sperm abnormality percentage and sperm MDA concentration decreased in T2 and T4 treatments. CONCLUSIONS: Therefore, using OH-SeMet may be a practical approach to help old broiler breeders' production and reproduction performance.

Selenomethionine Inhibited HADV-Induced Apoptosis Mediated by ROS through the JAK-STAT3 Signaling Pathway.

Adenovirus (HAdV) can cause severe respiratory infections in children and immunocompromised patients. There is a lack of specific therapeutic drugs for HAdV infection, and the study of anti-adenoviral drugs has far-reaching clinical implications. Elemental selenium can play a specific role as an antioxidant in the human immune cycle by non-specifically binding to the amino acid methionine in body proteins. Methods: The antiviral mechanism of selenomethionine was explored by measuring cell membrane status, intracellular DNA status, cytokine secretion, mitochondrial membrane potential, and ROS production. Conclusions: Selenomethionine improved the regulation of ROS-mediated apoptosis by modulating the expression of Jak1/2, STAT3, and BCL-XL, which led to the inhibition of apoptosis. It is anticipated that selenomethionine will offer a new anti-adenoviral therapeutic alternative.

The Influence of N-Acetyl-selenomethionine on Two RONS-Generating Cancer Cell Lines Compared to N-Acetyl-methionine.

N-acetyl-selenomethionine (NASeLM), a representative of the selenium compounds, failed to convince in clinical studies and cell cultures that it neither inhibits cancer growth nor has a chemoprotective effect. This study aims to find out whether NASeLM shows a growth-inhibiting property compared to the carrier substance N-Acetyl-L-methionine (NALM) on two different cancer cells, namely Jurkat cells and MTC-SK cells. METHODS: Jurkat and MTC-SK cells were cultured in the absence or presence of varying concentrations (0-500 µg/mL) of NASeLM and NALM solutions. After 0, 24, 48, and 72 h, mitochondrial activity, cancer cell membrane CP levels, cell growth, and caspase-3 activity were assessed in aliquots of Jurkat and MTC-SK cells. RESULTS: Both substances, NASeLM and NALM, were similarly able to inhibit cell growth and mitochondrial activity of Jurkat cells in a concentration-dependent and time-dependent manner up to 70%. Only the determination of caspase activity showed that only NASeLM was able to increase this to almost 40% compared to the control as well as the same lack of NALM. However, the experiments on MTC-SK cells showed a clear difference in favor of NASeLM compared to NALM. While NASeLM was able to reduce cell growth to up to 55%, the same amount of NALM was only at around 15%, which turned out to be highly significant (p < 0.001). The same could also be measured for the reduction in MTC-SK mitochondrial activity. Time dependence could also be recognized: the longer both substances, NASeLM and NALM, were incubated, the higher the effect on cell growth and mitochondrial activity, in favour of NASeLM. Only NASeLM was able to increase caspase-3 activity in MTC-SK cells: at 250 µg/mL NASeLM, caspase-3 activity increased significantly to 28% after 24 and 48 h compared to the control (14%) or the same NALM concentration (14%). After 72 h, this could still increase to 37%. A further increase in the NASeLM concentration did not result in higher caspase-3 activity. CONCLUSION: NASeLM could clearly increase caspase-3 activity in both cell types, Jurkat or MTC-SK cells, and thus induce cell death. NALM and NASeLM showed a reduction in cell growth and mitochondrial activity in both cell lines: While NALM and NASeLM showed almost identical measurements on Jurkat cells, NASeLM was much more effective on MTC-SK than the non-selenium-containing carrier, indicating that it has additional anti-chemoprotective effects.

Relationship between Serum Concentrations and Muscular Expressions of Selenoproteins on Selenium-Supplemented Insulin Resistance Mouse Model.

Previously, insulin resistance and hepatic oxidative stress with increased expressions of glutathione peroxidase (GPx) 1 and selenoprotein P (SelP) were induced in NSY mice, a diabetic mouse model, by administrating a high fat diet (HFD) and seleno-L-methionine (SeMet) for 12 weeks. In this study we developed an analysis method for serum selenoproteins using LC-tandem mass spectrometry (LC-MS/MS) and investigated the effects of supplementary selenium on serum concentrations of selenoproteins as well as protein expression in skeletal muscle as a major insulin target tissue under the same experimental condition. The glucose area under the curves for oral glucose tolerance and insulin tolerance tests indicated that the HFD induced insulin resistance, whereas the treatment of SeMet + HFD showed insignificant promotion compared with the HFD-induced insulin resistance. Although the expressions of GPx1 in gastrocnemius and soleus were not significantly induced by supplementary SeMet nor HFD administration, the expressions of SelP in both skeletal muscles were significantly induced by the treatment of SeMet + HFD. There were also significant increases in serum concentrations of SelP by supplementary SeMet + HFD administration, whereas GPx3 was augmented by supplementary SeMet only. These results indicated that the HFD intake under the sufficient selenium status augmented the blood secretion of SelP, which may participate in the reduction of insulin sensitivity in skeletal muscles as well as liver or adipose tissues, and it is a better indicator of deterioration than GPx3 as it is a major selenoprotein in serum.

Selenomethionine preconditioned mesenchymal stem cells derived extracellular vesicles exert enhanced therapeutic efficacy in intervertebral disc degeneration.

Extracellular vesicles (EVs) derived from Mesenchymal Stromal Cells (MSCs) have shown promising therapeutic potential for multiple diseases, including intervertebral disc degeneration (IDD). Nevertheless, the limited production and unstable quality of EVs hindered the clinical application of EVs in IDD. Selenomethionine (Se-Met), the major form of organic selenium present in the cereal diet, showed various beneficial effects, including antioxidant, immunomodulatory and anti-apoptotic effects. In the current study, Se-Met was employed to treat MSCs to investigate whether Se-Met can facilitate the secretion of EVs by MSCs and optimize their therapeutic effects on IDD. On the one hand, Se-Met promoted the production of EVs by enhancing the autophagy activity of MSCs. On the other hand, Se-Met pretreated MSC-derived EVs (Se-EVs) exhibited an enhanced protective effects on alleviating nucleus pulposus cells (NPCs) senescence and attenuating IDD compared with EVs isolated from control MSCs (C-EVs) in vitro and in vivo. Moreover, we performed a miRNA microarray sequencing analysis on EVs to explore the potential mechanism of the protective effects of EVs. The result indicated that miR-125a-5p is markedly enriched in Se-EVs compared to C-EVs. Further in vitro and in vivo experiments revealed that knockdown of miR-125a-5p in Se-EVs (miRKD-Se-EVs) impeded the protective effects of Se-EVs, while overexpression of miR-125a-5p (miROE-Se-EVs) boosted the protective effects. In conclusion, Se-Met facilitated the MSC-derived EVs production and increased miR-125a-5p delivery in Se-EVs, thereby improving the protective effects of MSC-derived EVs on alleviating NPCs senescence and attenuating IDD.

Assessment of dietary Selenium and its role in Mercury fate in cultured fish rainbow trout with two sustainable aquafeeds.

This study enhances the current limited understanding of the interaction between mercury (Hg) and selenium (Se) species in fish. Rainbow trout (Oncorhynchus mykiss), a model aquaculture fish, was exposed to Hg and Se species through controlled dietary conditions. Over a 6-month feeding trial, the impact of dietary Se on Hg bioaccumulation in fish, including flesh, brain, and liver, was tracked. Twelve dietary conditions were tested, including plant-based diets (0.25 µgSe g-1) and tuna byproduct diets (0.25 µgHg g-1, 8.0 µgSe g-1) enriched with methylmercury and/or Se as selenite or selenomethionine. The tuna byproduct diet resulted in lower Hg levels than the plant-based diets, with muscle Hg content below the European Commission's safe threshold. This study highlights the significant impact of specific Se compounds in the diet, particularly from tuna-based aquafeed, on Hg bioaccumulation. These promising results provide a strong recommendation for future use of fisheries byproducts in sustainable aquafeeds.

Comparison of different organic selenium supplementations on selenium status and serum biomarkers in dairy cows.

The objective of this study was to investigate the effects of two different organic selenium (Se) supplements, selenomethionine (Se-Met) and selenohomolanthionine (Se-Hlan), on the serum biochemical parameters and Se status of dairy cows. Different dietary Se supplementation treatments were set as follows: a control group (CON, adding sodium selenite at 0.3 mg Se/kg dry matter [DM]), 0.3 and 0.5 Se-Met (adding Se-Met at 0.3 and 0.5 mg Se/kg DM, respectively), as well as 0.3 and 0.5 Se-Hlan (adding Se-Hlan at 0.3 and 0.5 mg Se/kg DM, respectively). The experiment lasted 8 weeks. The serum measurements showed that both organic Se treatments resulted in higher uric acid than CON. Se-Met produced higher aspartate aminotransferase, glucose, urea, low-density lipoprotein cholesterol, and lactate dehydrogenase than Se-Hlan. Regarding the Se status, the highest milk Se values appeared in 0.5 Se-Met, with intermediate values in 0.3 Se-Met and 0.5 Se-Hlan, whereas the highest and lowest serum Se levels were presented in 0.5 Se-Met and 0.3 Se-Hlan, respectively. Our results suggest that Se-Hlan was not as efficient in boosting serum or milk Se as Se-Met and differences in serum biomarkers between Se-Met and Se-Hlan may be associated with distinct metabolic pathways for different forms of organic Se.

The application of organic selenium (SeMet) improve the photosynthetic characteristics, yield and quality of hybrid rice.

Rice is an important food in the world, and selenium (Se) is a necessary trace element for the human. So the effects of selenomethionine (SeMet) on photosynthetic capacity, yield and quality of rice at different stages were studied. The results show that SeMet can increase the Ppotosynthetic capacity of rice leaves during each growth stage, the effect of 5 mg/L SeMet treatment was the most significant. At the mature stage of rice, SeMet significantly increased rice yield and total plant biomass, 7.5and 5 mg/L SeMet treatments had the most significant effects, respectively. In addition, SeMet significantly improved the content of Se and processing quality of rice, decreased chalkiness, inhibited amylose synthesis, and optimized flavor. The above indices showed the best results after treatment with 5 mg/L SeMet. It is hoped that this study will provide a theoretical basis for the application of organic selenium in rice production.

Protective effect of selenomethionine on rabbit testicular injury induced by Aflatoxin B1.

The aim of this study was to investigate the alleviating effect of selenomethionine (SeMet) on aflatoxin B1 (AFB1)-induced testicular injury in rabbits. Twenty-five 90-d-old rabbits were randomly divided into 5 groups (the control group, the AFB1 group, the 0.2 mg/kg SeMet + AFB1 group, the 0.4 mg/kg SeMet + AFB1 group and the 0.6 mg/kg SeMet + AFB1 group). After 1 d of the experiment, the SeMet-treated groups were fed 0.2 mg/kg SeMet, 0.4 mg/kg SeMet, or 0.6 mg/kg SeMet daily, and the remaining two groups were fed a normal diet for 30 d. On Day 31, all rabbits in the model group and the three treatment groups were fed 0.5 mg/kg AFB1 for 21 d. The levels of testosterone (T), luteinizing hormone (LH) and follicle stimulating hormone (FSH) in rabbit plasma were detected. Rabbit semen was collected, and its quality was evaluated. Pathological changes in rabbit testes were observed by hematoxylin-eosin (HE) staining. The expression of related proteins in testicular tissue was detected by immunohistochemistry, immunofluorescence and western blot (WB) analysis. Enzyme-linked immunosorbent assays (ELISAs) were used to detect oxidative stress-related indices and inflammatory factors in testicular tissue. The results showed that AFB1 can induce oxidative stress and inflammation to activate the p38/MSK/NF-κB signalling pathway, mediate apoptosis, inhibit the proliferation and differentiation of testicular cells, destroy the integrity of the blood-testis barrier (BTB) and the normal structure of the testis, and reduce the content of sex hormones and semen quality. SeMet pretreatment significantly alleviated testicular injury oxidative stress, and the inflammatory response in rabbits. Thus, we demonstrated that SeMet restores AFB1-induced testicular toxicity by inhibiting the p38/MSK/NF-κB signalling pathway. In addition, in this study, 0.4 mg/kg SeMet had the most impactful effect.

Whole genome identification, molecular docking and expression analysis of enzymes involved in the selenomethionine cycle in Cardamine hupingshanensis.

BACKGROUND: The selenomethionine cycle (SeMTC) is a crucial pathway for the metabolism of selenium. The basic bioinformatics and functions of four enzymes involved in the cycle including S-adenosyl-methionine synthase (MAT), SAM-dependent methyltransferase (MTase), S-adenosyl-homocysteine hydrolase (SAHH) and methionine synthase (MTR), have been extensively reported in many eukaryotes. The identification and functional analyses of SeMTC genes/proteins in Cardamine hupingshanensis and their response to selenium stress have not yet been reported. RESULTS: In this study, 45 genes involved in SeMTC were identified in the C. hupingshanensis genome. Phylogenetic analysis showed that seven genes from ChMAT were clustered into four branches, twenty-seven genes from ChCOMT were clustered into two branches, four genes from ChSAHH were clustered into two branches, and seven genes from ChMTR were clustered into three branches. These genes were resided on 16 chromosomes. Gene structure and homologous protein modeling analysis illustrated that proteins in the same family are relatively conserved and have similar functions. Molecular docking showed that the affinity of SeMTC enzymes for selenium metabolites was higher than that for sulfur metabolites. The key active site residues identified for ChMAT were Ala269 and Lys273, while Leu221/231 and Gly207/249 were determined as the crucial residues for ChCOMT. For ChSAHH, the essential active site residues were found to be Asn87, Asp139 and Thr206/207/208/325. Ile204, Ser111/329/377, Asp70/206/254, and His329/332/380 were identified as the critical active site residues for ChMTR. In addition, the results of the expression levels of four enzymes under selenium stress revealed that ChMAT3-1 genes were upregulated approximately 18-fold, ChCOMT9-1 was upregulated approximately 38.7-fold, ChSAHH1-2 was upregulated approximately 11.6-fold, and ChMTR3-2 genes were upregulated approximately 28-fold. These verified that SeMTC enzymes were involved in response to selenium stress to varying degrees. CONCLUSIONS: The results of this research are instrumental for further functional investigation of SeMTC in C. hupingshanensis. This also lays a solid foundation for deeper investigations into the physiological and biochemical mechanisms underlying selenium metabolism in plants.

Genome-wide identification of HMT gene family explores BpHMT2 enhancing selenium accumulation and tolerance in Broussonetia papyrifera.

Broussonetia papyrifera, a valuable feed resource, is known for its fast growth, wide adaptability, high protein content and strong selenium enrichment capacity. Selenomethionine (SeMet), the main selenium form in selenium fortification B. papyrifera, is safe for animals and this enhances its nutritional value as a feed resource. However, the molecular mechanisms underlying SeMet synthesis remain unclear. This study identified three homocysteine S-methyltransferase genes from the B. papyrifera genome. The phylogenetic tree demonstrated that BpHMTs were divided into two classes, and BpHMT2 in the Class 2-D subfamily evolved earlier and possesses more fundamental functions. On the basis of the correlation between gene expression levels and selenium content, BpHMT2 was identified as a key candidate gene associated with selenium tolerance. Subcellular localization experiments confirmed the targeting of BpHMT2 in nucleus, cell membrane and chloroplasts. Moreover, three BpHMT2 overexpression Arabidopsis thaliana lines were confirmed to enhance plant selenium tolerance and SeMet accumulation. Overall, our finding provides insights into the molecular mechanisms of selenium metabolism in B. papyrifera, highlighting the potential role of BpHMT2 in SeMet synthesis. This research contributes to our understanding of selenium-enriched feed resources, with increased SeMet content contributing to the improved nutritional value of B. papyrifera as a feed resource.

Selenium loss during boiling processes and its bioaccessibility in different crops: Estimated daily intake.

Food crops provide a good selenium (Se) source for Se-deficient populations. This study assessed how boiling affects Se concentration, speciation, and bioaccessibility in common food crops to determine human Se intake. Boiling rice resulted in an 11.9% decrease in minimum Se content, while sorghum experienced a maximum (34.9%) reduction. Boiled vegetables showed a 21% - 40% Se loss. Cereals showed notable decreases in selenomethionine (SeMet) and selenocysteine (SeCys2), while most vegetables exhibited a significant reduction in Se-methylselenocysteine (SeMeCys). Boiling significantly reduced the Se bioaccessibility in all food crops, except cabbage and potato. Cereal crops were more efficacious in meeting the recommended daily intake (RDI) of Se compared to vegetables. Rice exceeds other crops and provides up to 39.2% of the WHO/FAO-recommended target minimum daily intake of 60 µg/day. This study provides insight into a substantial dissonance between the estimated daily intake (EDI) of Se and the bioaccessible Se in both raw and boiled crops. Consequently, revising EDI standards is imperative.

Effects of various selenium-enriched yeasts, selenomethionine, and nanoselenium on production performance, quality, and antioxidant capacity in laying hens.

This study aimed to compare the effects of various selenium (Se) sources (2 mg/kg) on the performance, quality, and antioxidant capacity of laying hens as well as the Se content in their eggs and blood. We selected 720 34-wk-old Lohmann pink-shell laying hens were randomly assigned into 6 groups and fed a basal diet (control) or a basal diet supplemented with various Se sources (Se-enriched yeast, SY-A, SY-C, SY-N; selenomethionine SM, nano-Se SN) for 16 wk. There were 10 replicates of 120 hens per group. Dietary Se supplementation increased the egg production rate of all laying hens. Egg and serum Se deposition was highest in the SM group. Yolk color scores of SY-A and SY-N groups were significantly lower than those of other groups (P < 0.01). The protein height and Haugh unit were significantly lower in the SN group than in the other groups (P < 0.05). The yolk height was significantly higher in the SN and SY-N groups than in the SY-A group (P < 0.05). Dietary supplementation of selenium can improve the antioxidant capacity of laying hens. The SOD content of SM group was significantly lower than that of SY-A and SN group (P < 0.05). The malondialdehyde (MDA) content was significantly higher in the SM group than in the SY-A group (P < 0.05). The present work empirically demonstrated that the production performance of laying hens supplemented with 2 mg/kg Se was superior to that of the hens receiving only a basal diet. The SY-C group exhibited the best production performance, the SY-A group had the highest antioxidant capacity, and the SM group produced eggs with the highest level of Se enrichment.