Forms Of Se Research Articles

Characteristics and Influencing Factors of Soil and Crops Selenium Content in Eastern Sanjiang Plain

Too identify seleniut（Se） content characteristics and influencing factors in soil and crops of Shengli Farm in eastern Sanjiang Plain, statistical analysis and correlation analysis were comprehensively used to analyze the test results of 83 groups of surface soil samples and 34 groups of crop seed samples. The results showed that the Se content in the study area ranged from 0.12 to 0.95 mg·kg-1, with an average value of 0.37 mg·kg-1, and the enrichment degree was stronger with an enrichment coefficient of 3.18. Oxidizable Se was the main Se fraction, accounting for 81%, 79%, 79%, and 80% of T-Se in marsh soil, white soil, dry land, and paddy field, respectively. The content of reducible Se was the lowest, accounting for less than 5%. The effects of soil physicochemical indexes on Se content differences mainly showed that Se was negatively correlated with pH and total potassium （TK） and significantly positively correlated with cation exchange capacity （CEC）, soil organic matter （SOM）, humus （HS）, total nitrogen （TN）, and total phosphorus （TP）. The average content of Se in different land use types was as follows： dryland > irrigated land > grassland > forest land, as the dryland soil with low pH and high SOM was more likely to enrich Se. Among different soil types, the average Se content in gleysols was the highest at 0.45 mg·kg-1, which was higher than the average value in the study area. The average content of Se in the quaternary alluvial layer was the highest at 0.43 mg·kg-1, and its parent material mainly consisted of lacustrine sediments rich in organic matter, which was one of the important factors in forming Se rich soil. The Se content in crops and root soil showed a negative correlation. Se in low pH or high SOM soil was not easily absorbed by crops, and its Se content was also controlled by the form of soil Se, which was positively correlated with available Se content and negatively correlated with oxidizable Se content. Therefore, it is suggested to reduce the amount of artificial fertilizer used in cultivated land as a means of increasing Se bioavailability to change the current situation of crop Se levels in this area.

The Immunomodulatory Effects of Selenium: A Journey from the Environment to the Human Immune System

Selenium (Se) is an essential nutrient that has gained attention for its impact on the human immune system. The purpose of this review is to explore Se’s immunomodulatory properties and to make up-to-date information available so novel therapeutic applications may emerge. People acquire Se through dietary ingestion, supplementation, or nanoparticle applications. These forms of Se can beneficially modulate the immune system by enhancing antioxidant activity, optimizing the innate immune response, improving the adaptive immune response, and promoting healthy gut microbiota. Because of these many actions, Se supplementation can help prevent and treat pathogenic diseases, autoimmune diseases, and cancers. This review will discuss Se as a key micronutrient with versatile applications that supports disease management due to its beneficial immunomodulatory effects. Further research is warranted to determine safe dosing guidelines to avoid toxicity and refine the application of Se in medical treatments.

Effect of Selol on Tumor Morphology and Biochemical Parameters Associated with Oxidative Stress in a Prostate Tumor-Bearing Mice Model.

Prostate cancer is the leading cause of cancer death in men. Some studies suggest that selenium Se (+4) may help prevent prostate cancer. Certain forms of Se (+4), such as Selol, have shown anticancer activity with demonstrated pro-oxidative effects, which can lead to cellular damage and cell death, making them potential candidates for cancer therapy. Our recent study in healthy mice found that Selol changes the oxidative-antioxidative status in blood and tissue. However, there are no data on the effect of Selol in mice with tumors, considering that the tumor itself influences this balance. This research investigated the impact of Selol on tumor morphology and oxidative-antioxidative status in blood and tumors, which may be crucial for the formulation's effectiveness. Our study was conducted on healthy and tumor-bearing animal models, which were either administered Selol or not. We determined antioxidant enzyme activities (Se-GPx, GPx, GST, and TrxR) spectrophotometrically in blood and the tumor. Furthermore, we measured plasma prostate-specific antigen (PSA) levels, plasma and tumor malondialdehyde (MDA) concentration as a biomarker of oxidative stress, selenium (Se) concentrations and the tumor ORAC value. Additionally, we assessed the impact of Selol on tumor morphology and the expression of p53, BCL2, and Ki-67. The results indicate that treatment with Selol influences the morphology of tumor cells, indicating a potential role in inducing cell death through necrosis. Long-term supplementation with Selol increased antioxidant enzyme activity in healthy animals and triggered oxidative stress in cancer cells, activating their antioxidant defense mechanisms. This research pathway shows promise in understanding the anticancer effects of Selol. Selol appears to increase the breakdown of cancer cells more effectively in small tumors than in larger ones. In advanced tumors, it may accelerate tumor growth if used as monotherapy. Therefore, further studies are necessary to evaluate its efficacy either in combination therapy or for the prevention of recurrence.

Comparative study of dietary selenium sources on gilthead seabream (Sparus aurata): Growth, nutrient utilization, stress response and final product quality

Selenium (Se) is a crucial trace mineral in human nutrition, known for its various health benefits, including the enhancement of antioxidant defenses. Enrichment of fish fillets with Se is seen as an interesting strategy to reduce the risk of Se deficiency in human diets. While inorganic sources have been traditionally used to supplement Se in fish diets, organic Se forms have demonstrated superior bioavailability and efficacy in managing oxidative stress and tissue retention rates compared to their inorganic counterparts.The main objective of this study was to assess the performance, stress resistance, and product quality of gilthead seabream (Sparus aurata) in response to diets supplemented with 0.2 mg kg−1 of Na2SeO3 (CTRL), Zn-L-SeMet (AVSe) or OH-Se-Met (ORGSe), complying therefore with the European Food Safety Agency (EFSA) maximum allowed supplementation of organic Se (0.2 mg kg−1). Diets were formulated to be similar in their protein (48% DM) and lipid content (17% DM), and hand-fed to apparent satiety to quadruplicate groups of 20 fish (initial body weight ∼ 75 g) gilthead seabream juveniles for 137 days. Fish were kept in a recirculating saltwater system (salinity 35‰, 22 ± 1 °C) until they reached commercial size (>250 g). At the end of the growth trial, all fish were individually weighed and measured, with 4 fish per tank sampled for whole-body composition analysis. Fillet yield, muscle lipid and mineral composition, and hepatic oxidative stress indicators were assessed (n = 12). Lipid peroxidation, muscle pH, water-holding capacity (WHC), color, and texture were evaluated on days 7 and 14 (n = 8), while sensory analysis was conducted on 20 fish. Additionally, 12 fish per treatment were subjected to overcrowding (100 kg m−3) for 5 min and air exposure for 1 min. After a 1-h recovery period, plasma and liver samples were collected from these fish, and results were compared to those of the non-stress group. All diets yielded equivalent growth performance, ensuring low feed conversion ratio. Fish fed the AVSe diet exhibited higher whole-body protein content compared to those fed the CTRL diet. Regarding mineral utilization, increased Se retention and gain in fish fed AVSe and ORGSe diets led to higher Se content in these fish compared to the CTRL. Additionally, the AVSe diet has also resulted in significantly increased Se deposition in the muscle compared to the other tested Se sources, contributing with 34% of the Se Daily Recommended Intake (DRI). The assessed flesh quality parameters and overall consumer acceptance did not reveal significant differences among the groups. Exposure to an acute stress was found to decrease the activities of Glutathione reductase and glutathione peroxidase, which in turn has increased the level of oxidized glutathione, particularly in the AVSe group. Compared to OH-Se-Met and Na2SeO3, Zn-L-SeMet was more effective in promoting response to stress and nutritional value of gilthead seabream as an important source of protein and Se in human diet.

Morphometric and functional changes in the kidney of rats induced by inorganic selenium.

Selenium (Se) is an essential trace element. Depending on concentration, Se can manifest both beneficial and harmful effects on the cell and can have both oxidative and antioxidant effects. Because the therapeutic index for Se is very narrow and it can depend on the form of Se used, we aimed to investigate the potential safety and side effects of inorganic Se on kidney function and structure in rats. After 8 days of treatment, no detectable signs of microscopic changes or oxidative stress in kidney tissue were observed. We detected a moderate increase in urea and creatinine levels in the blood as a sign of a slight decrease in kidney function. The most notable changes in our study were morphometric alterations in proximal tubules and glomeruli, both of which were considerably enlarged. The short-term application of inorganic Se to rats in a supratherapeutic dose induced mild functional and ultrastructural changes in the kidneys. The dose of inorganic Se used could be considered relatively safe for short-term application in situations where Se could be beneficial to the organism, such as the usage of known nephrotoxicants or high levels of oxidative stress in the body.

Characterization and subcellular localization of selenium in Limosilactobacillus fermentum Ln-9 obtained by intense pulsed light-ultraviolet combined mutagenesis

Lactic acid bacteria (LAB) can convert inorganic selenium (Se) to organic Se and elemental forms with low toxicity and high bioavailability, but a comprehensive Se analysis of Se-enriched LAB is lacking. In this study, Limosilactobacillus fermentum Ln-9 was obtained by intense pulsed light-ultraviolet combined mutagenesis, and its characteristics and subcellular localization of Se were analyzed. The results displayed that Ln-9 accumulated 3.03 times Se that of the original strain. Under optimal fermentation conditions, the total Se content of Se-enriched Ln-9 (SeLn-9) reached 12.16 mg/g with 96.34% contained in Se nanoparticles (SeNPs), which was much higher than that of organic macromolecules. Furthermore, SeNPs were mainly localized outside the cell, Se-proteins were in the membrane and cytoplasmic fractions, and Se-polysaccharides were in the membrane fraction. Besides, SeLn-9 maintained a good morphology and gastrointestinal tolerance and had an enhanced antioxidant capacity. These findings make Ln-9 promising for applications in the food industry.

The Role of Gut Microbiota in the Neuroprotective Effects of Selenium in Alzheimer's Disease.

The objective of the present review was to provide a timely update on the molecular mechanisms underlying the beneficial role of Se in Alzheimer's disease pathogenesis, and discuss the potential role of gut microbiota modulation in this neuroprotective effect. The existing data demonstrate that selenoproteins P, M, S, R, as well as glutathione peroxidases and thioredoxin reductases are involved in regulation of Aβ formation and aggregation, tau phosphorylation and neurofibrillary tangles formation, as well as mitigate the neurotoxic effects of Aβ and phospho-tau. Correspondingly, supplementation with various forms of Se in cellular and animal models of AD was shown to reduce Aβ formation, tau phosphorylation, reverse the decline in brain antioxidant levels, inhibit neuronal oxidative stress and proinflammatory cytokine production, improve synaptic plasticity and neurogenesis, altogether resulting in improved cognitive functions. In addition, most recent findings demonstrate that these neuroprotective effects are associated with Se-induced modulation of gut microbiota. In animal models of AD, Se supplementation was shown to improve gut microbiota biodiversity with a trend to increased relative abundance of Lactobacillus, Bifidobacterium, and Desulfivibrio, while reducing that of Lachnospiracea_NK4A136, Rikenella, and Helicobacter. Moreover, the relative abundance of Se-affected taxa was significantly associated with Aβ accumulation, tau phosphorylation, neuronal oxidative stress, and neuroinflammation, indicative of the potential role of gut microbiota to mediate the neuroprotective effects of Se in AD. Hypothetically, modulation of gut microbiota along with Se supplementation may improve the efficiency of the latter in AD, although further detailed laboratory and clinical studies are required.

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), β-sheets, and β-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 β-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 β-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.

Antioxidant Response of Maternal and Fetal Rat Liver to Selenium Nanoparticle Supplementation Compared to Sodium Selenite: Sex Differences between Fetuses.

To compare the effects of organic selenium nanoparticles (SeNPs, Se0) and inorganic sodium selenite (NaSe, Na2SeO3, Se4+) on the antioxidant response in maternal and fetal rat liver, pregnant females were treated with two forms of selenium (Se) at equivalent doses during gestation (0.5 mg SeNPs or 0.5 mg NaSe/kg body weight/day). Structural parameters of the liver of gravid females and their fetuses were examined in a sex-specific manner. The oxidative stress parameters superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GSH-Px), glutathione reductase (GR), glutathione S-transferase (GST), total glutathione (GSH) and sulfhydryl groups (SH) were established. In addition, the Se concentration was determined in the blood, liver, urine and feces of the gravid females and in the liver of the fetuses. The structure of the liver of gravid females remained histologically the same after supplementation with both forms of Se, while the oxidative stress in the liver was significantly lower after the use of SeNPs compared to NaSe. Immaturity of fetal antioxidant defenses and sex specificity were demonstrated. This study provides a detailed insight into the differences in the bioavailability of the nano form of Se compared to sodium selenite in the livers of pregnant females and fetuses.

Efficient gaseous mercury removal by nano-amorphous red selenium and recycling design of HgSe nanoparticles

Mercury, is a highly toxic chemical that poses serious hazards to both humans and the environment to be controlled. In this paper, Different Se forms have great varying performance of gaseous mercury(Hg0) removal. Nano-amorphous red selenium(ar-Se) has an excellent adsorption effect on Hg0 successfully synthesized by one step oxidation reduction. The factors to ar-Se such as flue gas components, temperature, gas flow rate, and pH affecting mercury removal effect were investigated. The results showed that the ar-Se achieved high utilization (>74.9 %) and mercury affinity (>97 %) at room temperature. Mercury removal rate was almost unaffected by gas components at room temperature, and it kept a stable mercury adsorption in long-time gaseous mercury recovery experiments, which responded to the high electron activity on its surface. Long-range periodic structures with no regular atomic arrangement decide ar-Se in an active state having high specific surface area, surface activity, good dispersion. The HgSe nanoparticles(NPs) was formed by the adsorption of gaseous mercury onto ar-Se. For further recycling of mercury, a recovery route for HgSe has been proposed and oxygen was found having a strong influence on the production of HgSe.

Elements characteristics and potential environmental risk assessment of jarosite residue and arsenic sulfide residue based on geochemical and mineralogical analysis

The waste slag known as jarosite residue (JR) and arsenic sulfide residue (ASR) were produced following the creation of zinc by hydrometallurgical procedures. The increasing annual zinc mining has led to growing pressure to dispose of the resulting JR and ASR from zinc smelting, making it crucial to assess their environmental impact and feasibility for utilization. The main components, distribution characteristics of elements, and potential environmental risks of zinc smelting wastes are studied through toxicity leaching tests, sequential extraction procedures, and various characterization technologies such as XRF, XRD, and SEM-EDS. The mineral compositions of JR are natrojarosite, franklinite, and gunningite, and zinc mainly adheres to the crevices of the natrojarosite mineral. Meanwhile, the ASR of flocculent structures is composed of orpiment, greenockite, arsenic oxide, and calvertite, and As appears in the form of the S-As-O phase. The Zn, Cu, and Cd in JR were dominated by exchangeable bound (81.53–96.6 %), and the main form of As, Cd, Se, and Tl in ASR was organic matter bound (87.0–99.21 %). The Risk Assessment Code (RAC) method confirmed the risk of Cd, Cu, Zn, and Mo in JR is high, while the risk of Cd, Pb, and Cr in ASR is moderate. Compared to the standard value of “Identification Standard for Toxicity of Hazardous Waste Leaching (GB5085.3-2007)”, the leachate concentrations of Zn in JR as well as Cd and As in ASR were exceeded, suggesting that the JR and ASR were in the type of hazardous waste and posed an environmental risk. The study provides theoretical guidance for the future rational management and effective utilization of hazardous waste.

Bio-nano selenium fertilizer improves the yield, quality, and organic selenium content in rice

To investigate the impact of bio-nano Se on rice yield and quality and Se accumulation, three different forms of Se were applied: Se nanoparticles (SeNPs) synthesized by Proteus penneri LAB-1, a conventional inorganic Se fertilizer (sodium selenite) and an organic Se fertilizer (selenomethionine). The relative chlorophyll content of rice increased in plants treated with the different Se treatments and reached the highest level in the 5 mg/L bio-nano Se treatment. However, the height of rice showed little change. Applying 20 mg/L SeNPs increased rice yield by about 5% compared with organic Se treatment and 6% with inorganic Se treatment. Compared with the control, spraying 20 mg/L bio-nano, organic and inorganic Se on the leaf surface increased the soluble sugar content of rice by about 70%, 59% and 61%, respectively, and the amylose content by 15%, 11% and 10% and decreased soluble protein content by 25%, 18% and 22%, respectively. The Se content of rice increased with the increasing of spraying Se concentration. After spraying 10 mg/L of bio-nano Se, the Se content in the rice reached 271.2–306.5 µg/kg, and the proportion of organic Se was over 85.0%, which met the Se-rich rice and safety standards. This study provides a reference for determining the appropriate bio-nano Se supply level and developing Se-rich rice.

Identification and Functional Characterization of a Surfactant-like Protein Region in Flagellin FliC for Stabilizing Selenium Nanoparticles and Enhancing Bioavailability.

Biogenic selenium nanoparticles (SeNPs) are the most favorable Se form for nutritional supplementation due to their high stability, low toxicity, and high activity. However, the interaction between the surface-binding proteins and their stable biogenic SeNPs, as well as their impact on the stability and bioavailability of SeNPs, remains to be understood. In vitro stabilization experiments revealed an amino acid segment (F(235-386)) in Rahnella aquatilis' flagellin FliC, with surfactant-like properties, stabilizing SeNPs under harsh conditions. FliC and F(235-386) were employed as stabilizers to synthesize SeNPs (FliC@SeNPs and F(235-386)@SeNPs), and surface chemistry analysis revealed coordination reactions between the proteins and Se atoms on the surface of SeNPs. Both FliC and F(235-386) enhanced SeNPs uptake in wheat seedlings but reduced it in bacteria and yeast. This study highlights FliC's core function in stabilizing SeNPs and enhancing their bioavailability, paving the way for agricultural and nutritional applications.

Combined Supplementation of Two Selenium Forms (Organic and Inorganic) and Iodine in Dairy Cows' Diet to Obtain Enriched Milk, Cheese, and Yogurt.

This study evaluated the effects of dietary supplementation in dairy cows with two Se forms (organic and inorganic) and I at the maximum levels permitted in the European Union, with the aim to obtain naturally enriched milk and derived products. A total of 20 Holstein Friesian cows in lactation were fed 2 diets for 64 days: a control diet with a supply of 0.57 mg of inorganic Se and 0.57 mg of I per kg of ration in dry matter (DM), and an experimental diet (SeI) with a supply of 0.34 mg of inorganic Se, 0.23 mg of organic Se, and 5.68 mg of I per kg of ration in DM. The SeI diet did not modify the performance or, in general, the metabolic profile of cows. Se and I levels in milk were affected by diet type and time of measurement (p < 0.01). Thus, a marked increase of both microminerals was evident between the beginning and the end of the test, when the SeI diet was administered. For Se, this increase ranged from 1.95 to 3.29 μg/100 g of milk; and for I, from 19.69 to 110.06 μg/100 g of milk. The SeI diet increased (p < 0.01) the Se and I content in the cheese, reaching levels of 16.4 μg/100 g for Se and 269.7 μg/100 g for I. An increase in I was observed in yogurt from the SeI diet (p < 0.001). The supplementation of two forms of Se and I in the cows' ration, at the levels evaluated, produced milk and dairy products enriched in these microelements without altering their quality parameters. However, a responsible intake of these products is necessary to avoid risks of deficiencies or excesses that could negatively affect the health of consumers.

Foliar selenium biofortification of soybean: the potential for transformation of mineral selenium into organic forms.

Selenium (Se) deficiency, stemming from malnutrition in humans and animals, has the potential to disrupt many vital physiological processes, particularly those reliant on specific selenoproteins. Agronomic biofortification of crops through the application of Se-containing sprays provides an efficient method to enhance the Se content in the harvested biomass. An optimal candidate for systematic enrichment, guaranteeing a broad trophic impact, must meet several criteria: (i) efficient accumulation of Se without compromising crop yield, (ii) effective conversion of mineral Se fertilizer into usable organically bound Se forms (Seorg), (iii) acceptance of a Se-enriched crop as livestock feed, and (iv), interest from the food processing industry in utilization of Se-enriched outputs. Hence, priority should be given to high-protein leafy crops, such as soybean. A three-year study in the Czech Republic was conducted to investigate the response of field-grown soybean plants to foliar application of Na2SeO4 solutions (0, 15, 40, and 100 g/ha Se); measured outcomes included crop yield, Se distribution in aboveground biomass, and the chemical speciation of Se in seeds. Seed yield was unaffected by applied SeO4 2-, with Se content reaching levels as high as 16.2 mg/kg. The relationship between SeO4 2-dose and Se content in seeds followed a linear regression model. Notably, the soybeans demonstrated an impressive 73% average recovery of Se in seeds. Selenomethionine was identified as the predominant species of Se in enzymatic hydrolysates of soybean, constituting up to 95% of Seorg in seeds. Minor Se species, such as selenocystine, selenite, and selenate, were also detected. The timing of Se spraying influenced both plant SeO4 2- biotransformation and total content in seeds, emphasizing the critical importance of optimizing the biofortification protocol. Future research should explore the economic viability, long-term ecological sustainability, and the broad nutritional implications of incorporating Se-enriched soybeans into food for humans and animals.

Nano-Selenium Alleviates Cd-Induced Chronic Colitis through Intestinal Flora.

Cadmium (Cd) is an environmental contaminant that poses risks to human and animal health. Selenium (Se), a beneficial element, alleviates the detrimental consequences of colitis and Cd toxicity. Se is found in food products as both inorganic Se (sodium selenite) and organic Se (typically Se-enriched yeast). Nano-selenium (nano-Se; a novel form of Se produced through the bioreduction of Se species) has recently garnered considerable interest, although its effects against Cd-induced enterotoxicity are poorly understood. The aim of this study was to investigate the impact of nano-selenium on mitigating cadmium toxicity and safeguarding the integrity of the intestinal barrier. For a total of two cycles, we subjected 6-week-old C57 mice to chronic colitis by exposing them to Cd and nano-selenium for two weeks, followed by DSS water for one week. The application of nano-selenium mitigated the intensity of colitis and alleviated inflammation in the colon. Nano-selenium enhanced the diversity of the intestinal flora, elevated the concentration of short-chain fatty acids (SCFAs) in feces, and improved the integrity of the intestinal barrier. In summary, nano-Se may reduce intestinal inflammation by regulating the growth of intestinal microorganisms and protecting the intestinal barrier.

Rapid Selenoprotein Activation by Selenium Nanoparticles to Suppresses Osteoclastogenesis and Pathological Bone Loss.

Osteoclast hyperactivation stands as a significant pathological factor contributing to the emergence of bone disorders driven by heightened oxidative stress levels. The modulation of the redox balance to scavenge reactive oxygen species emerges as a viable approach to addressing this concern. Selenoproteins, characterized by selenocysteine (SeCys2) as the active center, are crucial for selenium-based antioxidative stress therapy for inflammatory diseases. This study reveals that surface-active elemental selenium (Se) nanoparticles, particularly lentinan-Se (LNT-Se), exhibit enhanced cellular accumulation and accelerated metabolism to SeCys2, the primary active Se form in biological systems. Consequently, LNT-Se demonstrates significant inhibition of osteoclastogenesis. Furthermore, in vivo studies underscore the superior therapeutic efficacy of LNT-Se over SeCys2, potentially attributable to the enhanced stability and safety profile of LNT-Se. Specifically, LNT-Se effectively modulates the expression of the selenoprotein GPx1, thereby exerting regulatory control over osteoclastogenesis inhibition, and the prevention of osteolysis. In summary, these results suggest that the prompt activation of selenoproteins by Se nanoparticles serves to suppress osteoclastogenesis and pathological bone loss by upregulating GPx1. Moreover, the utilization of bioactive Se species presents a promising avenue for effectively managing bone disorders.

129 Selenium-form affects de novo cholesterol synthesis and catabolism of cholesterol and progesterone in the liver of beef heifers

Abstract A deficiency of selenium (Se) in soils and hence forages poses a challenge to producers in the southeast United States, necessitating supplementation of this trace mineral to the diet of pasture fed cattle. Se occurs in either inorganic (ISe) or organic (OSe) forms; ISe is conventionally available in commercial supplements, while OSe is available in grazed forages. We have investigated supplementation with either ISe or a 1:1 mixture of ISe:OSe (MIX) and demonstrated that MIX increases the relative abundance of mRNA encoding the low-density lipoprotein receptor (LDLR) and enzymes involved in de novo cholesterol synthesis in the corpus luteum, concurrent with a MIX-induced increase in systemic progesterone (P4) during the early luteal phase. We also observed a MIX-induced decrease in circulating cholesterol and low-density/very low-density lipoproteins during early gestation, and a MIX-induced increase in conceptus length at maternal recognition of pregnancy (MRP). The objective herein was to investigate the effect of form of Se (ISe versus MIX) on de novo cholesterol synthesis and cholesterol/steroid catabolism in the liver at MRP. We hypothesized form of Se would affect the abundance of transcripts that regulate synthesis, catabolism, and local concentrations of cholesterol and P4. Angus-cross heifers were supplemented with ISe or MIX for at least 90 d before insemination at observed estrus. On d 17 of pregnancy, heifers (n = 6/TRT) were killed and their reproductive tracts and conceptuses recovered. Hepatic samples were collected for qPCR analysis of mRNA transcripts encoding proteins involved in de novo cholesterol synthesis, regulation of cholesterol availability and steroid catabolism. Additionally, on d 7 and d 17 of pregnancy, we quantified systemic concentrations of high-density lipoproteins (HDL), indicative of cholesterol recycling to the liver. We quantified the relative abundance of 22 mRNAs and observed that heifers supplemented with MIX-form Se had an increase in the relative abundance of mRNA encoding the very low-density lipoprotein receptor (VLDLR, P = 0.01). Unexpectedly, we failed to detect an effect of TRT on the abundance of mRNA encoding the high-density lipoprotein receptor (SCARB1, P &amp;gt; 0.05) which was consistent with our inability to detect an effect on the serum concentration of total or free HDL (P &amp;gt; 0.05) during early pregnancy and at MRP. Of the 11 mRNA transcripts encoding enzymes involved in catabolism of cholesterol and progesterone, including steroid alpha reductases (SRD5A1 and SRD5A3) and cytochrome P450 enzymes (CYP4A2, CYP4A11, CYP11A1, and CYP17A1), we were unable to detect a difference in the relative abundance of any transcript. Overall, it appears that the form of Se is altering circulating concentrations of cholesterol and further affecting whole animal physiology and fertility; however, the mechanism involved remains to be fully elucidated and warrants further investigation.

131 Selenium-form effects on hepatic function and selenoprotein mRNAs in the early pregnant heifer

Abstract Selenium (Se) is an integral component of selenoproteins, with effective scavenging of harmful reactive oxygen species (ROS) by selenoproteins necessary to protect cells from oxidative stress. Due to the presence of Se-deficient soils in large portions of the US, including the southeast cow-calf producing states, grazed forages are insufficient in this trace mineral and dietary supplementation is recommended. We have investigated the effects of providing Se in an inorganic form (ISe, the industry standard) versus a 1:1 mixture (MIX) of ISe to organic Se (OSe), and have observed significant effects on luteal function, endometrial function and conceptus development. Herein, our objective was to determine the effect of form of Se on 1) clinical markers of total antioxidant capacity and liver function, and 2) the expression of mRNAs encoding selenoproteins in the liver. Following consecutive 45-d periods of Se-depletion then repletion, Angus-cross heifers were assigned to 90 d of treatment with a vitamin-mineral mix containing 35-ppm Se as ISe or MIX. Heifers were then inseminated at estrus (d 0) with serum collected at d 0, 7 and 17 to quantify albumin, beta-hydroxybutyrate (BHBA) and aspartate aminotransferase (AST). Liver samples were collected at euthanasia on d 17 (n = 6 pregnant heifers per treatment) for the quantification of the relative abundance of 25 selenoprotein mRNAs using qPCR. There was no effect of treatment on circulating albumin (P &amp;gt; 0.05). Hepatocyte-secreted albumin is the most prominent antioxidant in the circulation, with this result suggesting that albumin-driven redox capacity is not sensitive to the form of Se supplied to achieve a Se-adequate status. Systemic concentrations of BHBA and AST were increased (P &amp;lt; 0.05) in MIX- versus ISe-treated heifers at d 7 and 17 of pregnancy. Circulating BHBA is considered a primary indicator of liver function and the hepatic response to increased metabolic demands, whereas increased AST is conventionally considered a marker for liver damage. These results suggest increased demands on the liver in MIX versus ISe-treated heifers, however not at the level indicative of dysfunction or disease. Additionally, the serum concentration of urea nitrogen was quantified and determined to be reduced (P &amp;lt; 0.05) at estrus in MIX- versus ISe-treated heifers, indicative of form-induced changes in hepatic nitrogen metabolism. Targeted qPCR analysis to determine the effect of treatment on the abundance of encoding selenoproteins by mRNA, including the iodothyronine deiodinases, glutathione peroxidases and thioredoxin reductases, was largely unaffected by treatment, with only the abundance of mRNA encoding Selenoprotein V tending to differ (P = 0.07) with treatment. Overall, this study revealed form of Se-effects on markers of hepatic health and function, as well as blood urea nitrogen, but did not reveal form of Se-effects on the expression of hepatic selenoproteins mRNAs.

11 Transcriptomic changes in response to form of selenium on the interferon-tau signaling mechanism in the caruncular tissue of beef heifers at maternal recognition of pregnancy

Abstract It is necessary to supplement selenium (Se) to the diet of beef cattle in regions where the soils and forages are deficient in this trace mineral. Supplementation with Se conventionally occurs using an inorganic form (ISe) although the organic forms (OSe) are available when cattle consume forage. Previously we have investigated the effects of supplemental Se as ISe, or a 1:1 mixture of ISe to OSe (MIX) on grazing beef cows and heifers and have observed significant effects on the corpus luteum (CL) and endometrium. The MIX form of Se increased systemic progesterone (P4) during the early luteal phase of the estrous cycle at a time that can significantly improve early embryonic development. We subsequently investigated the effects of MIX form Se versus ISe on the mRNA transcripts encoding IFNτ- and P4-induced proteins in the caruncular (CAR) tissue of the uterine endometrium at maternal recognition of pregnancy (MRP). MIX-supplemented heifers had a decrease in the relative abundance of mRNAs encoding DGAT2, FGF2, IFIT3, ISG15, MX1, OAS2, and RSAD2 in CAR which was coupled with significantly longer conceptuses at MRP. Presently, we examined transcriptomic changes in the CAR tissue of the endometrium at MRP. Angus-cross heifers (n = 20) were exposed to a 45-d period of Se depletion (no supplemental Se) followed by a 45-day repletion period with ISe alone. Heifers were then randomly assigned to 90 days of treatment with a vitamin-mineral mix containing 35-ppm Se as ISe (n = 10), or 1:1 mixture of ISe and OSe (n = 10, MIX). Following insemination, heifers were killed at MRP (d 17) and their reproductive tracts collected. Only heifers with a fully intact recovered conceptus were utilized for further analyses (n = 6 per treatment). Transcriptomic analysis using RNA-sequencing was conducted using total mRNA from CAR biopsies. Differential gene expression was determined using Integrated Differential Expression and Pathway Analysis (iDEP.96), and DEG were subjected to canonical, functional, and network analyses using QIAGEN’s Ingenuity Pathway Analysis (IPA). RNA sequencing results were validated using qPCR. At P &amp;lt; 0.05, there was a total of 2,029 DEGs with 1,038 transcripts upregulated, and 991 transcripts downregulated in MIX versus ISe heifers. Saliently, the interferon JAK/STAT pathway signaling through the STAT1/2 heterodimer was significantly down regulated in CAR samples from MIX heifers, as were the following interferon-responsive genes: IFIT1, IFIT2, IFIT3, IRF1, IRF9, ISG15, ISG20, OAS2, RSAD2, and STAT2. Additionally, there were significant changes in mRNA contribution to the immunotolerant environment (IDO1, ISG20, SCARA1, and TGFB1) to allow the fetal allograft to closely interact with the maternal interface. In combination, these findings suggest more advanced preparation of the CAR and developing conceptus for placentation and to evade immune rejection by the maternal endometrium during implantation.