Dietary Selenium Levels Research Articles

Enhanced Sperm Quality in Aged Broiler Breeder Roosters with Organic Selenium and Selenium Nanoparticles: A Comparative Bioavailability Study.

This study aimed to investigate the impact of dietary selenium treatments on various sperm parameters and antioxidant responses in aged roosters to determine the relative bioavailability value (RBV) and optimize selenium supplementation. Over 40days, starting from week 47 of age, the roosters were fed ten experimental diets, including a basal diet without selenium supplement and nine selenium-treated diets. These selenium-treated diets comprised three different selenium sources (selenium selenite: SS; SelPlex: Se-enriched yeast; selenium nanoparticles: SeNPs), each with three levels of selenium supplements (0.15, 0.30, and 0.45mg/kg). Statistical analysis indicated significant treatment effects on all measured parameters except sperm volume. Sperm motility and viability increased linearly with higher dietary selenium levels. The relative bioavailability values (RBV) of SelPlex and SeNPs compared to SS were estimated using the slope ratio and exponential regression methods. Using the slope-ratio method, the RBV for sperm volume was 457% for SelPlex and 314% for SeNPs, compared to SS. Using exponential regression, the RBV of SelPlex and SeNPs for various parameters were as follows: for MDA (malondialdehyde), 260% and 317%; for TAC (total antioxidant capacity), 447% and 294%; for sperm morphology, 227% and 423%; and for sperm concentration, 346% and 298%, respectively. Principal component analysis revealed strong correlations between sperm motility, viability, and antioxidant parameters, with weaker associations observed between sperm volume and testosterone. Optimization using a desirability function identified 0.45mg/kg selenium supplementation using SeNPs as optimal, maximizing sperm parameters and antioxidant responses while minimizing MDA and morphology. These findings offer valuable insights into effective selenium supplementation strategies to enhance avian reproductive health in aged roosters.

The Association Between Psoriasis and Trace Element Serum Levels and Dietary Intake: Results from USA National Health and Nutrition Examination Survey 2011-2014.

Psoriasis is a common chronic inflammatory disease. However, trace elements are essential to biochemical processes of the skin, it is suspected that the trace elements are vital in the pathogenesis of psoriasis. Our research is aimed to investigate the association between serum levels and dietary intake levels of selenium, zinc, and copper with psoriasis. In this cross-sectional study, we utilized the National Health and Nutrition Examination Survey data from 2011 to 2014 to examine the association between psoriasis and serum concentration and dietary intake of trace elements including copper, zinc, and selenium in the US individuals. Our research combined two cycles and weighted the data. Student's t-tests and χ2 test were used. Subgroup analyses and interaction tests were conducted by IBM SPSS Statistics 22 and EmpowerStats. This study indicates that the population with psoriasis has a lower dose of dietary intake selenium than the controls, and risk analysis showed that the men with selenium daily intake >150 mcg/day have a decreasing risk for psoriasis compared to those with daily intaking selenium <75 mcg/day. However, there are no differences on daily intake of selenium, zinc, and copper and serum levels of Zinc and Copper between psoriasis and healthy controls. The current study showed that the psoriasis group was significantly older with a bigger waist circumference, a higher education level, a higher ratio of people with smoke every day, and a higher ratio of people in USA and being non-Hispanic White. This cross-section study showed that a high selenium intake may benefit USA adults from psoriasis, especially for males. The social and cultural background and ethnic differences between the two groups influence the eating and living models, including the trace element intake. The national recommended dietary allowances (RDAs) might be considered to be modified with more reliable investigative clinical data and certain considering the social and cultural models.

Evaluation of dietary selenium sources and levels on growth performance, carcass characteristics, selenium concentrations, and blood parameters of growing-finishing pigs

Evaluation of dietary selenium sources and levels on growth performance, carcass characteristics, selenium concentrations, and blood parameters of growing-finishing pigs

Selenium May Be Involved in Esophageal Squamous Cancer Prevention by Affecting GPx3 and FABP1 Expression: A Case-Control Study Based on Bioinformatic Analysis.

The role of selenium in the developmental process of esophageal cancer (EC) requires further investigation. To explore the relationship between selenium-related factors and EC through bioinformatic analysis, a case-control study was conducted to verify the results. Utilizing the GEPIA and TCGA databases, we delineated the differential expression of glutathione peroxidase 3 (GPx3) in EC and normal tissues, identified differentially expressed genes (DEGs), and a performed visualization analysis. Additionally, 100 pairs of dietary and plasma samples from esophageal precancerous lesions (EPLs) of esophageal squamous cancer (ESCC) cases and healthy controls from Huai'an district, Jiangsu, were screened. The levels of dietary selenium, plasma selenium, and related enzymes were analyzed using inductively coupled plasma mass spectrometry (ICP-MS) or ELISA kits. The results showed lower GPx3 expression in tumor tissues compared to normal tissues. Further analysis revealed that DEGs were mainly involved in the fat digestion and absorption pathway, and the core protein fatty acid binding protein 1 (FABP1) was significantly upregulated and negatively correlated with GPx3 expression. Our case-control study found that selenium itself was not associated with EPLs risk. However, both the decreased concentration of GPx3 and the increase in FABP1 were positively correlated with the EPLs risk (p for trend = 0.035 and 0.046, respectively). The different expressions of GPx3 and FABP1 reflect the potential of selenium for preventing ESCC at the EPLs stage. GPx3 may affect myocardial infarction through FABP1, which remains to be further studied.

The effects of dietary organic selenium on growth, body composition and hematological parameters of common Carp (Cyprinus carpio) reared in recirculating aquaculture system.

A feeding trial was conducted to examine the effects of different levels of dietary organic selenium (Se) on the growth, body composition, and hematological indices of common carp. Se element was supplemented to the basal diet at the rates of 0.0, 0.5, 1 and 2 mgkg-1. Fish were randomly stocked at a rate of 25 fish into 500L tanks in the Recirculating Aquaculture System (RAS) system for 10 weeks. Weight gain, final body weight, and specific growth rate were significantly higher (p<0.05) in fish fed 0.5 mgkg-1 followed by 1 and 2 mgkg-1 treatment diets fish. The lowest growth rate values were detected in fish-fed basal diets. Feed consumption of fish fed Se was not significantly different (p>0.05), also the survival rate was similar among the treatment groups. Whole-body composition showed that fish fed 1 mgkg-1 had significantly higher (p<0.05) body moisture and protein as dry weight basis. The highest fiber content was in fish fed 2 mgkg-1, but ash was significantly higher in fish fed only 0.5 mgkg-1 and fat remained unaffected. Whole-body Se concentrations were significantly (p<0.05) increased with increasing Se levels in test diets. the red blood cells and hemoglobin were significantly higher (p<0.05) in fish fed only 0.5mgkg-1 and the basal diet. The white blood cells increased in fish fed the basal and 2 mgkg-1 diet, but the lymphocyte percentage was increased (p<0.05) in fish fed basal and 0.5 mgkg-1. The study concludes that dietary Se has an overall positive effect on common carp. Growth performance, protein content in fish body, selenium deposition and some hematological parameters were observed in fish fed dietary organic selenium specifically in fish fed 0.5 and 1 mgkg-1. Therefore, inclusion of Se in the diet from 0.5 to 1 mgkg-1 would be an optimal level for common carp feed.

Dietary selenium levels affect mineral absorbability, rumen fermentation, microbial composition and metabolites of the grazing sheep

Selenium (Se) is an essential trace element for the growth of all livestock. However, little is known about the effects of dietary selenium levels on production metrics, nutrient digestion and absorption, ruminal microbiota, and metabolites in grazing sheep. Therefore, in this research, 28 individually-housed grazing sheep were randomly divided into a low-Se feeding group (LSe) and a control group for the low-Se feeding phase (LCG), supplemented with multi-nutrient salts containing 0 mg Se and 0.63 mg Se, respectively, for 53 days. After 53 days of feeding, a 7-day digestion test was conducted, then seven sheep in each group were randomly slaughtered. Then, the remaining sheep in LSe and LCG were transferred to a high-Se supplementation group (SSe) and a control group for the high-Se feeding phase (SCG), supplemented with multi-nutrient salts containing 1.90 mg and 0.63 mg Se, respectively. This phase consisted of a 34-day diet adaptation period, a 7-day digestive test, and eventual slaughter. LSe reduced and elevated ruminal Se and copper (Cu) content, respectively, and decreased Se apparent absorbability compared to LCG (P < 0.05). Conversely, SSe reduced and increased ruminal Cu and Se content, respectively, and increased Se apparent absorption in comparison to SCG (P < 0.05). It also increased the ruminal NH3-N concentration (P < 0.05). Amplicon sequencing analysis revealed a decrease in Lentimicrobium and Treponema abundance and an increase in Lawsonibacter and Sporobacter abundance (P < 0.05) in LSe group. Metabolomic analysis confirmed an elevated level of ruminal citrulline, ornithine and glutathione affecting amino acid and glutathione metabolic pathways (P < 0.05) in LSe group. In SSe group, Alistipes were significantly reduced (P < 0.05) with metabolomics showing elevated levels of L-carnitine and arginine, affecting ruminal antioxidant capacity and arginine biosynthesis pathways (P < 0.05). Notably, both treatments had no significant effect on production metrics and apparent digestibility of organic nutrients (P > 0.05). In conclusion, Se deficiency affects Se absorption and amino acid metabolism in grazing sheep, while supplementing Se in diet effectively ameliorates these deficiencies and improves ruminal antioxidant capacity.

Optimization of Selenium Inclusion Level in the Larval Diet of Labeo rohita.

The nutritional requirement of fish larvae remains a limiting factor in advanced aquaculture. Micronutrients are crucial for early development, but their dietary inclusion level in the larval feed of carps has not been standardized. The present study was executed to determine the optimum dietary inclusion level of organic and inorganic selenium in the larval feed of Rohu, Labeo rohita. A 35-day feeding trial in triplicate under semi-control conditions was conducted in 21 troughs divided into seven groups. Each trough (capacity 4.0 L) contained 200 larvae (average body weight 0.4mg). The first group (control) was reared on nano-particulate basal diet (CP 50%), while three groups Se-Na(0.5), Se-Na(1), and Se-Na(1.5) were fed basal diet supplemented with graded levels (0.5-1.5mg/kg diet) of inorganic form of Se, sodium selenite (Se-Na). The last three groups (Se-Met(0.5), Se-Met(1), and Se-Met(1.5)) were fed organic form of dietary Se, selenium methionine (Se-Met) at the same inclusion level as Se-Na. Results indicated the curvilinear relationship of dietary Se levels with body weight, activity of digestive enzymes (protease, amylase, lipases, and trypsin), and antioxidant enzymes (SOD, CAT, POD, and GSH-Px) activity, intestinal villi, width, and absorptive area. A positive correlation was observed with up to 0.5 and 1mg/kg diet of Se-Na and Se-Met, respectively; however, above these levels, a negative impact was observed. The upregulation of growth hormone mediator (IGF-1) and downregulation of heat shock protein (HSP-70) also followed a similar trend in response to Se-Na and Se-Met inclusion. Based on the results, 1mg/kg diet Se-Met could be considered the optimum level and is recommended for the early rearing of rohu larvae.

Dietary selenium and zinc supplementation alters growth and immunity of broiler chicken

This study evaluated the influence of varying dietary levels of selenium (Se) and Zinc (Zn) on the performance index, carcass characteristics, and immune response in broiler chicken. The experimental trial was carried for 42 days with a 3 × 3 factorial design involving three levels of each Se (0.15, 0.30, and 0.45 mg/kg diet) and Zn (40, 80, and 120 mg/kg diet) resulting in nine treatments. Six replicate groups with eight birds in each were assigned to each treatment (48 birds/treatment). During starter phase (0-3 weeks), optimum growth performance and growth efficiency of chicken was observed at 0.30 mg Se/kg diet. However, during finisher phase (4-6 week) and overall growth phase (0-6 week), 0.15 mg Se/kg diet was found to be optimum. Similarly, weight gain during starter phase was higher in birds fed at least 80 mg Zn/kg diet. The carcass characteristics did not reveal significant effect of Se and Zn supplementation in broiler chicken. And, on similar lines, cell mediated immunity remained unaffected. However, better humoral immunity was observed in birds supplemented with NRC recommended Se level in diet, but the NRC recommendation of 40 mg Zn/kg diet was inadequate for better humoral immune response compared to 80 or 120 mg level. Further, higher spleen and thymus weight was observed at 0.3 mg Se/kg diet and higher spleen weight at 80 mg Zn/kg diet. In conclusion, Se supplementation of 0.30 mg /kg diet and Zn supplementation of 80 mg/kg diet resulted in optimum growth performance, efficiency, and immunity of broiler chicken.

Selenoproteins synergistically protect porcine skeletal muscle from oxidative damage via relieving mitochondrial dysfunction and endoplasmic reticulum stress

BackgroundThe skeletal muscle of pigs is vulnerable to oxidative damage, resulting in growth retardation. Selenoproteins are important components of antioxidant systems for animals, which are generally regulated by dietary selenium (Se) level. Here, we developed the dietary oxidative stress (DOS)-inducing pig model to investigate the protective effects of selenoproteins on DOS-induced skeletal muscle growth retardation.ResultsDietary oxidative stress caused porcine skeletal muscle oxidative damage and growth retardation, which is accompanied by mitochondrial dysfunction, endoplasmic reticulum (ER) stress, and protein and lipid metabolism disorders. Supplementation with Se (0.3, 0.6 or 0.9 mg Se/kg) in form of hydroxy selenomethionine (OH-SeMet) linearly increased muscular Se deposition and exhibited protective effects via regulating the expression of selenotranscriptome and key selenoproteins, which was mainly reflected in lower ROS levels and higher antioxidant capacity in skeletal muscle, and the mitigation of mitochondrial dysfunction and ER stress. What's more, selenoproteins inhibited DOS induced protein and lipid degradation and improved protein and lipid biosynthesis via regulating AKT/mTOR/S6K1 and AMPK/SREBP-1 signalling pathways in skeletal muscle. However, several parameters such as the activity of GSH-Px and T-SOD, the protein abundance of JNK2, CLPP, SELENOS and SELENOF did not show dose-dependent changes. Notably, several key selenoproteins such as MSRB1, SELENOW, SELENOM, SELENON and SELENOS play the unique roles during this protection.ConclusionsIncreased expression of selenoproteins by dietary OH-SeMet could synergistically alleviate mitochondrial dysfunction and ER stress, recover protein and lipid biosynthesis, thus alleviate skeletal muscle growth retardation. Our study provides preventive measure for OS-dependent skeletal muscle retardation in livestock husbandry.

Interaction between dietary selenium and methylmercury on growth performance, deposition and health parameters in rainbow trout fed selenium-rich tuna-based diets or selenium-poor plant-based diets

This study evaluated the effect of dietary mercury (Hg) and selenium (Se) sources and levels on growth performance, Hg and Se accumulation, pro-inflammatory cytokine levels and global health parameters in rainbow trout juveniles. A 6-month feeding trial was carried out with a control plant-based diet (containing analyzed Se and Hg levels: 0.3 and 0 mg/kg diet, respectively) or a control tuna-based diet (containing analyzed Se and Hg levels: 7.5 and 0.3 mg/kg diet, respectively) supplemented with 0 or 1.5 mg Se/kg diet supplied either as sodium selenite (Se(IV)) or selenomethionine (SeMet) combined with 0, 1.6 or 2 mg Hg/kg diet supplied as methylmercury (MeHg). Fish sampling was carried out at 2 times: after a short (21 days) and a long term dietary exposure (168 days). In the short term, a temporarily reduced growth was noticed in fish fed MeHg-supplemented plant-based diet in absence of dietary Se supplementation. MeHg supplementation increased pro-inflammatory cytokine TNF-α and IL-1β levels in plant and tuna-based diets. MeHg supplementation also affected short-term fish global health parameters with an increase of glucose and albumin levels in tuna-based diets. The addition of SeMet in MeHg-supplemented tuna-based diets protected against the increase of TNF-α level in the long term whereas the addition of Se(IV) in MeHg-supplemented tuna-based diets decreased whole-body Hg level and retention in the short term. In the long term, a reduced growth, a higher feed conversion ratio and a lower protein efficiency ratio were recorded in fish fed Se(IV)-supplemented tuna-based diets in absence of MeHg supplementation. The addition of Se(IV) or SeMet in tuna-based diets increased plasma IL-6 level. The addition of MeHg in plant and tuna-based diets increased Se accumulation and retention. This work underlines that different forms of Se supplementation, in two dietary background context (low basal Se level in plant-based diets and high basal Se level in tuna-based diets), have specific effects on metabolism and biological consequences of dietary MeHg. Dietary inorganic Se (but not organic Se) affected MeHg metabolism by reducing Hg accumulation in fish. However, dietary organic Se displayed better ability to afford protection against MeHg pro-inflammatory effects.

Interaction Between Dietary Selenium and Zinc Intakes on Hypothyroidism.

This study assessed the independent association of dietary selenium and zinc intakes with the risk of hypothyroidism and interaction effect between dietary selenium and zinc intakes with the risk of hypothyroidism in Americans. The data of this cross-sectional study was from the National Health and Nutritional Examination Survey (NHANES) 2007-2012. The outcome was defined as new-onset hypothyroidism. Weighted univariate and multivariate logistic regression and the subgroup analyses based on gender and body mass index (BMI) were conducted to evaluate the association between the dietary selenium and zinc intakes and new-onset hypothyroidism. Odds ratio (OR) and 95% confidence interval (CI) were calculated. A total of 6402 participants were included with 131 (2.05%) developed a hypothyroidism in this study. Compared with participants with high zinc intake, those with low zinc intake had a higher risk of new-onset hypothyroidism (OR = 1.74, 95% CI: 1.05-2.90). Moreover, we also found a significant interaction between dietary selenium level intake and dietary zinc level intake on new-onset hypothyroidism risk (OR = 5.99, 95% CI: 1.77-20.23). There was an interaction between dietary selenium and zinc intakes on the risk of new-onset hypothyroidism, especially the significant effect for adults with women or overweight. The findings indicated that improving the levels of dietary zinc and selenium intake may be beneficial in preventing of new-onset hypothyroidism.

Dietary selenium levels modulates antioxidant, cytokine and immune response and selenoproteins mRNA expression in rats under heat stress condition

BackgroundHigher environmental temperature is a major abiotic stress factor for animals and human beings. The selenium (Se) is an important trace mineral having diverse health promoting effects under stress conditions. However, studies on dietary requirement of selenium under prolonged heat stress condition are lacking. Present study discern the effect of higher dietary Se levels on antioxidant, cytokine, haemato-biochemical profile, and immune response, and the selenoproteins mRNA expression in rats under prolonged heat stress (HS) condition. MethodsWeaned Wistar rats (4 wk age; 67.6 ± 1.53 g BW; n = 72) housed under thermoneutral (TN) or HS conditions and fed with purified diets containing three graded Se levels were divided in six experimental groups. The groups were 1) TN control with 138 ppb Se (TN_CON), 2) HS control with 138 ppb Se (HS_CON), 3) TN with higher Se @ 291 ppb (TN_Se1), 4) HS with higher Se @ 291 ppb (HS_Se1) 5) TN with higher Se @ 460 ppb (TN_Se2), 6) HS with higher Se @ 460 ppb (HS_Se2). Rats in all the six groups were maintained in TN environmental conditions (57.3 ± 0.22 temperature humidity index; THI) for initial 28 days period. Subsequently, rats of HS groups were exposed to 77.0 ± 0.11 THI for 6 h/d in a psychrometric chamber for last fourteen days. ResultsHigher dietary Se (291 and 460 ppb) significantly improved the blood hemoglobin concentration and reduced serum alanine aminotransferase activity of rats under HS conditions. The serum triiodothyronine and insulin levels were significantly higher in high dietary Se groups irrespective of the environmental conditions. Similarly, the serum reduced glutathione levels, and catalase and superoxide dismutase enzyme activity were increased and malondialdehyde levels were reduced in high dietary Se groups irrespective of stress conditions. The glutathione peroxidase (GPx) activity was significantly higher in 460 ppb dietary Se groups as compared to other groups. The serum pro-inflammatory cytokine interleukin (IL)− 1 was declined, whereas the anti-inflammatory cytokine IL-10 level was increased in high dietary Se fed rats under both HS and TN conditions with 460 ppb dietary Se groups showing pronounced effects. Further, there was heat stress- and dietary Se level dependent- up regulation in hepatic GPx and iodothyronine deiodinase-II mRNA expression and similar pattern was noticed in hepatic thioredoxin reductase mRNA expression. The selenoprotein-P mRNA expression was up regulated in 460 ppb Se fed HS group as compared to CON and Se1_C groups. High dietary Se improved the humoral immune response 7d after antigen inoculation under HS conditions whereas cell-mediated immune response was augmented in rats fed higher Se under TN condition. ConclusionIt is concluded that under prolonged heat stress conditions the dietary requirement of Se may be increased to 460 ppb for improving the antioxidant status and humoral immune response, cytokine levels, modulating the thyroid and insulin hormone, and the selenoproteins mRNA expression of rats.

Molecular characterization and expression analysis of selenoprotein W gene in rainbow trout (Oncorhynchus mykiss) with dietary selenium levels.

Selenium (Se) plays an essential role in the growth of fish and performs its physiological functions mainly through incorporation into selenoproteins. Our previous studies suggested that the selenoprotein W gene (selenow) is sensitive to changes in dietary Se in rainbow trout. However, the molecular characterization and tissue expression pattern of selenow are still unknown. Here, we revealed the molecular characterization, the tissue expression pattern of rainbow trout selenow and analyzed its response to dietary Se. The open reading frame (ORF) of the selenow gene was composed of 393 base pairs (bp) and encodes a 130-amino-acid protein. The 3' untranslated region (UTR) was 372bp with a selenocysteine insertion sequence (SECIS) element. Remarkably, the rainbow trout selenow gene sequence was longer than those reported for mammals and most other fish. A β1-α1-β2-β3-β4-α2 pattern made up the secondary structure of SELENOW. Furthermore, multiple sequence alignment revealed that rainbow trout SELENOW showed a high level of identity with SELENOW from Salmo salar. In addition, the selenow gene was ubiquitously distributed in 13 tissues with various abundances and was predominantly expressed in muscle and brain. Interestingly, dietary Se significantly increased selenow mRNA expression in muscle. Our results highlight the vital role of selenow in rainbow trout muscle response to dietary Se levels and provide a theoretical basis for studies of selenow.

The effect of varying dietary manganese and selenium levels on the growth performance and manganese-superoxide dismutase activity in nursery pigs

Antioxidant activity in the weaned piglet is important for the developing animal at a cellular level. This study examined the impact of varying dietary levels of manganese and selenium on piglet growth performance and plasma manganese superoxide-dismutase (MnSOD) specific activity. Weaned piglets were blocked by weight (N = 216; 5.21 ± 1.17 kg; 21 ± 3 d) and sex (2 barrows and 2 gilts/pen). Pens (n = 9 pens/treatment) within a block were randomly assigned to dietary treatments in a 2 × 3 factorial design to examine the effect of adding different levels of Mn (0, 12, and 24 mg/kg added Mn from MnSO4 when pigs were fed diets containing 2 levels of Se (0.1 and 0.3 mg/kg added Se from Na2SeO3). Diets were fed in three phases (P1 = d 1–7, P2 = d 8–21, P3 = d 22–35). Pigs and orts were weighed weekly and blood collected on d 0, 7, 21, and 35 for analysis of red blood cell MnSOD. Data were analyzed via the GLM procedure of SAS. No Mn x Se interactions were observed. There was a linear response (P < 0.05) in overall average daily gain across dietary Mn levels. There was a linear trend (P < 0.10) in overall average daily feed intake across Mn levels. Gain to feed ratio (d 0–35) was not impacted by Mn or Se (P > 0.10). MnSOD activity in RBC increased from d 0–7, peaked at d 7, and decreased until d 35. On d 7, diets with 12 mg/kg Mn significantly increased (P < 0.05) MnSOD specific activity (0.91 IU/mg) compared to diets with 24 mg/kg Mn (0.67 IU/mg) but did not differ from diets with 0 mg/kg Mn (0.87 IU/mg). The dietary treatment that maintained specific MnSOD activity was 12 mg/kg Mn and 0.1 mg/kg Se supplemented, while ADG was maximized in diets with 24 mg/kg Mn supplemented.

Comparison of Serum and Dietary Selenium Levels in Participants with a Positive History of Recurrent Herpes Lesions and Healthy Individuals.

Aim In this study, we aimed to compare the level of serum and dietary selenium in participants with a positive history of recurrent herpes labial lesions and healthy controls. Materials and Methods This cross-sectional study, conducted during 2020-2021, evaluated the selenium serum level of 40 participants with a positive history of recurrent herpes labial lesions who had referred to Motahhari Laboratory in Shiraz, compared with 38 healthy controls. The selenium level of the serum was assessed by an absorption device, Atomic Graphite Furnace Model FS-240-AAS, made by a US Company. Independent T-test was used to compare the selenium level of males and females. In order to assess the mean age value and gender distribution between the two evaluated groups, the independent T-test and chi-square test were used, respectively. The serum selenium level was compered between both control and test groups. Results The level of serum selenium was not statistically correlated with its dietary level in group 1 (participants with recurrent herpes labialis, P value = 0.18) and group 2 (healthy controls, P value = 0.6). The serum selenium level was compared between groups 1 and 2, which was significantly higher in healthy controls (P value < 0.0001). In contrast, dietary selenium level was not significantly different between patients with a history of herpes labialis and healthy controls (P value = 0.48). The level of serum selenium was not statistically correlated with its dietary level in group 1 (P value = 0.18) and group 2 (P value = 0.6). Conclusion Patients with recurrent herpes labialis had lower serum selenium level as compared to the healthy controls.

Optimum dietary sources and levels of selenium improve growth, antioxidant status, and disease resistance: re-evaluation in a farmed fish species, Nile tilapia (Oreochromis niloticus)

The objective of this study was to investigate the effects of sources and levels of selenium (Se) on juvenile Nile tilapia (Oreochromis niloticus). A completely randomized design involving a 2 × 3 factorial arrangement of treatments was used in this study. Organic Se (L-selenomethionine; SeMet) and inorganic Se (sodium selenite; Na2SeO3) were each added to the basal diet at 1, 3 and 5 mg Se/kg. The basal diet, without Se supplementation, was used as a control. There was a total of 7 experimental diets, and each was fed in triplicate to groups of fish with an initial average body weight of 13.5 g for 8 weeks. The results showed that growth performance was significantly affected by dietary sources and levels of Se (P < 0.05). Fish fed diets supplemented with SeMet of 1.0 mg Se/kg resulted in higher growth performance compared to basal diet (P < 0.05), but Na2SeO3 supplementation did not affect growth. The feed conversion ratio was significantly decreased as dietary sources of SeMet (P < 0.05). Interestingly, fish fed diets supplemented with both forms of Se had lower cholesterol levels than those fed the basal diet (P < 0.05). Moreover, dietary sources and levels of Se significantly increased (P < 0.05) the antioxidant enzyme activities such as lysozyme, catalase, myeloperoxidase, superoxide dismutase and glutathione peroxidase. Dietary sources and levels of Se significantly could enhance the Nile tilapia resistance against Streptococcusagalactiae infection (P < 0.05). Overall, it can be concluded that the inclusion level of 1.0 mg Se/kg of organic Se in the diet is suggested to be the optimal level for the growth performance and immune response of Nile tilapia. Therefore, dietary supplementation with Se is useful for improving growth, antioxidant status, immune response, and disease resistance.

Determination of optimal dietary selenium levels by full expression of selenoproteins in various tissues of broilers from 22 to 42 d of age.

The current NRC dietary selenium (Se) requirement (0.15 mg/kg) of broilers from 22 to 42 d of age is primarily based on a previous study reported in 1986, which might not be applicable to modern classes of rapidly growing broilers. The present experiment was conducted to determine the optimal dietary Se level for meeting metabolic and functional Se requirements of broilers fed a corn-soybean meal diet from 22 to 42 d of age. A total of 336 Arbor Acres male broilers at 22 d old were randomly assigned to 1 of 6 treatments with 7 replicates and fed a basal corn-soybean meal diet (control, containing 0.014 mg Se/kg) and the basal diet supplemented with 0.10, 0.20, 0.30, 0.40, or 0.50 mg Se/kg from Na2SeO3 for 21 d. The results showed that the Se concentrations in plasma, liver, kidney, pancreas, breast and thigh muscles, the activity of glutathione peroxidase (GPX) in plasma, liver and kidney, the mRNA expression levels of Gpx4, selenoprotein (Seleno) h and Selenou in liver, Selenop and Selenoh in kidney, and the protein expression levels of GPX4 in the liver and kidney of broilers were affected (P < 0.05) by supplemental Se level, and increased quadratically (P < 0.05) with the increase of supplemental Se level. The estimates of optimal dietary Se levels were 0.10 to 0.49 mg/kg based on the fitted broken-line or asymptotic models (P < 0.0001) of the above Se concentration indices, and 0.08 to 0.37 mg/kg based on the fitted broken-line, quadratic or asymptotic models (P < 0.007) of the above selenoprotein expression indices. These results indicate that the optimal dietary Se levels would be 0.49 mg/kg to support the maximum Se concentrations and 0.37 mg/kg to support the full expression of selenoproteins in plasma and various tissues of broilers fed a corn-soybean meal diet from 22 to 42 d of age.

Determination of optimal dietary selenium levels by full expression of selenoproteins in various tissues of broilers from 1 to 21 d of age.

The current NRC dietary selenium (Se) requirement (0.15 mg/kg) of broilers is primarily based on growth performance data reported in 1986. Our study aimed to determine optimal dietary Se levels of broilers fed a practical corn-soybean meal diet for the full expression of selenoproteins in various tissues. A total of 384 one-d-old male broilers (n = 8 replicates/diet) were fed a basal corn-soybean meal diet or the basal diet supplemented with 0.1, 0.2, 0.3, 0.4 or 0.5 mg Se/kg in the form of Na2SeO3 for 21 d. Regression analysis was conducted to evaluate the optimal dietary Se levels using broken-line, quadratic or asymptotic models. The activity of glutathione peroxidase (GPX) in the plasma, liver, kidney and pancreas, iodothyronine deiodinase (DIO) in the plasma, liver and pancreas, and thioredoxin reductase (Txnrd) in the liver and pancreas, the mRNA levels of Gpx1, Gpx4, Dio1, selenoprotein (Seleno) h, Selenop and Selenou in the liver, Gpx4, Dio1, Txnrd1, Txnrd2, Selenoh, Selenop and Selenou in the kidney, and Gpx1, Gpx4, Selenoh and Selenou in the pancreas, and the protein levels of GPX4 in the liver and kidney of broilers were influenced (P < 0.05) by added Se levels, and increased quadratically (P < 0.05) with the increase of added Se levels. The estimates of optimal dietary Se levels were 0.07 to 0.36 mg/kg based on the fitted broken-line, quadratic or asymptotic models (P < 0.001) of the aforementioned selenoprotein expression in the plasma, liver and kidney, and 0.09 to 0.46 mg/kg based on the fitted broken-line models (P < 0.001) of the aforementioned selenoprotein expression in the pancreas. The results indicate that the optimal dietary Se levels would be 0.36 mg/kg to support the full expression of selenoproteins in the plasma, liver and kidney, and 0.46 mg/kg to support the full expression of selenoproteins in the pancreas of broilers fed a practical corn-soybean meal diet from 1 to 21 d of age.

Dietary selenium promotes the growth performance through growth hormone-insulin-like growth factor and hypothalamic-pituitary-thyroid axes in grass carp (Ctenopharyngodon idella).

Selenium (Se), an essential component of deiodinases (DIOs), regulates the contents of thyroid hormones and thus improves animal growth. To explore the influences of selenium supplementation on fish growth metabolism, a total of 270 healthy grass carp (Ctenopharyngodon idella) were divided into three groups and feed three graded dietary selenium (0.141, 0.562, and 1.044mg Se/kg) levels. The results showed that after 60-day feeding, dietary selenium improved the final body weight and specific growth rate (SGR) of grass carp. The hepatic DIO activities in selenium-supplemented groups were higher than those in control group. A significant increase in triiodothyronine (T3), free triiodothyronine (FT3), and thyroid-stimulating hormone (TSH) levels was accompanied by a decrease in the contents of thyroxine (T4) and free thyroxine (FT4) in selenium-supplemented groups. The histopathological observation of thyroid suggested that selenium deficiency resulted in hypertrophy of follicular epithelial cells. Moreover, the gene relative expression levels of dio1, dio2, and dio3 showed an increasing trend with the rising concentration of dietary selenium. The transcription levels of HPT axis-related genes (crh, tsh-β, ttr, tr-s, tpo, nis) and GH/IGF1-related genes (gh, ghr, igf1, igf1r) were significantly upregulated in selenium-supplemented groups. No significant differences in the above indicators were observed between 0.562 and 1.044mg Se/kg diet group except T3 content and dio1 relative expression ratio. These results indicate that dietary selenium supplementation improves the hepatic DIO activities and thyroid hormone metabolism and regulates the transcription levels of HPT and GH/IGF axis-related genes, which may be responsible for the growth promotion in grass carp.

Selenium deficiency induces spleen pathological changes in pigs by decreasing selenoprotein expression, evoking oxidative stress, and activating inflammation and apoptosis

BackgroundThe immune system is one aspect of health that is affected by dietary selenium (Se) levels and selenoprotein expression. Spleen is an important immune organ of the body, which is directly involved in cellular immunity. However, there are limited reports on Se levels and spleen health. Therefore, this study established a Se-deficient pig model to investigate the mechanism of Se deficiency-induced splenic pathogenesis.MethodsTwenty-four pure line castrated male Yorkshire pigs (45 days old, 12.50 ± 1.32 kg, 12 full-sibling pairs) were divided into two equal groups and fed Se-deficient diet (0.007 mg Se/kg) or Se-adequate diet (0.3 mg Se/kg) for 16 weeks. At the end of the trial, blood and spleen were collected to assay for erythroid parameters, the osmotic fragility of erythrocytes, the spleen index, histology, terminal deoxynucleotidyl transferase nick-end labeling (TUNEL) staining, Se concentrations, the selenogenome, redox status, and signaling related inflammation and apoptosis.ResultsDietary Se deficiency decreased the erythroid parameters and increased the number of osmotically fragile erythrocytes (P < 0.05). The spleen index did not change, but hematoxylin and eosin and TUNEL staining indicated that the white pulp decreased, the red pulp increased, and splenocyte apoptosis occurred in the Se deficient group. Se deficiency decreased the Se concentration and selenoprotein expression in the spleen (P < 0.05), blocked the glutathione and thioredoxin antioxidant systems, and led to redox imbalance. Se deficiency activated the NF-κB and HIF-1α transcription factors, thus increasing pro-inflammatory cytokines (IL-1β, IL-6, IL-8, IL-17, and TNF-α), decreasing anti-inflammatory cytokines (IL-10, IL-13, and TGF-β) and increasing expression of the downstream genes COX-2 and iNOS (P < 0.05), which in turn induced inflammation. In addition, Se-deficiency induced apoptosis through the mitochondrial pathway, upregulated apoptotic genes (Caspase3, Caspase8, and Bak), and downregulated antiapoptotic genes (Bcl-2) (P < 0.05) at the mRNA level, thus verifying the results of TUNEL staining.ConclusionsThese results indicated that Se deficiency induces spleen injury through the regulation of selenoproteins, oxidative stress, inflammation and apoptosis.