Liver Selenium Concentrations Research Articles

The effects of in ovo feeding of selenized glucose on liver selenium concentration and antioxidant capacity in neonatal broilers

Selenium is an essential trace element for humans and animals. As the active center of selenoproteins, the addition of selenium is beneficial to enhance the antioxidant ability. However, the high cost limits the application of organic Se in agriculture animal production. Selenized glucose (SeGlu) is a newly invented organoselenium material with good stability, low toxicity and low cost. This assay found that SeGlu was able to increase selenium deposition in liver of newborn broilers, and enhance the antioxidant capacity of liver by elevating the activities of antioxidant enzymes such as total superoxide dismutase and glutathione peroxidase. This paper as the first example clarifying the mechanism of SeGlu to enhance the antioxidant ability of chicks, shows that SeGlu can be used as an organic selenium enrichment additive for early nutrition of poultry. As a cross-discipline study involving chemistry, biology and agriculture animal science, the work may be beneficial for studies in related fields and prompt the development of the selenium science.

Classical Selenium-Dependent Glutathione Peroxidase Expression Is Decreased Secondary to Iron Deficiency in Rats

While there are reports that classical selenium-dependent glutathione peroxidase (Se-GPX1) activity is decreased during iron deficiency, the relationship between tissue iron status and Se-GPX1 activity remains speculative. This study was undertaken to investigate the mechanism for the decrease in Se-GPX1 activity during iron deficiency. Male weanling Sprague-Dawley rats were given free access to either an iron-deficient or an iron-adequate diet for eight weeks, after which blood, livers, kidneys, hearts, brains and testes were surgically excised. During iron deficiency, Se-GPX1 mRNA levels in liver tissue were decreased by approximately 55%. Similarly, the concentration of immunoreactive Se-GPX1 protein and total selenium-dependent glutathione peroxidase (Se-GPX) activity were decreased by 55% and 60%, respectively. In kidney, heart and brain total Se-GPX activities were depressed as much as 33%. Selenium concentration in liver was reduced by 42%, whereas the decrease in Se concentrations in kidney, heart, and brain ranged from 17 to 25%. Concentrations of plasma Se also were reduced by 18%, but testes showed little change in either Se-GPX activity or Se concentration during iron deficiency. Results suggest that the synthesis of Se-GPX1 protein is decreased during iron deficiency possibly due to pretranslational regulation.

Short-term Dietary Selenium Deficiency Induced Liver Fibrosis by Inhibiting the Akt/mTOR Signaling Pathway in Rats.

The effects of short-term dietary selenium deficiency on the liver and protein kinase B (Akt)/mammalian target of rapamycin (mTOR) signaling pathway were evaluated. Fourteen growing rats were randomly divided into control and selenium deficiency groups and fed standard and selenium-deficient diets for 4weeks, respectively. The serum and liver selenium concentrations were measured to evaluate the construction of animal models with selenium deficiency. Liver tissues were analyzed by transmission electron microscope, hematoxylin-eosin staining, and Masson staining to observe the ultrastructural changes, pathological changes, and severity of liver fibrosis, respectively. Besides, immunohistochemical staining (IHC) was used to analyze the effects of selenium deficiency on the expression of key proteins in the Akt/mTOR signaling pathway. The results showed that selenium concentrations in the serum and liver tissue were significantly lower in the selenium deficiency group than in the control group, and the selenium deficiency intervention could affect the morphology and structure of hepatocytes and mitochondria. Meanwhile, the liver tissue showed structural damage and fibrotic changes in the selenium deficiency group. The IHC results showed the positive staining rates of Akt, phosphorylation-modified protein kinase B (p-Akt), mTOR, and phosphorylation-modified mammalian target of the rapamycin (p-mTOR) in the liver of the selenium deficiency group which were significantly lower than that of the control group. In conclusion, short-term selenium deficiency dietary intervention could lead to liver fibrosis by inhibiting the Akt/mTOR signaling pathway.

PSVIII-6 Impact of Naturally Occurring Water with High Sulfate Concentration on Feed and Water Intake, Growth, and Trace Mineral Status of Beef Cattle

Abstract This study evaluated the impact of naturally occurring water with a high-sulfate concentration on dry matter intake (DMI), water intake, growth, and trace mineral status of yearling beef heifers. Angus-based heifers (n = 48; 398.4 ± 22.1 kg) were randomly assigned to 1 of 12 pens (4 heifers/pen) and fed for 100 d arranged into 25 d periods. Heifers were provided water containing 350 (CON); 2,300 (MEDS); or 4,300 mg/L (HIGHS) sulfate. Concentrated water (71,482 mg/L sulfate) from natural source was collected and blended to achieve the treatments. All data were analyzed using the fixed effects of treatment, period (d 1-25, 26-50, 51-75, and 76-100), and the treatment × period interaction, with period as a repeated measure. Average daily gain, and gain-to-feed were not affected (P>0.29). Provision of HIGHS decreased (interaction, P< 0.01) DMI from d 1-25, 26-50 and 51-75, with no effect from d 76-100 compared with CON. Heifers drinking CON and MEDS during d 26-50 had greater (interaction, P< 0.01) water intake than HIGHS with no differences among treatments otherwise. Total sulfate intake (g/d) was greater for HIGHS, followed by MEDS and CON with a greater difference between treatments during d 26-50 (interaction, P< 0.01). Heifers provided MEDS and HIGHS had a greater (interaction, P< 0.01) reduction in serum copper compared with CON. Liver copper concentration did not differ at the start of the study but was 74% and 62% of CON for MEDS and HIGHS, respectively at the end of the study (interaction, P< 0.01). Serum selenium was greater for MEDS and HIGHS than CON; while liver selenium was least for HIGHS heifers at the end of the study (interaction, P< 0.01). These data highlight that beef heifers were able to tolerate 213 g/d of sulfate intake with no negative impact on growth performance; however, MEDS and HIGHS decreased liver copper and liver selenium concentrations.

2-Hydroxy-4-Methylselenobutanoic Acid Promotes Follicle Development by Antioxidant Pathway.

Selenium (Se) is assumed to promote the follicle development by attenuating oxidative stress. The current study was developed to evaluate the effects of dietary 2-hydroxy-4-methylselenobutanoic acid (HMSeBA) supplementation on the follicle development in vivo and on the function of ovarian granulosa cells (GCs) in vitro. Thirty-six gilts were randomly assigned to fed control diet (CON), Na2SeO3 diet (0.3 mg Se/kg) or HMSeBA diet (0.3 mg Se/kg). The results showed that HMSeBA and Na2SeO3 supplementation both increased the total selenium content in liver and serum compared with control, while HMSeBA increased the total selenium content in liver compared with Na2SeO3 group. HMSeBA tended to increase the total selenium content in ovary compared with control. HMSeBA and Na2SeO3 supplementation both increased the weight of uteri in gilts at the third estrus. Moreover, HMSeBA supplementation down-regulated the gene expression of growth differentiation factor-9 (GDF-9) and bone morpho-genetic protein-15 (BMP-15) in cumulus-oocyte complexes (COCs). HMSeBA supplementation decreased malondialdehyde (MDA) content in serum, liver and ovary, increased activity of T-AOC in liver, TXNRD in ovary and GPX in serum, liver and ovary, while up-regulated the liver GPX2, SOD1 and TXNRD1, ovarian GPX1 gene expression. In vitro, HMSeBA treatment promoted GCs' proliferation and secretion of estradiol (E2). HMSeBA treatment increased the activity of T-AOC, T-SOD, GPX, TXNRD and decreased MDA content in GCs in vitro. Meanwhile, HMSeBA treatment up-regulated SOD2 and GPX1 gene expression in GCs in vitro. In conclusion, HMSeBA supplementation is more conducive to promoting follicle development by antioxidant pathway.

114 Evaluation of Selenium Source on Nursery Pig Growth Performance, Serum and Tissue Selenium Concentrations, and Serum Antioxidant Status

Abstract A total of 3,888 pigs (337×1050, PIC, Hendersonville, TN; 6.0 kg at weaning) were used in a 42-d study to determine the influence of Se source on nursery pig selenium status and growth performance. At placement, pens of pigs were weighed and allotted to 1 of 3 dietary treatments in a randomized complete block design with blocking structure including sow farm origin, date of entry, and average pen BW. A total of 144 pens were used with 72 double-sided 5-hole stainless steel, fence-line feeders, with feeder serving as the experimental unit. For each feeder, 1 pen contained 27 gilts and the other 27 barrows. There were 24 replicates per treatment. Diets were fed in 3 phases, and all contained 0.3 ppm added Se. A common phase 1 diet contained added Se from sodium selenite and was fed in pelleted form to all pigs for 7 d prior to initiation of treatment diets. Three Se sources [sodium selenite; Se yeast; and hydroxy-selenomethionine (OH-SeMet)] were used to formulate 3 experimental treatments in meal form for phase 2 (d 7 to 21) and phase 3 (d 21 to 42). During the common phase 1 period, ADFI tended (P < 0.10) to be different (107, 103, and 102 g/d) for sodium selenite, Se yeast, and OH-SeMet, respectively. From d 7 to 42 (treatment period), pigs fed OH-SeMet tended to have decreased ADG (P < 0.10) and had increased (P < 0.05) serum, liver, and muscle selenium concentration compared with other treatments. There was no difference (P > 0.05) in antioxidant status as measured by serum GSH-Px or TBARS. In summary, compared with sodium selenite and selenium yeast, OH-SeMet had greater bioavailability as indicated by increased serum and tissue selenium concentration; however, antioxidant status was similar between treatments and OH-SeMet tended to reduce growth performance compared with pigs fed sodium selenite.

Element concentrations, histology and serum biochemistry of arctic char (Salvelinus alpinus) and shorthorn sculpins (Myoxocephalus scorpius) in northwest Greenland

The increasing exploratory efforts in the Greenland mineral industry, and in particular, the proposed rare earth element (REE) mining projects, requires an urgent need to generate data on baseline REE concentrations and their potential environmental impacts. Herein, we have investigated REE concentrations in anadromous Arctic char (Salvelinus alpinus) and shorthorn sculpins (Myoxocephalus scorpius) from uncontaminated sites in Northwest Greenland, along with the relationships between the element concentrations in gills and liver, and gill histology and serum biochemical parameters. Concentrations of arsenic, silver, cadmium, cerium, chromium, copper, dysprosium, mercury, lanthanum, neodymium, lead, selenium, yttrium, and zinc in gills, liver and muscle are presented. No significant statistical correlations were observed between element concentrations in different organs and gill histology or serum biochemical parameters. However, we observed positive relationships between age and histopathology, emphasizing the importance of including age as a co-variable in histological studies of fish. Despite no element-induced effects were observed, this study is considered an important baseline study, which can be used as a reference for the assessment of impacts of potential future REE mine sites in Greenland.

PSXII-10 The effects of different mineral supplementation strategies on feedlot performance of mineral deficient cattle

Abstract Mineral deficient cattle that enter a feedlot have been documented to have increased morbidity and mortality rates and decreased feedlot performance. The objective of this research was to explore current practices used by feedlot producers when receiving mineral deficient cattle. To accomplish this, forty steers were blocked by weight and mineral status, then assigned to one of four treatment groups: control (Con; n = 10), industry mineral requirements (IND; n = 10) top dressed on TMR fed, 2X industry mineral requirements (2XIND; n = 10) top dressed on TMR fed, and MultiMin® injection at labeled dose (MM; n = 10). All steers received the same ration in pens equipped with GrowSafe® bunks. Standing liver biopsies were collected on day 0, 5, 10, 20, 30 and 40 and analyzed for mineral content. Steers were weighed on day 0, 14, 28, 41, 56, 70, 84, and 110. Average daily gain (ADG), dry matter intake (DMI) and feed efficiency (FE) were recorded. After the trial, steers were harvested at a commercial facility and carcass data was obtained from the plant. There were no differences (P > 0.05) in weight gain or overall ADG between treatment groups. When analyzed over time, treatment had an effect (P < 0.001) on liver copper and selenium concentrations, but no effects (P > 0.05) were observed on liver manganese and zinc concentrations. Additionally, when DMI was analyzed over time, effects (P < 0.05) of time, treatment, and treatment*time were observed, and effects (P < 0.05) of time and treatment*time were observed on FE. Treatment had no effect (P > 0.05) on carcass data. These data indicate that different mineral supplementation strategies have diverse effects on feedlot performance and liver mineral concentrations over time.

EFFECT OF DIETARY NANO-SELENIUM ON PRODUCTIVE, IMMUNOLOGICAL PERFORMANCE, OXIDATION RESISTANCE AND SELENIUM DEPOSITION IN TISSUE FOR LAYING HENS

The experiment was designed to study the effect of dietary Nano-selenium on productive, immunological performance, oxidation resistance and selenium deposition in tissue of laying hens- A total number of 180 laying hens of Silver Montazah strain were used. Layers were divided randomly into six treatments. Five Nano-selenium diet concentrations (200, 160, 120, 80 and 40 mg/ton for treatments (T2, T3, T4, T5 and T6), respectively. The treatment (T1) was used as control with 200 mg/ton diet sodium selenite. The results were discussed and summarized as follows: Application of Nano-selenium in layer diets was effective in increasing egg number, egg mass, total serum protein, and albumin. Also, Nano-selenium improved some immunological traits, feed conversion, some egg quality traits and some antioxidant enzymes traits. The optimum level of Nano-selenium was 200 mg/ton diet, which recorded 5.409 feed/g egg mass compared to 9.249 feed / g egg mass in control treatment (200 mg/ton diet) Application of 200 mg/ton diets Nano-selenium were significantly decreased total cholesterol, high density Lipoprotein, triglycerides, heterophils (H%) and H/L ratio. Where, Lymphocyte was significantly (p≤ 0.01) increased. The concentration of selenium in liver, breast meat and whole egg were 30.9%, 40.5% and 102.3% higher in layers fed 200 mg/ton diet Nano- selenium compared to layers fed 200mg/ton sodium selenite. layers fed 200mg/ton diet Nano- selenium had 5.6 % and 5.4 % higher in dressing and edible meat, respectively.

IMPACT OF DIETARY SUPPLEMENTATION WITH NANO AND ORGANIC SELENUIM WITHOUT OR WITH VITAMIN E ON GROWTH PERFORMANCE AND SELENIUM METABOLISM IN GROWING RABBITS

The objective of the present study was to examine the effects of dietary supplementation with two sources of selenium (Se), organic (Org-Se) and Nano-Se without or with vitamin E (Vit-E) on growth performance and Se metabolism in New Zealand White (NZW) growing rabbits. In a factorial experimental design (2x3), ninety weaned NZW rabbits of 5 weeks old and with average body weight, 579.5 ± 5.53g were used in the study for 56 days. Rabbits were randomly distributed into 6 experimental groups and fed the following six diets : (1) control Basal diet without any supplementation, either Vit. E or Se; (2) Basal diet + 250 mg Vit. E/ kg diet; (3) Basal diet + 0.3 mg Org- Se /kg diet; (4) Basal diet + 0.3 mg Org -Se /kg diet+ 250 mg Vit. E/ kg diet; (5) Basal diet + 0.3 mg Nano-Se /kg diet; (6) basal diet + 0.3 mg Nano-Se /kg diet + 250 mg Vit. E/ kg diet. Results of the experiment revealed that live body weight (LBW) and total body gain (TBG) were significantly higher (P< 0.05) and feed conversion ratio (FCR) was the best with rabbits fedbasal diet plus Nano-Secompared to those fed the control diet or rabbits fed basal diet plus Org-Se. However,with adding Vit. E to the basal diet, the differences in these traits were not significant among the rabbit groups. Selenium concentrations in kidneys, liver, muscles and blood serum were insignificantly higher in rabbits fed supplemental Nano- Se than in those fed basal diet without any supplementation (control) or those fed supplemental Org-Se. However, Se concentration significantly increased (P< 0.05) in kidneys and liver in rabbit groups fedsupplementalvitamin E and was the highest in rabbitsfed supplemental Nano-Se plusVit. E. Selenium concentration in muscles and blood serum showed statistically similar values among rabbit groups fed diets supplemented with Vit. E. The economic efficiency (%) was statistically the same with rabbits fed either Nano-Se plus Vit. E or control diet plus Vit. E, while, it was the lowest with rabbits fed Org- Se compared to the control and other groups. Conclusively, based on the results of the present experiment and from the economic point of view and to ameliorate the adverse effects of heat stress on growing rabbits during the hot summer conditions in Egypt, it is advisable to supply the basal rabbit diet with Se, either as Nano- Se or Org- Se only without Vit E diet. There are still future studies to determine the effect of Nano Se on human and animal health.

Metal contamination of river otters in North Carolina.

Aquatic apex predators are vulnerable to environmental contaminants due to biomagnification. North American river otter (Lontra canadensis) populations should be closely monitored across their range due to point and nonpoint pollution sources. Nonetheless, no information exists on environmental contaminants in the North Carolina otter population. Metals and metalloids occur naturally across the landscape, are essential for cellular function, and become toxic when concentrated unnaturally. We conducted our study across the three Furbearer Management Units (FMU) and 14 river basins of North Carolina. We determined the concentrations of arsenic, cadmium, calcium, cobalt, copper, iron, lead, magnesium, manganese, mercury, molybdenum, selenium, thallium, and zinc in liver and kidney samples from 317 otters harvested from 2009 to 2016. Arsenic, lead, and thallium samples were tested at levels below the limit of detection. With the exception of cadmium, we detected all other elements at higher levels in the liver compared with the kidney. Specifically, cadmium, cobalt, copper, iron, magnesium, manganese, mercury, molybdenum, and zinc levels differed by tissue type analyzed. Most element concentrations remained stable or increased with otter age. We detected higher levels of mercury and selenium in the Lower Pee Dee and Cape Fear river basins. River basins within the Mountain FMU were higher in cadmium, copper, iron, lead, and zinc, whereas the Coastal Plain FMU was lower in cobalt and manganese. None of the elements occurred at toxic levels. Our research establishes baseline concentration levels for North Carolina, which will benefit future monitoring efforts and provide insight into future changes in the otter population.

Addition of tert-butylhydroquinone (TBHQ) to maize oil reduces lipid oxidation but does not prevent reductions in serum vitamin E in nursery pigs

BackgroundMaize oil is abundantly used in foods and feeds and is highly susceptible to oxidation. Consequently, commercially available antioxidants should be evaluated for effectiveness against lipid oxidation in swine diets. Our study was conducted to evaluate growth performance of nursery pigs fed oxidized maize oil and to determine effects of using antioxidants on oxidative status in a 2 × 2 factorial design. Two hundred eight weaned pigs were blocked by initial BW into 13 blocks, resulting in 4 pigs per pen and 13 pens per treatment. Dietary treatments included 6% unoxidized or oxidized maize oil, and 0 or 60 mg/kg of tert-butylhydroquinone (TBHQ), which was added after lipid oxidation. Data for growth performance were collected from 5 time periods of a two-phase feeding program (Phase 1 = d 0 to 12 and Phase 2 = d 13 to 34). Serum and liver samples were collected from one pig per pen, which had initial BW closest to average BW to determine oxidative status on d 34.ResultsOxidized maize oil was heated for 12 h at 185 °C with 12 L/min of air, yielding a peroxide value (PV) of 5.98 mEq O2/kg and TBARS of 0.11 mg MDA eq/g. Addition of TBHQ to diets containing oxidized maize oil decreased PV by 37% and increased the oil stability index by 69%. Final BW, ADG, ADFI, and G:F of pigs were not different among the four dietary treatments. However, pigs fed oxidized maize oil tended (P < 0.08) to increase hepatosomatic index by 5% compared with those fed unoxidized oil, and this was not affected by adding TBHQ. The serum vitamin E concentration of pigs fed oxidized maize oil was less (P < 0.03) than pigs fed unoxidized oil, but this reduction was not reversed by adding TBHQ. Finally, the serum and liver selenium concentration were not different among the treatments.ConclusionsThe addition of TBHQ did not affect growth performance and vitamin E status in pigs fed moderately oxidized maize oil, but TBHQ reduced lipid oxidation, enhanced the oil stability, and appeared to reduce oxidative stress.

Organic selenium supplementation increases muscle selenium content in growing lambs compared to inorganic source

The objective was to evaluate the selenium (Se) balance and Se concentration in serum, muscle and viscera as well hepatic glutathione peroxidase activity (GSH-Px) in lambs fed diets supplemented with different Se sources and levels. Forty male Suffolk lambs 90 ± 2.5 days old (19.8 ± 2.1 kg) received, during a 84 days period, a total mixed ration (TMR) with three Se sources [Sodium selenite (Na selenite), Selenium-Yeast (Se-Yeast) and Selenium-Methionine (Se-Methionine)] and three Se levels [0.2, 0.8 and 1.4 mg/kg dry matter (DM)]. Also, it was provided a control diet (no addition of Se) for regression comparisons. Contrasts and estimates were used for partition specific treatment effects and serum data were analyzed by time repeated measures. Absorption and retention of Se as well as Se excretion by feces and urine were higher as Se inclusion increased. At 1.4 mg/kg DM level, there was higher Se excretion by feces with inorganic source compared to organic sources. Also, linear increasing was detected to absorption of Se among sources supplemented relative to its intake. Regarding the Se retention efficiency (g/100 g of Se consumed) the Se-methionine treatment showed a linear pattern. Selenium concentrations in serum and liver were higher, regardless of the source, linearly to dose inclusion. The amount of Se in muscle was higher for organic sources at level 0.8 and 1.4 mg/kg DM. At the first cited level, Se-Methionine was superior compared to Se-Yeast and at the second, the opposite occurred. In addition, organic sources leaded to linear effect of Se content in muscle tissue. However, there was higher hepatic GSH-Px activity to Na selenite source compared to organic sources. Regarding to relative Se content, organic Se sources had higher content in muscle tissue compared to Na selenite.

Selenium Supplementation Alters Hepatic Energy and Fatty Acid Metabolism in Mice

Human and animal studies have raised concerns that supplemental selenium can increase the risk of metabolic disorders, but underlying mechanisms are unclear. We used an integrated transcriptome and metabolome analysis of liver to test for functional pathway and network responses to supplemental selenium in mice. Male mice (8-wk-old, C57BL/6J) fed a standard diet (0.41 ppm Se) were given selenium (Na2SeO4, 20 μmol/L) or vehicle (drinking water) for 16 wk. Livers were analyzed for selenium concentration, activity of selenoproteins, reduced glutathione (GSH) redox state, gene expression, and high-resolution metabolomics. Transcriptomic and nontargeted metabolomic data were analyzed with biostatistics, bioinformatics, pathway enrichment analysis, and combined transcriptome-metabolome-wide association study (TMWAS). Mice supplemented with selenium had greater body mass gain from baseline to 16 wk (55%±5%) compared with controls (40%±3%) (P<0.05); however, no difference was observed in liver selenium content, selenoenzyme transcripts, or enzyme activity. Selenium was higher in the heart, kidney, and urine of mice supplemented with selenium. Gene enrichment analysis showed that supplemental selenium altered pathways of lipid and energy metabolism. Integrated transcriptome and metabolome network analysis showed 2 major gene-metabolite clusters, 1 centered on the transcript for the bidirectional glucose transporter 2 (Glut2) and the other centered on the transcripts for carnitine-palmitoyl transferase 2 (Cpt2) and acetyl-CoA acyltransferase (Acaa1). Pathway analysis showed that highly associated metabolites (P<0.05) were enriched in fatty acid metabolism and bile acid biosynthesis, including acylcarnitines, triglycerides and glycerophospholipids, long-chain acyl-coenzyme As, phosphatidylcholines, and sterols. TMWAS of body weight gain confirmed changes in the same pathways. Supplemental selenium in mice alters hepatic fatty acid and energy metabolism and causes increases in body mass. A lack of effect on hepatic selenium content suggests that signaling involves an extrahepatic mechanism.

Relationship between selenium concentration in blood and liver of cattle.

The objective of this study was to investigate the relationship between total blood selenium concentration and liver tissue selenium concentration in cattle. Blood and liver samples were collected from 205 individuals brought to slaughter houses. The results had shown that there is a linear correlation between the concentration of selenium in total blood of cattle (X) and its concentration in the liver (Y). The linear regression equation was: Y=0.194+3.951± (0.265***) X (0.009 pg/ml &lt; X &lt; 0.219 pg/ml, 0.110 μg/g DM &lt; Y &lt; 1.512 μg/g DM) (r2=0.523, ***P&lt;0.001, n=205).

SHEEP FETAL GOITER: STUDY CASE IN MEXICO

&lt;p&gt;In a small-scale sheep flock located in the State of Mexico with eight ewes and one stud, four ewes had clinical signs of endemic goiter, two aborted fetuses were used for a diagnostic study. In fetuses, thyroid gland samples were used for histopathological evaluation, and liver, heart, kidney and skeletal muscle samples were used to measure selenium. In the ewes the blood serum profile of thyroid hormones was measured by ELISA test. In fetuses there was an increment of thyroid gland size (6-8 cm), firm consistency and red intense color, as well as scarce fleece and subcutaneous edema; there were hyperplasia and hypertrophy of follicular cells of thyroid, with cube-like aspect, diffuse expanded, irregular shape and distension with presence of vacuoles and abundant eosinophilic colloid. The selenium concentrations in liver and kidney of fetuses were low (0.25 and 0.90 ppm). In ewes, the thyroxin (T&lt;sub&gt;4&lt;/sub&gt;) and triiodothyronine (T&lt;sub&gt;3&lt;/sub&gt;) contents were deficient (0.48±0.08 and 4.14±0.29 µg dL&lt;sup&gt;-1&lt;/sup&gt;) and the ratio (T&lt;sub&gt;4&lt;/sub&gt;:T&lt;sub&gt;3&lt;/sub&gt;) was very broad (1:8.6 µg dL&lt;sup&gt;-1&lt;/sup&gt;). It is concluded that the lambs suffered from colloidal goiter; thyroid hormones concentrations in ewes were low and confirmed a thyroid metabolism altered; additionally goiter may be aggravated by selenium deficiency.&lt;/p&gt;

Arsenic, cadmium, cobalt, copper, lead, mercury, molybdenum, selenium and zinc concentrations in liver, kidney and muscle in Australian sheep

Matched muscle, liver and kidney samples from 152 sheep in different states of Australia were analysed for trace elements. Mean levels found in muscle, livers and kidneys were 0.010, 0.010 and 0.011mgkg−1 (fresh weight) for arsenic; 0.0035, 0.280 and 0.853mgkg−1 for cadmium; 0.006, 0.060 and 0.044mgkg−1 for cobalt; 0.74, 66.0 and 2.72mgkg−1 for copper; 0.007, 0.040 and 0.057mgkg−1 for lead; 0.0025, 0.0034 and 0.0061mgkg−1 for mercury; 0.014, 1.05 and 0.44mgkg−1 for molybdenum; 0.09, 0.31 and 0.95mgkg−1 for selenium; and 40.4, 37.2 and 20.8mgkg−1 for zinc. The lead, mercury and arsenic concentrations in meat and organs may be regarded as low, but the concentrations of cadmium in kidney and livers are sometimes relatively high. Apart from cadmium, lead and selenium, tissue trace element concentrations were not related to the age of the investigated animals. Differences in essential and non-essential trace element accumulation in sheep reared in different regions (states and territories) of Australia were also evaluated. Cadmium, lead and selenium were the only elements that appeared to show significant regional differences. Overall the results show that concentrations of the elements considered are within current acceptable ranges.

Effects of selenium supplement on atherogenesis of ApoE-knockout mice fed high fat diet

To investigate the effects of selenium supplement on atherogenesis and endothelial function in ApoE-knockout mice fed high fat diet. ApoE-knockout mice fed with selenium-deficient and high fat diet were randomly allocated into 3 groups based on random number table including control group (not supplied with sodium selenite, n=10), low dosage selenium supplement group (supplied water with 0.1 mg/L sodium selenite, n=10) and high dosage selenium supplement group (supplied water with 0.2 mg/L sodium selenite, n=10). After 15 weeks, the following values were measured: the concentrations of selenium in heart and liver, the levels of serum lipid, the parameters of antioxidant function including activities of superoxide dismutase(SOD) and glutathion peroxidase (GSH-Px) and malondialdehyde (MDA) level in serum, the parameters of endothelial function including serum nitric oxide (NO), endothelin 1(ET-1), and vascular endothelial growth factor (VEGF) levels, and ET-1 and VEGF levels in aorta roots. The atherosclerotic lesions in aorta roots were analyzed with oil red O staining. (1) The selenium concentrations in heart and liver were significantly higher in high dosage and low dosage selenium supplement groups compared to control group (both P<0.05). (2) The levels of triglyceride, total cholesterol, low density lipoprotein cholesterol, very low density lipoprotein cholesterol and high-density lipoprotein cholesterol were similar among groups (all P>0.05). (3) The activity levels of serum SOD were significantly higher in low dosage ((113.8±12.5)U/ml) and high dosage selenium supplement group ((152.3±11.3)U/ml) compared to control group ((90.7±10.7)U/ml, all P<0.05). The activity levels of serum GSH-Px were significantly higher in low dosage ((53.9±7.2)U/ml) and high dosage ((69.6±8.7)U/ml) selenium supplement groups than that of control group ((36.4±5.6)U/ml, all P<0.05). The serum MDA levels in low dosage ((4.73±1.05)nmol/ml) and high dosage ((4.13±1.21)nmol/ml) selenium supplement groups were significantly lower than that of control group ((5.97±1.08)nmol/ml, all P<0.05). (4) The serum NO concentrations in low dosage ((61.5±12.8)μmol/L) and high dosage ((79.0±14.6)μmol/L)selenium supplement groups were significantly higher than that of control group((42.7±9.1)μmol/L, all P<0.05). The concentrations of serum ET-1 in low dosage ((52.8±6.3)ng/L)and high dosage ((46.3±4.7)ng/L)selenium supplement groups were significantly lower than that of control group((72.2±6.3)ng/L, P<0.05). The concentrations of serum VEGF in low dosage ((97.4±16.5)ng/L)and high dosage ((83.5±22.0)ng/L)selenium supplement groups were significantly lower than that of control group((125.8±18.6)ng/L, P<0.05). The expression levels of ET-1 and VEGF in aorta roots among low dosage and high dosage selenium supplement groups were significantly lower compared to control group (all P<0.05). (5) The plaque area of aorta roots in low dosage ((0.95±0.19)×10(5) μm(2))and high dosage selenium supplement ((0.75±0.15)×10(5) μm(2)) groups were significantly smaller than that of control group((1.13±0.23)×10(5) μm(2)), and the plaque area in high dosage selenium supplement group was significantly smaller than in low dosage selenium supplement group (P<0.05). Supplement of selenium can attenuate atherogenesis in ApoE-knockout mice fed high fat diet, which is possibly mediated via reducing lipid peroxidation and improving endothelial functions.

Maternal transfer of contaminants in birds: Mercury and selenium concentrations in parents and their eggs

We conducted a detailed assessment of the maternal transfer of mercury and selenium to eggs in three bird species (n = 107 parents and n = 339 eggs), and developed predictive equations linking contaminant concentrations in eggs to those in six tissues of the mother (blood, muscle, liver, kidney, breast feathers, and head feathers). Mercury concentrations in eggs were positively correlated with mercury concentrations in each of the mother's internal tissues (R2 ≥ 0.95), but generally not with feathers. For each species, the proportion of mercury transferred to eggs decreased as mercury concentrations in the mother increased. At the same maternal mercury concentration, the proportion of mercury transferred to eggs differed among species, such that Forster's tern (Sterna forsteri) and black-necked stilt (Himantopus mexicanus) females transferred more methylmercury to their eggs than American avocet (Recurvirostra americana) females. Selenium concentrations in eggs also were correlated with selenium concentrations in the mother's liver (R2 = 0.87). Furthermore, mercury and selenium concentrations in tern eggs were positively correlated with those in the father (R2 = 0.84). Incubating male terns had 21% higher mercury concentrations in blood compared to incubating females at the same egg mercury concentration. We provide equations to predict contaminant concentrations in eggs from each of the commonly sampled bird tissues.

Effect of short-term zinc supplementation on zinc and selenium tissue distribution and serum antioxidant enzymes.

A significant association between Zn and Se homeostasis exists. At the same time, data on the influence of zinc supplementation on selenium distribution in organs and tissues seem to be absent. Therefore, the primary objective of the current study is to investigate the influence of zinc asparaginate supplementation on zinc and selenium distribution and serum superoxide dismutase (SOD) and glutathione peroxidase (GPx) activity in Wistar rats. 36 rats were used in the experiment. The duration of the experiment was 7 and 14 days in the first and second series, respectively. The rats in Group I were used as the control ones. Animals in Groups II and III daily obtained zinc asparaginate (ZnA) in the doses of 5 and 15 mg/kg weight, respectively. Zinc and selenium content in liver, kidneys, heart, muscle, serum and hair was assessed using inductively coupled plasma mass spectrometry. Serum SOD and GPx activity was analysed spectrophotometrically using Randox kits. Intragastric administration of zinc asparaginate significantly increased liver, kidney, and serum zinc content without affecting skeletal and cardiac muscle levels. Zinc supplementation also stimulated selenium retention in the rats' organs. Moreover, a significant positive correlation between zinc and selenium content was observed. Finally, zinc asparaginate treatment has been shown to modulate serum GPx but not SOD activity. The obtained data indicate that zinc-induced increase in GPx activity may be mediated through modulation of selenium status. However, future studies are required to estimate the exact mechanisms of zinc and selenium interplay.