Tissue Selenium Concentrations Research Articles

Effects of dietary and/or parental supplementation with selenium and mercury on their localisation in rainbow trout fry tissues (Oncorhynchus mykiss) by quantitative LA-ICP MS imaging

The increasing use of alternative feeds for sustainable aquaculture leads to a reduced selenium content requiring the use of supplements to maintain the antioxidant status of farmed fish. The introduction of tuna by-products in fish feed is attractive for their selenium content, but the presence of mercury limits their use as it may negatively impact fish health. Indeed, selenium and mercury metabolism, in relation to their interaction and biological effects in fish, is far from being fully understood. This study aims to assess the impact of parental and dietary supplementation with selenomethionine and methylmercury on selenium and mercury localisation and concentrations in tissues of 3-week rainbow trout fry. Six diets were used. Broodstock were fed a plant-based diet Bpc (with 0.2 μg g−1 selenium and 0 μg g−1 mercury) or a tuna by-product-based diet Bt (with 4 μg g−1 selenium and basal mercury at 0.2 μg g−1) during 6 months, supplemented or not with 4 μg g−1 of selenomethionine for the plant-based diet Bpo and/or with 2 μg g−1 of methylmercury for diets Bph, Bpho and Bth. Their offspring were fed the plant-based diet Fpc, supplemented or not with the same levels of selenomethionine and methylmercury, until their third week. Mercury and selenium concentrations were determined in fry whole-body by ICP MS and quantitative images of selenium and mercury were produced by LA–ICP MS from fry whole-body thin sections. Dietary supplementation of fry with selenium and/or mercury increased their concentration in all tissues, especially in liver, kidney, muscle and intestine. Parental selenomethionine supplementation had a more pronounced effect on fry selenium levels than tuna by-products diet. Mercury transfer from broodstock to their offspring was weak. Mercury concentrations decreased in the kidney of fry supplemented with both selenium and mercury, which could be related to the presence of selenium.

Mercury and Selenium Accumulation in the Tissues of Stranded Bottlenose Dolphins (Tursiops truncatus) in Northeast Florida, 2013-2021.

Bottlenose dolphins (Tursiops truncatus) are long-lived marine mammals, upper-level predators, and they inhabit near-shore environments, which increases their exposure to pollution. Mercury is a ubiquitous and persistent metal pollutant that can bioaccumulate and biomagnify up the food chain. Dolphins are known to accumulate mercury, and limited research has shown that mercury exposure can weaken the immune system of dolphins. The objectives of this study were to assess the mercury concentrations in the tissues (muscle, small intestine, liver) of stranded bottlenose dolphins and to compare the tissue mercury levels in dolphins that were stranded during the 2013-2015 morbillivirus Unusual Mortality Event (UME; immunosuppressed individuals) with the levels of those that were stranded at a normal rate (2016-2021). Selenium has been shown to reduce mercury toxicity in many animals; therefore, tissue selenium concentration and the molar ratio of selenium to mercury were also assessed. The tissue mercury (muscle, liver) and selenium (liver) concentrations increased with the age of the dolphins, with the liver accumulating the highest concentrations. No sex differences were observed in the mercury and selenium concentrations. While differences in tissue mercury concentrations were not observed due to the UME, the selenium accumulation profiles were significantly different between the two time periods. These results suggest that selenium may not have been as protective against mercury toxicity in the bottlenose dolphins that were stranded during the UME, possibly due to infection with morbillivirus.

ZAWARTOŚĆ SELENU W GONADACH SAMCÓW I SAMIC DZIKA EUROAZJATYCKIEGO (SUS SCROFA) Z WOJEWÓDZTWA MAZOWIECKIEGO

Selenium is counted among the trace elements necessary to maintain metabolic processes occurring in the animal body, including reproductive processes. The aim of the study was to assess selenium content in testes and ovaries of wild boars (Sus scrofa) in an attempt to establish a range of reference values for individuals of this species. Selenium concentrations in tissues tested were determined using spectrofluorometric method after wet mineralization in HNO3 and HClO4 mixture. Based on the results, it was found that male wild boars accumulated significantly higher concentrations of Se than females. The average content of this element in the testes of wild boars was 0.32 mg · kg−1 while in the ovaries it was at the level of 0.14 mg · kg−1 wet weight. In addition, the gonads of males were characterized by a higher variability of the analyzed parameter in relation to samples obtained from female wild boars. The coefficient of variation in their case was almost 40.9, while the value of the coefficient of variation for selenium content in the parenchymal layer of the ovaries was 24.9. On the basis of statistical analysis, highly significant differences were found at p ≤ 0.01 according to the sex of the individuals studied. Despite the fact that samples were taken from individuals living in areas with selenium deficiencies due to the biogeochemical background, it should be considered that the supply of Se is optimal, which is evident in the population growth dynamics of individuals of this species in the study area.

ZAWARTOŚĆ SELENU W JAJNIKACH WOLNO ŻYJĄCYCH CERVIDAE Z TERENU PÓŁNOCNO-WSCHODNIEJ POLSKI

Selenium is counted among the trace elements necessary for the maintenance of metabolic processes occurring in the animal body, including the proper functioning of the reproductive system. The aim of the study conducted was to analyze the selenium content in the ovaries of red deer (Cervus elaphus) and European roe deer (Capreolus capreolus) in an attempt to establish a range of reference values for individuals of these species. Selenium concentrations in tissues tested were determined using spectrofluorometric method after wet mineralization in HNO3 and HClO4 mixture. Ovaries Se concentrations ranged from 0.034–0.338 mg⋅kg−1 wet weight and 0.015–0.285 mg⋅kg−1 wet weight in roe deer and red deer respectively. Based on the results, it was found that the average selenium content was higher in the ovaries of red deer and was 0.11 while in roe deer it was 0.09 mg⋅kg−1 wet weight. The gonads of European roe deer were characterized by higher variability of the analyzed pa- rameter in relation to samples obtained from female red deer. The coefficient of variation in their case was almost 90.1, while the value of the coefficient of variation for selenium content in the parenchymal layer of ovaries in red deer was almost 67.6.

Analysis of Selenium in Fish Tissue: An Interlaboratory Study on Weight Constraints.

Environmental monitoring programs that target fish tissues for selenium (Se) analysis present unique sampling and analytical challenges. Se monitoring programs ideally focus on egg/ovary sampling but frequently sample multiple tissues with varying lipid content, often target small-bodied fish species due to their small home ranges, and require reporting in units of dry weight. Additionally, there is a growing impetus for non-lethal tissue sampling in fish monitoring. As a result, Se monitoring programs often generate low-weight tissue samples of varying lipid content, which challenges analytical laboratories to quantify tissue selenium concentrations accurately, precisely, and at desired detection limits. The objective of this study was to stress-test some conventional analytical techniques used by commercial laboratories in terms of their ability to maintain data quality objectives in the face of sample weight constraints. Four laboratories analyzed blind a suite of identical samples, and data were compared against a priori data quality objectives for accuracy, precision, and sensitivity. Data quality tended to decrease with decreasing sample weight, particularly when samples were less than the minimum weights requested by the participating laboratories; however, effects of sample weight on data quality were not consistent among laboratories or tissue types. This study has implications for accurately describing regulatory compliance in selenium monitoring programs, highlighting some important considerations for achieving high data quality from low-weight samples.

Comparison of Sodium Selenite and Selenium-Enriched Spirulina Supplementation Effects After Selenium Deficiency on Growth, Tissue Selenium Concentrations, Antioxidant Activities, and Selenoprotein Expression in Rats.

Selenium contributes to physiological functions through its incorporation into selenoproteins. It is involved in oxidative stress defense. A selenium deficiency results in the onset or aggravation of pathologies. Following a deficiency, the repletion of selenium leads to a selenoprotein expression hierarchy misunderstood. Moreover, spirulina, a microalga, exhibits antioxidant properties and can be enriched in selenium.. Our objective was to determine the effects of a sodium selenite or selenium-enriched spirulina supplementation. Thirty-two female Wistar rats were fed for 12 weeks with a selenium-deficient diet. After 8 weeks, rats were divided into 4 groups and were fed with water, sodium selenite (20 μg Se/kg body weight), spirulina (3 g/kg bw), or selenium-enriched spirulina (20 μg Se/kg bw + 3 g spirulina/kg bw). Another group of 8 rats was fed with normal diet during 12 weeks. Selenium concentration and antioxidant enzyme activities were measured in plasma, urine, liver, brain, kidney, heart, and soleus. Expression of GPx (1, 3), Sel (P, S, T, W), SEPHS2, TrxR1, ApoER2, and megalin were quantified in liver, kidney, brain, and heart. We showed that a selenium deficiency leads to a growth delay, reversed by selenium supplementation despite a minor loss of weight in week 12 for SS rats. All tissues displayed a decrease in selenium concentration following deficiency. The brain seemed protected. We demonstrated a hierarchy in selenium distribution and selenoprotein expression. A supplementation of sodium selenite improved GPx activities and selenoprotein expression while a selenium-enriched spirulina was more effective to restore selenium concentration especially in the liver, kidney, and soleus.

Evaluation of selenium source on nursery pig growth performance, serum and tissue selenium concentrations, and serum antioxidant status.

A total of 3,888 pigs (337 × 1050, PIC, Hendersonville, TN; initially 6.0 ± 0.23 kg) were used in a 35-d study. At the time of placement, pens of pigs were weighed and allotted to one of three dietary treatments in a randomized complete block design with a blocking structure including sow farm origin, date of entry into the facility, and average pen body weight. A total of 144 pens were used with 72 double-sided 5-hole stainless steel fence line feeders, with one feeder serving as the experimental unit. For each feeder, 1 pen contained 27 gilts, and 1 pen contained 27 barrows. There were 24 replicates per dietary treatment. Diets were fed in three phases, and all contained 0.3 mg/kg added Se. A common phase 1 diet contained added Se from sodium selenite and was fed in pelleted form to all pigs from day 7 to approximately day 0. Three Se sources sodium selenite, Se yeast, and hydroxy-selenomethionine (OH-SeMet) were used to formulate three experimental diets in meal form for phase 2 (days 0 to 14) and phase 3 (days 14 to 35). During the pre-treatment period (days 7 to 0), there was a tendency (P = 0.097) of a difference in average daily feed intake between treatments, although no significant pairwise differences were observed (P > 0.05). There were no other differences in growth performance between treatments from days 7 to 0. Clinical disease attributed to Streptococcus suis was observed within the trial between days 0 and 14, and water-soluble antimicrobial therapy was administered to all treatment groups for 7 d. From days 0 to 35, pigs fed OH-SeMet tended to have decreased average daily gain (P < 0.10) and increased (P < 0.05) serum and tissue selenium concentration compared to other treatments. There was marginally significant evidence of a source × day interaction (P = 0.027) for total antioxidant capacity where the numerical increase over time was less for the OH-SeMet than sodium selenite or selenium yeast treatments. There was no difference (P > 0.05) in antioxidant status as measured by serum glutathione peroxidase or thiobarbituric acid reactive substances assay between treatments. In summary, compared to sodium selenite and selenium yeast, OH-SeMet may have a 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.

Study of the effect of a seven -containing drug on the concentration of selenium in the organs and tissues of the lambs of the Romanov breed in the conditions of industrial complexes North-Western region

Purpose: to study the effects of a selenic -containing drug on the concentration of selenium in blood serum, organs and tissues of lambs of the Romanov breed.Materials and methods. In the course of the study, 120 novels of the Romanov breed and 80 lambs obtained from the data of disemeters were used. The formation of control and experimental groups was carried out taking into account the principle of pair analysis. In experiments on assessing the effect of the drug, clinically healthy animals were used on the body. During the study, four groups of lambs were formed at the age of 30 days. The mothers of the first group during the period of suyagnity received the drug “e-sel” at the rate of 1 ml per 50 kg of live weight; The lambs of the first experimental group introduced the drug “E-sel” at the rate of 0.2 ml per 10 kg of live weight according to the instructions. The second group was a control - a physiological solution was administered in the same quantity as the drug with experimental animals; Feeding was carried out by the main diet. The studies were carried out in the period before the chopping (4 months of age) was carried out. Blood fence was carried out from the jugular vein. The concentration of selenium in blood serum lambs was determined by fluorimetrically with 2.3-diaminonaftalin. After the chopping, the lambs were slaughtered. The concentration of selenium in the organs and tissues of the lamb was examined by atomic-adsorption spectrometry.Results. It was established that the concentration of selenium in the lambs of the first experimental group increased, starting from the 60s from the moment of birth. At the same time, in the lambs of the first experimental group, the concentration increased 2.84 times by the 60th knocks compared to control, 4.08 times compared to control by the 90s from the moment of birth and 8.5 times by 120 -It day from the moment of birth. The concentration of selenium in the kidneys, liver and muscles (the broadest back muscle) of the first experimental group significantly exceeded the values of control. The maximum concentration was noted in the kidneys. No reliable changes were noted between the 1st and 2nd experimental groups in the concentrations of selenium in the kidneys and liver. The concentration of selenium in the liver of the experimental group was 2.94 times higher in comparison with control. In the kidneys, the concentration of selenium was 2.26 times higher for the experimental group in comparison with control. It is noted that an increase in the concentration of selenium in the muscles exceeded control indicators of 4.59, respectively.

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 &amp;lt; 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 &amp;lt; 0.10) and had increased (P &amp;lt; 0.05) serum, liver, and muscle selenium concentration compared with other treatments. There was no difference (P &amp;gt; 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.

Effects of bacterial organic selenium, selenium yeast and sodium selenite on antioxidant enzymes activity, serum biochemical parameters, and selenium concentration in Lohman brown-classic hens

This study compares the effects of sodium selenite, selenium yeast, and enriched bacterial organic selenium protein on antioxidant enzyme activity, serum biochemical profiles, and egg yolk, serum, and tissue selenium concentration in laying hens. In a 112-d experiment, 144 Lohman Brown Classic hens, 23-wks old were divided into four equal groups, each has six replicates. They were assigned to 4 treatments: 1) a basal diet (Con), 2) Con plus 0.3mg/kg feed sodium selenite (SS); 3) Con plus 0.3mg/kg feed Se-yeast (SY): 4) Con plus 0.3mg/kg feed bacterial enriched organic Se protein (ADS18) from Stenotrophomonas maltophilia bacteria. On d 116, hens were euthanized (slaughtered) to obtain blood (serum), liver organ, and breast tissue to measure antioxidant enzyme activity, biochemical profiles, and selenium concentration. The results show that antioxidant enzyme activity of hens was increased when fed bacterial organic Se (ADS18), resulting in a significant (P < 0.05) increase in serum GSH-Px, SOD, and CAT activity compared to other treatment groups. However, ADS18 and SY supplementation increase (P < 0.05) hepatic TAC, GSH-Px, and CAT activity, unlike the SS and Con group. Similarly, dietary Se treatment reduced total cholesterol and serum triglycerides concentrations significantly (P < 0.05) compared to the Con group. At 16 and 18weeks, selenium concentration in hen egg yolks supplemented with dietary Se was higher (P < 0.05) than in Con, with similar patterns in breast tissue and serum. Supplementation with bacterial organic Se (ADS18) improved antioxidant enzyme activity, decreased total serum cholesterol and serum lipids, and increased Se deposition in egg yolk, tissue, and serum. Hence, organic Se may be considered a viable source of Se in laying hens.

Effects of Selenium Auricularia cornea Culture Supplementation on Growth Performance, Antioxidant Status, Tissue Selenium Concentration and Meat Quality in Growing-Finishing Pigs.

Simple SummarySelenium Auricularia cornea culture (SAC) is a dried product via full fermentation, containing organic-Se, Auricularia cornea (AC) mycelium, and various metabolites of AC. The objective of this study was to evaluate whether SAC could effectively improve the health, growth, meat quality, and oxidative stability of meat in growing-finishing pigs. Currently, dietary SAC supplementation positively impacts growth performance and oxidative stability of fresh meat.Selenium Auricularia cornea culture (SAC) is a new source of organic selenium. Two experiments were conducted to determine the available energy of SAC fed to pigs and to evaluate the effects of dietary SAC supplementation on growth performance, serum biochemical profiles, fecal short chain fatty acids (SCFA), meat quality, tissue selenium concentration, and oxidative stability of fresh meat in growing-finishing pigs. In Experiment (Exp.) 1, 12 barrows with average body weight (BW) of 42.40 ± 5.30 kg were randomly allotted to two groups and fed the basal diet and SAC-supplemented diet, individually. In Exp. 2, 96 growing-finishing pigs (BW: 91.96 ± 7.55 kg) were grouped into four dietary treatments; each treatment contained six replicates with four pigs per replicate. The four treatments fed a control diet and three experimental diets supplemented with 0.6%, 1.2%, and 2.4% SAC, respectively. The trial lasted for 45 days. The results revealed that digestible energy (DE) of SAC was 11.21 MJ/kg. The average daily gain (ADG) was improved in pigs fed 1.2% and 2.4% SAC during day 24 to 45 and the overall period. Dietary 1.2% and 2.4% SAC supplementation had a lower F/G (p < 0.05) than the control diet during different stages. Dietary SAC supplementation increased fecal butyrate contents (p < 0.05), and pigs fed 1.2% and 2.4% SAC diets had a higher MCT1 mRNA expression (p = 0.04) in the colon. Pigs fed 2.4% SAC had higher GSH-Px contents (p < 0.05) in serum, liver, and longissimus dorsi muscle (LDM) than those in the control group. The 2.4% SAC-supplemented group revealed a higher Se content (p < 0.05) in LDM and a lower MDA concentration (p < 0.05) in fresh meat during the simulated retail display on day six. In conclusion, this study suggested that SAC was more effective in improving growth, enhancing the antioxidant status, depositing Se in muscle, and increasing meat oxidative stability of pigs.

Organic Selenium Increased Gilts Antioxidant Capacity, Immune Function, and Changed Intestinal Microbiota.

Selenium is an indispensable essential micronutrient for humans and animals, and it can affect biological functions by combining into selenoproteins. The purpose of this study was to investigate the effects of 2-hydroxy-4-methylselenobutanoic acid (HMSeBA) on the antioxidant performance, immune function, and intestinal microbiota composition of gilts. From weaning to the 19th day after the second estrus, 36 gilts (Duroc × Landrace × Yorkshire) were assigned to three treatments: control group, sodium selenite group (0.3 mg Se/kg Na2SeO3), and HMSeBA group (0.3 mg Se/kg HMSeBA). Dietary supplementation with HMSeBA improved the gilts tissue selenium content (except in the thymus) and selenoprotein P (SelP1) concentration when compared to the Na2SeO3 or control group. Compared with the control group, the antioxidant enzyme activity in the tissues from gilts in the HMSeBA group was increased, and the concentration of malondialdehyde in the colon had a decreasing trend (p = 0.07). Gilts in the HMSeBA supplemented group had upregulated gene expression of GPX2, GPX4, and SelX in spleen tissue, TrxR1 in thymus; GPX1 and SelX in duodenum, GPX3 and SEPHS2 in jejunum, and GPX1 in the ileum tissues (p < 0.05). In addition, compared with the control group, the expression of interleukin-1β (IL-1β), interleukin-6 (IL-6), interleukin-8 (IL-8), and monocyte chemotactic protein-1 (MCP-1) in the liver, spleen, thymus, duodenum, ileum, and jejunum of gilts in the HMSeBA group were downregulated (p < 0.05), while the expression of interleukin-10 (IL-10) and transforming growth factor-β (TGF-β) in the liver, thymus, jejunum, and ileum were upregulated (p < 0.05). Compared with the control group and the Na2SeO3 group, HMSeBA had increased concentration of serum cytokines interleukin-2 (IL-2) and immunoglobulin G (IgG; p < 0.05), increased concentration of intestinal immunoglobulin A (sIgA; p < 0.05), and decreased concentration of serum IL-6 (p < 0.05). Dietary supplementation with HMSeBA also increased the abundance of intestinal bacteria (Ruminococcaceae and Phascolarctobacterium; p < 0.05) and selectively inhibited the abundance of some bacteria (Parabacteroides and Prevotellaceae; p < 0.05). In short, HMSeBA improves the antioxidant performance and immune function of gilts, and changed the structure of the intestinal microflora. And this study provided data support for the application of HMSeBA in gilt and even pig production.

Mercury and selenium concentrations in different tissues of brown smooth-hound shark (Mustelus henlei) from the western coast of Baja California Sur, Mexico

A study on mercury (Hg) and selenium (Se) concentrations in the liver and muscle of brown smooth-hound shark Mustelus henlei and its principal prey items, was conducted in the western coast of Baja California Sur, Mexico. Average Hg concentrations were found to be high in the muscle than in the liver; however, Hg concentrations were below the maximum permissible limits, and hence, the consumption of this species does not constitute a risk to human health. The mean Se concentrations were higher in the liver than in the muscle. The results of Hg: Se molar ratio revealed that Se counteracts the toxicity of Hg in hepatic tissues, whereas the contrary occurs in the muscle. Significant differences in Hg and Se accumulation were observed between females and males. Biomagnification factor values >1 demonstrate a biomagnification process from its principal prey species (i.e., red crab, Pleuroncodes planipes and Pacific mackerel, Scomber japonicus).

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

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

Profile of Tissue Selenium Concentration In A Cohort Of Nigerian Men With Prostate Cancer

Profile of Tissue Selenium Concentration In A Cohort Of Nigerian Men With Prostate Cancer

Comparison of toxic effects of dietary organic or inorganic selenium and prediction of selenium intake and tissue selenium concentrations in broiler chickens using feather selenium concentrations

The present experiment aimed to compare toxic effects of dietary organic or inorganic selenium (Se) and to predict of Se intake and tissue Se concentrations in broiler chickens based on feather Se concentrations. A total of four hundred twenty 7-day-old Ross 308 male broiler chicks were allotted to 1 of 7 dietary treatments in a completely randomized design. Each treatment had 6 replicates with 10 birds per replicate. Organic Se (selenium yeast) or inorganic Se (sodium selenite) was added to the basal diet at the levels of 5, 10, or 15 mg/kg Se. All experimental diets were fed to birds on an ad libitum basis for 28 d. Results indicated that a significant interaction (P < 0.01) was observed between Se sources and inclusion levels for the BW gain and feed intake of broiler chickens with inorganic Se at 15 mg/kg in diets showing a greatest negative effect. Increasing inclusion levels of Se in diets increased (linear, P < 0.01) plasma concentrations of uric acid. Increasing inclusion levels of Se in diets increased (linear, P < 0.01) relative liver weight. No significant interactions were observed between Se sources and inclusion levels in diets on hepatic antioxidant capacity. Increasing inclusion levels of Se in diets increased (linear, P < 0.01) Se concentrations in the liver, breast, and feather. The concentrations of Se in the breast, liver, and feather were greater (P < 0.05) for organic Se than for inorganic Se in diets. The toxic levels of organic or inorganic Se in broiler diets were near 7 or 9 mg/kg based on the BW gain, respectively. The prediction equations indicate that feather Se concentrations in broiler chickens can be used to predict both daily Se intake and Se concentrations in the liver and breast.

Relationship between mercury and selenium concentrations in tissues from stranded odontocetes in the northern Gulf of Mexico

Odontocetes are apex predators that, despite accumulating mercury (Hg) to high concentrations in their tissues, show few signs of Hg toxicity. One method of Hg detoxification in odontocetes includes the sequestering of Hg in toxicologically inert mercury selenide (HgSe) compounds. To explore the tissue-specific accumulation of Hg and Se and the potential protective role of Se against Hg toxicity, we measured the concentrations of total mercury (THg) and selenium (Se) in multiple tissues from 11 species of odontocetes that stranded along the northern Gulf of Mexico coast [Florida (FL) and Louisiana (LA)]. Tissues were collected primarily from bottlenose dolphins (Tursiops truncatus; n = 93); however, individuals from species in the following 8 genera were also sampled: Feresa (n = 1), Globicephala (n = 1), Grampus (n = 2), Kogia (n = 5), Mesoplodon (n = 1), Peponocephala (n = 4), Stenella (n = 9), and Steno (n = 1). In all species, mean THg concentrations were greatest in the liver and lowest in the blubber, lung, or skin. In contrast, in most species, mean Se concentrations were greatest in the liver, lung, or skin, and lowest in the blubber. For all species combined, Se:Hg molar ratios decreased with increasing THg concentration in the blubber, kidney, liver, lung, and skin following an exponential decay relationship. In bottlenose dolphins, THg concentrations in the kidney, liver, and lung were significantly greater in FL dolphins compared to LA dolphins. On average, in bottlenose dolphins, Se:Hg molar ratios were approximately 1:1 in the liver and >1:1 in blubber, kidney, lung, and skin, suggesting that Se likely protects against Hg toxicity. However, more research is necessary to understand the variation in Hg accumulation within and among species and to assess how Hg, in combination with other environmental stressors, influences odontocete population health.

Knockout of Selenoprotein V Affects Regulation of Selenoprotein Expression by Dietary Selenium and Fat Intakes in Mice

Background:The metabolic function of selenoprotein V (SELENOV) remains unknown. Objectives:Two experiments were conducted to determine effects of the Selenov knockout (KO) on selenium concentration and mRNA, protein, and/or activity of 4 major selenoproteins [glutathione peroxidase (GPX) 1, GPX4, thioredoxin reductase-1 (TXNRD1), and selenoprotein P (SELENOP)] in the serum, liver, testis, and/or white adipose tissue (WAT) of mice fed different dietary selenium and fat concentrations. Methods:In Experiment (Expt) 1, 40 KO and 40 wild-type (WT) mice (males, 8 wk old) were fed (n= 10/genotype) a casein-sucrose basal diet plus 0, 0.3, 1, or 3 mg Se/kg (as sodium selenite) for 32 wk . In Expt 2, 20 KO and 20 WT mice (males, 8 wk old) were fed (n = 10/genotype) a normal-fat diet (NF; 10% calories from fat) or a high-fat diet (HF; 60% calories from fat) for 19 wk. Results:In Expt 1, the KO caused consistent or substantial decreases (P < 0.05) of mRNA amounts of Gpx1, Txnrd1,and Selenop in the testis (≤52%), but selenium concentrations (19–29%) and GPX activities (≤ 50%) were decreasedin the liver across different dietary selenium concentrations . Hepatic and testis GPX1 protein was elevated (≤31%) anddecreased (≤45%) by the KO, respectively. In Expt 2, the genotype and dietary fat intake exerted interaction effects (P < 0.05) on Gpx1 mRNA amounts in the WAT; Gpx1, Txnrd1, and Selenop mRNA amounts and TXNRD activities in thetestis; and selenium concentrations in the serum and liver. However, these 2 treatments produced largely independentor additive effects (P < 0.05) on the GPX1 and SELENOP protein amounts in the liver and testis (up to } 50% changes) Conclusions:The KO-mediated changes in the tissue selenium concentrations and functional expression of 3 major selenoproteins implied potential for SELENOV in regulating body selenium metabolism in the mouse.

Effects of dietary glycine selenium nanoparticles on loin quality, tissue selenium retention, and serum antioxidation in finishing pigs

Selenium is an indispensable nutrient for finishing pigs and it plays key roles in several physiological processes. Glycine selenium nanoparticles (G-SeNPs) is a new source of organic selenium. This study was conducted to determine the effects of dietary supplementation of G-SeNPs on the growth performance, loin quality, tissue selenium concentration, and serum antioxidation of finishing pigs. A total of 160 DLY (Duroc × Landrace × Large Yorkshire) crossbred pigs were grouped into 4 dietary treatments, each treatment contains 10 pens (replicates) with 10 pigs per replicate. Pigs were fed a basal diet (control group), and basal diets supplemented with 0.1, 0.3 or 0.5 mg/kg G-SeNPs (treatment groups). The effects of dietary G-SeNPs on average daily gain, average daily feed intake and feed-to-gain ratio were not significant, whereas the linear trends were found in L* and a*. Although drip loss did not differ upon treatment, the pH (24 h) showed a linear trend difference between the treated and untreated animals (P = 0.056). Selenium concentration in tissues increased linearly (P < 0.001) with and was linearly increased (P < 0.001) with the increase in dietary G-SeNPs concentrations. Additionally, the total antioxidant capability, glutathione peroxidase, superoxide dismutase, and catalase activity levels in the serum were linearly increased (P < 0.001) with the increase in dietary G-SeNPs concentrations. Conversely, malondialdehyde concentration in serum, which has an inverse relationship with antioxidation capability, was linearly (P < 0.001) reduced in pigs with dietary supplementation of G-SeNPs compared to pigs fed a basal diet. These results indicate that dietary G-SeNPs can increase the concentrations of selenium in tissues and enhance the serum antioxidant profile, and did not show detrimental effects on growth performance and loin quality in commercial finishing pigs.

Effect of Different Selenium Sources on Growth Performance, Tissue Selenium Content, Meat Quality, and Selenoprotein Gene Expression in Finishing Pigs.

Se-methylselenocysteine (MeSeCys) is a natural organic selenium (Se) supplement. However, its effects on animal nutrition are poorly understood. This study compared the effects of sodium selenite (SeNa), MeSeCys, and selenomethionine (SeMet) on immune function, tissue Se concentration, meat quality, and selenoprotein gene expression in pigs. A total of 72 finishing pigs were divided into four groups, which received a basal diet (BD, 0.1mg Se/kg) without Se supplementation or one supplemented with SeNa, MeSeCys, or SeMet at a concentration of 0.25mgSe/kg. Organic Se supplementation significantly increased the immune globulin A (IgA), IgG, and IgM serum levels compared with BD and SeNa groups (P < 0.05). There were no statistically significant differences in growth performance among the four groups. SeMet was more efficient in increasing Se concentrations in the heart, muscle, and liver than MeSeCys and SeNa (P < 0.05), while no statistically significant differences were observed between MeSeCys and SeNa. Se supplementation significantly decreased the pressing muscle loss compared with the BD group (P < 0.05). Meat color and pH were not significantly affected. Se supplement effects on liver selenoprotein gene mRNA level enhancement were ranked as follows: MeSeCys > SeMet > SeNa (P < 0.05). In muscle tissues, only the SELENOW mRNA level was significantly increased by the MeSeCys and SeMet treatment, compared with the SeNa group. In conclusion, SeMet was more efficient in increasing Se concentrations than MeSeCys and SeNa in pigs, while MeSeCys was more efficient in enhancing selenoprotein gene expression than SeMet and SeNa.