The importance of selenium and the effects of its deficiency in animal health

Selenised yeast sources differ in their capacity to protect porcine jejunal epithelial cells from cadmium-induced toxicity and oxidised DNA damage

In recent years there has been increasing interest in the use of selenised yeast (Se-Y) as an antioxidant feed supplement. Here, three selenised yeast products are differentiated in terms of bioefficiency and the ameliorative effect on Cadmium (Cd) toxicity in porcine epithelial cells. A porcine digestion in vitro model was chosen to more accurately simulate the bioavailability of different Se-Y preparations, allowing a comprehensive understanding of the bio efficiency of each Se-Y compound in the porcine model. To elucidate a possible mechanism of action of selenium a number of bioassays were applied. Levels of Se dependent antioxidant enzymes (glutathione peroxidase and thioredoxin reductase) were evaluated to analyze the ROS neutralizing capacity of each Se-Y compound. The effects of Se-Y sources on Cd-induced DNA damage and apoptosis-associated DNA fragmentation was assessed using comet and terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) assays, respectively. Lesion-specific DNA damage analysis and in vitro DNA repair assay determined the DNA repair capacity of each Se-Y source. The results presented in this study confirm that the ability of different commercially available Se-Y preparations to enhance a range of cellular mechanisms that protect porcine gut epithelial cells from Cd-induced damage is concentration-dependent and illustrates the difference in bioefficiency of different Se-Y compounds.

Immuno-protective role of biologically synthesized dietary selenium nanoparticles against multiple stressors in Pangasinodon hypophthalmus

An environment friendly and sustainable approach is being emerged in the area of nanotechnology for accelerated growth and development of culturable aquatic animals hence green chemistry is gaining momentum in recent years. The present study has been carried out to delineate the effects of selenium nanoparticles (Se-NPs) on growth performance, antioxidative status and immunity of fish reared under lead (Pb) and high temperature (34 °C). Three hundred and fifteen fish were equally distributed in seven treatments in triplicates. Three isocaloric and isonitrogenous experimental diets viz. control (Se-NPs-0 mg/kg), Se-NPs at 1 mg/kg and Se-NPs at 2 mg/kg were formulated. The fish were reared under lead (Pb, 1/21st of LC₅₀ (4 ppm)) and high temperature (34 °C) stress and fed with or without dietary Se-NPs. The effects of dietary Se-NPs were studied in terms of growth performance (Weight gain %, feed conversion ratio, protein efficiency ratio and specific growth rate), antioxidative status (catalase, superoxide dismutase, glutathione-S-transferase and glutathione peroxidase), neurotransmitter enzymes (AChE), stress biomarkers (heat shock protein 70, serum cortisol, blood glucose, vitamin C), immunological status (total protein, A/G ratio and respiratory burst activity) in Pangasinodon hypophthalmus post challenge with Aeromonas veronii biovar sobria. Results of the investigation demonstrated significant improvement of growth performance, antioxidative status, neurotransmitter enzyme activity, stress markers and more importantly enhanced immunity of the fish with dietary incorporation of Se-NPs at 1 mg/kg. In addition, post bacterial infection, the relative % survival increased and cumulative mortality % decreased in the group fed with Se-NPs at 1 mg/kg diet. Pb and high temperature treated and fed with control diet group showed devastating impact on the growth performance, antioxidative status, stress markers and immunity of the fish. Similarly, application of Se-NPs at 2 mg/kg showed poor growth performance and elevated level of oxidative stress and other stress biomarkers including other biochemical attributes. Inclusive results indicated that, Se-NPs at 1 mg/kg has capability to enhance overall performance and alleviate multiple stresses in P. hypophthalmus. Hence, Se-NPs at optimum level have ability to develop green chemistry in feed industry for better growth performance of the fish.

Bioaccessible selenium sourced from Se-rich mustard cake facilitates protection from TBHP induced cytotoxicity in melanoma cells

Selenium (Se) is an essential dietary supplement that resolves inflammatory responses and offers antioxidant cytoprotection. In this study, we present the data on the cytoprotective effect of Se-rich mustard protein isolated from mustard cultivated in seleniferous soils in Punjab, India. The concentrations of total Se in mustard seed, oil-free mustard cake, and mustard protein were 110.0 ± 3.04, 143.0 ± 5.18, and 582.3 ± 6.23 μg g-1, respectively. The cytoprotective effect of Se-rich mustard protein was studied on tert-butyl hydroperoxide (TBHP)-induced cytotoxicity in a mouse melanoma cell line (B16-F10). When compared with TBHP treated cells (where no viable cells were found), Se-rich protein made bioaccessible through simulated gastrointestinal digestion protected melanoma cells from cytotoxicity with decreased levels of oxidative stress resulting in 73% cell viability. Such an effect was associated with a significant increase in glutathione peroxidase activity as a function of bioaccessible Se and its response towards cytoprotection.

Accuracy of a diagnostic model based on serum biochemical parameters in detecting cows at an increased risk of chronic fascioliasis

In adult cattle Fasciola hepatica infection usually follows a chronic subclinical course, and reduces both the milk yield and milk quality, resulting in considerable financial losses. Effective control of the disease is based on reliable identification of asymptomatically infected individuals, which now requires special parasitological or serological diagnostic tests. It is also known that F. hepatica infection induces alterations in some serum biochemical parameters. Therefore, the study was conducted to develop a model based on serum biochemical parameters allowing to identify cows at higher risk of chronic fascioliasis. Six hundred sixty eight adult dairy cows from 97 herds located in central and northeastern Poland were clinically examined, and blood and fecal samples from them were collected for a routine monitoring of fascioliasis and metabolic profile. Using the combination of fecal sedimentation test and indirect ELISA based on excretory/secretory products 203 cows, apparently healthy in clinical examination, were definitively classed as affected by (47 cows, 23.2%) or free from (156 cows, 76.8%) chronic fascioliasis. Their serum was screened for the activity of 4 enzymes (γ-glutamyl transpeptidase, glutamate dehydrogenase, aspartate aminotransferase, creatine kinase) and concentration of 18 other components (total bilirubin, total protein, albumin, globulin, urea, glucose, non-esterified fatty acids, β-hydroxybutyrate, sodium, potassium, chloride, calcium, magnesium, copper, zinc, iron, selenium, and haptoglobin). Logistic regression analysis was used to build 4 multivariable models allowing for identification of cows at risk of chronic fascioliasis. Then, the accuracy was compared between the models using the area under the receiver operating characteristic curve (AUROC), and an optimal cut-off value was determined for the most accurate model using Youden J index. The most accurate proved to be the model based on glutamate dehydrogenase activity and globulin, urea (all three positively linked with risk of chronic fascioliasis), and selenium concentration (negatively linked) adjusted by the access to pasture and cow's age. At the optimal cut-off of 0.37 this model had sensitivity of 85.1% (CI 95%:72.3%, 92.6%), specificity of 90.4% (CI 95%:84.7%, 94.1%), positive likelihood ratio of 8.8 (CI 95%:5.4, 14.5), and negative likelihood ratio of 0.16 (CI 95%:0.08, 0.33). This model performed significantly better than model including only γ-glutamyl transpeptidase or model including both γ-glutamyl transpeptidase and aspartate aminotransferase (both also adjusted by the access to pasture and cow's age), and was the only model which performed significantly better than the basic model based solely on the access to pasture and cow's age.

Trace elements in the liver of captive and free-ranging European bison (Bison bonasus L.)

European bison is classified as a vulnerable species because of many threats. We analyzed the content of toxic and essential elements (Ag, Al, As, Ba, Be, Cd, Co, Cr, Cu, Hg, Mg, Mn, Na, Ni, Pb, Se, Th, Tl, U, V, and Zn) in the livers of 30 captive and free-ranging European bison from the Bison Breeding Center in Smardzewice and from Białowieża Primeval Forest in Poland. The contents of toxic elements were lower than reported previously in European Bison and were similar to those of wild ungulates from non-polluted areas. Accumulation of Cd and Cr was related to the age of animals. We compared the mineral status between captive and free-ranging European bison to verify whether the maintenance type could affect concentrations of trace elements in the liver. The concentration of Mn and Zn differed between captive and free-ranging group. Our results were compared to the reference values of essential elements for cattle. All animals from this study were Se-deficient and more than 80% of them have Cu deficiency. Deficiency of Mn was present in 20% of captive and 37% of free-ranging animals whereas Zn in 37% and 3% respectively. Statistical analysis confirmed that Mn and Zn deficiencies were related o the maintenance of animals (p<0.05). We revealed that mineral deficiencies could be an additional threat to the Polish population of European bison. Thus, the monitoring of essential minerals is necessary and future work is required to optimize the supplementation and foddering for preventing the occurrence of mineral deficiencies.

Effects of feeding pregnant beef cows selenium-enriched alfalfa hay on selenium status and antibody titers in their newborn calves

In newborn dairy calves, it has been demonstrated that supranutritional maternal and colostral Se supplementation using Se yeast or sodium selenite, respectively, improves passive transfer of IgG. In beef cattle, agronomic biofortification with Se is a more practical alternative for Se supplementation, whereby the Se concentration of hay is increased through the use of Se-containing fertilizer amendments. It has been previously demonstrated that agronomic Se biofortification is an effective strategy to improve immunity and performance in Se-replete weaned beef calves. The objective of this experiment was to determine the effects of feeding beef cows Se-enriched alfalfa (Medicago sativa) hay during the last 8 to 12 wk of gestation on passive transfer of antibodies to calves. At 10 wk ± 16 d before calving, 45 cows were assigned to 1 of 3 treatment groups with 3 pens (5 cows/pen) per treatment: Control cows were fed non-Se-fortified alfalfa hay plus a mineral supplement containing 120 mg/kg Se from sodium selenite, Med-Se cows were fed alfalfa hay fertilized with 45.0 g Se/ha as sodium selenate, and High-Se cows were fed alfalfa hay fertilized with 89.9 g Se/ha as sodium selenate; both the Med-Se and the High-Se groups received mineral supplement without added Se. Colostrum and whole blood (WB) were collected from cows at calving, and WB was collected from calves within 2 h of calving and at 12, 24, 36, and 48 h of age. Concentrations of IgG1 and J-5 Escherichia coli antibody in cow colostrum and calf serum were quantified using ELISA procedures. Selenium concentrations linearly increased in WB (P < 0.001) and colostrum (P < 0.001) of cows and in WB of newborn calves (P < 0.001) with increasing Se concentration in alfalfa hay. Colostrum concentrations of IgG1 (P = 0.03) were increased in cows fed Se-biofortified alfalfa hay, but J-5 E. coli antibody (P = 0.43) concentrations were not. Calf serum IgG1 (P = 0.43) and J-5 E. coli antibody (P = 0.44) concentrations during the first 48 h of age were not affected by prior Se treatment of cows. These data suggest that feeding Se-biofortified alfalfa hay promotes the accumulation of Se and antibodies in colostrum but does not affect short-term serum antibody concentrations in calves.

A Summary of New Findings on the Biological Effects of Selenium in Selected Animal Species-A Critical Review

Selenium is an essential trace element important for many physiological processes, especially for the functions of immune and reproductive systems, metabolism of thyroid hormones, as well as antioxidant defense. Selenium deficiency is usually manifested by an increased incidence of retention of placenta, metritis, mastitis, aborts, lowering fertility and increased susceptibility to infections. In calves, lambs and kids, the selenium deficiency demonstrates by WMD (white muscle disease), in foals and donkey foals, it is associated with incidence of WMD and yellow fat disease, and in pigs it causes VESD (vitamin E/selenium deficiency) syndrome. The prevention of these health disorders can be achieved by an adequate selenium supplementation to the diet. The review summarizes the survey of knowledge on selenium, its biological significance in the organism, the impact of its deficiency in mammalian livestock (comparison of ruminants vs. non-ruminants, herbivore vs. omnivore) and possibilities of its peroral administration. The databases employed were as follows: Web of Science, PubMed, MEDLINE and Google Scholar.

Metabolomics and Trace Element Analysis of Camel Tear by GC-MS and ICP-MS

Camel tear metabolomics and elemental analysis are useful in getting the information regarding the components responsible for maintaining the protective system that allows living in the desert and dry regions. The aim of this study was to correlate that the camel tears can be used as artificial tears for the evaluation of dryness in the eye. Eye biomarkers of camel tears were analyzed by gas chromatography-mass spectroscopy (GC-MS) and inductively coupled plasma mass spectroscopy (ICP-MS). The major compounds detected in camel tears by GC-MS were alanine, valine, leucine, norvaline, glycine, cadaverine, urea, ribitol, sugars, and higher fatty acids like octadecanoic acid and hexadecanoic acid. GC-MS analysis of camel tears also finds several products of metabolites and its associated metabolic participants. ICP-MS analysis showed the presence of different concentration of elemental composition in the camel tears.

Maternal selenium-supplementation at various stages of periconception period: influence on murine blastocyst morphology and implantation status

BACKGROUND

Selenium is one of the trace minerals whose deficiency is known to lead to complications of female reproduction. The identified gaps in researches regarding selenium and pregnancy include optimizing the dosage of selenium supplementation, timing of supplementation, finding the best form and type of selenium, and selenium administration combined with other antioxidants. Hence, this study was conceptualized to address one of the identified gaps, that is, to find out the best timing of selenium administration around the time of pregnancy. Specifically, this study aimed to assess the effects of maternal Selenium-supplementation, administered at various stages of periconception period, on murine blastocyst morphology, percent occurrence of good quality blastocysts, and implantation status.

METHODS

ICR female mice were randomly assigned into the unsupplemented group (Group I) receiving basal diet without selenium, and treatment groups given with 3.0 μg selenium-supplement per day during pregestation only (Group II), pregestation-throughout-gestation (Group III) and gestation only (Group IV). Both blastocyst morphology and implantation status were assessed.

RESULTS

The morphometric measurements of blastocysts appeared to be unaffected by selenium-supplementation at different stages of periconception. Selenium-supplementation at pregestation only (Group II) and gestation only (Group IV) produced higher percent occurrence of good quality blastocysts and lower percent pre-implantation loss than Group III. Among all the treatment groups, Group III (Selenium-supplementation during pregestation-to-gestation) yielded the lowest quality blastocysts and highest percent pre-implantation loss.

CONCLUSION

Maternal selenium-supplementation during pregestation and gestation stages of the periconception period yielded a high percent occurrence of good quality blastocysts and pre-implantation success.

The Influence of Selenium Yeast on Hematological, Biochemical and Reproductive Hormone Level Changes in Kunming Mice Following Acute Exposure to Zearalenone

Healthy male Kunming mice received selenium yeast for 14 days prior to a single oral administration of zearalenone (ZEN). After 48 h, blood samples were collected for analysis and showed that mice in the ZEN-treated group has significantly decreased lymphocytes (P < 0.05) and platelets (P < 0.05) along with an increased white blood cell (WBC) count and other constituents (P < 0.05). The serum biochemistry analysis of the ZEN group indicated that glutamic pyruvic transaminase (ALT), glutamic oxaloacetic transaminase (AST), urea, and uric acid were significantly increased (P < 0.05), whilst total bilirubin (TB) and albumin (ALB) were decreased along with serum testosterone and estrogen (P < 0. 05). The level of malondialdehyde (MDA) in the serum of the ZEN group was significantly increased whilst glutathione peroxidase (GSH-Px) and superoxide dismutase (SOD) had significantly decreased (P < 0.05). Treatment with selenium yeast had a significant effect on response with most of the experimental parameters returning to levels similar to those observed in the untreated control mice. From these data, it can be concluded that ZEN is highly poisonous in Kunming mice with high levels of toxicity on the blood, liver, and kidneys. High levels of oxidative stress were observed in mice and pre-treatment with selenium yeast by oral gavage is effective in the ameliorated effects of ZEN-induced damage.

Selenium Deficiency-Induced Inflammation and Increased Expression of Regulating Inflammatory Cytokines in the Chicken Gastrointestinal Tract

Selenium (Se), a nutritionally essential trace element, plays an important role in various aspects of health for a wide range of species, including birds. Se deficiency inhibits the growth of immune organs and decreases immune function, leading to many inflammatory diseases. The present study determined the effects and mechanism of dietary Se deficiency on gastrointestinal tract tissue inflammation. The histopathological changes showed that Se deficiency induced inflammatory lesions in the gastrointestinal tract tissues (glandular stomach, gizzard, duodenum, small intestine, and rectum). The expression levels of PTGE (prostagland E synthase), COX-2 (cyclooxygenase-2), TNF-α (tumor necrosis factor α), and NF-κB (nuclear transfer factor κB) in the gastrointestinal tract tissues (glandular stomach, gizzard, duodenum, small intestine, and rectum) were determined by qPCR on days 15, 25, 35, 45, and 55, respectively. The results showed that Se deficiency induced high expression levels of PTGE, COX-2, TNF-α, and NF-κB in the gastrointestinal tract tissues. The effects were more obvious in the duodenum and small intestine than those in the glandular stomach, gizzard, and rectum. In addition, the expression levels of these proteins in the gastrointestinal tract tissue increased in a time-dependent manner with Se deficiency feeding time. Furthermore, Se deficiency induced the production of pro-inflammatory factors, thus aggravating inflammatory lesions in the gastrointestinal tract. The effect of Se deficiency on inflammation and other gastrointestinal tract diseases should be further studied.

Effects of Sodium Fluoride on Lipid Peroxidation and PARP, XBP-1 Expression in PC12 Cell

This study aims to clarify the molecular mechanism of fluorine exposure that leads to nerve injury. PC12 cells were treated with fluorine at different concentrations (0.5, 1.0, 1.5, and 2.0 mM). Cytoactivity was detected at different time points (2, 4, 6, 8, 12, 24, and 48 h). After 2 h, DCF was used to detect and mark the level of reactive oxygen species (ROS) within cells. After 24 h, cellular metamorphosis was observed using an inverted microscope. After 2 h, Hoechst-33342 was used to detect apoptosis. After 24 h, Western blot analysis was performed to detect apoptosis-related poly (ADP-ribose) polymerase (PARP) protein, p-elF, and expression of the endoplasmic reticulum stress-related X-box binding protein 1 (XBP-1). The results showed that Fluorine exposure resulted in a reduction of cell viability, which was negatively correlated with fluorine dose. Within certain fluorine exposure duration, the ROS level within the cell and the apoptotic level are linearly related to fluorine exposure level. XBP-1 and PARP protein are sensitive to variations in fluorine concentration, which indicates that oxidative stress from fluorine exposure can lead to apoptosis. XBP-1 and PARP may be the key proteins during the entire process. These results provide a valid basis for fluorine-induced free radical injury theory.

High dietary selenium and vitamin E supplementation ameliorates the impacts of heat load on oxidative status and acid-base balance in sheep

The objective of this study was to determine the efficacy of supranutritional dietary selenium and vitamin E (Vit E) to ameliorate the effect of heat stress (HS) on oxidative status and acid-base balance in sheep. Thirty-two Merino × Poll Dorset ewes were acclimated to indoor individual pen feeding of a pelleted control diet (0.24 g Se and 10 IU of Vit E/kg DM) for 1 wk. Sheep were then moved to metabolism cages in climatic chambers and randomly allocated to a 2 × 2 × 2 factorial design with the respective factors being dietary Se (0.24 and 1.20 mg/kg DM as Sel-Plex; Alltech, Australia), Vit E (10 and 100 IU/kg DM), and temperature for 2 wk. After 1 wk of acclimation in metabolic cages, 1 climatic chamber continued on thermoneutral (TN) conditions (18°C to 21°C and 40% to 50% relative humidity [RH]), and the other one was set to HS conditions (28°C to 40°C and 30% to 40% RH) for 1 wk. The sheep were then returned to individual pens and fed the control diet for 1 wk before being returned to the same diet as in the first period but a reversed thermal treatment for a further 2 wk. Physiological parameters were recorded 3 times daily, and blood samples were collected on d 1 and 7 of thermal treatment. Average respiration rate and rectal temperature of sheep were increased (P < 0.001) during HS; however, combined supranutritional supplementation of Se and Vit E reversed the effects of HS. Sheep given the high Se and high Vit E diet had a lower respiration rate (191 vs. 232 breaths/min; P = 0.012) and rectal temperature (40.33°C vs. 40.58°C; P = 0.039) under peak HS (1700 h) compared with those fed the low Se and low Vit E diet. Plasma reactive oxygen metabolites concentrations were reduced (P = 0.048) by 20%, whereas biological antioxidant potential was increased (P = 0.17) by 10% in sheep fed the high Se and high Vit E diet compared with those fed the low Se and low Vit E diet. Blood pH was elevated (P = 0.007) and bicarbonate was reduced (P = 0.049) under HS, and again, these effects were ameliorated by the high Se and high Vit E diet. Both white blood cell glutathione peroxidase gene expression and red blood cell lysate glutathione peroxidase activity were increased in sheep fed the high Se and high Vit E diet. These data suggest that supranutritional dietary Se or Vit E can reduce some of the negative effects of HS. However, the synergism between the 2 antioxidants improves their potential to ameliorate the impacts of HS in sheep.

Selenium Deficiency Facilitates Inflammation Following S. aureus Infection by Regulating TLR2-Related Pathways in the Mouse Mammary Gland

Selenium (Se) is an essential micronutrient affecting various aspects of health. Se deficiency has been associated with inflammation and immune responses. Mastitis poses a serious problem for humans and animals in the postpartum period. Staphylococcus aureus (S. aureus) is the most common infectious bacterial pathogen associated with mastitis. The present study sought to determine the effects and underlying mechanism of dietary Se on S. aureus-induced inflammation using a model of mouse mastitis. ELISA and Western blotting were performed to detect protein levels. Quantitative PCR (qPCR) was performed to detect messenger RNA (mRNA) levels. The histopathological changes indicated that Se deficiency resulted in increased inflammatory lesions in S. aureus mastitis, whereas Se deficiency did not induce inflammatory lesions in the mammary gland. Myeloperoxidase (MPO) activity was increased in Se-deficient mice with S. aureus mastitis. Analysis of cytokine mRNA and protein showed that Se deficiency leads to increased TNF-α, IL-1β, and IL-6 production in S. aureus mastitis. In addition, Se deficiency enhanced the mRNA and protein expressions of toll-like receptor 2 (TLR2), which were originally upregulated by S. aureus in the mammary gland tissues and human embryonic kidney 293 (HEK293)-mTLR2 cells. When Se-deficient mice were infected with S. aureus, the phosphorylation of IκB, nuclear factor-κB (NF-κB), extracellular signal-regulated kinase (ERK), c-Jun N-terminal kinase (JNK), and p38 was greatly increased. The results indicate that Se deficiency could intensify the inflammatory reaction in S. aureus mastitis. This work contributes to the exploration of new methods of preventing or treating of S. aureus mastitis and other infectious diseases.

Critical Thresholds of Antioxidant and Immune Function Parameters for Se deficiency Prediction in Dairy Cows

The aim of this study was to determine the plasma selenium (Se) levels of lactating cows and to evaluate its association with antioxidant ability and immune function. In a descriptive study, 20 healthy Holstein cows with normal Se level (C) and 30 Holstein cows with subclinical Se deficiency (T) were randomly selected between 14 and 21 days postpartum from a dairy farm, according to a cutoff point of 70 mg/L Se in plasma. Analysis of biochemical parameters of antioxidant and immune function were performed on all the cows, and the risk prediction thresholds for subclinical Se deficiency were determined by area under receiver operating characteristic curve. Cows in the T group had significantly lower plasma Se concentrations compared with cows in the C group (52.16 ± 8.81 vs. 80.37 ± 8.46 μg/L, P = 0.02). There was a marked decrease in plasma glutathione peroxidase (GSH-Px) activity in the T group that correlated positively with the plasma Se level (R = 0.65, P = 0.00), and a significant increase of plasma methane dicarboxylic aldehyde (MDA), total nitric oxide synthase, and lipid peroxidation that correlated negatively with plasma Se levels (R = -0.47, P = 0.01; R = -0.33, P = 0.04; R = -0.40, P = 0.03). Furthermore, there were significantly lower plasma tumor necrosis factor-α and immunoglobulin G levels in the T group that correlated positively with plasma Se levels (R = 0.41, P = 0.01 and R = 0.45, P = 0.01), and a markedly lower plasma interleukin-6 level that correlated negatively with plasma Se levels (R = -0.38, P = 0.02). In addition, if plasma GSH-Px activity was less than 42.37 U/ml, the risk of Se deficiency was significantly increased in lactating cows. These results suggest that low plasma Se levels may reduce the antioxidant ability and immune function, and the risk of low plasma Se level may be predicted effectively by plasma GSH-Px activity in lactating cows.

Selenium Deficiency Deteriorate the Inflammation of S. aureus Infection via Regulating NF-κB and PPAR-γ in Mammary Gland of Mice

Selenium (Se) is an essential micronutrient contributing to a strong immune system for the prevention of infections and diseases in humans and animals. Dietary Se regulates the immune status and mediates anti-inflammatory action. Mastitis is an inflammation in the mammary gland typically induced through the major pathogen S. aureus. The aim of the present study was to determine the regulating effect of Se on S. aureus-induced inflammation using a mouse mastitis model. Immunofluorescence staining was used to detect histopathological injury. ELISA was used to detect cytokine expression, while protein and mRNA levels were analyzed through Western blotting and qPCR analysis, respectively. The results showed that Se deficiency increased inflammatory lesions in individuals with S. aureus infection in the mammary gland. The NO levels showed a significant increase in Se-deficient mice with S. aureus mastitis. Se deficiency accelerated the production of pro-inflammatory factors and reduced IL-10 expression. Furthermore, the results of the present study showed that the regulating effect of Se on S. aureus-induced mastitis was associated with the NF-κB pathway. Indeed, Se deficiency suppressed PPAR-γ activity and promoted NF-κB pathway activation. Thus, Se supplementation could improve the effect on PPAR-γ and NF-κB. These results suggest that Se deficiency could aggravate the inflammatory injury resulting from S. aureus-induced mastitis. Moreover, the results of the present study contribute to the development of new prevention or treatment methods for S. aureus-induced mastitis and other infectious diseases.

Selenium in Cattle: A Review

This review article examines the role of selenium (Se) and the effects of Se supplementation especially in the bovine species. Selenium is an important trace element in cattle. Some of its roles include the participation in the antioxidant defense the cattle farms. The nutritional requirements of Se in cattle are estimated at 100 μg/kg DM (dry matter) for beef cattle and at 300 μg/kg DM for dairy cows. The rations high in fermentable carbohydrates, nitrates, sulfates, calcium or hydrogen cyanide negatively influence the organism's use of the selenium contained in the diet. The Se supplementation may reduce the incidence of metritis and ovarian cysts during the postpartum period. The increase in fertility when adding Se is attributed to the reduction of the embryonic death during the first month of gestation. A use of organic Se in feed would provide a better transfer of Se in calves relative to mineral Se supplementation. The addition of Se yeasts in the foodstuffs of cows significantly increases the Se content and the percentage of polyunsaturated fatty acids (PUFA) in milk compared to the addition of sodium selenite. The enzyme 5-iodothyronine deiodinase is a seleno-dependent selenoprotein. It is one of the last proteins to be affected in the event of Se deficiency. This delay in response could explain the fact that several studies did not show the effect of Se supplementation on growth and weight gain of calves. Enrichment of Se in the diet did not significantly affect the slaughter weight and carcass yield of bulls. The impact and results of Se supplementation in cattle depend on physiological stage, Se status of animals, type and content of Se and types of Se administration. Further studies in Se supplementation should investigate the speciation of Se in food and yeasts, as well as understanding their metabolism and absorption. This constitute a path to exploit in order to explain certain different effects of Se.

Effect of pre- and post-weaning dietary supplementation with Digestarom® herbal formulation on rabbit carcass traits and meat quality

This study evaluated effects of Digestarom® (D) dietary inclusion before weaning (0-5weeks old; BW) and/or after weaning (5-12weeks old; AW) on growing rabbit carcass traits and meat quality. During BW, Pannon-Ka rabbits (does, kits) received two diets: a control diet (C) and one supplemented with 300mg Digestarom®/kg (D). At weaning, each group was divided into 3 dietary sub-groups: CC and DD received C and D diets from 5 to 12weeks of age, whereas DC was fed D from 5 to 8weeks and C from 8 to 12weeks of age (54 rabbits/group; AW). Rabbits were slaughtered at 12weeks of age. Digestarom® supplementation improved carcass yield and body mid part proportion only when administered BW. Rabbits fed D BW had higher hind leg meat cooking losses. Loin meat spiciness and rancidity increased with D both BW and AW. In conclusion, Digestarom(®) herbal formulation was ineffective in improving growing rabbit carcass traits or meat quality.

Exhaled breath condensate hydrogen peroxide concentration, a novel biomarker for assessment of oxidative stress in sheep during heat stress

The present study aimed to measure hydrogen peroxide (H2O2) in exhaled breath condensate (EBC) as an index of oxidative stress induced by heat stress (HS) and to evaluate the antioxidant potential of supranutritional levels of selenium (Se) and vitamin E under HS conditions in sheep. Thirty-two Merino × Poll Dorset ewes (in two replicates) were acclimated to indoor individual pen feeding of a pelleted control diet (0.24 g Se and 10 IU of vitamin E/kg DM) for 1 week. Sheep were then randomly allocated to a 2 × 2 factorial design with the respective factors being dietary Se (0.24 and 1.20 mg/kg DM as Sel-Plex) and vitamin E (10 and 100 IU/kg DM) for 2 weeks. After 1 week acclimation to the diets the sheep were placed in metabolism cages in one of two climatic chambers set to either thermoneutral (18−21°C and 40–50% relative humidity) or HS (28−40°C and 30–40% relative humidity) conditions for 1 week. Average respiration rate and rectal temperature were increased (P < 0.001) during HS. Similarly, H2O2 concentration in EBC and plasma reactive oxygen metabolites were increased significantly (P = 0.041 and P = 0.002, respectively), in sheep exposed to HS. The EBC H2O2 concentration was reduced (P < 0.05) in sheep fed the diet supplemented with supranutritional levels of both Se and vitamin E. Sheep supplemented with antioxidants also had lower respiration rates (191 vs 232 breaths/min, P = 0.012) and rectal temperature (40.33 vs 40.58°C, P = 0.039) under peak HS (1300 hours and 1700 hours) compared with those on the control diet indicating an improved capacity to handle HS. These data suggest that the H2O2 concentration in EBC can be utilised as a novel biomarker to demonstrate oxidative stress induced by HS in sheep.

Functionality and genomics of selenium and vitamin E supplementation in ruminants

Selenium (Se) and vitamin E are essential micronutrients for animal health and production. The major function of both Se and vitamin E is to prevent the oxidative damage of biological membranes and they can influence growth, reproduction, immune function, health, and product quality in ruminants. Both Se and vitamin E are important for maintaining low cellular and systemic concentrations of reactive oxygen species and lipid hydroperoxides, to ensure optimum cellular function. Discovery of various selenoproteins and vitamin E-responsive genes has contributed significantly to improving our understanding about multiple functions of Se and vitamin E. There is evidence that these functions extend beyond the classical antioxidant properties to immunomodulation and intracellular cell signalling and gene regulation. Research in recent years has also shown that supranutritional supplementation of Se and vitamin E is required to improve the performance of ruminants under certain stressful conditions such as heat stress and during transition period. Considering the growing awareness among consumers of the benefits of antioxidant-rich food, there is a great opportunity for the livestock industries to focus on producing antioxidant-enriched milk and meat products or functional foods. The present review focuses on the recent developments in understanding multiple functions of Se and vitamin E at the cellular and molecular level and the effects of supranutritional supplementation on ruminant performance. In addition, the paper also articulates the potential opportunities to produce functional foods enriched with antioxidants, and underlines the need for optimum supplementation of these micronutrients for efficient ruminant production.

Selenium Supplementation Affects Physiological and Biochemical Processes to Improve Fodder Yield and Quality of Maize (Zea mays L.) under Water Deficit Conditions

Climate change is one of the most complex challenges that pose serious threats to livelihoods of poor people who rely heavily on agriculture and livestock particularly in climate-sensitive developing countries of the world. The negative effects of water scarcity, due to climate change, are not limited to productivity food crops but have far-reaching consequences on livestock feed production systems. Selenium (Se) is considered essential for animal health and has also been reported to counteract various abiotic stresses in plants, however, understanding of Se regulated mechanisms for improving nutritional status of fodder crops remains elusive. We report the effects of exogenous selenium supply on physiological and biochemical processes that may influence green fodder yield and quality of maize (Zea mays L.) under drought stress conditions. The plants were grown in lysimeter tanks under natural conditions and were subjected to normal (100% field capacity) and water stress (60% field capacity) conditions. Foliar spray of Se was carried out before the start of tasseling stage (65 days after sowing) and was repeated after 1 week, whereas, water spray was used as a control. Drought stress markedly reduced the water status, pigments and green fodder yield and resulted in low forage quality in water stressed maize plants. Nevertheless, exogenous Se application at 40 mg L^-1 resulted in less negative leaf water potential (41%) and enhanced relative water contents (30%), total chlorophyll (53%), carotenoid contents (60%), accumulation of total free amino acids (40%) and activities of superoxide dismutase (53%), catalase (30%), peroxidase (27%), and ascorbate peroxidase (27%) with respect to control under water deficit conditions. Consequently, Se regulated processes improved fodder yield (15%) and increased crude protein (47%), fiber (10%), nitrogen free extract (10%) and Se content (36%) but did not affect crude ash content in water stressed maize plants. We propose that Se foliar spray (40 mg L^-1) is a handy, feasible and cost-effective approach to improve maize fodder yield and quality in arid and semi-arid regions of the world facing acute shortage of water.

Dietary antioxidants at supranutritional doses modulate skeletal muscle heat shock protein and inflammatory gene expression in sheep exposed to heat stress

The objective of this study was to investigate the effects of chronic heat (thermal) stress and dietary antioxidant supplementation on the expression of heat shock proteins and inflammatory genes in the skeletal muscle of sheep. Twenty-four Merino × Poll Dorset crossbred ewes were allocated to either a control (10 IU vitamin E and 0.24 mg Se/kg DM) or high-antioxidant (VitE+Se; 100 IU vitamin E and 1.20 mg Se/kg DM) diet and were exposed to 2 thermal (temperature) treatments (thermoneutral [TN]: 18°C-21°C and 26%-30% relative humidity; heat stress [HS]: 28°C-40°C and 40%-50% relative humidity) for 1 wk. Physiological parameters were recorded daily, and muscle biopsies were conducted at the end of thermal treatments. Total RNA was extracted from muscle samples and reverse transcribed to cDNA for real-time PCR analysis. Respiration rates and rectal temperature were increased in response to HS (84.2 vs. 161 breaths per minute and 39.52°C vs. 40.06°C for TN and HS conditions, respectively; P < 0.001). There were interactions between dietary and thermal treatments, indicating that dietary antioxidant supplementation reduced respiration rate (P = 0.097) and rectal temperature (P = 0.086) of sheep during HS but not TN conditions. Skeletal muscle heat shock transcription factor 1 (HSF1) mRNA abundance was increased by HS (1.3-fold; P < 0.050) but was not changed (P = 0.77) by dietary antioxidant supplementation. The expression of skeletal muscle heat shock protein 70 (HSP70) mRNA was increased (P < 0.001) 3.5-fold by HS and tended (P = 0.08) to be increased by dietary antioxidant supplementation. Although there were no main effects of diet (P = 0.42) or HS (P = 0.47) on skeletal muscle HSP90 mRNA expression, there was an interaction (P = 0.040) such that HSP90 mRNA expression was increased (P = 0.010) in antioxidant-supplemented sheep under HS compared to TN conditions. Skeletal muscle nuclear factor kappa B (NF-κB) and tissue necrosis factor α (TNF-α) mRNA abundances were increased by exposure to heat (5.2-fold, P = 0.005 for NF-κB; 5.7-fold, P = 0.013 for TNF-α) ,but there was no main effect (P > 0.05) of dietary antioxidant supplementation. There was, however, an interaction between thermal and dietary treatments such that dietary antioxidant supplementation ameliorated the effect of HS on NF-κB and TNF-α mRNA expression. Taken together, these results indicate that high dietary antioxidants modulate skeletal muscle expression of heat shock proteins, proinflammatory cytokine, and NF-κB transcription, which may protect against HS in sheep.

Effect of Sodium Selenite on Pathological Changes and Renal Functions in Broilers Fed a Diet Containing Aflatoxin B₁

To evaluate the renal toxicity of dietary aflatoxin B₁ (AFB₁) and ameliorating effects of added dietary sodium selenite in broiler, renal histopathological changes, ultrastructural changes, and renal function parameters were monitored at 7, 14, and 21 days of age. Two hundred one-day-old healthy male Avian broilers were divided into four groups, namely control group, AFB₁ group (0.3 mg/kg AFB₁), +Se group (0.4 mg/kg Se), and AFB₁+Se group (0.3 mg/kg AFB₁+0.4 mg/kg Se). Compared with that of the control group, the relative weight of kidney was increased in the AFB₁ group. There were no significant differences between the AFB₁+Se group and the control group. By histopathological observation, the renal epithelia were swelling and necrosis at 7 and 21 days of age. Ultrastructurally, the lipid droplets and expanded endoplasmic reticulum appeared in the plasma of epithelia cells in the AFB₁ group. Enlarged mitochondria with degenerated cristae were observed in the +Se group. Compared with the control group, the contents of serum creatinine and serum uric acid in the AFB₁ group were increased, while the activity of renal Na⁺-K⁺ ATPase was decreased. When 0.4 mg/kg selenium was added into the diet containing 0.3 mg/kg AFB₁, there were no obvious histological changes in the AFB₁+Se group, and the contents of the serum creatinine and serum uric acid contents and the activity of renal Na⁺-K⁺ ATPase were close to those in the control group. In conclusion, sodium selenite exhibited protective effects on AFB₁-induced kidney toxicity in broilers.

Osteopathology and selenium deficiency co-occurring in a population of endangered Patagonian huemul (Hippocamelus bisulcus)

Background

About 1,000 endangered Patagonian huemul deer (Hippocamelus bisulcus) remain in Chile and 350–500 in Argentina. Most groups (>100) are not recovering, and prevalence of osteopathology in Argentina was at least 57%. Here I describe relevant cases of osteopathology from a Chilean population which, however, recently also provided data on trace mineral status, supporting the initial hypothesis that nutrition may be a primary etiologic factor. Additionally, recent data on bone chemical composition of Argentine cases and soil analyses are discussed.

Results

Fluoride levels in Argentine cases with osteopathology were low and fluorosis was discarded as an etiological factor. Selenium deficiency occurred in 73% of huemul from the Chilean population which exhibited several cases with osteopathology. The pathophysiognomy included extensive erosion; tooth loss; porosification; perforations of palate, maxillar and mandibular bone with frequent exposure of tooth roots; and fractured mandibula. Areas currently used by remaining huemul have mainly acidic volcanic soils, which reduces selenium bioavailability: mean soil selenium levels from areas typically used by extant huemul were very deficient (0.19 ppm), corroborating documented overt selenium deficiency in local livestock and plants. The area of extant huemul is known to result in primary iodine deficiency in livestock which is aggravated by selenium deficiency.

Conclusions

Currently the most parsimonious explanation for frequent osteopathology and lack of numerical recovery are the combined effects of selenium and iodine deficiencies based on: osteopathology in a population of selenium deficient huemul; selenium deficient livestock, plants and soils; acidic soils; and regional primary iodine deficiency. The nexus between mineral nutrition and population dynamics of huemul may be due to constraints on their movements to fertile lowlands, including the elimination of historic migratory traditions, and concomitant elimination of source populations.

Selenium Supplementation in Fish: A Combined Chemical and Biomolecular Study to Understand Sel-Plex Assimilation and Impact on Selenoproteome Expression in Rainbow Trout (Oncorhynchus mykiss)

Background

Selenium (Se) is an essential oligonutrient, as a component of several Se-containing proteins (selenoproteins), which exert important biological functions within an organism. In livestock, Se-enriched products have been proposed as dietary supplements to be included into functional feeds for animal preventive health care. To this end, it is important to understand the optimal range of concentrations for supplementation and how long it takes to be assimilated into the organism.

Methods

In this study, rainbow trout (Oncorhynchus mykiss) were fed a control diet containing 0.9 g Kg^-1 Se or the same diet supplemented with a Se-Yeast product (Sel-Plex) to achieve Se concentrations ranging from 1.5–8.9 g Kg^-1 for a period of ten weeks. Fish were sampled every two weeks for analysis. The kinetics of Se bioaccumulation and the effects on fish selenoprotein expression was determined in different tissues combining chemical and bimolecular techniques.

Results

The Sel-Plex enriched diets did not have any effect on survival and growth performance. The highest Se levels were found in liver and kidney followed by muscle and blood cells. Analysis of the Se concentration factor showed that liver is able to initially regulate the amount of Se accumulated. However, with higher dietary Se level (4.8 and 8.9 g Kg^-1) and longer times of exposure (10 weeks), regulation is ineffective and the Se tissue concentration increases. The expression of the selected trout selenoprotein transcripts showed an inverse correlation with Sel-Plex augmentation in most cases. In liver, kidney and blood cells the highest up-regulation of the trout selenoprotein genes was seen mostly in the group fed the diet enriched with the lowest concentration of Sel-Plex (0.5 g Kg^-1) for 10 weeks.

Conclusion

Sel-Plex may represent an excellent Se supplement to deliver a high level of Se without provoking harm to the fish and to guarantee the maximal absorption of the element. According to our results, a dietary supplementation of Sel-Plex between 0.5 and 4 g Kg^-1 may allow maximal benefits, whereas 8 g Kg^-1 may be excessive for the purpose of supplementation.

Postpartum injection with vitamin E and selenium failed to improve the performance of Awassi ewes and their lambs

Awawdeh, M. S., Talafha, A. Q. and Obeidat, B. S. 2015. Postpartum injection with vitamin E and selenium failed to improve the performance of Awassi ewes and their lambs. Can. J. Anim. Sci. 95: 111–115. The objective of this study was to investigate the effect of vitamin E and Se injection of nursing Awassi ewes on the performance of ewes (body weight change, milk yield, and composition) and their lambs (growth rate and weaning weight). Twenty-eight Awassi ewes were randomly assigned upon lambing to one of two groups; Control (n=13) and Inject (n=15), where ewes received 0 (control) or 15 plus 0.05 mg kg−1 BW of vitamin E and Se, respectively (inject). Intramuscular injections were given at 1 and 4 wk postpartum. Body weight (BW) of ewes and their lambs were recorded at lambing and at 2, 4, 6, and 8 wk postpartum. Milk yield and composition were measured at 2, 4, and 6 wk postpartum and somatic cell count (SCC) was evaluated weekly (from lambing through 8 wk). Injecting nursing ewes with vitamin E and Se had no effects (P≥0.10) on BW change of ewes, milk yield and composition, composition yields, or milk SCC. Injecting nursing ewes with vitamin E and Se had no significant effects (P≥0.29) on weaning weight, BW gain, or growth rate of their lambs. Under conditions similar to the current study, injecting nursing Awassi ewes with vitamin E and Se at 1 and 4 wk postpartum was not effective in improving the performance of ewes and their suckling lambs. Such observations could be attributed to the time of supplementation (pre- or post-partum) and/or the adequate basal vitamin E status in ewes.

Nutritional strategies to alleviate heat stress in pigs

Pigs are comparatively less heat tolerant than other species of production animals, which poses challenges for stock productivity and management during seasonal heat waves that occur in summer. The issues surrounding heat and pig production are predicted to increase, based on the actions of climate change increasing the intensity, frequency and duration of heat waves. Furthermore, future growth areas of pig production are going to be in tropical regions such as South-east Asia and Latin America. Efforts by the pig to dissipate excess body heat come at a cost to health and divert energy away from growth, compromising efficient pig production. Management of heat stress requires multiple strategies, and recent research is improving the understanding of the application of nutritional strategies to ameliorate the effects of heat stress. In particular the use of feed additives is an important, flexible and economical method to alleviate heat stress and the intensive nature of pig production lends itself to the use of additives. Some specific examples include antioxidants, betaine and chromium, which have been proved effective or being tested in mitigating some certain impacts of heat stress in pigs. The aim of this review is to summarise recent advances in the nutritional management of heat stress in pigs.

Biology and Diseases of Ruminants (Sheep, Goats, and Cattle)

Ruminants continue to be important in their traditional role in agricultural research and teaching. They are now also extensively used for studies in molecular biology; genetic engineering; and biotechnology for basic science, agricultural and clinical applications. Concern and interest for the welfare for these species and improved understanding of their biology and behavior have continued and are reflected in changing husbandry and management systems. This chapter addresses at high levels basic biology, husbandry, and the more common or important diseases of the three ruminant species used most commonly in the laboratory, namely sheep, goats and cattle.

Effect of selenium yeast supplementation on naturally acquired parasitic infection in ewes

Gastrointestinal parasites cause substantial economic losses in pasture-based sheep production systems. Supranutritional organic selenium (Se) supplementation may be beneficial because it improves immune responses to pathogens. To evaluate the effect of Se-yeast supplementation on gastrointestinal parasite load, 30 ewes per treatment group were drenched weekly with no Se, 4.9 mg Se/week as Se yeast (maximum FDA-allowed concentration), or supranutritional concentrations of Se yeast (14.7 and 24.5 mg Se/week) starting early fall for 85 weeks. Fecal samples were collected at weeks 63, 66, 78, and 84 and counted for total trichostrongyle-type eggs and Haemonchus contortus eggs (in samples with ≥200 trichostrongyle eggs/g feces). During breeding season (fall), ewes were kept on pasture; ewes receiving 24.5 mg Se/week had lower fecal trichostrongyle egg counts (93 ± 40 eggs/g feces) compared with ewes receiving no Se (537 ± 257 eggs/g feces; P = 0.007) or ewes receiving 4.9 mg Se/week as Se yeast (398 ± 208 eggs/g feces; P = 0.03). In winter, fecal trichostrongyle egg counts decreased, and group differences were not apparent. During lambing season (spring), ewes were kept in the barn and fecal trichostrongyle egg counts increased, although no group differences were observed. However, none of the ewes receiving supranutritional Se yeast, and with trichostrongyle egg counts ≥200 eggs/g of feces, but four of the ewes receiving lower Se dosages had H. contortus egg counts ≥1,000 eggs/g feces (P = 0.04). Our results suggest that supranutritional Se-yeast supplementation may enhance resistance to naturally occurring H. contortus gastrointestinal parasitism in sheep.

Effect of supranutritional organic selenium supplementation on postpartum blood micronutrients, antioxidants, metabolites, and inflammation biomarkers in selenium-replete dairy cows

Dairy cows have increased nutritional requirements for antioxidants postpartum. Supranutritional organic Se supplementation may be beneficial because selenoproteins are involved in regulating oxidative stress and inflammation. Our objective was to determine whether feeding Se-yeast above requirements to Se-replete dairy cows during late gestation affects blood micronutrients, antioxidants, metabolites, and inflammation biomarkers postpartum. During the last 8-weeks before calving, dairy cows at a commercial farm were fed either 0 (control) or 105 mg Se-yeast once weekly (supranutritional Se-yeast), in addition to Na selenite at 0.3 mg Se/kg dry matter in their rations. Concentrations of whole-blood (WB) Se and serum Se, erythrocyte glutathione (GSH), and serum albumin, cholesterol, α-tocopherol, haptoglobin, serum amyloid A (SAA), calcium, magnesium, phosphorus, non-esterified fatty acids, and β-hydroxybutyrate were measured directly after calving, at 48 h, and 14 days of lactation in 10 cows of each group. Supranutritional Se-yeast supplementation affected indicators of antioxidant status and inflammation. Cows fed a supranutritional Se-yeast supplement during the last 8-weeks of gestation had higher Se concentrations in WB (overall 52 % higher) and serum (overall 36 % higher) at all-time points, had higher SAA concentrations at 48 h (98 % higher), had higher erythrocyte GSH (38 % higher) and serum albumin concentrations (6.6 % higher) at 14 days, and had lower serum cholesterol concentrations and higher α-tocopherol/cholesterol ratios at calving and at 48 h compared with control cows. In conclusion, feeding Se-replete cows during late gestation a supranutritional Se-yeast supplement improves antioxidant status and immune responses after calving without negatively impacting other micronutrients and energy status.

Protein profile of lambs experimentally infected with Haemonchus contortus and supplemented with selenium and copper

Background

Gastrointestinal nematodes cause significant economic losses in the sheep industry, with frequent reports of anthelmintic resistance. Therefore, alternative methods to control these parasites are necessary. Thus, the aim of the present study was to assess the effect of treatment with selenium and copper on the protein profile of sheep that were experimentally infected with Haemonchus contortus.

Methods

Twenty-eight lambs were experimentally infected with H. contortus and divided into four experimental groups as follow: G1 - untreated animals; G2 - treated with sodium selenite; G3 - treated with copper; G4 - treated with sodium selenite and copper. The serum protein, body weight and egg count per gram of feces (EPG) were assessed at the baseline and after 20, 40, 60 and 80 days. The parasite burden was assessed 80 days after the beginning of the experiment.

Results

Higher levels of total protein and gamma globulin were observed in the lambs treated with sodium selenite and copper on D80. Copper acted as a growth promoter. The copper-supplemented groups exhibited higher daily and total weight gain. The association of selenium and copper altered the protein profile of sheep. Copper and selenium supplementation reduced EPG and worm burden at the end of the experiment. To the best of our knowledge, this is the first study to demonstrate the positive effect of the combined parenteral supplementation of Se and Cu on H. contortus infection.

Conclusions

This injectable supplementation could be used as an auxiliary method to control H. contortus in sheep.

Effects of housing systems and the diet supplements on the slaughter value and concentration of mineral elements in the loin muscle of lambs

The objective of this study was to investigate the effect of maintenance system as well as the effect of Se, Zn, and vitamin E supplementation of ram-lambs on the slaughter value and concentration of mineral elements in the loin muscle of lambs. The experiment was conducted on 72 Polish Merino ram-lambs divided into three groups: group C, indoor with no supplement, 19 lambs; S, indoor with supplement, 23 lambs; G, outdoor with no supplement, 30 lambs. From birth all the lambs were maintained indoor with their dams and then weaned at the age of 8 weeks. The rams from group C and S were placed in individual straw-bedded pens and fattened individually with concentrate mixture offered ad libitum until the age of 16 weeks. The lambs from group G were grazed every day from May to July (2 months). During the fattening period each lamb from the supplemented group S was administered per os 1 mL 0.1% Na₂SeO₄ (Se, 0.42 mg), 3 mL 10% ZnSO₄ (Zn, 68 mg), and 1 mL premix protect vitamin E (0.1 g α-tocopherol, 5 mg lysine, 5 mg methionine) daily. A comparison of half carcasses across the groups has shown no difference between the control group and the one with supplements, while the weight of half carcasses in the grazing group was smaller in comparison with groups C and S (p<0.001). The meat content in the pelvic limb showed no differences across all groups under study. The pelvic limb of grazing lambs contained less fat compared to the control and supplemented groups (p<0.001). The concentrations of Se and Zn in the blood plasma of ram-lambs from the supplemented group were significantly higher than for the control and grazing lambs. Inorganic Se and Zn supplementation with vitamin E to the diet of lambs increased Se and Zn levels in loin muscle (p<0.001) to 0.46 μg/g and 32.9 μg/g in fresh tissue, respectively.

Dietary antioxidants at supranutritional doses improve oxidative status and reduce the negative effects of heat stress in sheep

The present study was undertaken to investigate the impact of heat (thermal) stress and dietary antioxidant supplementation on the oxidative and physiological status of sheep. Twenty-four Merino × Poll Dorset crossbred ewes were housed in 1 of 2 climatic chambers (thermoneutral or heat stress) and offered either a control (10 IU vitamin E/kg DM and 0.24 mg Se/kg DM) or high antioxidant (100 IU vitamin E/kg DM and 1.20 mg Se/kg DM) diet. The sheep were exposed to 2 thermal (temperature) treatments (thermoneutral [TN]: 18-21°C and 26-30% relative humidity; and heat stress [HS]: 28-40°C and 40-50% relative humidity) for 2 wk in a single reversal design. After 1 wk of dietary treatment, animals in 1 chamber were subjected to HS for 1 wk, with the temperature being increased to 40°C between 0900 and 1700 h and then maintained at 28°C overnight. Those sheep in the TN group were maintained at 18 to 21°C. Physiological parameters were recorded 4 times a day (0900, 1300, 1700, and 2100 h) and blood samples were collected on d 1 and 7 of heat treatment. Plasma samples and red blood cell lysates were assayed for oxidative stress biomarkers. The thermal treatments were then reversed and the above measures repeated. All measured physiological parameters were elevated (P < 0.001) by thermal treatment. Respiration rate was lower during HS in sheep supplemented with antioxidants as indicated by a diet × temperature × time interaction (P = 0.010). There was 13% decline (P = 0.014) in feed intake of the unsupplemented animals during HS whereas the same was maintained in sheep supplemented with high doses of antioxidants. Plasma reactive oxygen metabolites concentrations were reduced (114 vs. 85 units/dL; P < 0.005) while biological antioxidant potential tended to be increased (3,688 vs. 3,985 μmol/L; P = 0.070) in heat stressed sheep supplemented with antioxidants. The oxidative stress index was 30% lower (P < 0.001) in supplemented sheep (2.16 ± 0.06 arbitrary units) during HS than in unsupplemented sheep (3.12 ± 0.08 arbitrary units). Plasma advanced oxidation protein products tended (P = 0.070) to decrease in antioxidant supplemented heat stressed sheep as compared to their unsupplemented counterparts. It was concluded that heat stress negatively affects the oxidative status of sheep along with the physiological responses and some of these affects can be ameliorated through dietary antioxidants supplementation at supranutritional concentrations.

The Relationship between Selenium and T3 in Selenium Supplemented and Nonsupplemented Ewes and Their Lambs

Twenty pregnant ewes were selected and classified into two groups. The first group received subcutaneous selenium supplementation (0.1 mg of sodium selenite/kg BW) at the 8th and 5th weeks before birth and 1st week after birth while the other was control group without selenium injection. Maternal plasma and serum samples were collected weekly from the 8th week before birth until the 8th week after birth and milk samples were taken from ewes weekly, while plasma and serum samples were collected at 48 hours, 1st, 2nd, 3rd, 5th, and 8th weeks after birth from the newborn lambs. Results demonstrated significant positive relationship between maternal plasma selenium and serum T3 in supplemented and control ewes (r = 0.69 to 0.72, P < 0.05). There was significant (P < 0.001) increase in T3 in supplemented ewes and their lambs until the 8th week after birth. There was positive relationship between milk, selenium concentration, and serum T3 in the newborn lambs of the supplemented group (r = 0.84, P < 0.01), while the relationship was negative in the control one (r = −0.89, P < 0.01). Muscular and thyroid pathological changes were independent of selenium supplementation. Selenium supplementation was important for maintaining T3 in ewes and newborn lambs until the 8th week after birth.

The effect of dietary vitamin E level on selenium status in rats

The effect of varying levels of dietary vitamin E on selenium status was determined using 40 Wistar rats with similar initial body weight. The rats were equally divided into four groups and fed the following dietary treatments (mg vitamin E/kg DM): 18 (control; C-diet), 0 (0E-diet), 9 (0.5E-diet) and 36 (2E-diet) for either 4-week (Phase 1) or 8-week (Phase 2) period. At the end of experiment, animals were slaughtered to measure vitamin E and selenium levels in the brain, liver, spleen, kidney, muscles and blood tissues. Dietary vitamin E levels did not affect feed and water intake and body weight. But whole-blood selenium concentration in rats fed 0E-diet was higher than in rats fed 2E-diet after 4 weeks. Selenium level in muscle, spleen and brain was also higher (p < 0.05) in rats fed the 0E-diet than in rats fed C-diet after 4 weeks of feeding. On the other hand, selenium level in the muscle was lower (p < 0.05) in rats fed 0.5E-diet than in those fed 0E-diet after 4 weeks of feeding, but not after 8 weeks of feeding. Increasing dietary vitamin E level directly influenced selenium content of the spleen and brain after 8 weeks of feeding 2E-diet. Moreover, the twofold increase in vitamin E intake resulted in a tendency to reduce whole-blood selenium level and total selenium in the liver and kidney after 4 and 8 weeks. The results showed that the increasing dietary vitamin E level resulted in a tendency to reduce Se contents in some vital organs of the body such as the liver and kidney, suggesting their close compensatory interrelationship. Therefore, dietary vitamin E level directly influenced selenium metabolism in the animal body.

Antioxidant dynamics in the live animal and implications for ruminant health and product (meat/milk) quality: role of vitamin E and selenium

The global population is predicted to grow to over 9 billion by the middle of 21st century, with 70% of people living in urban areas, and food demand is projected to grow by 70% by 2050. Climate change presents a series of challenges for global animal agriculture. As a result of thermal challenges associated with climate variability, availability of quality pasture, animal behaviour, physiological and immunological functions are potentially impacted. Oxidative status plays an important role in the regulation and maintenance of several physiological and immunological functions of the body. Ruminants are exposed to several environmental and metabolic challenges that can trigger oxidative stress. In this scenario, it is possible for an increase in free radical production and a depletion of antioxidant reserves, resulting in damage to lipids, proteins and DNA. Since oxidative stress can affect animal health and the quality of their products (meat/milk), antioxidant supplementation of ruminant diets represents a useful tool to sustain redox homeostasis when the ruminants are exposed to oxidative stress. This paper will examine the roles that oxidative stress plays in some physiological functions, and it will discuss the implications of antioxidant supplementation on ruminant health and production. Physiological levels of dietary antioxidants underpin efficient energy utilisation, optimal antioxidant potential, and balanced mitochondrial function to enhance protein deposition without impacting animal health. The research conducted over the last decade has improved the understanding of physiological functions of antioxidants, with selenium and vitamin E receiving particular attention. There is evidence that the functions of selenium and vitamin E extend beyond the classical antioxidant properties to immunomodulation especially when administered at higher doses than recommended. Improving the oxidative status of ruminants will play an important role in delivering high-quality milk and meat products to consumers. Considering the growing awareness among consumers of the benefits of antioxidant-rich food, there is a great opportunity for the livestock industries to focus on producing antioxidant-enriched milk and meat products or functional foods. Therefore, the premise of this paper is to review the recent developments in understanding antioxidant dynamics in ruminants and their role in reducing the impact of environmental stress and metabolic diseases. In addition, the paper will explore the putative implications that antioxidant supplementation has on the quality animal products and how the improved understanding can be best utilised to achieve efficient and sustainable animal production systems to ensure quality animal products for human consumption.

Effects of organic and inorganic selenium supplementation during late pregnancy on colostrum and serum Se status, performance and passive immunity in Merghoz goats

This study was conducted to determine the effects of organic and inorganic selenium (Se) supplementation during late pregnancy on serum Se status, colostrum, performance and passive immunity in Merghoz goats in Iran. Thirty Merghoz goats (30 ± 3 kg) were given the same basal diet containing 0.11 mg Se/kg DM and were randomly allocated to one of three dietary treatments in a randomised complete block design. Four weeks before the expected kidding, the basal diets were supplemented with 0 (control), 0.3 mg Se/head.day in the form of L-selenomethionin (Se-Met) and 0.3 mg Se/head.day in the form of sodium selenite. Blood samples were collected from the goats in three phases: (1) a couple of days before starting the supplementation; (2) before the expected kidding; and (3) on the day of kidding. Blood samples were also taken from the newborn kids from the jugular vein at birth and 7 days of age. The serum Se and immunoglobulin G (IgG) concentrations, the white blood cells (WBC) and differential leukocyte counts were measured. The reproductive parameters such as the number of kids born per kidding, total weight of kids born per goat mating, the pregnancy period and kid birthweights were determined. The results indicated that the serum Se concentration increased in supplemented goats compared with controls. The Se concentrations also significantly increased in the colostrum of treated goats (P < 0.05). Similarly, serum Se concentrations in kids of treated goats were increased at birth. On the other hand, colostrum and daily milk production were not affected by Se supplementation. Likewise, the change in the mean serum IgG levels was not different among goats and kids (P > 0.05). However, the WBC, neutrophil and lymphocyte counts were higher in the kids of goats in the Se-Met group compared with the control group on the day of birth and 7 days of age (P < 0.05). It seemed that Se-Met could have influenced the lamb’s immunity at birth and 7 days of age. By contrast, selenite has not affected the performance and passive immunity in Merghoz goats.

Selenium supplementation restores innate and humoral immune responses in footrot-affected sheep

Dietary selenium (Se) alters whole-blood Se concentrations in sheep, dependent upon Se source and dosage administered, but little is known about effects on immune function. We used footrot (FR) as a disease model to test the effects of supranutritional Se supplementation on immune function. To determine the effect of Se-source (organic Se-yeast, inorganic Na-selenite or Na-selenate) and Se-dosage (1, 3, 5 times FDA-permitted level) on FR severity, 120 ewes with and 120 ewes without FR were drenched weekly for 62 weeks with different Se sources and dosages (30 ewes/treatment group). Innate immunity was evaluated after 62 weeks of supplementation by measuring neutrophil bacterial killing ability. Adaptive immune function was evaluated by immunizing sheep with keyhole limpet hemocyanin (KLH). The antibody titer and delayed-type hypersensitivity skin test to KLH were used to assess humoral immunity and cell-mediated immunity, respectively. At baseline, FR-affected ewes had lower whole-blood and serum-Se concentrations; this difference was not observed after Se supplementation. Se supplementation increased neutrophil bacterial killing percentages in FR-affected sheep to percentages observed in supplemented and non-supplemented healthy sheep. Similarly, Se supplementation increased KLH antibody titers in FR-affected sheep to titers observed in healthy sheep. FR-affected sheep demonstrated suppressed cell-mediated immunity at 24 hours after intradermal KLH challenge, although there was no improvement with Se supplementation. We did not consistently prevent nor improve recovery from FR over the 62 week Se-treatment period. In conclusion, Se supplementation does not prevent FR, but does restore innate and humoral immune functions negatively affected by FR.

Cardiac troponin I in healthy newborn goat kids and in goat kids with cardiac nutritional muscular dystrophy

This study was designed to establish serum cardiac troponin I (cTnI) concentrations in healthy newborn goat kids and in those with cardiac nutritional muscular dystrophy (NMD). Thirty-five single full-term newborn goat kids (20 males and 15 females; age: 6.1 ± 3.5 h; weight 3.4 ± 0.68 kg), together with their respective mothers (Group 1; G1) were enrolled consecutively. Thirty-one goat kids (age: 9.5 ± 4.3 days) with NMD, together with 20 control goat kids (age: 7.8 ± 4.3 days) were also included in this study (Group 2; G2). Blood samples were collected from G1 within 12 h of birth and from G2 on admission. Serum samples were collected and analysed for cTnI. In G1, the mean serum concentration of cTnI in goat kids was 0.290 ± 0.37 ng/mL, with no statistically significant difference between male and female kids (P = 0.61). The mean cTnI concentration in the does was 0.017 ± 0.04, ng/mL. Serum values of cTnI in the goat kids and in their respective mothers differed significantly (P = 0.0001). In G2, the mean cTnI concentration was 0.02 ± 0.05 ng/mL in the control and 11.18 ± 20.07 ng/mL in the diseased goat kids, with a statistically significant difference between diseased and control goat kids (P = 0.017). Serum concentrations of cTnI are higher in goat kids than in their respective mothers. In conclusion, the cTnI assay appears to be a sensitive and specific marker for myocardial injury in goat kids.