Cell Glutathione Peroxidase Activity Research Articles

Tryptophan can alleviate the inhibition in growth and immunity of tilapia (GIFT Oreochromis spp.) induced by high dietary soybean meal level

A 85-day feeding trial was designed to verify the effects of soybean meal on growth, feed utilization, antioxidants, and immune response of tilapia (GIFT Oreochromis spp.), and evaluated the effects of dietary tryptophan on alleviating the negative responses induced by high inclusion of soybean meal. Five experimental diets, two of which substituted 15 % and 45 % of the fish meal with soybean meal, the others supplemented with 0.2 %, 0.4 % and 0.6 % L-tryptophan on the basis of 45 % soybean meal, respectively, were fed 400 juvenile fish (initial weight: 2.98 ± 0.04 g). The results showed that the crude ash content, red blood cell count (RBC), lipase (LPS) and glutathione peroxidase (GSH-Px) activities of tilapia significantly decreased when the soybean meal replaced fish meal by 45 % (p < 0.05). Although the growth performance values of replacing 45 % soybean meal were slightly lower than that of replacing 15 % soybean meal, while there was no significant difference between them (p > 0.05). However, supplementation with tryptophan in the high soybean meal replacement groups significantly improved the final weight, weight gain rate (WGR), specific growth rate (SGR), phagocytosis index (PI), RBC, trypsin (TPS), LPS and GSH-Px activities of tilapia (p < 0.05), and the apparent digestibility and feed coefficient of tilapia were significantly decreased (p < 0.05). Taken together, these results suggested that excessive soybean meal inhibited the feed utilization and immunity of tilapia to a certain extent, while the inclusion of 0.2 %−0.4 % tryptophan in the diet could alleviate the negative effects of high soybean meal diet in tilapia. This study will provide ideas and a theoretical basis for further expanding the application of soybean meal in tilapia feed.

Nrf2 and Antioxidant Response in Animal Models of Type 2 Diabetes.

This perspective examines the proposition that chronically elevated blood glucose levels caused by type 2 diabetes (T2D) harm body tissues by locally generating reactive oxygen species (ROS). A feed-forward scenario is described in which the initial onset of defective beta cell function T2D becomes sustained and causes chronic elevations in blood glucose, which flood metabolic pathways throughout the body, giving rise to abnormally high local levels of ROS. Most cells can defend themselves via a full complement of antioxidant enzymes that are activated by ROS. However, the beta cell itself does not contain catalase or glutathione peroxidases and thereby runs a greater risk of ROS-induced damage. In this review, previously published experiments are revisited to examine the concept that chronic hyperglycemia can lead to oxidative stress in the beta cell, how this relates to the absence of beta cell glutathione peroxidase (GPx) activity, and whether this deficiency might be ameliorated by genetic enrichment of beta cell GPx and by oral antioxidants, including ebselen, a GPx mimetic.

Effects of astaxanthin on microRNA expression in a rat cardiomyocyte anoxia-reoxygenation model.

Introduction: The protective effects of astaxanthin against myocardial ischemia-reperfusion injuries are well documented, although the mechanisms are not defined. Methods: The anoxia-reoxygenation injury model was established after astaxanthin treated H9c2 cells for 24 h. Cell viability, lactate dehydrogenase, oxidative stress level and western blot were tested. Secondly, measured the effects of astaxanthin pretreatment on microRNA expression in a rat myocardial cell anoxia-reoxygenation injury model. Results: After anoxia-reoxygenation injury, in a dose dependent manner, astaxanthin increased cell viability, superoxide dismutase and glutathione peroxidase activity, decreased lactate dehydrogenase and malondialdehyde levels, downregulated protein expression of caspase-3, caspase-8, nuclear factor erythroid-2-related factor 2 and heme oxygenase-1, and upregulated the Bcl-2/Bax ratio. High-throughput sequencing and qPCR showed that microRNAs rno-miR-125b-5p and rno-let-7c-1-3p were differentially expressed (|log2| ≥ 0.585, q < 0.1) between the normal, anoxia-reoxygenation, and astaxanthin (1.25 μM) groups. Kyoto Encyclopedia of Genes and Genomes and GO Gene ontology pathway enrichment analyses showed that TNF signaling, axon guidance, NF-κB signaling pathway, and other pathways displayed differentially expressed microRNA target genes associated with myocardial injuries. Discussion: These results suggested that thetarget genes of rno-miR-125b-5p were enriched in inflammation and apoptosis-related signaling pathways. Also, the results imply that simultaneous targeting of these related signaling pathways could significantly prevent myocardial anoxia-reoxygenation injury in the presence of astaxanthin.

Dietary supplementation with garcinol during late gestation alleviates disorders of bile acid metabolism and improves the performance of sows and newborn piglets.

The present study was conducted to evaluate the effects of dietary garcinol supplementation during late gestation on bile acid metabolism and performance of sows. Sixty sows (Duroc × Yorkshire × Landrace; second- or third-parity; n = 20) with disorder of bile acid metabolism were randomly divided into three groups: control diet (CON; basal diet), basal diet with 200 mg garcinol (Low Gar), and basal diet with 600 mg garcinol (High Gar) per kg of feed. The body weight (BW); backfat thickness and litter size of the sows; and birth weight, weaning weight, and mortality of piglets were recorded. Sows' blood was collected for the measurements of hematological parameters and antioxidative and immune indexes, and indicators related to bile acid metabolism, respectively. The colostrum and fecal samples of the sows were also collected for analysis of colostrum composition and apparent total tract nutrient digestibility. Garcinol had no effect on the BW and backfat thickness of the sows but significantly decreased the mortality and number of weak litter (P < 0.05). Moreover, the white blood cell counts, superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), and catalase (CAT) activity in the plasma of the sows were increased more significantly (P < 0.05) in the garcinol groups than that in the CON group, whereas the malondialdehyde (MDA) content was decreased (P < 0.05). Dietary supplementation with garcinol significantly reduced TBA concentrations (P < 0.05). The content of immunoglobulin A (IgA) and immunoglobulin G (IgG) in the plasma and in colostrum of sows were increased more significantly (P < 0.05) in the garcinol groups than that in the CON group. In addition, dry matter (DM), Ash, and EE in the colostrum were similar between groups (P > 0.05), whereas the garcinol significantly increased the crude protein (CP) in the colostrum. The apparent total tract nutrient digestibility was similar between treatments. Garcinol treatment induced a gradually decreased (P > 0.05) the expression of genes involved in BA synthesis (CYP7A1, CYP8B1), BA uptake (NTCP, OATP1A2), BA secretion (BSEP and MRP2), BA detoxification (SULT2A1), and BA efflux into the blood circulation (OSTβ). Collectively, this study indicates that sows fed with garcinol in late gestation showed relieved bile acid metabolism disorder and improved sows performance, antioxidative status, colostrum protein content, showing promise in natural plant extract nutrition for sows with disorder of bile acid metabolism.

Cyclophilin A inhibits A549 cell oxidative stress and apoptosis by modulating the PI3K/Akt/mTOR signaling pathway.

The excessive and inappropriate production of reactive oxygen species (ROS) can cause oxidative stress and is implicated in the pathogenesis of lung cancer. Cyclophilin A (CypA), a member of the immunophilin family, is secreted in response to ROS. To determine the role of CypA in oxidative stress injury, we investigated the role that CypA plays in human lung carcinoma (A549) cells. Here, we showed the protective effect of human recombinant CypA (hCypA) on hydrogen peroxide (H2O2)-induced oxidative damage in A549 cells, which play crucial roles in lung cancer. Our results demonstrated that hCypA substantially promoted cell viability, superoxide dismutase (SOD), glutathione (GSH), and GSH peroxidase (GSH-Px) activities, and attenuated ROS and malondialdehyde (MDA) production in H2O2-induced A549 cells. Compared with H2O2-induced A549 cells, Caspase-3 activity in hCypA-treated cells was significantly reduced. Using Western blotting, we showed that hCypA facilitated Bcl-2 expression and inhibited Bax, Caspase-3, Caspase-7, and PARP-1 expression. Furthermore, hCypA activates the PI3K/Akt/mTOR pathway in A549 cells in response to H2O2 stimulation. Additionally, peptidyl-prolyl isomerase activity was required for PI3K/Akt activation by CypA. The present study showed that CypA protected A549 cells from H2O2-induced oxidative injury and apoptosis by activating the PI3K/Akt/mTOR pathway. Thus, CypA might be a potential target for lung cancer therapy.

Leukemia inhibitory factor protects photoreceptor cone cells against oxidative damage through activating JAK/STAT3 signaling.

BackgroundThe present study aimed to investigate the protective role of leukemia inhibitory factor (LIF) against oxidative damage in photoreceptor cone cells.MethodsIn vivo, dark-adapted mice were injected with LIF or phosphate-buffered saline (PBS) intravitreously prior to being exposed to 5,000 lux bright light to determine the protective effect of LIF against light damage in cone cells. Oxidative damage to cone cells was analyzed using electroretinograms, immunostaining, Western blotting and reverse transcription quantitative polymerase chain reaction (RT-qPCR). In vitro, 661W cells were pretreated with 5 ng/mL of LIF with or without 50 µM of signal transducer and activator of transcription 3 (STAT3) inhibitor S3I201 for 1 h prior to treatment with 1 mM H2O2; cell survival, apoptosis, the oxidative stress index, and the activation of STAT3, extracellular signal-regulated kinase (ERK1/2), and AKT were subsequently determined.ResultsIn vivo, light induction damaged the function and morphology of cone cells, and LIF was observed to protect cone cells from this light damage. Moreover, the activation of the Janus tyrosine kinase (JAK)/STAT3 signaling pathway and the subsequent changes in apoptosis and proliferation-related genes were found to be involved in the protective effect of LIF against light-induced retinal damage. In the H2O2-induced 661W cell model, H2O2 increased cellular apoptosis rates, the expression levels of Bcl-2–associated X-protein (BAX) and cleaved caspase 3, reactive oxygen species (ROS) production, and malondialdehyde content, while decreasing the cell viability, and Bcl-2, superoxide dismutase, catalase, and glutathione peroxidase activity. LIF was observed to block these events; however, the administration of the STAT3 inhibitor S3I201 reversed the beneficial effects of LIF on H2O2-triggered apoptosis and ROS production.ConclusionsIn conclusion, the present study suggested that LIF may relieve oxidative damage in cone cells through suppressing apoptosis and oxidative stress by targeting the STAT3 signaling pathway.

Galectin-1 reduces the severity of dextran sulfate sodium (DSS)-induced ulcerative colitis by suppressing inflammatory and oxidative stress response.

Ulcerative colitis is an inflammatory bowel disease that affects a large number of people around the world. Galectin-1 is a β-galactoside-binding lectin with a broad range of biological activities. The effects of galectin-1 on dextran sulfate sodium (DSS)-induced ulcerative colitis in vivo is not clear. We investigated the effect of galectin-1 on colon morphology, cell proliferation, oxidative stress, antioxidant system, and proinflammatory/antiinflammatory cytokines in a DSS-induced mouse model of ulcerative colitis. Thirty-two C57BL/6 mice were randomly assigned to one of the four groups: control, acute colitis, galectin-1, and DSS+galectin-1. Controls were treated with phosphate-buffered saline (PBS) for seven days. Acute colitis was induced by 3% DSS in drinking water administered orally for five days. Mice in galectin-1 groups were treated with 1 mg/kg recombinant human galectin-1 in PBS for seven consecutive days. Oral DSS administration resulted in acute colitis by causing histopathological changes; an increase in disease activity index (DAI), lipid peroxidation (malondialdehyde [MDA]), myeloperoxidase (MPO), and tumor necrosis factor (TNF)-α levels; a decrease in body weight, colon length, cell proliferation index, catalase, glutathione peroxidase (GSH-Px) and superoxide dismutase (SOD) activities, and GSH and interleukin (IL)-10 levels. The treatment with galectin-1 attenuated DSS-induced acute colitis by reducing DAI, MDA, MPO, and TNF-α levels and by increasing body weight, colon length, cell proliferation, antioxidant enzyme activity, GSH, and IL-10 levels. These findings suggest that galectin-1 has proliferative, antioxidant, antiinflammatory, and cytoprotective effects against DSS-induced ulcerative colitis in mice. Due to its antiinflammatory and antioxidant activity galectin-1 may be effective in preventing and treating ulcerative colitis.

Dietary supplementation with garcinol during late gestation and lactation facilitates acid-base balance and improves the performance of sows and newborn piglets1.

The present study was conducted to evaluate the effects of dietary garcinol supplementation during late gestation (from the 90th day of pregnancy; day 90) and lactation on the acid-base balance of the umbilical cord blood and performance of sows and piglets. Sixty sows (Duroc × Yorkshire × Landrace; second- or third-parity; n = 20) were randomly divided into 3 gestation (day 90 of pregnancy) or lactation treatments, control diet (CON; basal diet), basal diet with 200 mg garcinol, and basal diet with 600 mg garcinol per kg of feed. The body weight (BW); backfat thickness and litter size of the sows; and birth weight, weaning weight, and mortality of piglets were recorded. Sows' blood and piglets' umbilical cord blood were collected for the measurements of hematological parameters and antioxidative and immune indexes, and acid-base balance parameters, respectively. The colostrum and milk and fecal samples of the sows were also collected for analysis of milk composition and apparent total tract nutrient digestibility. Garcinol had no effect on the BW and backfat thickness of the sows but significantly increased the birth weight and weaning weight of piglets (P < 0.05) and decreased the mortality (P < 0.05). Moreover, the white blood cell counts and neutrophil count, mean cell hemoglobin, superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), and catalase (CAT) activity in the plasma of the sows were increased more significantly (P < 0.05) in the garcinol groups than that in the CON group, whereas the malondialdehyde (MDA) content was decreased (P < 0.05). The garcinol treatment significantly increased the pH, HCO3- and base excess values (P < 0.05), whereas it decreased the pCO2 and lactate content (P < 0.05) in the umbilical blood. Dry matter (DM), ash, and ether extract in the colostrum were similar between groups (P > 0.05), whereas the garcinol significantly increased the crude protein (CP) in the milk. In addition, the content of immunoglobulin A (IgA) and immunoglobulin G (IgG) in the plasma of piglets and in colostrum and milk of sows were increased more significantly (P < 0.05) in the garcinol groups than that in the CON group. The apparent total tract nutrient digestibility was similar between treatments. Collectively, this study indicates that sows fed with garcinol in late gestation and lactation showed improved maternal health and antioxidative status, milk protein content, acid-base balance in the umbilical cord blood, and growth performance in piglets, showing promise in natural plant extract nutrition for sows.

Effect of l-theanine on the growth performance, immune function, and jejunum morphology and antioxidant status of ducks

l-theanine is a unique nonproteinogenic amino acid found in tea, and has recently received considerable attention because of its various biological activities. However, there is no available research report on the use of l-theanine as a feed additive in ducks. This study was conducted to investigate the potential benefits and appropriate dosages of l-theanine on the growth performance, immune function, serum biochemical parameters, and jejunum morphology and antioxidant capacity of ducks. A total of 600 1-day-old Chaohu ducks were randomly allocated into five dietary treatment groups supplemented with 0 (control group), 300, 600, 900 and 1500 mg/kg of l-theanine. Each group included five replicates of 24 birds each. Body weight at day 28 was increased (P<0.05) by l-theanine. From days 15 to 28, l-theanine elevated cumulative BW gain (BWG) and cumulative feed intake (FI), and decreased feed to gain ratio. From days 1 to 28, l-theanine elevated (P<0.05) cumulative BWG and cumulative FI. l-theanine elevated (P<0.05) the relative weight of bursa of Fabricus (day 14), thymus (day 14), spleen (day 28) and liver (day 28). On day 28, l-theanine decreased (P<0.05) serum glucose, uric acid, triacylglycerol, total cholesterol, low-density lipoprotein cholesterol, insulin, interleukin-2 (IL-2) and IL-6 contents, and elevated (P<0.05) serum total protein, globulin (GLB), immune globulin A (IgA) and IgG contents, but only serum insulin, interferon-γ, tumor necrosis factor-α and IL-6 contents was decreased (P<0.05) and serum GLB and IgM content was elevated (P<0.05) by l-theanine on day 14. On day 14, l-theanine decreased (P<0.05) jejunum crypt depth, and elevated (P<0.05) jejunum villus height, villus height to crypt depth ratio (V/C), goblet cell number and total superoxide dismutase (T-SOD) activity. On day 28, l-theanine decreased (P<0.05) jejunum malondialdehyde content, and elevated (P<0.05) jejunum villus height, V/C, goblet cell number, and T-SOD, catalase and glutathione peroxidase activities. l-theanine levels caused quadratic effect on the growth performance, relative organ weight, serum parameters, jejunum morphology and antioxidant capacity. In conclusion, l-theanine can be used as a promising feed additive for ducks, and its optimal supplementation level was 600 to 900 mg/kg based on the current experimental condition.

Retinoic acid attenuates oxidative injury in bovine mammary epithelial cells induced by hydrogen peroxide

The objective of this study was to explore how retinoic acid (RA) attenuates oxidative injury induced by hydrogen peroxide (H&lt;sub&gt;2&lt;/sub&gt;O&lt;sub&gt;2&lt;/sub&gt;) in bovine mammary epithelial cells (BMEC). Subconfluence BMEC were randomly divided into four groups with six replicates: the control group (incubated in serum-free medium without RA or H&lt;sub&gt;2&lt;/sub&gt;O&lt;sub&gt;2 &lt;/sub&gt;for 30 h), H&lt;sub&gt;2&lt;/sub&gt;O&lt;sub&gt;2&lt;/sub&gt; group (pre-incubated for 24 h without RA, then for another 6 h with 600 μM H&lt;sub&gt;2&lt;/sub&gt;O&lt;sub&gt;2&lt;/sub&gt;), RA group (incubated with 1 mg/ml RA for 30 h without H&lt;sub&gt;2&lt;/sub&gt;O&lt;sub&gt;2&lt;/sub&gt;), and RA + H&lt;sub&gt;2&lt;/sub&gt;O&lt;sub&gt;2&lt;/sub&gt; group (RA prevention group, pre-incubated with 1 mg/ml RA for 24 h and then for another 6 h with 600 mM H&lt;sub&gt;2&lt;/sub&gt;O&lt;sub&gt;2&lt;/sub&gt;). The results showed that the H&lt;sub&gt;2&lt;/sub&gt;O&lt;sub&gt;2&lt;/sub&gt; treatment significantly decreased several measured traits, including the cell viability, glutathione peroxidase (GPX) and thioredoxin reductase (TRXR) activities, selenoprotein P (SELP) content, catalase and superoxide dismutase activities, total antioxidant capacity, and GPX1, TRXR1, and SELP gene expression, as well as GPX1 and TRXR1 protein expression. H&lt;sub&gt;2&lt;/sub&gt;O&lt;sub&gt;2&lt;/sub&gt; treatment also increased the malondialdehyde and reactive oxygen species contents and induced a marked increase of several measured traits, including the arachidonic acid (ARA) concentration, cytosolic phospholipase A2 and 5-lipoxygenase gene expression and activity, and 15-hydroxy twenty-four arachidonic acid and hydroxy peroxide tetracosenic arachidonic acid contents. RA pre-treatment prevented corresponding increases in parameters related to ARA metabolism and increased the activity of TRXR. Moreover, RA pre-treatment attenuated the phosphorylation levels of p38 mitogen-activated protein kinase (MAPK) and c-Jun N-terminal kinase and effectively decreased the ARA content. These results suggest that RA protected BMEC from oxidative stress by elevating TRXR activity, which inhibited the MAPK signaling pathway and led to a decreased concentration of ARA.

Antioxidant ameliorating effects against H2O2-induced cytotoxicity in primary endometrial cells

Oxidative stress and a disrupted antioxidant system are involved in a variety of pregnancy complications. In the present study, the role of vitamin E (Vit E) and folate as radical scavengers on the GSH homeostasis in stress oxidative induced in rat endometrial cells was investigated. Primary endometrial stromal cell cultures treated with 50 and 200 µM of H2O2 and evaluated the cytoprotective effects of Vit E (5 µM) and folate (0.01 µM) in H2O2-treated cells for 24 h. Following the exposure of endometrial cells to H2O2 alone and in the presence of Vit E and/or folate, cell survival, glutathione peroxidase (GPx) and glutathione reductase activities and the level of reduced glutathione (GSH) were measured. Cell adhesions comprise of cell attachment and spreading on collagen were determined. Flow cytometric analysis using annexin V was used to measure apoptosis. H2O2 treatment showed a marked decrease in cell viability, GPx and GR activities and the level of GSH. Although Vit E or folate had some protective effect, combination therapy with Vit E and folate attenuated all the changes due to H2O2 toxicity. An increasing number of alive cells was showed in the cells exposed to H2O2 (50 µM) accompanied by co-treatment with Vit E and folic acid. The present findings indicate that co-administration of Vit E and folate before and during pregnancy may maintain a viable pregnancy and contribute to its clinical efficacy for the treatment of some idiopathic infertility.

Toxicity and oxidative stress induced by T-2 toxin in cultured mouse Leydig cells

To explore the toxic mechanism of T-2 toxin on Leydig cells of mice, we would investigate the toxicity and oxidative stress induced by T-2 toxin in the cells. Leydig cells were isolated and cultured with control or T-2 toxin (10−7 M, 10−8 M, or 10−9 M) for 24 h, then cells and supernatants were harvested to examine cell viability, superoxide dismutase (SOD), glutathione peroxidase (GSH-Px) and catalase (CAT) activities, expression of messenger RNA (mRNA) related to oxidative stress, malondialdehyde (MDA) content and DNA damage. The cell viability was evaluated in mouse Leydig cells by MTT assay, MDA content and SOD, GSH-Px and CAT activities were measured by routine kits, expression of mRNA related to oxidative stress were examined by quantitative real-time polymerase chain reaction (PCR), and DNA damage was investigated by comet assay. Leydig cells treated with T-2 toxin showed significant reductions in cell viability, SOD, GSH-Px and CAT activities, and expression of mRNA related to oxidative stress, and remarkable increases in MDA content and levels of DNA damage. This study proves that T-2 toxin is toxic to Leydig cells of mice. Furthermore, oxidative stress plays an important role in the above-mentioned negative effects of T-2 toxin.

Growth, antioxidant capacity and muscle histochemistry of yellowtail kingfish (Seriola lalandi Valenciennes 1883): Selenium and temperature interaction

The aim of this study was to investigate the interactive effects of temperature and dietary selenium concentrations on antioxidant capacity, muscle histochemistry and the growth, of juvenile yellowtail kingfish (Seriola lalandi). The yellowtail kingfish were exposed to two temperatures (21°C or 26°C) and three selenium levels (0.0, 2.0 or 4.0mgSekg−1 of feed) for 30 days. Final weight and specific growth rate (SGR) were significantly affected by water temperature (ρ<0.001) and dietary Se (ρ<0.001) supplementation, and there were significant differences in the interaction between these two factors. Juvenile yellowtail kingfish fed Se-supplemented diets, attained a higher final weight and SGR than those without Se supplementation at 21°C, but not at 26°C. Regardless of the temperature, the red blood cell (RBC) glutathione peroxidase (GPx) activity of yellowtail kingfish fed Se-supplemented diets was significantly higher (ρ<0.05) than with the control diet. However, GPx activity of yellowtail kingfish when fed either 2.0mgSekg−1 or 4.0mgSekg−1 showed no significant difference (ρ>0.05). Se concentration in the muscles of juvenile yellowtail kingfish fed Se-supplemented diets was higher than that of the yellowtail kingfish that were fed the control diet. A histopathological test confirmed that 20.3% of fish muscles exhibited lesions, which occurred in the absence of dietary Se. The outcome of the present study helps in understanding the interactive effects of dietary Se concentrations and the temperature in the farming of yellowtail kingfish.

Effect of zirconium dioxide nanoparticles on glutathione peroxidase enzyme in PC12 and n2a cell lines.

Today, special attention is paid to the use of zirconium dioxide nanoparticle (nano-ZrO2), a neutral bioceramic metal, particularly for drug and gene delivery in medicine. However, there are some reports implying that use of nano-ZrO2 is associated with cytotoxic effects like inhibiting the cell proliferation, DNA damage and apoptosis. In the present study, we examined whether nano-ZrO2 alters cell viability and glutathione peroxidase (GPx) activity in two neuronal cell lines. The PC12 and N2a cells were cultured in the absence or presence of varying concentrations (31.25-2000 µg/mL) of nano-ZrO2 for 12, 24 or 48 h. The cell viability was evaluated using 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium (MTS) assay and GPx activity was determined by quantifying the rate of oxidation of the reduced glutathione to the oxidized glutathione. Nano-ZrO2 caused a significant reduction in cell viability and GPx activity after 12, 24 and 48 h, as compared with control group. These effects were concentration dependent and started from 250 µg/mL. The present study demonstrated that nano-ZrO2, at concentrations of > 250 µg/mL, has antiproliferative effects via reducing the cell defense mechanism against oxidative stress.

Selenium and vitamin E interaction in the nutrition of yellowtail kingfish (Seriola lalandi): physiological and immune responses

Six dietary treatments were prepared in a 3 × 2 factorial design (unsupplemented or supplemented with Se at 1 or 2 mg kg-1 × supplemented with vitamin E at 40 or 180 mg kg-1) and fed to yellowtail kingfish (Seriola lalandi) for 6 weeks to evaluate the effects of dietary Se and vitamin E on growth performance, immune and antioxidant responses and to investigate the potential interaction between these two micronutrients in this species. The results have revealed significantly interactive effects with positive physiological responses. Se significantly increased weight gain of fish fed diets low in vitamin E, but not high in vitamin E, whereas serum lysozyme activity was significantly improved by Se in diets high in vitamin E, but not low in vitamin E. Moreover, there was evidence of myopathy in fish deficient in both Se and vitamin E, but not single deficiency. There was no significant effect of dietary Se, vitamin E or their interaction on survival, antibody titre, feed intake, feed conversion ratio and fillet proximate composition; however, fillet Se and vitamin E were significantly responsive to dietary Se and vitamin E, respectively, and higher dietary Se intakes produced significantly higher red blood cell glutathione peroxidase activity.

Bioavailability of selenium from different dietary sources in yellowtail kingfish (Seriola lalandi)

Different forms of selenium (Se) were supplemented to a fishmeal-based diet to investigate the digestibility and bioavailability of Se in yellowtail kingfish (Seriola lalandi). Five groups of fish in triplicate were fed a basal diet (containing 3.31mg/kg Se) either unsupplemented or supplemented with 2mg/kg Se from selenite, selenocystine (SeCys), selenomethionine (SeMet) or Se-yeast for 6 weeks. The basal unsupplemented diet resulted in significantly lower weight gain, red blood cell glutathione peroxidase (GPx) and bactericidal activities than the supplemented diets. Muscle Se concentration was increased by Se supplementation from SeCys, SeMet or Se-yeast, but not selenite. There was no difference in GPx activity of fish fed with any supplemented diets. The bioavailability of Se from SeMet and Se-yeast was similar for all measurements. The most digestible sources of Se were from SeMet and Se-yeast, whereas the least was from fishmeal. Se from SeMet or Se-yeast produced more weight gain, higher Se accumulation in muscle tissues and bactericidal activity in yellowtail kingfish than Se from SeCys or selenite. This study shows that SeMet and Se-yeast are the most bioavailable sources of Se to yellowtail kingfish and are recommended to be supplemented to fishmeal-based formulated diets for yellowtail kingfish.

Effect of polyphenols extracted from tamarind (Tamarindus indica L.) seed coat on pathophysiological changes and red blood cell glutathione peroxidase activity in heat-stressed broilers

The purpose of this study was to determine the effect of polyphenols extracted from the tamarind seed coat (PETSC) on glutathione peroxidase (GPx) activity, red blood cell parameters and bilirubin in heat-stressed broilers. One hundred forty-seven broilers, 18-days old were divided into two groups. In group 1, broilers were maintained at an environmental temperature of 26 ± 2 °C throughout the experimental period. In group 2, the broilers were maintained at 38 ± 2 °C (cyclic temperature: 26 ± 2 °C; -38 ± 2 °C; and -26 ± 2 °C, and broilers were maintained at 38 ± 2 °C for 6h/ day) and received PETSC at a concentration of 0, 100, 200, 300, 400 or 500mg/kg in their diet ad libitum. Parameters were investigated on days 1, 7, 14 and 21 of the experimental period. Results showed that GPx activity of heat-stressed broilers that received 100mg/kg of PETSC in their diet was lower (P < 0.05) than that in broilers fed the other concentrations. The mean total red blood cell count and hemoglobin concentration of heat-stressed broilers that received 100mg/kg PETSC was higher (P < 0.05) than those in broilers in group 1 and those fed the other concentrations. The mean bilirubin level in the excreta of heat-stressed broilers that received 100mg/kg of PETSC was lower (P < 0.05) than that in broilers that received 0, 300, 400 and 500mg/kg of PETSC. This showed that PETSC could reduce GPx activity and bilirubin in feces, and increase red blood cell parameters in heat-stressed broilers.

The effects of organic selenium (Sel-Plex) on the viability of pneumonic Holstein suckling calves

The objective of this study was to determine the effects of supplemented selenium (Se) on plasma cortisol, red blood cell glutathione peroxidase activity (RBC GSH-PX-1), concentration of immunoglobulin G (IgG) and body weight in pneumonic suckling calves. Ten Holstein suckling male calves were randomly allocated to two groups and fed either unsupplemented milk (control) or with milk supplemented with 0.3 mg/kg DM Se (Sel-Plex) for two months. Sel-Plex had no significant effect on cortisol plasma concentration. A significant increase in red blood cell GSH-PX-1, body weight and serum concentration of IgG was observed in the treated group, along with a non-significant increase in body weight. The results indicate that Sel-Plex supplementation of suckling calves with a marginal selenium status increases GSH-PX-1, serum concentration of IgG and body weight of calves. The objective of this study was to determine the effects of supplemented selenium (Se) on plasma cortisol, red blood cell glutathione peroxidase activity (RBC GSH-PX-1), concentration of immunoglobulin G (IgG) and body weight in pneumonic suckling calves. Ten Holstein suckling male calves were randomly allocated to two groups and fed either unsupplemented milk (control) or with milk supplemented with 0.3 mg/kg DM Se (Sel-Plex) for two months. Sel-Plex had no significant effect on cortisol plasma concentration. A significant increase in red blood cell GSH-PX-1, body weight and serum concentration of IgG was observed in the treated group, along with a non-significant increase in body weight. The results indicate that Sel-Plex supplementation of suckling calves with a marginal selenium status increases GSH-PX-1, serum concentration of IgG and body weight of calves.

Effect Of Avenanthramide Supplementation On Responses To Eccentric Exercise In Young Women

Avenanthramides (AVA) are a group of nitrogen-containing diphenolic phytochemicals found exclusively in oats that have exhibited antioxidant and anti-inflammatory potential in vitro and in rodents; however, the effects of chronic AVA consumption in humans have been unexplored. PURPOSE: To investigate the effects of 8 weeks of AVA supplementation on the inflammatory and oxidative responses to a single bout of downhill running in college-aged women. METHODS: Ten women aged 18-29 yr were randomly assigned to receive cookies fortified with either high-AVA (23.5 mg/day) oat flour (O, Ceapro Inc., Canada) or with equal content of wheat flour as a placebo (PL). They were instructed to eat one 115 g cookie per day for 8 wks, during which dietary and physical activity levels were recorded. Before and after the supplementation period, subjects ran on a treadmill at -9% grade at a speed that elicited 75% of their maximal heart rate for 4 x 15 min bouts with 3 rest intervals of 5 min each. Blood samples were collected before and immediately and 24-h post exercise. RESULTS: There was no difference in pain and soreness ratings between O and PL groups post-exercise. During the post-supplementation test, O showed a higher plasma reduced to oxidized glutathione ratio (P<0.05) at 24 h post-exercise vs. PL group. Red blood cell (RBC) glutathione peroxidase activity decreased (P<0.05) immediately after exercise in O, but not in PL. RBC superoxide dismutase activity was higher (P<0.05) in O vs. PL post-exercise. There were trends toward lower plasma tumor necrosis factor (TNF)-alpha levels and white blood cell reactive oxygen species production in O compared to PL immediately and 24-h after exercise. CONCLUSIONS: High-AVA oat supplementation appears to attenuate downhill exercise-induced oxidative stress and blood inflammatory markers in college-aged women.

Dietary selenium requirements based on tissue selenium concentration and glutathione peroxidase activities in old female rats

Dietary nutrient requirements for older animals have been studied far less than have requirements for young growing animals. To determine dietary selenium (Se) requirements in old rats, we fed female weanling rats a Se-deficient diet (0.007 μg Se/g) or supplemented rats with graded levels of dietary Se (0–0.3 μg Se/g) as Na 2SeO 3 for 52 weeks. At no point did Se deficiency or level of Se supplementation have a significant effect ( P>0.05) on growth. To determine Se requirements, Se response curves were determined for 7 Se-dependent parameters. We found that minimum dietary Se requirements in year-old female rats were at or below 0.05 μg Se/g diet based on liver Se, red blood cell glutathione peroxidase (Gpx1) activity, plasma Gpx3 activity, liver and kidney Gpx1 activity, and liver and kidney Gpx4 activity. In conclusion, this study found that dietary Se requirements in old female rats were decreased at least 50% relative to requirements found in young, rapidly growing female rats. Collectively, this indicates that the homeostatic mechanisms related to retention and maintenance of Se status are still fully functional in old female rats.