Comparison of Nutritional Availability of Biogenic Selenium Nanoparticles and Chemically Synthesized Selenium Nanoparticles.

Selenium (Se) is an essential micronutrient, and animals biosynthesize selenoproteins from various selenocompounds such as inorganic salts and organic selenocompounds as a Se source. In addition to the inorganic and organic forms of Se, it is also known that elemental Se is biologically synthesized at the nanoscale in nature. Biologically synthesized Se nanoparticles (Se-NPs), i.e., biogenic Se-NPs (Se-BgNPs), have not been fully investigated as a Se source compared with the other forms of Se. In this study, we evaluated the nutritional availability of Se-BgNPs biosynthesized in E. coli and revealed that Se-BgNPs were less assimilated into selenoproteins in rats as a Se source than inorganic Se salt or chemically synthesized Se-NPs. Se-BgNPs showed tolerance toward digestion and low absorbability in gut, which resulted in the low nutritional availability. Se-BgNPs seem to be coated with a biomaterial that functions to reduce their toxicity toward E. coli and at the same time lowers their availability to animals.

Distributions of mercury and selenium in rats ingesting mercury selenide nanoparticles.

Mercury (Hg) is one of the most toxic environmental pollutants, and is biocondensed via the food chain. Selenium (Se) is an essential element that possesses an antagonistic property towards Hg in vivo. The antagonistic property is explained by the assumption that Hg and Se directly interact to form HgSe nanoparticles (HgSe NPs) in organs. It is presumed that the toxic effects of HgSe NPs are lower than that of ionic Hg; however, no precise evaluation has been conducted so far. In the present study, we evaluated the distribution of HgSe NPs ingested in Se-deficient rats. The recovery of serum selenoproteins from a deficient level was not observed in rats orally administered HgSe NPs. In addition, the excretion of Hg and Se via urine was not observed. Interestingly, the biosynthesis of selenoproteins and urinary selenometabolites would have required the production of selenide through the degradation of HgSe NPs. Therefore, it seems that selenide and Hg are not released from HgSe NPs in vivo. The administration of HgSe NPs did not increase Hg and Se concentrations in organs, and almost all HgSe NPs were recovered in feces, indicating no or low bioaccessibility of HgSe NPs even in Se-deficient rats. These results suggest that HgSe NPs are biologically inert and do not become a secondary environmental pollutant of Hg.

Effect of gut microflora on nutritional availability of selenium.

Since selenium (Se) is an essential mineral, animals must be able to metabolize the various selenocompounds in meat, fish and vegetables. It is unclear how animals, including humans, utilize selenocompound efficiently, but we hypothesized that gut microflora might contribute to these processes. In this study, we revealed that Se-methylselenocysteine and selenocyanate were metabolized to selenomethionine (SeMet) by intestinal microflora, suggesting selenocompounds might be metabolized to SeMet, which can be used by the host organism. The major urinary selenosugar, 1ß-methylseleno-N-acetyl-d-galactosamine, was utilized less in microflora-suppressed than healthy rats, suggesting that this sugar can be transformed to a nutritionally available form by gut microflora in animals with a healthy microbiota. We concluded that, in rats at least, gut microflora has a role in the metabolism of Se in the host animal, and this finding might be worth investigating in humans.

Biotransformation of organic selenium compounds in budding yeast, Saccharomyces cerevisiae.

Selenium (Se) is not essential for yeast growth, but it has a metabolic capacity to transform inorganic Se species to organic Se compounds such as selenomethionine (SeMet). Although the metabolism of inorganic Se species has been well discussed, there are no studies revealing how organic Se compounds are metabolized in yeast. The aim of this study was to show the specific metabolic pathway of organic Se species in yeast. We performed the speciation analysis of selenometabolites in budding yeast, Saccharomyces cerevisiae, exposed to selenometabolites produced by animals, plants, and microorganisms, such as methyl-2-acetamido-2-deoxy-1-seleno-ß-d-galactopyranoside (SeSug1, selenosugar 1), methyl-2-acetamido-2-deoxy-1-seleno-ß-d-glucopyranoside (SeSug2, selenosugar 2), trimethylselenonium ions (TMSe), Se-methylselenocysteine (MeSeCys), and SeMet. Four selenometabolites, SeSug1, SeSug2, SeMet, and MeSeCys, were commonly metabolized into SeMet in yeast. Yeast was able to incorporate TMSe but could not metabolize it. Since MeSeCys and selenosugars are the major selenometabolites in plants and animals, respectively, yeast is useful for recovering Se as SeMet from the selenometabolites produced by other organisms in the ecosystem.

Effect of dietary supplementation of astaxanthin from Phaffia rhodozyma on lipopolysaccharide-induced early inflammatory responses in male broiler chickens (Gallus gallus) fed a corn-enriched diet.

Effect of dietary supplementation of astaxanthin (Ax) from Phaffia rhodozyma on lipopolysaccharide-induced inflammatory responses was investigated in male broiler chickens fed a corn-based diet. Birds (1 week of age) were fed a corn-enriched diet containing either 0 or 100 ppm Ax for 2 weeks and were intraperitoneally injected with lipopolysaccharide (LPS, 1 mg/kg body weight). Inflammatory responses were evaluated by determining changes in expression of messenger RNA (mRNA) in cytokines and mediators related to inflammatory responses (interleukin (IL)-1 beta and -6, inducible nitrite synthase (iNOS), interferon (IFN)- γ and cyclooxygenase (Cox)-2 in the liver and spleen after 2 h of LPS injection and plasma ceruloplasmin concentration as an acute phase protein. Birds fed Ax showed significantly higher iNOS mRNA expression in the liver and spleen compared to that of control birds. Ax-fed birds also showed greater increase in mRNA expression in the liver of IL-1, IL-6 and IFN-γ compared to that of control birds. The enhancing effect of Ax was further progressed when LPS was injected. No difference was found in plasma ceruloplasmin concentration between the Ax-fed group and control group. The results suggest that feeding supplementation of Ax (100 ppm) to a corn-enriched diet possibly does not have anti-inflammatory effect in male broiler chickens.

Effect of L-carnitine on proliferative response and mRNA expression of some of its associated factors in splenic mononuclear cells of male broiler chicks.

The effect of L-carnitine supplementation on mitogen (concanavalin A, Con A) induced proliferation of mononuclear cells (MNC) in the spleen was investigated in broiler chickens at different ages. Day-old chickens were fed a diet supplemented with or without L-carnitine (100 ppm) for 24 days. The carnitine-supplemented group showed greater proliferation of MNC in the spleen in response to Con A than that of the control group at 24 days of age. In addition, at 24 days of age the carnitine-supplemented group showed higher expression of interleukin (IL)-2 and interferon (IFN)-gamma mRNA, but lower expression of inducible nitric oxide synthase (iNOS) in the Con A-stimulated splenic MNC than the control group. The enhancement effect of L-carnitine on MNC proliferation and IL-2 mRNA expression was not found in chicks at 14 days of age. Addition of L-carnitine (50 nmol/mL) to the culture medium enhanced proliferation and IL-2 mRNA expression of splenic MNC obtained from 24-day-old but not from 14-day-old broiler chickens. The results suggest that L-carnitine is capable of enhancing MNC proliferation in broiler chickens at 24 days of age partly through increasing IL-2 and IFN-gamma production and decreasing NO production.

Dietary supplementation of glycine modulates inflammatory response indicators in broiler chickens.

Three experiments were conducted to investigate the effect of dietary glycine (Gly) supplementation on inflammatory responses in broiler chicks fed a basal diet using maize and soybean meal as the primary ingredients. Inflammation-related processes following lipopolysaccharide (LPS) injection were examined by analysing plasma concentrations of nitrate plus nitrite (NOx) and ceruloplasmin (Cer) in experiments 1 and 2, or expression of several genes in the spleen and liver including IL-1 beta and -6, TNF-like ligand (TL)1A, inducible NO synthase, interferon (IFN)-gamma and toll-like receptor (TLR) 4 were examined in experiment 3. Growth performance was also determined following immunological stimulation by both LPS and Sephadex injection in experiment 2. In experiment 1, birds fed a diet supplemented with Gly at 10 or 20 g/kg showed lower responses in plasma NOx and Cer than birds fed the diet supplemented with Gly at 0 or 40 g/kg. In experiment 2, a similar effect of Gly supplementation at 10 g/kg on plasma NOx and Cer was observed when chicks were fed either an isonitrogenous diet with Gly or glutamic acid (Glu). Gly-supplemented diet-fed birds showed better growth performance than Glu-supplemented diet-fed birds. The splenic expression of inflammatory response-related genes in birds fed a diet supplemented with Gly at 10 g/kg diet was lower than that of birds fed the basal diet in experiment 3. These results suggest that dietary Gly supplementation modulates the inflammatory response partly through changes in the expression of pro-inflammatory cytokines such as IL-1, IL-6, IFN-gamma and TL1A.

Negatively-charged air conditions and responses of the human psycho-neuro-endocrino-immune network.

BACKGROUND: Against increasing environmental adverse effects on human health such as those associated with water and ground pollution, as well as out- and indoor air conditions, trials were conducted to support and promote human health by improving the indoor air atmosphere. This study was performed to estimate the effect of negatively-charged air conditions on human biological markers related to the psycho-neuro-endocrino-immune (PNEI) network. OBJECTIVES: After construction of negatively-charged experimental rooms (NCRs), healthy volunteers were admitted to these rooms and control rooms (CTRs) and various biological responses were analyzed. METHODS: NCRs were constructed using a fine charcoal coating and applying an electric voltage (72 V) between the backside of walls and the ground. Various biological markers were monitored that related to general conditions, autonomic nervous systems, stress markers, immunological parameters and blood flow. RESULTS: Regarding the indoor environment, only negatively-charged air resulted in the difference between the CTR and NCR groups. The well-controlled experimental model-room to examine the biological effects of negatively-charged air was therefore established. Among the various parameters, IL-2, IL-4, the mean RR interval of the heart rate, and blood viscosity differed significantly between the CTR and NCR groups. In addition, the following formula was used to detect NCR-biological responses: Biological Response Value (BRV)=0.498+0.0005 [salivary cortisol]+0.072 [IL-2]+0.003 [HRM-SD]-0.013 [blood viscosity]-0.009 [blood sugar]+0.017 [pulse rate]. CONCLUSIONS: Negatively-charged air conditions activated the immune system slightly, smoothened blood flow and stabilized the autonomic nervous system. Although this is the first report to analyze negatively-charged air conditions on human biological responses, the long-term effects should be analyzed for the general use of these artificial atmospheres.

Effect of a mixture of conjugated linoleic acid isomers on growth performance and antibody production in broiler chicks.

The effect of dietary conjugated linoleic acid (CLA) isomers mixture on antibody titres against sheep blood erythrocytes (SRBC) and immunoglobulin (Ig) G concentration in plasma was studied in broiler chickens. In experiment 1, male and female broiler chicks (11 d of age, Cobb strain) were fed a diet supplemented with 10 g CLA or 10 g safflower-seed oil/kg diet for 2 weeks. An SRBC suspension (5:100, v/v) in a phosphate buffer was intravenously injected at 18 d of age and a blood sample was taken from the wing vein at 25 d of age. Chicks fed the CLA-supplemented diet had enhanced first antibody titres in plasma to SRBC as compared with those fed the safflower-seed oil-supplemented diet, irrespective of sex differences. In experiment 2, male broiler chicks (8 d of age, Ross strain) were fed a basal diet or a diet containing 10 g CLA/kg diet for 3 weeks. CLA in the CLA diet partially replaced the soyabean oil in the basal diet. The SRBC suspension was intravenously injected at 15 and 25 d of age and a blood sample was obtained at 21 and 29 d of age. The first antibody titres against SRBC were higher in chicks fed the CLA diet than those in chicks fed the basal diet, but the second titres were not. Plasma IgG concentrations in chicks fed the CLA diet were higher than those in chicks fed the basal diet on both sampling days. The results showed that dietary CLA enhanced antibody production in broiler chickens.