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Selenium, as part of selenocysteine, is the active centre of selenoenzymes. Excess amount of selenium generates oxygen free radicals and reacts with thiol compounds such as reduced glutathione, composing seleno-diglutathione. These reactions impair the amount and/or activity of the biological antioxidant defence system. In the present experiment the effects of two inorganic selenium sources (Na2SeO3, Na2SeO4) on lipid peroxidation and on the content and activity of some components of the antioxidant defence mechanism were studied in Ross 308 hybrid cockerels. In the tissues examined, the glutathione redox system was altered in different ways as an effect of excess selenium. The amount of glutathione and, consequently, glutathione peroxidase activity declined in the blood plasma and in the red blood cell haemolysate, while in the liver malondialdehyde concentration increased only at the end of the experimental period as a result of the boosted enzyme activity. The authors suppose that the cause of increased lipid peroxidation was the potential toxic effect of selenium accumulation above the actual demand.

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This study was designed to investigate the effects of excess (24.5 mg Se/kg feed) inorganic and organic dietary selenium supplementation on 3-week-old broilers. The experiments lasted 4 days. Intensity of lipid peroxidation processes (malondialdehyde, MDA) and the amount (reduced glutathione, GSH) and activity (glutathione peroxidase activity, GSHPx) of gluathione redox system were measured in blood plasma, red blood cell hemolysate and liver: Voluntary feed intake in the selenium-treated groups reduced remarkably. Elevated GSH concentration and GSHPx activity were measured in plasma and liver of both selenium-treated groups compared to the untreated control and the ‘pair-fed’ controls. The lipid peroxidation processes in the liver showed higher intensity than the control due to both selenium treatment. The applied dose of selenite and selenomethionine does not inhibit, but even improves the activity of glutathione redox system in the liver during the early period of selenium exposure.

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Nanopages
Authors:
I. Szendrő
,
K. Erdélyi
,
Zs. Puskás
,
M. Fábián
,
N. Adányi
, and
K. Somogyi

Due to the changes of the refractive indices, the planar optical waveguides are sensitive to the surrounding media, to the adsorbates, etc. on their surface. The sensitivity of such a waveguide layer can be enhanced when its thickness is lowered down to the nanometer range. Such sensors can be successfully operated both in inorganic chemistry and in life sciences as label free biosensors. Principles and some results are demonstrated. Further on, application of transparent conductive oxides for voltammetric measurements in combination with the classical waveguide sensor will be demonstrated. Development and results of a combined system is described and first results with simultaneous measurements are demonstrated. An indium tin oxide nanolayer is deposited and activated on the top of the sensor chip. This electrically conductive oxide layer serves as working electrode in the specially developed electrochemical cuvette. In this work results are presented for simultaneous use of these two methods and for simultaneous measurement of refractive index changes of the waveguiding system and that of electrical current changes. The first basic results are demonstrated using H2O2 and dye solutions, using KCl and TRIS as buffer and transport media.

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The purpose of the present study was to investigate the effect of experimental T-2 toxin load (2.35 mg/kg of feed) and vitamin E supply in the drinking water (10.5 mg/bird/day) on vitamin E levels of the blood plasma and liver in broiler chickens in a 14-day experiment. It was found that T-2 toxin load did not influence vitamin E content of the blood plasma except at day 3 after the toxin load when a moderate increase was detected in plasma vitamin E. No significant changes were found in vitamin E content of the liver. The simultaneous use of high-dose vitamin E supplementation and T-2 toxin load caused a significantly higher plasma vitamin E content but the changes were less expressed in the group subjected to T-2 toxin load. Vitamin E supply also resulted in a marked and significant increase in vitamin E concentrations of the liver on days 3 and 7 even in the T-2 loaded group, but this concentration significantly decreased thereafter. The results show that T-2 contamination of the diet has an adverse effect on the utilisation of vitamin E in broiler chickens.

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The effect of feeding ochratoxin A (OTA) contaminated diet (379.6 and 338.1 μg/kg in starter and grower diets) on production traits, lipid peroxidation and some parameters of the glutathione redox system were investigated in weaned piglets over a seven-week period. Feed intake and feed conversion ratio (FCR) did not differ significantly, but in the first phase (0–28 days) the daily weight gain was significantly lower in the piglets fed the OTA-contaminated diet. Lipid peroxidation, as measured by the amount of malondialdehyde, glutathione content and glutathione peroxidase activity, did not change significantly in the blood plasma and red blood cell haemolysate in the OTA-loaded group, while malondialdehyde content increased significantly in the liver and markedly but not significantly in the kidney of piglets fed OTA-contaminated feed. Glutathione content did not differ significantly in the studied organs of the two groups while glutathione peroxidase activity of the OTA-loaded animals was significantly lower both in the liver and in the kidney. The results suggest that the use of feed-stuffs contaminated with low levels of OTA for seven weeks did not cause marked differences in the production traits or in lipid peroxidation and amount or activity of the glutathione redox system in the blood plasma, red blood cells and kidney, while significant changes occurred in the liver homogenate.

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Acta Alimentaria
Authors:
K.O. Bartha
,
L. Csengeri
,
A. Lichthammer
,
A. Erdélyi
,
J. Kubányi
, and
Zs. Szűcs

Abstract

COVID-19 lockdown affects people's daily routine and has an impact on their lifestyle. Recent studies documented associations between body weight changes and children's lifestyle during social isolation. Childhood obesity is associated with a higher risk of COVID-19 severity and mortality. Our aim was to assess the effects of lockdown due to the COVID-19 pandemic on children's sleep, screen time, physical activity, and eating habits. 387 parents of five elementary school students between 16 and 26 June 2020 were interviewed through an online questionnaire. Physical activity level decreased (63.8%), sleep (60.9%) and screen (5.64 ± 3.05 h/day) times and food intake (39.8%) increased. 80.6% of parents reported changes in children's diet: increased consumption of fruits and vegetables (32.4%), breakfast (15.5%), water and sugar-free beverages (17.6%), snacks (40.4%), sugary drinks (9.9%) was observed. Body weight increased in 44.4% of children. The results of the survey conducted under GYERE®-Children's Health Program are in line with the international literature findings: body weight change during the quarantine is significantly associated with food intake, snacking, sugary drinks, and we also found association with fruit and vegetable consumption and lack of breakfast. Effective strategies and electronic health interventions are needed to prevent sedentary lifestyle and obesity during lockdown.

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