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  • Author or Editor: Miklós Mézes x
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Az antioxidánsok az egészségre számos kedvező hatással rendelkeznek, amelyek közül napjainkig kevés figyelem irányult az élelmi rost antioxidáns tulajdonságaira. Az élelmi rost antioxidáns hatása mögött az azt alkotó poliszacharidkomplexhez kapcsolt polifenolvegyületek állnak, amelyek a bélcsatornában felszabadulva fejtik ki hatásukat. Növényi sejtfalból izoláltak egy, az előbbiektől eltérő molekulát, a kalcium-fruktoborátot, amelynek szintén van antioxidáns kapacitása, annak aktív komponense azonban a bór. Számos olyan élelmiszer és élelmiszeripari melléktermék ismert, amelynek jelentős antioxidáns élelmirost-tartalma van, így ezek is hozzájárulhatnak a bélcsatorna, ennek révén a szervezet antioxidáns védelméhez. Ilyenek például a gabonamagvak, a káposzta, a kávébab és a guáva, vagy a melléktermékek közül a szőlőtörköly. Az antioxidáns élelmi rost polifenolvegyületei az egyes növényekben eltérőek, így azok antioxidáns kapacitása is változó, de grammonként hozzávetőlegesen 50–100 mg DL-α-tokoferollal egyenértékűek. Ez olyan számottevő antioxidáns kapacitás, amely alkalmassá teszi az antioxidáns élelmi rostot egyes, bizonyítottan oxidatív stressz által kiváltott betegségek, így például az atherosclerosis, egyéb cardiovascularis kórképek vagy a colorectalis carcinoma elleni prevencióban. Orv. Hetil. 2018; 159(18): 709–712.

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Ingredients used in animal feeds and their contamination with undesirable substances, such as mycotoxins, are fundamentally important both in terms of the quality of animal products and the potential human health impacts associated with the animal-based food production chain. Feed ingredients contaminated with mycotoxins may have a wide range of toxicological effects on animals. Therefore, mycotoxin contamination of feed ingredients constituting complete feed products represents an important potential hazard in farm animal production. This review summarises the potential effects of some preventive methods used during the storage of cereal grains as well as of nutritive (e.g. antioxidants, amino acids, fats) or non-nutritive compounds (e.g. pharmacological substances, carbon- or silica-based polymers) and detoxifying enzymes recommended for use against the toxic effects of different mycotoxins.

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To study the possible effects of different inclusion levels of distillers dried grain with solubles (DDGS) on the lipid peroxidation and glutathione redox status of chickens, 200 three-week-old Ross 308 cockerels were assigned to four treatment groups of 50 birds each. The groups were fed a control and three experimental, isocaloric and isonitrogenous grower diets containing 15, 20 and 25% DDGS, respectively, combined with lysine (Lys) and methionine (Met) supplementation until 6 weeks of age. It was found that DDGS inclusion increased the ether extract content of the diets which resulted in higher reduced glutathione (GSH) content and elevated glutathione peroxidase activity (GSHPx) in the liver. However, DDGS addition with Lys and Met supplementation did not influence the malondialdehyde content of the blood and the liver. The oleic acid proportion of the diet showed a close positive correlation with GSH content of the liver. A smaller ratio of methionine and cysteine in the diet with DDGS resulted in significantly higher liver GSH content. GSHPx activity increased parallel with the elevated GSH content of the liver homogenate, suggesting that the enzyme is activated by the actual supply of its co-substrate. In conclusion, the results show that DDGS, even at a high inclusion level combined with Lys and Met supplementation, has no initiative effect on lipid peroxidation in the blood and liver of broiler chickens.

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Authors: László Pál, Károly Dublecz, Mária Weber, Krisztián Balogh, Márta Erdélyi, Gábor Szigeti and Miklós Mézes

Three groups of cockerels were fed with a control diet, with a diet contaminated with T-2 and HT-2 toxin (0.31 and 0.26 mg/kg) or with that containing a combination of T-2 and HT-2 toxin (0.32 and 0.25 mg/kg) and aflatoxin B 1 (AFB 1 , 0.38 mg/kg) for 21 days. Body weight gain and feed conversion ratio did not differ significantly among the groups. Malondialdehyde concentration of the liver was lower in the group fed the diet contaminated with the combination of T-2 + HT-2 toxin and aflatoxin B 1 as compared to the control group or the group fed T-2 + HT-2 toxins. Reduced glutathione (GSH) content of the liver was lower in the T-2 + HT-2 group than in the group fed a combination of T-2, HT-2 and aflatoxin. Reduced glutathione content of the heart was higher in the T-2 + HT-2 group than in the control group. Mycotoxin contamination had no effect on glutathione peroxidase (GSH-Px) activity in comparison to the control, but significantly lower GSH-Px activity was found in the heart of chickens in the T-2 + HT-2 + AFB 1 group than in the T-2 + HT-2 group. In this study, T-2 + HT-2 toxin and aflatoxin B 1 contamination of the diets did not affect the production traits adversely and did not exert additive effects on lipid peroxidation and on the glutathione redox system.

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Authors: András Szabó, Judit Szabó-Fodor, Hedvig Fébel, Miklós Mézes, Imre Repa and Melinda Kovács

Adult male Wistar rats were enrolled in a study to test the acute hepatic effects of 50 mg/kg fumonisin B1 in feed for 5 days. Fumonisin B1 depressed growth and feed intake, and absolute and relative liver weight showed a significant increase. The proportions of C17:0, C18:3 n3, C22:5 n3 and C22:6 n3 fatty acids decreased in the hepatic phospholipid fraction. All proportional decreases modified the hepatocellular membrane lipids into a more rigid state. The fatty acid profile modifications were partly compensated for by endogenous glutathione (preventing the formation of conjugated dienes and trienes as initial phase lipid peroxidation indicators), while the enzymatic antioxidant defence system (glutathione peroxidase) was unaltered. In contrast, hepatic malondialdehyde, the cytotoxic product of end-phase lipid peroxidation showed a concentration increase even after 5 days of feeding. The results indicate a rather strong and rapid hepatic effect of FB1, immediately impairing membrane phospholipids, even before the enzymatic antioxidant defence is activated.

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Authors: Csilla Pelyhe, Benjámin Kövesi, Erika Zándoki, Balázs Kovács, Judit Szabó-Fodor, Miklós Mézes and Krisztián Balogh

The purpose of this study was to investigate the short-term effects of a single oral dose of T-2 and HT-2 toxin at 0.15, 0.33 and 1.82 mg kg−1 body weight, or deoxynivalenol (DON) and 15-acetyl-DON at 0.13, 0.31 and 1.75 mg kg−1 body weight in common carp. Conjugated dienes and trienes (the early markers of lipid peroxidation) were elevated in all DON-treated groups at the 16th hour, while thiobarbituric acid reactive substances (TBARS; termination marker) were increased at the highest dose of DON at the 16th and 24th hours. T-2 toxin did not cause changes in these parameters. Glutathione content and glutathione peroxidase activity showed higher levels at the 16th hour as the effect of both mycotoxins. The expression of glutathione peroxidase (GPx4) genes (gpx4a and gpx4b) revealed a dual response. Downregulation was observed at the 8th hour, followed by an induction at the 16th hour, at the lowest dose of both mycotoxins. Higher doses revealed long-drawn emergence and an elevation was observed only at the 24th hour. However, at the lowest and highest doses of DON or T-2 toxin the changes in gene expression were delayed, which may be related to the low oxidative stress response, as suggested by the expression profiles of the nrf2, keap1, gpx4a and gpx4b genes.

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Authors: Rubina Tu¨nde Szabó, Mária Kovács-Weber, Márta Erdélyi, Krisztián Balogh, Natasa Fazekas, Ákos Horváth, Miklós Mézes and Balázs Kovács

Background and aims

The aim of this study was to verify that the comet assay can be used to investigate the DNA damaging effects of T-2 and HT-2 toxins in the liver of broiler chickens. The comet assay is a favorable genotoxic analysis because it is cheap, simple, and can be used in many organisms and different tissues.

Materials and methods

Male broiler chickens were fed with T-2/HT-2 toxins-contaminated diet for 14 days. The comet assay was successfully adapted to chicken liver cells, and the DNA damage was determined by a decrease in the comet parameter (DNA % in the tail) in the experimental groups.

Results

The method of evaluation was found to be critical because DNA damage could not be detected exactly using the CometScore software, due to inaccurate separation of head and comet. However, this problem can be solved by visual evaluation.

Conclusion

In the case of the visual evaluation, each toxin-treated group differed significantly from the control group, indicating that the assay can be useful for the assessment of primary DNA damage caused by T-2/HT-2 toxins.

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Authors: Andrea Győrffy, Mónika Keresztes, Vera Faigl, Vilmos Frenyó, Margit Kulcsár, Tibor Gaál, Miklós Mézes, Attila Zsarnovszky, Gyula Huszenicza and Tibor Bartha

In the regulation of energy metabolism, the liver plays an important role in the reinforcement of energy production. In periparturient cows the energy homeostasis turns into a negative energy balance that may shift the physiological regulation of energy balance towards pathological processes. Propylene glycol (PG), as a complementary source of energy used in the nutrition of dairy cows, alters systemic thyroid hormone economy; however, the exact mechanism through which highly glycogenic feed supplements impact liver metabolism is little known. Previous studies showed that only leptin receptors are expressed in the liver of cows, and now we report that leptin mRNA is expressed in the liver of cows as well. The present results show that the mRNA of leptin and its receptors are differentially modulated by the increased energy content of the feed consumed. Simultaneous changes in hepatic type I deiodinase activity suggest that hepatic modulation of the leptin system by PG supplementation may be mediated by an increased local thyroxine-triiodothyronine conversion. Since PG supplementation with simultaneous T4–T3 turnover and increased hepatic leptin- and short-form leptin receptor mRNA were not associated with a significant change in hepatic total lipid levels, it is suggested that the leptin system, directly or indirectly modulated by thyroid hormones, may represent a local defence mechanism to prevent fatty liver formation.

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Authors: Mangesh Nakade, Csilla Pelyhe, Benjámin Kövesi, Krisztián Balogh, Balázs Kovács, Judit Szabó-Fodor, Erika Zándoki, Miklós Mézes and Márta Erdélyi

Short-term (48-hour) effects of 3.74/1.26 mg kg−1 T-2/HT-2 toxin or 16.12 mg kg−1 DON in feed were investigated in the liver of three-week-old cockerels (body weight: 749.60 ± 90.98 g). Markers of lipid peroxidation showed no significant changes. At hour 24, glutathione content in the T-2/HT-2 toxin group was significantly higher than in the control. Glutathione peroxidase activity was significantly higher than the control at hour 24 in the T-2/H-2 toxin group and at hour 48 in the DON group. In the DON group, expression of the glutathione peroxidase 4 gene (GPX4) was significantly lower than in the control at hours 12 and 14, and higher at hour 48. Expression of the glutathione reductase gene (GSR) was significantly lower than in the control at hour 12 in the T-2/HT-2 toxin group, and at hours 12, 24 and 48 in the DON group. However, at hour 36 higher GSR expression was measured in the DON group. Due to the effect of both trichothecenes, expression of the glutathione synthetase gene (GSS) was significantly lower than in the control at hours 24 and 48. In conclusion, T-2/HT-2 toxin and DON had a moderate short-term effect on free radical formation. T-2/HT-2 toxin induced more pronounced activation of the glutathione redox system than did DON.

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Authors: Dániel J. Kócsó, Judit Szabó-Fodor, Miklós Mézes, Krisztián Balogh, Szilamér Ferenczi, András Szabó, Brigitta Bóta and Melinda Kovács

The objective of this experiment was to determine whether fumonisin B1 (FB1) added to the diet of rats in a dose of 50 mg/kg changes the production of heat shock protein 70 (Hsp70) in the lungs and kidney of rats. We also studied the effect of this mycotoxin on the antioxidant system of the body. Mature (8 weeks old) male Wistar Crl:WI BR rats (n = 6/group) were fed the toxin-containing diet for 5 days. FB1 resulted in a 7% body weight reduction without significantly changing the feed intake. Western blot analysis of the lungs and kidney demonstrated a substantial (1.4-fold and 1.8-fold, respectively) increase in Hsp70 expression. Alterations could not be detected in the clinical chemical parameters (total protein, albumin, total cholesterol, glucose, creatinine and urea concentrations, and aspartate aminotransferase activity). There was no statistically significant change in malondialdehyde concentrations and the measured antioxidant parameters (the amount of reduced glutathione, GSH and glutathione peroxidase activity, GPx) in the blood plasma, lung and kidney tissue. Thus, it can be concluded that FB1 did not induce oxidative stress in the lungs and kidney, but increased Hsp70 production.

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