Duration of the Flaxseed Supplementation Affects Antioxidant Defence Mechanisms and the Oxidative Stress of Fattening Pigs.

This study was conducted to investigate the effect of the duration of a flaxseed diet on fattening pigs' antioxidant defence mechanism in blood and tissues. Eighteen 20-week-old Landrace breed fattening pigs (BW 76.61 ± 2.30 kg) were divided into three groups of six animals. The control group was fed a basal diet. The FS3 group was fed the basal diet supplemented with 10% flaxseed for 3 weeks. The FS6 group received the same basal diet with flaxseed for 6 weeks. The total antioxidant capacity of the blood, measured as the total antioxidant status (TAS), total plasma antioxidant capacity (FRAP), reactive oxygen metabolites (dROMs) and total antioxidant capacity (PAT), was not affected by the flaxseed diet. The superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx) and glutathione reductase (GR) activities were significantly decreased in the FS3 pigs in the heart (p < 0.05). However, in the FS3 group, the glutathione-S-transferase (GST) activity significantly increased compared to the control, but in the FS6 group, the activity was inhibited (p < 0.05). In the muscle, the CAT and GST activity was significantly decreased in the FS3 group (p < 0.05). The thiobarbituric acid reactive substance (TBARS) content was significantly reduced in the brain, muscle and heart in the FS3 group(p < 0.05). In FS6, the TBARS content significantly increased in the heart and brain (p < 0.05). Our results showed that the health effect of a flaxseed diet is significantly conditioned by the length of the flaxseed addition.

The adverse effects of synthetic acaricide tau-fluvalinate (tech.) on winter adult honey bees.

Currently several pyrethroids (e.g., flumethrin and tau-fluvalinate) are used in apiculture worldwide as acaricides/miticides. The long half-lives of pyrethroids in synthetic acaricides applied to hive matrices, may adversely affect the health of bee colony. The potentially adverse effects of synthetic acaricide/miticide tau-fluvalinate (tech.) on winter honeybees were assessed in this study (OECD 245 2017). No dose-dependent mortality in in vitro reared winter honeybees was observed after chronic oral 10-day exposure to syrup (50% w/v) spiked with a maximum concentration of 750 µg a.i./kg diet and its 1/10 concentration. The No Observed Effect Concentration is ≥ 750 µg a.i./kg diet. Tau-fluvalinate testing for the sublethal effects on bee immune system showed up-regulated gene expression encoding abaecin, lysozyme, and defensin in both tested groups, however the expression of hymenoptaecin gene was reduced. Moreover, tau-fluvalinate significantly induced levels of DNA damage in exposed bees, which can result in adverse genotoxic effect.

Toxicity of oxalic acid and impact on some antioxidant enzymes on in vitro-reared honeybee larvae.

Nowadays, Varroa destructor is considered as a serious pest of honeybees (Apis mellifera) and its resistance to acaricides has been reported in Europe since the early 1990s. That is why new methods of treatment for Varroa mites are still in focus of many scientists. In our study, we determined the lethal concentration LC50 (72 h) of 2.425% oxalic acid solution following single spray exposure of honeybee larvae under laboratory conditions (Guideline OECD 237 2013). Potential sublethal effects of oxalic acid were monitored through the determination of the activity of antioxidant enzymes. Activation of primary antioxidant enzymes was observed at 1.75% of oxalic acid; 3.5% of oxalic acid brought on a statistically significant increase of glutathione S-transferase activity. This change was accompanied by an increase in thiobarbituric acid reactive substances, products of lipid peroxidation. Our results indicate that oxalic acid may be harmful to bee brood when present during application.

Formetanate toxicity and changes in antioxidant enzyme system of Apis mellifera larvae.

Substantial percentage of world food production depends on pollinating service of honeybees that directly depends on their health status. Among other factors, the success of bee colonies depends on health of developed larvae. The crucial phase of larval development is the first 6 days after hatching when a worker larva grows exponentially and larvae are potentially exposed to xenobiotics via diet. In the present study, we determined the lethal concentration LC50 (72 h) following single dietary exposure of honeybee larvae to formetanate under laboratory conditions, being also the first report available in scientific literature. Activities of antioxidant enzymes, superoxide dismutase (SOD), catalase (CAT) and glutathione-S-transferase (GST) were also measured in the homogenates of in vitro reared honeybee larvae after single formetanate exposure. Decreased specific activity of SOD and increased activities of CAT and GST suggest the induction of oxidative stress. Higher levels of thiobarbituric reactive species in all samples supported this fact. Comparing determined larval toxicity (LC50 of 206.01 mg a.i./kg diet) with adult toxicity data, we can suppose that the larvae may be less sensitive to formetanate than the adult bees.

The another toxic effect of carbamate insecticides.

The activities of the antioxidant and detoxifying enzymes, superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GSHPx), glutathione reductase (GR), glutathione-S-transferase (GST), and the content of thiobarbituric acid reactive substances (TBARS) were determined in the liver and kidney of rabbits after exposure to bendiocarb. In the liver, the activities of SOD, CAT and GR were not affected by bendiocarb. The induction or inhibition of isoenzymes of SOD (mainly MnSOD) were observed in the experimental groups. The activities of GSHPx-cum and GSHPx-H2O2 significantly decreased on the days 3 and 10 of the experiment. The activity of GST significantly increased on the day 9 of the experiment. In the kidney, the activity of SOD was significantly increased and the new MnSOD isoenzymes were detected. The activities of CAT and GSHPx-H2O2 were significantly decreased in the experimental groups. The activity of GR significantly increased on days 3 and 10, and the activity of GST was significantly increased on days 3, 10, and 30. Exposure of rabbit to bendiocarb did not affect the content of TBARS in the kidney. In the liver, the content of TBARS was significantly increased in the experimental groups as compared to the control. Our results showed that the response of organs to bendiocarb is different and may depend on the specific organ damage and their protective abilities. The alterations in the activities of the antioxidant defence system, increased TBARS values, and changes in the SOD isoenzyme pattern showed that the toxic effect of bendiocarb is not only in the acetylcholine esterase inhibition, but also in ROS production.

Antioxidant and detoxifying enzymes in the liver of rats after subchronic inhalation of the mixture of cyclic hydrocarbons.

The activity of antioxidant and detoxifying enzymes, superoxide dismutase (SOD), glutathione peroxidase (GSHPx), glutathione-S-transferase (GST), the SOD isoenzyme patterns and the contents of thiobarbituric acid reactive substances (TBARS), were determined in the livers of male and female rats after subchronic inhalation of mixtures of benzene, cyclohexanone and cyclohexane. Except for decreased GSHPx (with substrate cumene hydroperoxide) and GST activities in female rats, no differences in the activities of antioxidant and detoxifying enzymes and TBARS content occurred. Between the activities of GSHPx and GST was observed an indirect relationship. The activities of GSHPx-cum and GST were influenced by sex.