BACKGROUND: Oxidative stress reflects an imbalance between the reactive oxygen species (ROS) and a biological system's ability to readily detoxify the oxidative agents. Disturbances in the normal redox state of cells can cause toxic effects through production of peroxides and free radicals that damage all components of the cell, including proteins, lipids, and DNA. ObjectiveS: The purpose of this study was to evaluate the oxidative status in calves within 3 days of birth. Methods: Twenty calves from Zagros dairy farm were selected. Blood samples were collected from the jugular vein at 0 (before administration of colostrum), 24, 48 and 72 hours after birth for measurement of serum levels of TBARS, Superoxide dismutase and catalase. Results: The results indicated higher levels of serum malondialdehyde concentration at birth that subsequently decreased at 24 and 48 hours after birth (p<0.05). There were lower levels of serum concentration of catalase at birth that followed by increasing in it at 24 and 48 hours after birth (p<0.05). Also, the concentration of superoxide dismutase was lower at the birth that subsequently increased at 24 hours after birth (p<0.05). Conclusions: Based on this study, it seems that antioxidant capacity of calves has been increased within 3 days of birth. Improvement of oxidative status in calves could be due to gradual increasing of their antioxidative capacity and also beneficial effects of colostrum.

Canine brachycephalic obstructive airway syndrome (BOAS) is a conformation-related respiratory disorder of dog breeds having congenitally flattened facial and skull anatomy. The aim of the study was to determine oxidative stress parameters, the lipid peroxidation product malondialdehyde, and antioxidant enzymes superoxide dismutase (SOD) and glutathione peroxidase in BOAS patients before and after surgical treatment and in healthy brachycephalic dogs. Nine healthy brachycephalic dogs that had not undergone surgery and 39 BOAS patients were included in the study. The BOAS patients were classified as grade 1 (5/34), grade 2 (16/34), and grade 3 (13/34) based on the decrease in the radius of the airway in the larynx. In BOAS patients, oxidative stress parameters were determined before and two weeks after surgery, while in control dogs, blood samples were collected only on inclusion to the study. All BOAS patients showed various degrees of improvement in clinical signs after surgery. Significantly lower (P < 0.05) SOD activity was found in grade 2 and 3 BOAS patients than in grade 1 patients. Two weeks after surgery, a significant (P < 0.05) increase in SOD activity in grade 2 and 3 patients was observed. Antioxidant enzyme SOD may play an important role in BOAS and can be used as a biomarker of antioxidant status assessment in BOAS patients.

Ochratoxin A (OTA) is a mycotoxin notably produced by Aspergillus and Penicillium spp. Bacillus subtilis fermentation extract (BSFE) contains specific enzymes which hydrolyse OTA. This study evaluated the efficiency of BSFE in ameliorating the immunotoxic and nephrotoxic effects of OTA in broiler chickens. Day-old broiler chicks were divided equally into four groups of ten: control, OTA (0.5 mg/kg feed), BSFE product (1 mL/L water) and OTA + BSFE at the same concentrations. The chicks were vaccinated against avian influenza, Newcastle disease, and infectious bronchitis, and lymphoproliferation was induced in all birds by phytohaemagglutinin-P (PHA-P). Serum samples were taken before sacrifice and organ tissue samples were taken after, in which renal function biomarkers were assayed and the presence of OTA residue was evaluated by high-performance thin-layer chromatography. Protein markers of apoptosis were determined by qPCR, and tissue lesions were examined histopathologically. Exposure to OTA significantly decreased the antibody response to the vaccines and the lymphoproliferative response to PHA-P, and significantly elevated the renal function indicators: serum urea, uric acid and creatinine. It also induced oxidative stress (reduced catalase activity and glutathione concentration), lipid peroxidation (increased malondialdehyde content), apoptosis (increased Bax and Caspase-3 and decreased Bcl-2 gene levels) and pathological lesions in kidney, bursa of Fabricius, spleen and thymus tissue. Residues of OTA were detected in the serum and tissue. BSFE mitigated most of these toxic effects. BSFE counters OTA-induced immunotoxicity and nephrotoxicity because of its content of carboxypeptidase and protease enzymes.

Introduction: The goal of this study was to assess the influence of vaccination against enteric redmouth disease on oxidative stress biomarkers and antioxidant defence in the muscle tissue of rainbow trout (Oncorhynchus mykiss Walbaum) vaccinated against Yersinia ruckeri in the first and second month after immunisation. Material and Methods: Healthy fish were vaccinated orally with inactivated whole cells of a virulent strain of Y. ruckeri. One and two months after immunisation the muscle samples were collected. Results: No significant difference was noted in lipid peroxidation level in either the first or second month after vaccination, while aldehydic and ketonic derivatives of oxidatively modified proteins (OMB) in the vaccinated group were significantly lower in the second month compared to those in the first month after vaccination (P < 0.05). The content of ketonic derivatives of OMB in muscles in the first month after immunisation was higher compared to untreated control. All these culminated in a depletion of glutathione peroxidase (GPx) activity and low level of total antioxidant capacity (TAC). Conclusion: Correlations between catalase activity and lipid peroxidation and TAC confirmed the pivotal role of catalase in antioxidant defence during immunisation. From a broader perspective, it is suggested that immunisation of fish with Yersinia vaccine is associated with induced free radical formation and oxidative stress. Free radicals would therefore be at least partially responsible for the induction of both humoral and cellular elements of the immunity and increased protective immunity against Y. ruckeri infection.

Introduction: The main goal of the study was to investigate the effect of KATP channel modulators on development of oxidative stress in the heart of rats showing different resistance to hypoxia.

The efficiency of five natural antioxidants (curcumin, cranberry, pomegranate, grape seed extract (GSE), and açai berry) in reducing lipid oxidation in dog food was compared to that of the synthetic antioxidant butylated hydroxyanisole (BHA). In two different experiments content parameters were measured after 12 days of storage at 55°C. In experiment one, the natural antioxidants were added at 0.2% and BHA at 0.02% of the food (DM basis), and samples were analysed for thiobarbituric acid-reactive substances (TBARS). In experiment two, the effects of GSE and curcumin at two admixture proportions (0.1% and 0.2% of food DM) on omega-3 fatty acid (FA) content were evaluated. TBARS values were lower than the control (P < 0.01) for curcumin, cranberry, pomegranate, and GSE but not for the açai berry (P > 0.05). By day 12, although there were no significant differences (P > 0.05) between the two curcumin treatments, they preserved higher concentrations of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) (P < 0.05) than the BHA and control treatments. The addition of GSE or BHA to dog food held (P < 0.05) the concentrations of EPA higher than the control. The concentrations of EPA and DHA for the 0.2% GSE treatment were greater (P < 0.05) than the 0.1% GSE treatment. Grape seed extract at 0.2% lost less (P < 0.05) EPA concentration than BHA. The present results showed that, except for açai berry, the tested natural antioxidants could be used as a substitute for BHA in dog food.

Introduction: The main goal of the study was to investigate the effect of KATP channel modulators on development of oxidative stress in the heart of rats showing different resistance to hypoxia.Material and Methods: The study has been performed on rats showing high- (HR) or low-resistance (LR) to hypoxia under modulators of ATP-sensitive potassium (KATP) channel opener pinacidil (0.06 mg/kg) and blocker glibenclamide (1 mg/kg) upon cobalt (Co) treatment (30 mg of cobalt chloride/kg b.w., 3 h). Changes in the oxidative stress parameters of the heart tissue, such as lipid peroxidation (LPO), level of oxidatively modified protein (OMP), and antioxidant defence system (superoxide dismutase - SOD, catalase -CAT, glutathione peroxidase - GPx, glutathione reductase - GR) as well as total antioxidant activity (TAA) were analysed.Results: Co treatment caused a significant decrease in SOD and CAT activity in the heart of LR rats and GPx activity in HR rats. It also led to a decrease in OMP level in the heart of rats with HR in comparison with controls.Conclusion: The obtained results suggest that individual resistance to hypoxia plays a crucial role in Co actions and provides evidence that the effects of KATP channel opener pinacidil in the heart are mediated through different pathways of the antioxidative system, depending on the individual resistance to hypoxia. Pinacidil exerts a protective effect on the heart tissue by preventing the LPO decrease and significantly reducing OMP levels, as well as increasing TTA in rats with LR.

In this study, we aimed to evaluate the oxidative damage caused by lipid peroxidation due to renal coccidiosis by histopathological and immunohistochemical methods. Material-The material of this study was made up of tissue samples taken from 139 geese whose average age was 10 weeks, who were brought to our department dead between 2013-2020. Tissue samples taken were fixed in 10% buffered formaldehyde solution. 5 µm-thick sections were taken from the paraffin blocks prepared after routine tissue follow-up procedures. Hematoxylin & Eosin staining was applied to the sections in order to detect histopathological changes. Sections were examined and photographed under a light microscope.Various clinical signs such as fever, respiratory distress, weakness, anorexia, tremors, inability to get up from the ground, balance disorders, rotational movement, diarrhea, wheezing were detected in geese. In systemic necropsies of geese, large and small white nodular structures were detected in the kidney. In histopathological examinations, coccidiosis agents (E. truncata) were found in the tubular epithelium of the kidney. Necrosis and mononuclear cell infiltration were observed in the tubules due to the presence of E. truncata. In addition, edema and hyperemia in the lungs, multifocal necrosis in the liver, cell infiltration in the portal spaces and enteritis were other important histopathological findings. In one case, aspergillosis was detected together with renal coccidiosis. We observed that MDA expression was more severe in oocyst stages, which is the mature form of the parasite, compared to other parasitic life stages.Based on the results obtained from this study, it was revealed that renal coccidiosis in geese caused lipid peroxidation / oxidative damage through the increase in MDA expression.

When incubated with solutions of hydrogen peroxide, erythrocytes of stress-susceptible pigs produced more by-products of lipid peroxidation (as measured as thiobarbituric acid-reactive substances [TBARS]) than did erythrocytes from stress-resistant pigs. Using this technique, discrimination between the 2 pig types was absolute at hydrogen peroxide concentrations of 0.9 and 1.5%. This was in contrast to other methods of identifying stress-susceptible pigs, such as osmotically induced erythrocyte lysis and the determination of plasma pyruvate kinase and creatine kinase activities, for which considerable overlap of data was observed between pig types. The increased TBARS production by erythrocytes was further evidence for the existence of an antioxidant abnormality in stress-susceptible pigs. However, because there were no discernible differences in the major blood antioxidant-related values between stress-susceptible and stress-resistant pigs, the nature of the defect remains unclear. The production of TBARS by erythrocytes when incubated with hydrogen peroxide provides an improved method for identifying stress-susceptible pigs.

In this study, the effect of vitamin E plus selenium (Se) application on malondialdehyde (MDA), glutathione (GSH), vitamin E, C, A and -carotene were aimed to investigate in exercised horses. For this purpose, 50 healthy Anatolian type local horse breed aged between 3-5 from Altındere Study Farm were used. The animals were divided into two equal groups. While 1st group received nothing, horses in second group were received vitamin E+Se intramuscularly. Then animals in both groups were exercised for 1500 meters. Blood samples were taken handily from all animals before and after exercise. This samples were analyzed for MDA, GSH, vitamin E, C, A and β-caroten spectrophotometrically.MDA and GSH concentration in 1st group were found to increase significantly (p<0.001) after exercise. On the other hand, serum vitamin E, C, A and β-carotene levels did not changed significantly. In the second group, serum vitamin E levels increased significantly (p<0.001) after vitamin E+selenium application. Furthermore, MDA (p<0.05) and GSH (p<0.001) levels increased significantly after exercise in the second group. Vitamin E levels decreased significantly (p<0.01) after exercise. However, vitamin A and C levels did not change significantly. In addition, in the second group, β-carotene levels were also changed significantly (p<0.05) when the values obtained before vitamin E application compared with the values obtained after vitamin E application. When comparison made between groups, while MDA and vitamin E values were statistically important (p<0.05), GSH, vitamin C, A and β-carotene values were not important statisticallyAs a result, acute exercise can increase free-radical production which, the results shows that increase in both MDA and GSH can be shown as the indicator of it. Furthermore, decrease in MDA level in vitamin E applied group the indicator of the rise in antioxidant defense and protective effect of vitamin E.