Comprehensive fitness evaluation of common carp (Cyprinus carpio L.) after twelve weeks of atrazine exposure

Atrazine is frequently detected in surface waters and negatively affect physiological function in aquatic organisms. Even though numerous authors have intensively studied its toxicity, only limited information concerning the long-term fish exposure is available. The aim of this study was evaluation of chronic exposure in common carp. Fish were exposed to a range of atrazine concentrations (0.3 - environmentally relevant concentration; 300; 1000; and 3000 µg/l) for twelve weeks. The potential impact of atrazine exposure was studied using various markers (behaviour; biometrical characteristics; haematological, biochemical and oxidative stress indices and histopathological changes). Most alterations were recorded at the highest concentration (3000 µg/l) which is probably due to a combined effect of both the herbicide exposure and intensive parasite infection development during second week. This group was cancelled after three weeks due to adverse health status, which partly confirmed atrazine immunotoxicity. Chronic exposure resulted in long-term reduction in feed intake followed by a significant decrease in body weight and morphological changes in gill at 1000 µg/l. At the same concentration, significant alterations in haematological (e.g. increase in erythrocyte, leukocyte, lymphocytes and neutrophil counts as well as decrease in monocyte counts) and biochemical (e.g. changes in enzyme activities; increase in glucose; decrease in ammonia) indices were documented, especially during first three weeks. Similar trend, but not so intensive, was observed at 300 µg/l. Moreover, significant changes were observed in various indicators of oxidative stress. These alterations were highly variable with both increasing and decreasing trends depending on dose and analysed tissue. Significant changes, especially in white blood profile, enzyme activities and oxidative stress indices, were proven even at 0.3 µg/l. Obtained results indicate that chronic atrazine exposure of common carp can negatively influence many indicators of health status such as behaviour, immune response, haematological and biochemical profile, oxidative stress indices and organ histopathology.

The effect of the antidepressant venlafaxine on gene expression of biotransformation enzymes in zebrafish (Danio rerio) embryos

The effect of venlafaxine, a pharmaceutical commonly found in aquatic environment, was analyzed on non-target organism, Danio rerio (Hamilton, 1822). D. rerio embryos were treated by two different concentrations of venlafaxine: either concentration relevant in aquatic environment (0.3 μg/L) or concentration that was two orders of magnitude higher (30 μg/L) for the evaluation of dose-dependent effect. Time-dependent effect was rated at 24, 96, and 144 h post-fertilization (hpf). For gene expression, genes representing one of the phases of xenobiotic biotransformation (0 to III) were selected. The results of this study showed that the effect of venlafaxine on the zebrafish embryos is the most evident at hatching (96 hpf). At this time, the results showed a downregulation of gene expression in each phase of biotransformation and in both tested concentrations. In contrast, an upregulation of most of the genes was observed 144 hpf for both tested venlafaxine concentrations. The study shows that venlafaxine can affect the gene expression of biotransformation enzymes in D. rerio embryos even in the environmentally relevant concentration and thus disrupt the process of biotransformation. Moreover, the pxr regulation of genes seems to be disrupted after venlafaxine exposure in dose- and time-dependent manner.

Oxidative stress induced by fluoroquinolone enrofloxacin in zebrafish (Danio rerio) can be ameliorated after a prolonged exposure

The purpose of our experiment was to evaluate the effect of enrofloxacin on biotransformation, oxidative stress and mRNA expression of related genes in fish as a non-target organisms. Zebrafish (Danio rerio) juveniles were treated with enrofloxacin at concentrations of 5, 10 and 500 μg/L for 14 days. A three-day-long test caused changes of catalytic activity of glutathione peroxidase and glutathione-S-transferase. Moreover, lipid peroxidation was observed at the highest concentration. No significant changes either in catalytic activity of antioxidant enzymes or elevated lipid peroxidation were observed from sampling day 7 on. mRNA expression of genes encoding antioxidant enzymes was also not affected by enrofloxacin after a 14-day exposure. This suggests the ability of D. rerio juveniles to adapt to enrofloxacin in a short time period. Moreover, enrofloxacin was not shown to affect collagen, cathepsin K, optic atrophy 1 and pyruvate kinase L/R mRNA expression in this study.

The effects of a therapeutic formalin bath on selected immunological and oxidative stress parameters in common carp (Cyprinus carpio)

Formalin is commonly used as a component of antiparasitic baths in fisheries. In this study the impact of this bath on the immune profile and oxidative stress parameters was evaluated. A formalin bath was prepared in the concentration of 185.3 mg L^-1 (0.17 mL L^-1) at a temperature of 20 °C. A total of 96 common carp Cyprinus carpio (Linnaeus, 1758) individuals were immersed in this bath for 60 min. The effects were monitored immediately, and then after 24, 48 h and 10 days following the treatment. The study revealed the most effects 10 days after the treatment, when we observed the decrease of lysozyme in skin mucus, the decrease of anti-inflammatory cytokine transforming growth factor beta in gill tissue and increase of interleukin 10 in cranial kidney tissue. The pro-inflammatory cytokine interleukin 1b showed an increase in gill tissue immediately after the bath and the increase in glutathione peroxidase in gill tissue was also observed 24 h and 10 days after bath treatment. The other investigated parameters did not show any significant changes. In conclusion, even though the formalin bath elevated some parameters as mentioned above, formalin used in the bath is probably safe as an antiparasitic treatment of fish.

Factors Affecting Antioxidant Response in Fish from a Long-term Mercury-Contaminated Reservoir

The objective of this work was to evaluate antioxidant defence and oxidative damage in organs (liver, gills, kidney, and brain) of five fish species (Aspius aspius, Esox lucius, Sander lucioperca, Abramis brama, Rutilus rutilus) from the long-term mercury-contaminated Skalka Reservoir in the Czech Republic. Special emphasis was placed on a comprehensive assessment of the factors that may affect the antioxidant response to mercury in fish. Antioxidant enzymes (glutathione reductase, glutathione peroxidase, and glutathione-S-transferase) did not significantly respond to mercury contamination. Levels of the analysed enzymes and oxidative damage to lipids were predominantly determined by a separate organ factor or species factor, or by the combination of both (p < 0.001). Levels of total glutathione and the reduced/oxidized glutathione ratio were influenced by mercury contamination in combination with their specific organ distribution (p < 0.001). Our results suggest that species and type of organ alone or in combination are more important factors than chronic exposure to mercury contamination with respect to effects on antioxidant defence in fish under field conditions. Our findings suggest that the main antioxidant defensive mechanism in fish from the studied long-term mercury contaminated site was the inter-tissue distribution of glutathione.

Effect of salicylic acid on early life stages of common carp (Cyprinus carpio)

Environmental concentrations of pharmaceutical residues are often low; nevertheless, they are designed to have biological effects at low doses. The aim of this study was to assess the effects of salicylic acid on the growth and development of common carp (Cyprinus carpio) early life stages with respect to antioxidant defence enzymes. An embryo-larval toxicity test lasting 34 days was performed according to OECD guidelines 210 (Fish, Early-life Stage Toxicity Test). The tested concentrations were 0.004, 0.04, 0.4, 4 and 20mg/l of salicylic acid. Hatching, early ontogeny, and both morphometric and condition characteristics were significantly influenced by subchronic exposure to salicylic acid. Also, changes in antioxidant enzyme activity and an increase in lipid peroxidation were observed. The LOEC value was found to be 0.004 mg/l salicylic acid. The results of our study confirm the suggestion that subchronic exposure to salicylic acid at environmental concentrations can have significant effects on aquatic vertebrates.

The effect of the fluoroquinolone norfloxacin on somatic indices and oxidative stress parameters in early stages of common carp (Cyprinus carpio L.)

OBJECTIVES

The aim of this study was to assess the effect of the subchronic exposure of early stages of common carp (Cyprinus carpio L.) to norfloxacin using morphometric data and oxidative stress parameters.

METHODS

A subchronic toxicity test was performed on fertilized embryos of common carp according to the OECD Guidelines No. 210. Embryos were exposed to norfloxacin concentrations of 0.0001 (environmental), 0.1, 1.0, 5.0, and 10.0 mg.L(-1) for 34 days.

RESULTS

At the end of the test (day 34), significant (p<0.05) stimulation of development was observed in all experimental groups, in contrast to the control. Significantly greater (p<0.01) total body length was also observed in the group exposed to 10.0 mg.L(-1) of norfloxacin compared to the control. A significant increase in the activity of glutathione S-transferase in all carp exposed to norfloxacin concentrations of 0.1 and 1.0 mg.L(-1) (p<0.01), and 5.0 mg.L(-1) (p<0.05) compared to control group was revealed. The activity of glutathione peroxidase was significantly lower (p<0.01) in experimental carp exposed to a norfloxacin concentration of 10.0 mg.L(-1). In experimental carp exposed to a norfloxacin concentration of 0.0001 mg.L(-1), a significant increase (p<0.05) in glutathione reductase activity was found. Significant (p<0.01) decreases in the content of thiobarbituric acid reactive substances in the groups exposed to norfloxacin concentrations of 1.0, 5.0, and 10.0 mg.L(-1) were revealed.

CONCLUSION

From the results, we can conclude that norfloxacin has a negative impact on selected biochemical processes related to the production of reactive oxygen species in early-life stages of common carp.

Biochemical markers for the assessment of pollution of selected small streams in the Czech Republic

OBJECTIVES

The objective of the presented study was to investigate levels of the most important biochemical markers in fish which were caught upstream and downstream from sites near waste water treatment plants situated at 3 selected small streams of the Czech Republic. Organic pollutants and mercury were determined in muscle tissue of fish for complex assessment.

DESIGN

Levels of biochemical markers (cytochrome P450 (CYP450), ethoxyresorufin-O-deethylase (EROD), glutathione S-transferase (GST), vitellogenin (VTG)) were measured in selected tissues (liver, plasma, brain, gill and kidney) samples of brown trout. The concentrations of persistent organic pollutants (POPs) and mercury were determined in muscle samples.

RESULTS

Significantly higher levels of biochemical markers (EROD, GST, VTG) were measured downstream from waste water treatment plant (WWTP) in Vlachovo Březí (the small Libotýňský brook). Values of biochemical markers at the other localities Černý brook and Moravice River were measured downstream from WWTP consistently or slightly lower with values of upstream. The values of POPs and mercury were in all monitored sites higher upstream compared with downstream from WWTP. The highest values of POPs and mercury were found on Černý brook in Bruntál (more industrial and agricultural activity).

CONCLUSION

The highest occurrence of selected POPs and mercury was generally upstream suggesting that small WWTP are able to partially remove these substances in those locations. But finding higher values of biochemical markers in downstream shows that there are many other substances endocrine disrupting chemicals (EDCs) that WWTP are unable to remove.

Evaluation of ibuprofen toxicity for zebrafish (Danio rerio) targeting on selected biomarkers of oxidative stress

OBJECTIVES

The aim of the study was to investigate the effects of subchronic exposure of zebrafish to ibuprofen, using selected oxidative stress parameters as a target.

DESIGN

Toxicity tests were performed on Danio rerio according to OECD No. 203 and No. 215. In the growth test, fish were exposed to subletal concentrations of ibuprofen (0.0001, 0.05, 1, 8, and 25 mg.L-1) for 28 days. For the assessment of free radical defense in fish, the catalytic activities of glutathione reductase (GR), glutathione S-transferase (GST), glutathione peroxidase (GPx), and catalase (CAT), as well as the concentration of malondialdehyde (MDA) were measured.

RESULTS

Ibuprofen did not affect the activity of glutathione reductase and catalase. A significant (p<0.01) increase in the activity of glutathione peroxidase was found, which was proved dose-dependent (10.58 nmol NADPH per min per mg protein in the control and 20.53, 26.36, 26.89, and 45.87 nmol NADPH per min per mg protein in the ibuprofen concentrations of 0.5, 1, 8, and 25 mg.L-1. An increased (p<0.05) activity of glutathione S-transferase in the highest concentration was found compared to control. Malondialdehyde levels were found significantly (p<0.01) decreased from control in the concentrations of 0.0001 and 8 mg.L-1, but no dose-dependence was found.

CONCLUSION

The results suggest that ibuprofen causes the increase in the activity of some antioxidative and biotransformation enzymes in zebrafish (GPx and GST). We also found a significant decrease in lipid peroxidation in the concentrations of 0.0001 and 8 mg.L-1 compared to control.

Effect of β-1.3/1.6-D-glucan derived from oyster mushroom Pleurotus ostreatus on biometrical, haematological, biochemical, and immunological indices in rainbow trout (Oncorhynchus mykiss)

OBJECTIVES

Effect of long-term oral administration of three different concentrations (0.5, 1.0, and 2.0%) of micronized β-1.3/1.6-D-glucan derived from oyster mushroom (Pleurotus ostreatus, Hiratake) on biometrical, haematological, biochemical, and immunological indices of half-year-old rainbow trout (Oncorhynchus mykiss) was assessed in the study.

DESIGN

Rainbow trout were feed commercial feed pellets containing β-1.3/1.6-D-glucan in the concentrations of 0.5, 1.0, and 2.0% for 85 days. Biometrical indices consisted in total and standard length, body and liver weight, from which derived somatic parameters such as Fulton´s condition factor and hepatosomatic index were calculated. Haematological parameters were evaluated according to unified methods for haematological examination in fish. Plasma biochemical profile was analysed using biochemical analyser Konelab 20i and Easy Lyte Analyzer. A phagocyte cells metabolic activity (induced chemiluminescence of phagocytes) was determined as an immunological parameter by a microplate luminometric method on Immunotech LM-01T.

RESULTS

No clinical signs of behavioral, respiratory, or neurologic distress were observed in rainbow trout. Fish showed normal feeding behavior. As for biometric parameters, no significant changes in total and standard length, body weight, liver weight, as well as in condition factor and hepatosomatic index of experimental and control fish were found. In the course of the study, weight gains in rainbow trout were similar and continuous. Shifts in PCV (p<0.05), haemoglobin (p<0.05), and MCHC (p<0.01) were found within haematological indices. Plasma concentration of glucose, lactate, total protein, cholesterol, calcium, natrium, potassium (all p<0.05), albumins and chlorides (both p<0.01), as well as catalytic activities of ALT and AST (both p<0.05) were changed in the course of the study. A phagocyte cells metabolic activity (luminol-induced chemiluminescence) in rainbow trout was not altered by oyster mushroom β-1.3/1.6-D-glucan administration.

CONCLUSION

After long-term oral administration of three concentrations of micronized β-1.3/1.6-D-glucan derived from oyster mushroom (Pleurotus ostreatus, Hiratake) shifts in haematological and biochemical profiling were found in half-year-old rainbow trout (O. mykiss) in environmental conditions of a commercial rainbow trout fishery. Biometrical indices were not found significantly altered. No specific effect of β-glucan on immune system response of rainbow trout was found in the study. The use of β-glucan in prosperous, clinically healthy aquaculture is still an issue, nevertheless, its use in breedings endangered by stress stimuli, infectious diseases or adverse environmental factors is indisputable.

Effects of subchronic nitrite exposure on rainbow trout (Oncorhynchus mykiss)

Subchronic toxicity of nitrite in rainbow trout (Oncorhynchus mykiss; mean mass ± S.D., 18.9 ± 1.3g) was assessed in a 28-day trial. The influence of nitrite on fish mortality, growth rate, haematology, blood biochemistry, and gill histology was observed. Survival was not affected by exposures up to 1 mg l(-1) NO(2)(-) (at 10 mg l(-1) Cl(-)). On the basis of growth rate inhibition data, the values of NOEC (28 d LC(0)) and LOEC (28 d LC(10)) were estimated at 0.01 and 0.2 mg l(-1) NO(2)(-), respectively. At 0.01 mg l(-1) NO(2)(-) (the lowest concentration tested), there was segmental hyperplasia of the respiratory epithelium of secondary lamellae and elevated glucose and decreased potassium. Elevated nitrite concentrations were found in blood plasma of fish exposed to concentrations of 1.0 mg l(-1) NO(2)(-) and higher, and in muscle tissue at the highest concentration 3.0 mg l(-1) NO(2)(-). Plasma and muscle nitrite levels were lower than those in the ambient water in all experimental groups.

Stress in Broilers Resulting from Shackling

The aim of this study was to assess stress response of broilers to different periods of shackling. Stress effects of shackling were monitored in a group of male Ross 308 broilers (total number: 400) aged 42 d. Three shackling treatments were used in our experiment: shackling of broilers for 30 s (group T30), 60 s (group T60), and 120 s (group T120). Corticosterone plasma concentration was elevated in T60 broilers (P<0.05) and in T120 birds (P<0.01); glucose plasma concentration was increased (P<0.05) in both T60 and T120 broilers when compared with nonshackled control. Lactate concentrations increased in T30 birds (P<0.05) and in both T60 and T120 birds (P<0.01). Furthermore, T120 broilers exhibited an increase (P<0.01) in heterophil counts and heterophil:lymphocyte ratio. Duration of tonic immobility was increased (P<0.05) in T60 and T120 broilers. Number of attempts to induce tonic immobility decreased (P<0.01) in all test groups (T30, T60, T120). Duration of shackling period was positively correlated (P<0.001) with corticosterone, glucose and lactate level, tonic immobility duration, and heterophil:lymphocyte ratio. The number of inductions was negatively correlated (P<0.001) with duration of the shackling period. According to the results of our study, the act of shackling is a considerable traumatic procedure for broilers, and its stress effect is markedly dependent on duration of shackling period that the broiler chickens experience. It follows from our study that the optimal shackling period should be less than 60 s.