The Effects of Salicylic Acid on Juvenile Zebrafish Danio rerio Under Flow-Through Conditions.

The aquatic environment is becoming increasingly contaminated with pharmaceuticals. Salicylic acid (SA), which can be used individually or appear as a degradation product of the widely used acetylsalicylic acid was chosen for testing. Juvenile zebrafish Danio rerio were subjected to OECD test No. 215 (fish, juvenile growth test) with salicylic acid concentrations of 0.004; 0.04; 0.4; 4 and 40 mg/L. Specific growth rate (SGR), histological changes, and parameters of oxidative stress were evaluated. SA had no effects on histological changes, SGR, glutathione reductase, and lipid peroxidation. Increased catalytic activity of GPx was found at 0.04 mg/L compared to control, increased catalytic activity of catalase was found at 0.04 and 4 mg/L compared to control, and increased catalytic activity of glutathione-S-transferase was found at 0.004 and 0.04 mg/L compared to control (P < 0.05). Juvenile zebrafish turned out to be relatively insensitive to both environmentally relevant (0.004 mg/L) and higher concentrations of salicylic acid.

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.