A. Çağlan Karasu Benli

Sublethal cyfluthrin toxicity to carp (Cyprinus carpio L.) fingerlings: Biochemical, hematological, histopathological alterations

This study measures a whole series of biological endpoints, and histopathological and behavioral changes of carp (Cyprinus carpio L.) fingerlings in order to investigate the adverse effects of a sublethal concentration of 10 microg/L cyfluthrin for 48h and one week using the semi-static test system. The most significantly altered findings of this study was that total antioxidant status levels decreased in 48h, chloride levels decreased in one week, and sodium and phosphorous levels increased in the 48h-exposed group. Plasma cortisol increased in both the 48h-exposed and the one-week-exposed groups. The unique tissue was the brain that had an increased level of malondialdehyde after one week of exposure. Such biomarkers may be used in assessing adverse/toxic effects of pesticides as environmental stressors. Potential oxidative-stress-inducing effect of synthetic pyrethroid cyfluthrin, as lipid peroxidation, in addition to its sodium channel blocking, is reported for the first time as an additional mechanism of action.

Sublethal toxicity of esbiothrin relationship with total antioxidant status and in vivo genotoxicity assessment in fish (Cyprinus carpio L., 1758) using the micronucleus test and comet assay

Esbiothrin, synthetic pyrethroid with quick activity against insects, is widely used against household pests and in public health. Despite widespread use, data on ecotoxicity and genotoxic effects are extremely scarce. The aim of the present study is to evaluate the genotoxic potential of esbiothrin on a model fish species Cyprinus carpio L., 1758 (Pisces: Cyprinidae, koi) using the micronucleus test and comet assay in peripheral blood erythrocytes. Effects of two sublethal exposure concentrations on plasma total antioxidant status (TAS mmol/L), and Hct values were examined. On the basis of the 96 h LC50 data from U.S. EPA ecotox database (32 μg/L) two sublethal exposure concentrations (5 and 10 μg/L) were used together with ethyl methanesulfonate (EMS) (5 mg/L) as positive control. Five fish were used for each dose/duration group (24, 48, and 72 h) under controlled laboratory conditions. The fish showed behavioral changes at the higher dose. Plasma TAS (mmol/L) levels decreased in 24 h; an increase was observed slightly for 48 and obviously for 72 h in both exposure doses. Similarly, hematocrit (Hct) values differed between exposure duration but no significant differences in mean values were found between groups of the same exposure time. The general trend was a rise after 48 h, which decreased afterwards. Our results revealed significant increases in the frequencies of micronuclei and levels of DNA strand breaks and thus demonstrated the genotoxic potential of this pesticide on fish, a nontarget organism of the aquatic ecosystem. To our knowledge this is the first study to report observable genotoxic effects of esbiothrin on fish.

Sublethal propoxur toxicity to juvenile common carp (Cyprinus carpio L., 1758): biochemical, hematological, histopathological, and genotoxicity effects.

The sublethal toxicological and genotoxic potential of propoxur, a widely used carbamate insecticide against household pests, in veterinary medicine, and in public health, was evaluated on carp as a model species (Cyprinus carpio L., 1758) using the erythrocyte micronucleus test. Based on the 96-h lethal concentration, 50% (LC50) data from the U.S. Environmental Protection Agency ECOTOX Database (10 mg/L), a sublethal exposure concentration of 5 mg/L was used under static bioassay laboratory conditions. Histopathological evaluation showed no significant changes in spleen, intestine, muscle, or skin tissues. However, the following conditions were recorded: hyperemia, branchitis in primary lamella, and telangiectasis, hyperplasia, fusion, epithelial lifting, and epithelial desquamation in secondary lamella of gill tissues; hemorrhage, destruction, prenephritis, and inflammation and desquamation in the tubules; edema in the kidney; passive hyperemia, albumin, and hydropic degeneration in the liver; and hyperemia, chromatolysis, and glial proliferation in brain tissues. No statistically significant increases in micronuclei frequencies were found. Hematological parameters showed decreased hematocrit values and mean corpuscular volume values, as well as increased erythrocyte and leukocyte counts compared with the control group (p < 0.01). Plasma glucose, cholesterol, triglycerides, phosphorus, sodium, total plasma protein, chloride, and aspartate aminotransferase levels were increased (p < 0.01). Only plasma calcium and potassium levels decreased in the experimental group. Propoxur has an ecotoxicological potential on fish, a nontarget organism.

Genotoxicity assessment of carp (Cyprinus carpio L.) fingerlings by tissue DNA damage and micronucleus test, after environmental exposure to fenitrothion

The purpose of this study was to evaluate the adverse effects of sublethal doses of fenitrothion, an organophosphothionate insecticide on brain, gill, liver, and muscle tissues as a ratio of 8-OHdG to dG to indicate the DNA damage and erythrocyte micronucleus frequency for genotoxicity of carp (Cyprinus carpio L.) fingerlings. In our study, the mean weights and lengths of the fish (n = 4–12) were 31.13 ± 14.24 g and 12.53 ± 1.41, respectively. Before the experiment, fish were maintained in aerated dechlorinated tap water at 21.8 ± 1°C and fed daily with commercial feed at a rate of 2% of their body weights. Experiments were conducted under static conditions in the aquaria. Technical grade (95%) fenitrothion was diluted in acetone to give a dosing solution of 10 mg/L. The increased lesions/106 DNA bases (p < 0.05) of liver tissue of exposure group (0.49 ± 0.18) was observed when compared to control group (0.28 ± 0.30). There was not any significant differences between brain tissues, no damage were detectable in gill and muscle tissues of control groups, and in exposure groups altered levels of damage were detected for gill (0.06 ± 0.05) and muscle (0.16 ± 0.21) tissues. The increased micronucleus frequencies (%) in erythrocytes of carp following the exposure to 48 h fenitrothion (6.43 ± 3.89; p<0.05) was observed when compared to control group (1.29 ± 1.03). The available data indicate that there is still lack of well-established dose–response relationships between occupational or environmental exposures and the induction of 8-OHdG. Such biomarkers may be used in assessing adverse/toxic effects of pesticides as environmental stressors.

The sublethal effects of (2,4-Dichlorophenoxy) acetic acid (2,4-D) on narrow-clawed crayfish (Astacus leptodactylus Eschscholtz, 1823).

Abstract 2,4-D is a widely used phenoxy herbicide, potentially toxic to humans and biota. The objective of the present study was to reveal short term sublethal effects of 2,4-D on narrow-clawed freshwater crayfish (Astacus leptodactylus Eschscholtz, 1823), based on histology, total haemocyte counts, selected haemolymph parameters, and oxidative stress parameters. In the laboratory conditions crayfish specimens were exposed to 9 mg L-1 of 2,4-D for one week. Experiments were conducted under semi-static conditions in 20 L-capacity aquaria where 10 freshwater crayfish were stocked per aquarium. Exposure (experimental) and control groups were used and the experiments were repeated two times. No mortality and behavioural changes were recorded during the experiments. Total haemocyte counts decreased significantly, while haemolymph glucose levels increased (P<0.05), when compared to the control group. Haemolymph levels of calcium, chloride, sodium, potassium, magnesium, total protein, and lactate did not change. Exposure resulted with increased levels of malondialdehyde (MDA) only in hepatopancreas. However, results of gill FOX assay showed a significant decrease in oxidative stress parameters (P<0.05). MDA levels of gill and abdominal muscle tissues and FOX levels of hepatopancreas and abdominal muscle tissues did not change when compared to the control group. Significant histopathological alterations were observed both in hepatopancreas (multifocal deformations in tubule lumen) and gill tissue (melanisation of gill lamella). Exposure of crayfish even to a sublethal concentration of 2,4-D alters histopathology and lipid peroxidation due to stress. Biomarkers studied here seem to be useful for the assessment of adverse/toxic effects of pesticides on non-target, indicator aquatic organisms.

Physiological Response of the Crayfish, Astacus Leptodactylus to Saline Water

Crayfish can spend their whole life, including reproduction and development, in fresh water. It is considered that many advanced features, like direct development and maternal brood care, can be interpreted as adaptations to life in fresh water (Scholtz, 1995). However, crayfish may also be found in environments that are subject to variations in salinity (Holdich et al., 1997). P?queux (1995) stated that, although under natural conditions most crayfish have adapted to a stenohaline way of life, they may survive to some degree in experimentally increased salinity. Cherkasina (1975) reported that Astacus leptodactylus Eschscholtz, 1823 and Astacus pachypus (Rathke, 1837) live in waters of up to 14 ppt salinity in the Caspian Sea. A. leptodactylus, the only crayfish native to Turkish waters, is known from estuarine environments. K?ksal (1988) also reported A. leptodactylus from the Black Sea. Various studies have been conducted on determining the salinity tolerance of a number of crayfish species through survival and growth trials (McMahon, 1986; Austin, 1995; Holdich et al., 1997; Susanto & Charmantier, 2000). Holdich et al. (1997) have shown that juveniles and adults of A. leptodactylus are well adapted to survive in salinities of at least 21 ppt in the long term, and to being transferred directly back into fresh water. However, some researchers state that their ability to colonize the estuarine environment may be restricted to areas of low salinity (Susanto & Charmantier, 2000) due to the adverse effects of sea water on egg development and hatching. Hence, consideration of a brackish-water environment may be more realistic. The ability of A. leptodactylus to grow at relatively high salinities opens up the opportunity of culturing this species in brackish water and also provides the op

Determination of antioxidant enzyme levels of narrow clawed crayfish (Astacus leptodactylus Eschsholtz 1823) exposed to carbaryl

Aim: The aim of the present study was the determination of antioxidant enzyme levels on different organs of narrow clawed crayfish (Astacus leptodactylus Eschsholtz 1823) after exposure to group of carbamate pesticides, contaminating aquatic ecosystems as toxic pollutant after agricultural activities. Materials and methods: The intermould stage crayfish were obtained from fishermen at fishing season. The mean lenght and weight were 10.74±0.84 cm, 32.78±7.12 g, respectively. All experimental procedures were done according to Toxicity Dilution Factor and semi-static method was used. The sublethal concentation of carbaryl was selected by 1/10 of 96 h LC50 values as 25 μg/L. The aquarium water were renewed every 48 h to provide the stability of test concentrations. In addition, two different control groups were conducted as negative control and acetone control. Gill, hepatopancreas and muscle tissues from crayfish exposed to 2 and 7 days to carbaryl were examined for superoxide dismutase, glutathion peroxidase and catalase enzyme activities. Results: Following to carbaryl treatment for 48 h and 7 days, gill superoxide dismutase and glutathion peroxidase enzyme activities were significantly increased (p<0.05) and catalase enzyme activities were not altered. After the 48 h treatment, the superoxide dismutase levels of hepatopancreas were decreased according to control groups, glutathion peroxidase and catalase values were increased significantly (p<0.05). At the 7th day glutathion peroxidase enzyme activities were increased, superoxide dismutase and catalase values were turned back to control levels. Conclusion: It is necessary to control the pesticide levels around the environment and avoid reaching them to water supplies because of being able to have rapid tissue spesific metabolic effects.