Impact of deltamethrin on serum calcium and inorganic phosphate of freshwater catfish, Heteropneustes fossilis

Assessment of the exposure of two pesticides on common carp (Cyprinus carpio Linnaeus, 1758): Are the prolonged biomarker responses adaptive or destructive?

Chlorpyrifos (CPF) and cypermethrin (CYP) are two insecticides that have a proven negative effect on non-target aquatic organisms when they enter the surface waters. However, literature on the comparative effects of these pesticides on important aquaculture fish species, such as common carp (Cyprinus carpio Linnaeus, 1758) is not yet scientifically detailed, especially over the long-term. The idea of conducting a long-term exposure is to find out how the observed biomarkers would change compared to the short-term exposure. In the natural environment, toxicants are not present alone, but in combination. By monitoring the long-term impact of individual substances, the state of aquatic ecosystems exposed to various toxicants could be predicted. Thus, this study aimed to evaluate the toxicity of different concentrations of CYP (0.0002, 0.0003, and 0.0006 μg/L) and CPF (0.03, 0.05, and 0.10 μg/L) in 50-L glass tanks on C. carpio, exposed for 30 days under laboratory conditions. A set of histological and biochemical biomarkers in the gills and liver were applied with the chemical analyses of water and fish organs. Furthermore, the condition and hepatosomatic index were calculated to assess the physiological status of the treated carps. The behavioral responses were also monitored, and the respiration rate was analyzed. The results suggest that CYP had a more prominent effect on the histological structure of fish organs, biochemical responses of anti-oxidant enzymes, behavior, and respiration rate compared to the effect of CPF. In addition, the results also indicate that the liver is more susceptible to chronic and chemically induced cellular stress compared to the gills, with overall destructive changes in the histological biomarkers rather than adaptive. Regardless of the scenario, our results provide novel insights into pesticide exposure and the possible biological impacts on economically important freshwater fish, exposed to lower CYP and CPF concentrations, based on the EU legislation (maximum allowable concentrations, MAC-EQS).

Responses of Corpuscles of Stannius to intra-peritoneal vitamin-D3 administration in teleost Labeo rohita (Hamilton, 1822) reared in water with two different levels of calcium concentration

This study assessed the responses of vitamin-D3 intraperitoneally injected to Rohu, Labeo rohita @ of 0 IU/kg bw (only solvent), 100 IU/kg bw and 500 IU/kg bw reared in 20 and 40 ppm of calcium (Ca) enriched water. The cellular changes in Corpuscles of Stannius (CS) gland, serum Ca, and inorganic phosphate (Pi) level were analysed up to the 60th day. Rohu administered with 100 IU/kg bw D3 and exposed to 40 ppm Ca-rich water exhibited notable hyperplasia of CS compared with their control groups. Notable changes with high serum Ca level (13.87 ± 0.3 mg/dl) was detected on the 5th day in fish exposed to 40 ppm Ca-rich water, while related values attained (13.74 ± 0.1 mg/dl) only after 7 days in 20 ppm Ca-rich water of 500 IU/kg bw vitamin D3 injection. Similarly, high serum Pi level (7.66 ± 0.2 mg/dl) in 40 ppm Ca injected with D3 at 500 IU/kg bw. The results demonstrated that the Ca homeostasis of Labeo rohita is influenced by intra-peritoneal vitamin D3. Progressive studies should be conducted by increasing the dose of vitamin D3 to investigate optimum dose/supplement in feed for commercially important aquaculture teleost Labeo rohita for maximum and sustainable absorption of Ca from the variable water Calcium levels to maintain Ca2+ homeostasis.

Mediation of oxidative stress toxicity induced by pyrethroid pesticides in fish

Organophosphate and organochlorine pesticides are banned in most countries because they cause high toxicity and bioaccumulation in non-target organisms. Pyrethroid pesticides have been applied to agriculture and aquaculture since the 1970s to replace traditional pesticides. However, pyrethroids are approximately 1000 times more toxic to fish than to mammals and birds. Fish-specific organs such as the gills and their late metabolic action against this type of pesticide make fish highly susceptible to the toxicity of pyrethroid pesticides. Oxidative stress plays an important role in the neurological, reproductive, and developmental toxicity caused by pyrethroids. Deltamethrin, cypermethrin, and lambda-cyhalothrin are representative pyrethroid pesticides that induce oxidative stress in tissues such as the gills, liver, and muscles of fish and cause histopathological changes. Although they are observed in low concentrations in aquatic environments such as rivers, lakes, and surface water they induce DNA damage and apoptosis in fish. Pyrethroid pesticides cause ROS-mediated oxidative stress in fish species including carp, tilapia, and trout. They also cause lipid peroxidation and alter the state of DNA, proteins, and lipids in the cells of fish. Moreover, changes in antioxidant enzyme activity following pyrethroid pesticide exposure make fish more susceptible to oxidative stress caused by environmental pollutants. In this review, we examine the occurrence of pyrethroid pesticides in the aquatic environment and oxidative stress-induced toxicity in fish exposed to pyrethroids.

The influence of dietary β-glucan on immune, transcriptomic, inflammatory and histopathology disorders caused by deltamethrin toxicity in Nile tilapia (Oreochromis niloticus)

The protective role of β-glucan (BG) on liver function, histopathology, immune and antioxidant related gene expressions in Nile tilapia exposed to subacute deltamethrin (DLM) was investigated for 30 days. Fish (28.18 ± 1.34 g) of the 1st and 2nd groups fed the control diet, while the 3rd and 4th groups fed BG at 0.5 g/kg and the 2nd and 4th groups were exposed to DLM (15 μg/L) in rearing water. DLM-treated fish displayed a considerable increase in blood biochemical parameters (creatinine, urea and bilirubin) as well as hepatic enzymes (ALP, AST and ALT) (P < 0.05). Blood total protein, globulin, albumin, WBCs, RBCs, Hb, phagocytic index, phagocytic and lysozyme activities were significantly decreased in fish subjected to DLM (P < 0.05). Fish fed BG showed significantly the lowest cortisol and glucose levels, while fish exposed to DLM without feeding BG showed the highest cortisol and glucose levels (P < 0.05) after 15 and 30 days. Additionally, DLM toxicity caused downregulation in antioxidant (CAT and GPx) and immune (IL-1β and IL-8) related gene expressions, while and IFN-γ, HSP70 and CASP3 were upregulated. The histopathological examination of Nile tilapia exposed to DLM revealed damage in gills, intestine, spleen and liver which confirmed the toxic effects. Conversely, BG presented protective effects and restored the above-mentioned parameters when fish exposed to DLM and fed BG. Thus, BG supplementation exhibited defensive effects against DLM toxicity in Nile tilapia through improving blood biochemical responses, immune, and antioxidant related gene expressions as well as histopathological effects.

Ameliorative effects of Lactobacillus plantarum L-137 on Nile tilapia (Oreochromis niloticus) exposed to deltamethrin toxicity in rearing water

Deltamethrin (DLM) is a synthetic pyrethroid used for agricultural purposes to control insects and has been found to pollute the aquatic environment and leads to serious health problems. Lactobacillus plantaruml-137 (L-137) has gained more popularity as functional supplement for its immunomodulatory effects and antioxidant potential. This study was designed to examine the potential of l-137 on liver function, histopathology, immune and antioxidant related gene expressions in Nile tilapia exposed to subacute DLM for 30 days. Fish (mean weight of 28.18 ± 1.34 g) was distributed into four groups (triplicates): the first and second groups fed the control diet, while the third and fourth groups fed l-137 at 50 mg/kg and the second and fourth groups were exposed to DLM (15 μg/L) in rearing water (control, DLM, l-137 and DLM + L-137, respectively). DLM-treated fish groups showed a significant increase in blood biochemical parameters (creatinine, urea and bilirubin) as well as hepatic enzymes (ALP, AST and ALT) (P < 0.05). Blood total protein, globulin, albumin, WBCs, RBCs, Hb, phagocytic index, phagocytic and lysozyme activities were significantly decreased in fish exposed to DLM (P < 0.05). Additionally, DLM toxicity downregulated the transcription of immune genes (IL-1β and IL-8), while upregulated the stress related genes (HSP70 and CASP3). The histopathological images of Nile tilapia exposed to DLM revealed damage in gills, intestine, spleen and liver which confirmed the toxic effects. Conversely, l-137 presented protective effects and restored the aforementioned parameters when fish exposed to DLM and fed l-137. Further, l-137 restored the antioxidative capacity (CAT and GPx). Thus, l-137 supplementation exhibited defensive effects against DLM toxicity in Nile tilapia through improving blood biochemical responses, immune, and antioxidant related gene expressions as well as histopathological effects.

Biochemical and endocrine-disrupting effects in Clarias gariepinus exposed to the synthetic pyrethroids, cypermethrin and deltamethrin

In the present study, we investigated plasma biochemical and steroid hormone responses, together with gonado-histopathological alterations in Clarias gariepinus exposed to sublethal concentrations of two synthetic pyrethroids (cypermethrin and deltamethrin). Fish were exposed to environmentally-relevant concentrations of cypermethrin at 0 (ethanol solvent control), 0.07, 0.014, 0.028, 0.056) and deltamethrin at 0.22, 0.44, 0.88 and 1.76 μg/L, for 7, 14, 21 and 28 days. Plasma enzyme (aspartate transaminase: AST, alanine transaminase: ALT and alkaline phosphatase: ALP) and steroid hormones (estradiol-17β: E2, testosterone: T) levels were analyzed. Gonado-histopathological evaluation shows the presence of ovo-testis (intersex), oocytes atresia, cytoplasmic degeneration and clumping of vitellogenic oocytes in females, while male fish displayed enlargement and degeneration of testicular seminiferous tubules after 28 days exposure to cypermethrin and deltamethrin. Plasma biochemical analysis in pesticides exposed fish revealed that AST, ALT and ALP were significantly increased in a concentration-dependent manner. In addition, we observed respective and apparent concentration- and time-dependent increase and decrease of plasma E2 and T levels, compared to control. Interestingly, the significant increase in E2 levels paralleled gonadal ovo-testis (intersex) condition in exposed fish, indicating endocrine disruptive effects of cypermethrin and deltamethrin that favor the estrogenic pathway, in addition to overt negative consequences on reproductive, biochemical and physiological health of the exposed fish.

Xenobiotic metabolism in the fish hepatic cell lines Hepa-E1 and RTH-149, and the gill cell lines RTgill-W1 and G1B: Biomarkers of CYP450 activity and oxidative stress

The use of fish cell cultures has proven to be an effective tool in the study of environmental and aquatic toxicology. Valuable information can be obtained from comparisons between cell lines from different species and organs. In the present study, specific chemicals were used and biomarkers (e.g. 7-Ethoxyresorufin-O-deethylase (EROD) activity and reactive oxygen species (ROS)) were measured to assess the metabolic capabilities and cytotoxicity of the fish hepatic cell lines Hepa-E1 and RTH-149, and the fish gill cell lines RTgill-W1 and G1B. These cell lines were exposed to β-naphthoflavone (BNF) and benzo[a]pyrene (BaP), the pharmaceutical tamoxifen (TMX), and the organic peroxide tert-butylhydroperoxide (tBHP). Cytotoxicity in gill cell lines was significantly higher than in hepatic cells, with BNF and TMX being the most toxic compounds. CYP1-like associated activity, measured through EROD activity, was only detected in hepatic cells; Hepa-E1 cells showed the highest activity after exposure to both BNF and BaP. Significantly higher levels of CYP3A-like activity were also observed in Hepa-E1 cells exposed to TMX, while gill cell lines presented the lowest levels. Measurements of ROS and antioxidant enzymes indicated that peroxide levels were higher in gill cell lines in general. However, levels of superoxide were significantly higher in RTH-149 cells, where no distinctive increase of superoxide-related antioxidants was observed. The present study demonstrates the importance of selecting adequate cell lines in measuring specific metabolic parameters and provides strong evidence for the fish hepatocarcinoma Hepa-E1 cells to be an excellent alternative in assessing metabolism of xenobiotics, and in expanding the applicability of fish cell lines for in vitro studies.

Evaluation of mosquito Culex quinquefasciatus mortality rate in the face of lethal concentration of deltamethrin and diazinon toxins

Because of huge consumption for agricultural purpose, presence of pesticides in surface waters of Golestan province (north east of Iran) is very common. These pesticides finally could be stored in aquatic ecosystems and have proven toxic effects on aquatic animals. Culex quinquefasciatus is one of the most common aquatic insects living mainly in the wetlands. The aim of this study was to determine the acute toxicity of deltamethrin and diazinon as potentially perilous organic pesticides and to assess mortality effects of these chemicals on the mosquito Culex quinquefasciatus in the form of LC50.

Pharmacodynamic interaction of Spirulina platensis and deltamethrin in freshwater fish Nile tilapia, Oreochromis niloticus: impact on lipid peroxidation and oxidative stress

Spirulina platensis (SP) is one of the most commonly used dietary supplements in human and many animal species, including fish. Recently, it has gained more attention in fish not only for its growth-promoting and immunomodulatory effects but also for its antioxidant potential. The present study was conducted to investigate the protective role of two different dietary levels of SP on freshwater Nile tilapia; Oreochromis niloticus exposed to subacute deltamethrin (DLM) intoxication. Spirulina was supplemented at levels of 0.5 and 1 % in the diet along with DLM at a concentration of 1.46 μg/l for 28 days. Serum biochemical parameters, alanine aminotransferase (ALT), aspartate aminotransferase (AST), alkaline phosphatase (ALP), total protein, albumin, cholesterol, urea, uric acid and creatinine, were estimated. In addition, the level of malondialdehyde (MDA) was analysed as a lipid peroxidation marker. Reduced glutathione (GSH) content and glutathione peroxidase (GSH-Px), superoxide dismutase (SOD) and catalase (CAT) activities were analysed as antioxidant biomarkers in liver, kidney and gills. The results revealed that DLM intoxication increased serum AST, ALT, ALP, cholesterol, urea, uric acid, creatinine and tissue MDA, while decreased serum total protein and albumin as well as tissue GSH level and GSH-Px, SOD and CAT activities. SP supplementation at the two tested levels enhanced all altered serum biochemical parameters as well as tissue lipid peroxidation and antioxidant biomarkers. Therefore, it could be concluded that SP administration could minimize DLM-induced toxic effects by its free radical scavenging and potent antioxidant activity.

Antagonistic activity of dietary allicin against deltamethrin-induced oxidative damage in freshwater Nile tilapia; Oreochromis niloticus

Allicin, the main biologically active component of garlic clove extracts, has been evaluated for its' efficacy in preventing deltamethrin-induced oxidative damage in Nile tilapia; Oreochromis niloticus. Fish were fed on 2 different doses of 0.5 g and 1 g of allicin/kg diet for 28 days. Serum aspartate aminotransferase (AST), alanine aminotransferase (ALT), alkaline phosphatase (ALP), cholesterol, urea, uric acid, creatinine, total protein, albumin and globulin were estimated. Moreover, the level of malonaldehyde (MDA) was analyzed as a lipid peroxidation marker. In addition, reduced glutathione (GSH), glutathione peroxidase (GSH-Px), superoxide dismutase (SOD) and catalase (CAT) were analyzed as antioxidant biomarkers in liver, kidney and gills. Results show that deltamethrin subacute intoxication (1.46 µg/L for 28 days) increased serum AST, ALT, ALP, cholesterol, urea, uric acid, creatinine and tissue MDA. At the same time, serum total protein and albumin as well as tissue level of GSH, GSH-Px, SOD and CAT were reduced. Allicin supplemented diets enhanced all the altered serum biochemical parameters as well as tissues' lipid peroxidation and antioxidant biomarkers in a dose-dependent manner. The results suggest that feeding allicin can ameliorate deltamethrin-induced oxidative stress and might have some therapeutic properties to protect Nile tilapia on subacute deltamethrin toxicity.

Transcriptional responses in Atlantic salmon (Salmo salar) exposed to deltamethrin, alone or in combination with azamethiphos

Recently, Atlantic salmon (Salmo salar) fish farmers have applied a combination of deltamethrin and azamethiphos in high-concentration and short-duration immersion treatment to improve protection against sea-lice (Lepeophtheirus sp.). In this work we aimed to study the effects of deltamethrin, alone or in combination with azamethiphos, on the transcription of stress and detoxification marker genes. Atlantic salmon kept at 12°C (one group was also kept at 4-5°C) were treated with deltamethrin alone or in combination with azamethiphos for a total of 40min, and gill and liver tissue harvested for transcriptional analysis 2 and 24h post treatment. No lethality was observed during the experiment. The result showed that deltamethrin, alone or in combination with azamethiphos, affected the transcriptional levels of several oxidative stress markers, including MnSOD (SOD2) and HSP70 (HSPA8) in the liver, and GPX1, CAT, MnSOD, HSP70 and GSTP1 in the gills. Significant responses for CASP3B, BCLX, IGFBP1B and ATP1A1 (Na-K-ATPase a1b) by some of the treatments suggest that the pharmaceutical drugs may affect apoptosis, growth and ion regulation mechanisms. In fish kept at 4-5°C, different effects were observed, suggesting a temperature-dependent response. In conclusion, the observed responses indicate that short-term exposure to deltamethrin has a profound effect on transcription of the evaluated markers in gills and liver of fish. Co-treatment with azamethiphos appears to have small mitigating effects on the transcriptional response caused by deltamethrin exposure alone.

Modulatory effects of deltamethrin-exposure on the immune status, metabolism and oxidative stress in gilthead seabream (Sparus aurata L.)

Deltamethrin, a sintetic pyrethroid, is the insecticide that has been replacing recently to others like organochlorines, organophosphates and carbamates which are less toxic for birds and mammals, although, unfortunately, all of them are highly toxic to various non-targeted aquatic organisms including fish. In the present study, the consequences of the exposition of gilthead seabream (Sparus aurata L.) specimens to sublethal bath dose of deltamethrin (0.1 ppb) on organo-somatic indexes, immunity, seric metabolic parameters, oxidative stress and liver histology were determined after 1, 3, 7 and 14 days of exposure. Deltamethrin alters gilthead seabream immune status, the hepato-somatic index and various seric metabolic parameters since the first exposure day while important progressive deleterious morphological changes in liver were also observed. However, no statistically significant deviation was detected in the expression of oxidative stress-related genes whilst the expression of cytochrome P450 gene was up-regulated in head-kidney and liver of exposed fish. Overall, the present results indicate severe immunotoxicological and metabolic effects of deltamethrin in gilthead seabream, the species with the highest rate of production in Mediterranean aquaculture. In general, the values obtained for the tested parameters during the trial seem to indicate that specimens try to adapt to this adverse situation although the continuous presence of the toxic impede the hypothetic recovery of homoeostasis. The use of deltamethrin in the proximities of seabream farms should be carefully considered.

In vitro determination of 6PGD enzyme activity purified from Lake Van fish (Chalcalburnus tarichii Pallas, 1811) liver exposed to pesticides

In the present study, the effect of methidathion, cypermethrin, and deltamethrin pesticides on Lake Van fish (Chalcalburnus tarichii Pallas, 1811) liver 6-phosphogluconate dehydrogenase enzyme activity was investigated due to the fact that these pesticides are extensively used to improve agricultural productivity in the Van region. 2',5'-ADP Sepharose 4B affinity chromatography was used to purify 6-phosphogluconate dehydrogenase enzyme from fish liver and SDS-PAGE technique was used to control the purity of this enzyme. The in vitro effect of methidathion, cypermethrin, and deltamethrin pesticides on the enzyme activity was investigated. The enzyme was purified 1,050-fold with specific activity of 27.04 EU/mg protein. Moreover, Ki constants of methidathion, cypermethrin, and deltamethrin were to be 3.294 ± 0.215, 0.718 ± 0.095, and 0.084 ± 0.009 mM respectively. The IC50 value were estimated as 9.95 × 10(-5) ± 0.1844 × 10(-5) mM for methidathion, 1.01 × 10(-4) ± 0.01413 × 10(-4) mM for cypermethrin, and 4.43 × 10(-6) ± 0.05653 × 10(-6) mM for deltamethrin. In conclusion, deltamethrin inhibits the enzyme activity more than methidathion and cypermethrin.

Different sensitivities of biomarker responses in two epigeic earthworm species after exposure to pyrethroid and organophosphate insecticides

In many studies that investigate the toxic effects of pollutants on earthworms, experiments are performed using only one species of earthworms, most commonly the Eisenia species. However, the differences in sensitivities of different earthworm species could potentially lead to an underestimation of environmental aspects of pollutants. Therefore, the aim of this study was to compare the sensitivity of biomarker responses of Eisenia andrei, an epigeic compost species commonly used in laboratory experiments, with those of Lumbricus rubellus, an epigeic species widely distributed in temperate regions. The earthworms were exposed to the three commonly used insecticides: organophosphates dimethoate (0.03, 0.3, and 3 mg kg(-1)) and pirimiphos-methyl (0.02, 0.2, and 2 mg kg(-1)), as well as pyrethroid deltamethrin (0.01, 0.1, and 0.5 mg kg(-1)), for 1 and 15 days using an artificial soil test. The effects of the pesticides were assessed by measuring the activities of acetylcholinesterase (AChE), carboxylesterase (CES), catalase (CAT), glutathione S-transferase (GST) as well as the concentration of glutathione (GSH). The pesticides caused a significant inhibition of AChE and CES activities and significant changes in activities of CAT, GST, and GSH concentration in both earthworm species. A comparison of biomarker responses between E. andrei and L. rubellus showed significant differences; E. andrei proved to be less susceptible to pesticide exposure than L. rubellus. In addition, the results from the filter-paper contact test mortality experiments showed that lethal concentrations were lower for L. rubellus compared with the E. andrei, further showing a greater sensitivity of L. rubellus. The difference in sensitivities of these epigeic species should be taken into account when conducting toxicity studies.

Effects of deltamethrin on biometric parameters and liver biomarkers in common carp (Cyprinus carpio L.)

The present study is aimed to evaluate the effect of sublethal exposure to the pyrethroid pesticide deltamethrin, according to biometric parameters and important liver biomarkers in the common carp (Cyprinus carpio). Fish were exposed for 4, 15 and 30 days to deltamethrin mixed to the aquaria water at the concentrations of 0.08, 0.4 and 0.8μg/L. The exposure did not affect fish biometric parameters. Glutathione-S-transferase (GST) activity in liver (hepatopancreas) increased in fish exposed to the high concentration of pesticide only after 30 days when compared to controls. A significant increase of malondialdehyde (MDA) content (79.4% and 90.2% of control) was remarked after 15 and 30 days of exposure to the highest concentration of pesticide. Catalase activities (CAT) went up after 4 days of was to the concentration of 0.4μg/L and 0.8μg/L and at 15 days of exposure to 0.4μg/L. The most significant change of glutathione reductase (GR) activity was recorded at the fourth day, when GR activity was significantly increased after exposure to the concentrations of 0.4μg/L and 0.8μg/L of deltamethrin.

Effects of subchronic exposure to phosalone on oxidative stress and histopathological alterations in common carp (Cyprinus carpio, L., 1758)

In this study, possible oxidative stress, biomarkers, and histopathological alterations were investigated in common carp (Cyprinus carpio, L., 1758) that were exposed to various phosalone concentrations in vivo. Fish were exposed to 0.15, 0.3, and 0.6 mg/L phosalone concentrations in a semistatic regime for 14 d. Biomarkers, including Na(+), K(+)-ATPase, reduced glutathione (GSH), thiobarbituric acid-reactive substances (TBARS), and histopathological changes, were determined in gills, liver, and kidney tissues of fish. Sublethal phosalone concentrations produced lipid peroxidation and impairment in the antioxidant defense system by increasing reactive oxygen species (ROS) production. While GSH increased in all groups at d 7 compared to control, GSH fell significantly at medium and high doses at d 14. Reduced GSH levels were diminished in all tissues and a significant induction in lipid peroxidation (TBARS) was observed. Na(+),K(+)-ATPase enzyme activity was significantly inhibited especially in gills. No histopathological effects were observed in the control group. Lamellar aneurysm, lamellar fusion, hyperplasia, epithelial lifting, and hemorrhages were observed in gill tissues exposed to phosalone. Histopathological effects in the liver tissues of fish exposed to phosalone were characterized by cytoplasmic vacuolation, congestion, hypertrophy, and nuclear degeneration. Hypertrophy, tubule degeneration, mononuclear cell infiltration, and dilation of glomerular capillaries were noted in kidney tissues exposed to phosalone. The results indicate that phosalone exposure adversely affected the health of the fish, attributable to oxidative stress.

Deltamethrin-induced oxidative stress and biochemical changes in tissues and blood of catfish (Clarias gariepinus): antioxidant defense and role of alpha-tocopherol

Background

The pyrethroid class of insecticides, including deltamethrin, is being used as substitutes for organochlorines and organophosphates in pest-control programs because of their low environmental persistence and toxicity. This study was aimed to investigate the impact of commonly used pesticides (deltamethrin) on the blood and tissue oxidative stress level in catfish (Clarias gariepinus); in addition to the protective effect of α-tocopherol on deltamethrin induced oxidative stress.

Catfish were divided into three groups, 1^st control group include 20 fish divided into two tanks each one contain 10 fish, 2^nd deltamethrin group, where Fish exposed to deltamethrin in a concentration (0.75 μg/l) and 3^rd Vitamin E group, Fish exposed to deltamethrin and vitamin E at a dose of 12 μg/l for successive 4 days.

Serum, liver, kidney and Gills were collected for biochemical assays. Tissue oxidative stress biomarkers malondialdhyde (MDA) and catalase activity in liver, kidney and gills tissues, serum liver enzymes (ALT and AST), serum albumin, total protein, urea and creatinine were analysed.

Results

Our results showed that 48 h. exposure to 0.75 μg/l deltamethrin significantly (p < 0.05) increased lipid peroxidation (MDA) in the liver, kidney and gills while catalase activity was significantly decreased in the same tissues. This accompanied by significant increase in serum ALT, AST activity, urea and creatinine and a marked decrease in serum albumin and total proteins.

Conclusions

It could be concluded that deltamethrin is highly toxic to catfish even in very low concentration (0.75 μg/l). Moreover the effect of deltamethrin was pronounced in the liver of catfish in comparison with kidneys and gills. Moreover fish antioxidants and oxidative stress could be used as biomarkers for aquatic pollution, thus helping in the diagnosis of pollution. Adminstration of 12 μg/l α-tocopherol restored the quantified tissue and serum parameters, so supplementation of α-tocopherol consider an effective way to counter the toxicity of deltamethrin in the catfish.

Toxic effects of deltamethrin and λ-cyhalothrin on Xenopus laevis tadpoles

This study evaluates the toxic effects of deltamethrin and λ-cyhalothrin on Xenopus laevis tadpoles after 168 h of exposure. The LC(50) of deltamethrin and λ-cyhalothrin at 168 h was calculated as the μg of active ingredient per liter (μg AI/L). According to these values, the LC(50) was 6.26 and 3.94 μg AI/L for deltamethrin and λ-cyhalothrin, respectively. Several enzymes were studied for early signs of intoxication following exposure to the pesticides for 24 h. Glutathione-S-transferase,carboxylesterase, and lactate dehydrogenase were inhibited by λ-cyhalothrin, and both pesticides inhibited acid phosphatase and aspartate aminotransferase. In contrast, acetylcholinesterase was activated by deltamethrin. The results suggest that X. laevis is sensitive to the pyrethroids that were tested, and the enzyme responses suggest that they are potential biomarkers for evaluating the toxic effect of pyrethroids on amphibians in environmental conditions.

Alterations in blood electrolytes of a freshwater catfish Heteropneustes fossilis in response to treatment with a botanical pesticide, Nerium indicum leaf extract

The present study aimed at investigating the effects of Nerium indicum leaf extract on the blood electrolytes of Heteropneustes fossilis for short- and long term. Fish were subjected to Nerium indicum leaf extract for short term (11.27 mg/L i.e. 0.8 of 96 h LC₅₀) and long term (2.81 mg/L i.e. 0.2 of 96 h LC₅₀). Fish were killed on each time intervals from control and experimental (Nerium indicum) groups after 24, 48, 72, and 96 h in short-term exposure and after 7, 14, 21, and 28 days in long-term experiment. Blood samples were analyzed for calcium and inorganic phosphate levels. Acute exposure of Nerium indicum leaf extract caused a progressive decrease in the serum calcium levels after 48 h in fish H. fossilis, which persists till the close of the experiment (96 h). The serum inorganic phosphate levels remain unaffected till 48 h in the Nerium indicum leaf extract-exposed fish. After 72 and 96 h, the levels exhibit a decrease. Chronic Nerium indicum leaf extract treatment provoked a decrease in serum calcium levels at day 14. This decrease continues till 28 days. The serum phosphate level of the Nerium indicum leaf extract-treated fish decreases on day 14 and 21. However, on day 28, the levels become close to the normal values. We conclude that Nerium indicum leaf extract exposure alters the blood electrolytes of the fish, thus causing physiological disturbances which might affect seriously the normal vital functions, growth rate, reproduction, and their survival in nature.

Histological alterations in the prolactin cells of a teleost, Heteropneustes fossilis, after exposure to cypermethrin

Freshwater fish Heteropneustes fossilis (H. fossilis) were subjected to 5.76 μg/L (80% of 96 h LC(50) ) and 1.44 μg/L (20% of 96 h LC(50) ) of cypermethrin for short-term (96 h) and long-term (28 days) duration, respectively. Plasma calcium of H. fossilis exposed for short term (96 h) to cypermethrin exhibited no change at 24 h. The levels indicate a decrease in plasma calcium at 48 h. This response persists till the close of experiment (96 h). No change has been noticed throughout the experiment in the histological structure and nuclear volume of prolactin cells of short-term cypermethrin treated fish. Long-term exposure of cypermethrin to fish provoked hypocalcemia. The prolactin cells remain unchanged till 7 days following cypermethrin treatment. After 14 days, the nuclear volume exhibits an increase and the cells exhibit degranulation. These changes increase progressively 21 days onwards. Also, few degenerating cells are discerned after 28 days.

Blood electrolytes of the freshwater catfish Heteropneustes fossilis in response to treatment with a botanical pesticide (latex of Euphorbia royleana)

The aim of the present study was to determine changes in blood electrolytes (calcium and phosphate) in the freshwater catfish Heteropneustes fossilis following short- and long-term exposure to latex of Euphorbia royleana. To investigate the effects of short-term exposure, fish were exposed to 80% of the 96-h LC(50) of E. royleana latex (2.47 mg/L) for 96 h. To assess the effects of long-term exposure, fish were exposed to 20% of the 96-h LC(50) of E. royleana latex (0.618 mg/L) for 28 days. Fish were killed after 24, 48, 72 and 96 h (short-term experiments) or after 7, 14, 21 and 28 days (long-term experiments). Blood samples were collected and sera were analyzed to determine calcium and inorganic phosphate levels. Serum calcium levels decreased progressively in H. fossilis after 48 h exposure to E. royleana latex. This decrease persisted until the end of the experiment (96 h). Serum inorganic phosphate levels in treated fish decreased progressively from 72 h. After 7 days exposure to E. royleana latex, decreased serum calcium levels were noted in H. fossilis that persisted until the end of the experiment. Serum phosphate levels were decreased in H. fossilis on days 21 and 28 of exposure to E. royleana latex. It is concluded that E. royleana latex alters the blood electrolyte content of the fish. The change in these electrolytes, particularly calcium levels, may cause disturbances in the normal vital physiological functions of the fish, its growth rate, and even its ability to survive in nature.

Effects of Cypermethrin (pyrethroid insecticide) on the valve activity behavior, byssal thread formation, and survival in air of the marine mussel Mytilus galloprovincialis

Cypermethrin is a pyrethroid pesticide widely used to combat agricultural pests. However, little information is available about its toxicity in aquatic macroinvertebrates in the context of the Moroccan coastline. In this study, a suite of physiological and behavioral biomarkers for water quality surveillance using mussels are used to characterize the toxicity of Cypermethrin. In these tests, sublethal effects on valve activity behavior, byssal thread formation, and survival in air of the mussel Mytilus galloprovincialis were assessed in short-term exposure. The results show that Cypermethrin impaired the valve activity in a concentration-dependent manner, leading to a reduction in the time of normal opening. The lowest effect concentration was determined as 100 μg/l Cypermethrin. Prolonged closures of mussels were also observed for the exposures to 400 and 800 μg/l. The delay to the first detection of the pesticide was concentration dependent. The capacity to produce new byssus threads in a Cypermethrin exposure was inhibited at all concentrations and especially at high concentrations. Survival in air was not affected even at 800 μg/l Cypermethrin.

Modulatory effects of deltamethrin on antioxidant defense mechanisms and lipid peroxidation in Carassius auratus gibelio liver and intestine

Pyrethroids, such as deltamethrin, are toxic substances that lead to generation of reactive oxygen species, which harm living organisms. We assessed the level and patterns of imbalance evolved by a single dose of 2 microg/L deltamethrin on the lipid peroxidation (LPO) and the antioxidant defense system of Carassius auratus gibelio liver and intestine, and monitored the recovery dynamics of these parameters during a 14-day post-exposure period. LPO and antioxidative defense mechanisms displayed different responses in the investigated tissues. Sudden increase of LPO in the liver, persisting at this elevated level throughout the test period, was observed on the third day post-exposure, while in the intestine significant enhancement of this parameter was recorded from the seventh day. Reduced glutathione (GSH) showed a transient increase in the liver, and was depleted in the intestine by the second day of exposure, with signs of recovery by the end of the experimental tenure. In the liver of fish a temporary inhibition of superoxide dismutase (SOD) and catalase (CAT) activity, and activation of glutathione peroxidase (GPX), glutathione transferase (GST), and glutathione reductase (GR) enzymes was observed, with maximum thresholds recorded on the third and second days, respectively. In the intestine a relevant increase in CAT and GST activity up to the second day and almost complete recovery by the end of the experiment was recorded, while for GR a continuous enhancement was apparent.

Oxidative stress, protein carbonylation and heat shock proteins in the black tiger shrimp, Penaeus monodon, following exposure to endosulfan and deltamethrin

The impact of commonly used pesticides, endosulfan and deltamethrin, on the molecular stress level in black tiger shrimp Penaeus monodon, was assessed using classical oxidative stress biomarkers, protein carbonylation profiles, and levels of heat shock proteins. Results showed that 4 days exposure to 0.1 μg L(-1) deltamethrin significantly (p<0.05) increased lipid peroxidation (LPO) level in gills (64.3 ± 3.2 compared to 34.2 ± 5.3 nmol MDA equiv.g(-1) tissue at day 0). However, no pesticide treatment had significant effect on the activities of antioxidant enzymes catalase (CAT), glutathione peroxidase (GPx) and glutathione S-transferase (GST). Carbonylated protein profiles were determined on gills following 2,4-dinitrophenylhydrazine derivatization and 2D-PAGE along with Western blotting. Immunoblotting with dinitrophenol-specific antibody revealed 17 protein spots carbonylated in response to 4 days exposure to 0.1 μg L(-1) deltamethrin while 24 protein spots specifically oxidized at day 0 were no longer detected after deltamethrin treatment. On the other hand, endosulfan exposure at 0.1 and 1 μg L(-1) induced up to 2.1-fold increase of HSP90 level in muscle. This approach is providing new insights into the molecular impacts of deltamethrin and endosulfan on an economically important crustacean. While deltamethrin has shown a pro-oxidant effect in gills, endosulfan exposure rather induced proteotoxic effects in muscles. This argues that LPO level, protein carbonylation specificities, and HSP90 levels may be potential discriminating biomarkers to assess the chemical stress level in farm shrimp.

Cypermethrin induced histological changes in gonadotrophic cells, liver, gonads, plasma levels of estradiol-17beta and 11-ketotestosterone, and sperm motility in Heteropneustes fossilis (Bloch)

The aim of the present investigation is to assess the impact of cypermethrin on reproductive physiology in catfish, Heteropneustes fossilis during prespawning phase. Results indicate that there is a decrease in the size of gonadotrophic cells with less granulation, pycnosis in the liver, presence of immature oocytes and atretic follicles in the ovaries and gross condensation of spermatogenic cells in testes after cypermethrin exposure at sublethal concentration. The gonado-somatic index (GSI), plasma levels of estradiol-17beta (E2) and 11-ketotestosterone (11-KT) also decreases. The motility of sperm cells is dependent on the dilution (2000 times) and duration of motility is recorded 2min maximally at 90s after post-activation. The dose 0.1 and 0.01ppm is sublethal, while 1ppm is lethal on sperm motility. Results indicate that cypermethrin causes inhibition of reproduction by acting at the hypothalamo-hypophyseal-gonadal axis as is manifest from the histological observations of gonadotrophs along with disruption of follicular wall and spermatogenic cells. Obviously such changes are responsible for decreasing the steroid hormone levels which result in decreasing scale and duration of sperm motility after 45d exposure of cypermethrin in this species.

Acute toxicity of deltamethrin for freshwater mussel, Unio elongatulus eucirrus bourguignat

In this study, the acute toxicity of deltamethrin, contaminating aquatic ecosystems as a pollutant, on freshwater mussel, Unio elongatulus eucirrus, was examined. Deltamethrin was applied at concentrations of 1, 2, 3, 4, 5, 6, 7, 8, 16 and 32 mg L(-1). The 1, 24, 48, 72 and 96 h LC(50) values of deltamethrin for freshwater mussels were determined as 10.07, 8.99, 8.09, 7.30 and 6.60 mg L(-1), respectively. There were significant differences in LC(10-90) values obtained for different times of exposure. The results show that deltamethrin is moderately toxic for freshwater mussel and it should be used with caution in agriculture to protect natural waters from contamination.

Effects of deltamethrin on rainbow trout (Oncorhynchus mykiss)

The aim of this study was to assess the effect of deltamethrin on rainbow trout (Oncorhynchus mykiss). Control and experimental group of fish were exposed to Decis EW 50 pesticide preparation (active substance 50g/l of deltamethrin). The acute semistatical toxicity test lasting 96h was performed on rainbow trout juveniles. The 96hLC(50) value of Decis EW 50 was 0.02mg/l. Examination of haematological and biochemical profile and histological tissue examination was performed on 1-2-year-old rainbow trout after 96h of exposure to Decis EW 50 in a concentration of 0.02mg/l. The experimental group showed significantly lower values (p<0.05) of plasma glucose, alanine aminotransferase, cholinesterase and significantly higher (p<0.05) values of erythrocyte count, haemoglobin content, haematocrit and plasma total protein, albumins, ammonia, aspartate aminotransferase, creatinekinase and calcium compared to the control group. The deltamethrin-based Decis EW 50 pesticide preparation was classified among substances strongly toxic for fish.

Acute toxicity, behavioral changes, and histopathological effects of deltamethrin on tissues (gills, liver, brain, spleen, kidney, muscle, skin) of Nile tilapia (Oreochromis niloticus L.) fingerlings

Deltamethrin, a synthetic pyrethroid contaminating aquatic ecosystems as a potential toxic pollutant, was investigated in the present study for acute toxicity. The purpose of this study was to evaluate LC(50) values of deltamethrin on Nile tilapia (Oreochromis niloticus L.) fingerlings and investigate histopathological responses of fish exposed to deltamethrin. The 48 h LC(50) value for Nile tilapia fingerlings was estimated as 4.85 microg/L using static test system. In addition, behavioral changes at each deltamethrin concentration were observed closely. All fish, exposed to 5 microg/L deltamethrin revealed severe morphological alterations in the gills and liver. In the gills hyperemia, fusion of secondary lamellae and telangiectasis were observed; whereas hydropic degenerations in liver were observed in all examined fish. The results are significant for reporting acute deltamethrin toxicity in terms of behavioral and histopathological changes: Deltamethrin is highly toxic to fingerlings.

Gill and kidney histopathology in the freshwater fish Cyprinus carpio after acute exposure to deltamethrin

The histopathological effects of deltamethrin on the gill and kidney tissues of the common carp, Cyprinus carpio were determined by light microscopy. The fish were exposed to 0.029mgl(-1) (50% of 96h LC(50)) and 0.041mgl(-1) (70% of 96h LC(50)) solutions of deltamethrin for short-term (96h). The most common gill changes at all doses of deltamethrin were desquamation and necrosis. Besides, aneurism in secondary lamellae, lifting of the lamellar epithelium, oedema, epithelial hyperplasia and fusion of the secondary lamellae were reported. Lesions in the kidney tissues of fish exposed to deltamethrin were characterized by degeneration in the epithelial cells of renal tubule, pycnotic nuclei in the hematopoietic tissue, dilation of glomerular capillaries, degeneration of glomerulus, intracytoplasmatic vacuoles in epithelial cells of renal tubules with hypertrophied cells and narrowing of the tubular lumen.

Protein carbonyls: novel biomarkers of exposure to oxidative stress-inducing pesticides in freshwater fish Channa punctata (Bloch)

It has been established in mammalian system including humans that direct damage to proteins or chemical modification of amino acids in proteins during oxidative stress can give rise to protein carbonyls. Protein carbonyl induction, as a biomarker of oxidative stress was used in laboratory studies to assess the toxic effects of pesticides in freshwater fish, Channa punctata (Bloch), exposed to deltamethrin, endosulfan and paraquat. Protein carbonyls were measured in gills, kidney and liver. Significant (P<0.05-0.001) increase in protein carbonyls was observed in response to single 48h exposure to various pesticides in all the tissues. The time kinetics study involving deltamethrin (0.75μg/L) also showed a significant (P<0.05-0.001) induction of protein carbonyls in all the organs. The induction was significant (P<0.05-0.001) in all the durations of exposure (12h, 96h, 7 days, 14 days, 28 days). However, relatively pronounced induction was observed during shorter duration of exposure. The findings of the present investigation showed that deltamethrin had the maximum oxidative stress-inducing potential among the three pesticides used and gills are the most sensitive organs prone to oxidative damage. It is suggested that measurement of carbonyl groups may provide a convenient technique for detecting and quantifying oxidative modification of proteins during oxidative stress. The induction of protein carbonyl in fish was identified as a potentially useful biomarker of oxidative stress that warrants its application in the field investigations.

Oxidative stress biomarkers of exposure to deltamethrin in freshwater fish, Channa punctatus Bloch

The pyrethroid class of insecticides, including deltamethrin, are being used as substitutes for organochlorines and organophosphates in pest-control programs because of their low environmental persistence and toxicity. Ecotoxicological consequences of deltamethrin, particularly its effects on antioxidants in fish and other aquatic organisms, are not well understood. We investigated the effect of deltamethrin (0.75 microg/L) on antioxidants in a freshwater fish, Channa punctatus Bloch, using standard laboratory conditions. A single exposure for 48 h caused induction of various antioxidant enzymes and nonenzymatic antioxidants in kidney and liver. The induction of these antioxidants was not very prominent in gills. In fact, certain antioxidants were found to be depleted in gills. Catalase activity was decreased in all the tissues. Deltamethrin also induced lipid peroxidation in all the tissues, gills showing the highest levels. Glutathione, which is an established nonenzymatic antioxidant in fish, was significantly (P<0.001) increased in all the tissues. Ascorbic acid content increased in kidney and liver while it decreased in gills. The findings of the present investigation show that deltamethrin has oxidative-stress-inducing potential in fish, and gills are the most sensitive organs. It is also interesting to note that gills are the primary sites of deltamethrin absorption and their antioxidant potential is also very poor. The various parameters studied in this investigation can also be used as biomarkers of exposure to deltamethrin. It is suggested that appropriate ecotoxicological risk assessment should be made in the areas where deltamethrin is proposed to be used in pest control activities.

Investigation of acute toxicity of deltamethrin on guppies (Poecilia reticulata)

Deltamethrin, a synthetic pyrethroid pesticide contaminating aquatic ecosystems as a potential toxic pollutant, was investigated in the present study for acute toxicity. Guppy fish (Poecilia reticulata) were selected for the bioassay experiments. The 48-h LC50 was determined for the guppies. The experiments were repeated three times and a total of 210 guppies were used. The static test method of acute toxicity test was used. In addition, behavioral changes at each deltamethrin concentration were determined for the individuals. Data obtained from the deltamethrin acute toxicity tests were evaluated using the Probit Analysis Statistical Method. The 48-h LC50 value for guppy was estimated as 5.13 microg/L.