Oxidative Stress Response in Liver, Kidney and Gills of Ctenopharyngodon Idellus (Cuvier & Valenciennes) Exposed To Chlorpyrifos

Activity pattern of antioxidant enzymes in relation to the time of exposure of hexavalent chromium to Nile tilapia Oreochromis niloticus

Hexavalent chromium (Cr (VI)), a toxicant of environmental concern, frequently enters into water bodies and produces oxidative stress in fish. The antioxidant enzymes, Superoxide dismutase (SOD), Catalase (CAT), and Glutathion S-transferase (GST) are activated to counteract the oxidative stress in fish. This study explores the pattern of activation of these enzymes in gill, muscle, liver, and kidney tissues of Nile tilapia Oreochromis niloticus exposed to 9.35 mg/L and 18.70 mg/L of Cr (VI) for 96 h. The optimal hour of activity of these enzymes was revealed through extensive regression analysis. The results indicate a bell-shaped time response curve in the activity of the enzymes in both the treatments, except CAT in the gill of fish exposed to 18.70 mg/L Cr (VI) and GST in the gill, liver, and kidney of fish exposed to 18.70 mg/L Cr (VI). The results indicate that the optimal hour of activity of SOD changes in tandem with CAT, SOD responding first followed by CAT, both diminishing within 96 h. However, deviating from the bell-shaped pattern, the activity of CAT in gill and GST in gill, liver, and kidney in fish exposed to 18.70 mg/L Cr (VI) continued to rise even at 96 h, indicating that these antioxidant enzymes could not diminish the oxidative stress produced by the higher dose of Cr (VI). It was concluded that the activity of SOD, CAT, and GST between 30 and 70 h in the gill, liver, and kidney of Nile tilapia could serve as excellent biomarkers of oxidative stress under low doses of Cr (VI).

Benzalkonium chloride induced acute toxicity and its multifaceted implications on growth, hematological metrics, biochemical profiles, and stress-responsive biomarkers in tilapia (Oreochromis mossambicus)

This study aimed to investigate the toxic effects of benzalkonium chloride (BAC) on Oreochromis mossambicus, a freshwater fish species. Probit analysis was used to determine the lethal concentration (LC50) of BAC for different exposure periods (24, 48, 72, and 96 h). The viability of fish exposed to BAC was assessed using the general threshold survival models (GUTS) and confirmed with relevant datasets to evaluate model accuracy. Experimental groups of fish were exposed to BAC concentrations equivalent to 10% and 20% of the 96-h LC50 for 45 days. The study revealed significant alterations in various parameters during sublethal BAC exposure. These effects included decreased specific growth rate (SGR), red blood cell count (RBC), hemoglobin (Hb) concentration, hematocrit (Ht) value, plasma protein, and albumin levels, as well as acetylcholinesterase (AChE) activities in both gills and liver. Additionally, an increase in gastrosomatic index (GSI), feed conversion ratio (FCR), plasma glucose and creatinine concentrations, alanine aminotransferase (ALT), aspartate aminotransferase (AST) enzymatic activities, catalase (CAT), superoxide dismutase (SOD), and malondialdehyde (MDA) levels were observed in the exposed fish's gills and liver. Furthermore, the study found that glutathione S-transferase (GST) and glutathione peroxidase (GPx) levels initially increased and then decreased in both gills and liver after exposure to BAC. Correlation matrix analysis, multivariate multiple regression (MMR), canonical correspondence analysis (CCA), integrated biomarker response (IBR), and biomarker response index (BRI) were utilized to assess the impact of BAC on fish, highlighting significant effects on multiple biomarkers in O. mossambicus following surfactant exposure. Thus, the study provides valuable insights into the toxic effects of BAC on this fish species, emphasizing the importance of monitoring such pollutants in aquatic environments.

Antioxidant Properties of Lippia alba Essential Oil: A Potential Treatment for Oxidative Stress-Related Conditions in Plants and Cancer Cells

Lippia alba (Mill.) N.E.Br. ex Britton and P. Wilson is used in folk medicine of Central and South America for its biological activities: i.e., antifungal, antibacterial, antiviral, and anti-inflammatory. Based on ethnopharmacological information and the increasing interest in this species, this work aimed to test a possible wide use of its essential oil (EO) in pharmaceutical and horticultural applications. Therefore, we focused the attention on the antioxidant activity of the oil as a possible tool to overcome the oxidative stress in both applications. For this purpose, we have chosen three aggressive breast cancer cell lines and two horticultural species (Solanum lycopersicum L. and Phaseolus acutifolius L.) that are very sensitive to salt stress. We determined the antioxidant activity of L. alba EO through the quantification of phenols and flavonoids. Regarding tomato and bean plants under salt stress, L. alba EO was used for the first time as a seed priming agent to enhance plant salt tolerance. In this case, the seed treatment enhanced the content of phenolic compounds, reduced power and scavenger activity, and decreased membrane lipid peroxidation, thus mitigating the oxidative stress induced by salt. While in breast cancer cells the EO treatment showed different responses according to the cell lines, i.e., in SUM149 and MDA-MB-231 the EO decreased proliferation and increased antioxidant activity and lipid peroxidation, showing high cytotoxic effects associated with the release of lactate dehydrogenase, vice versa no effect was observed in MDA-MB-468. Such antioxidant activity opens a new perspective about this essential oil as a possible tool to counteract proliferation in some cancer cell lines and in horticulture as a seed priming agent to protect from oxidative damage in crops sensitive to salinity.

Long term integrated biomarker responses in freshwater African catfish Clarias gariepinus exposed to a new brand of herbicide fluazifop-p-butyl

The study investigated the sublethal effects of Fluazifop-p-butyl (FPB) on the haematological, biochemical and oxidative stress changes in Clarias gariepinus. Juvenile C. gariepinus were exposed to FPB concentrations of 1.80, 3.50, and 7.10 mg/l corresponding to 5, 10 and 20% of 96 h LC50 value of FPB respectively for 21 days and allowed to recover for 7 days. The blood, liver and gills were removed and analyzed. Fish exposed to different concentrations of FPB showed significant decline in the values the pack cell volume, hemoglobin and red blood cells but the white blood cell values increased. The neutrophil values increased while the lymphocyte declined but the monocytes, basophil and eosinophil values remain unchanged. The liver and gill aspartate aminotransferase, alanine aminotransferase and alkaline phosphatase significantly increased compared to the control. There were mixed trends in the values of glucose but total protein was reduced in both tissues of the fish. There was significant decline in superoxide dismutase, catalase and glutathione peroxidase while malondialdehyde, total glutathione, and glutathione reductase increased in both liver and gill of the exposed fish. Following the 7-day withdrawal, most of the observed parameters returned to normal values. The present study revealed that FPB is toxic to C. gariepinus juveniles and prolonged exposure could result to major health risks to aquatic organisms, hence, they should be carefully used.

Multiple biomarker responses in female Clarias gariepinus exposed to acetaminophen

Several authors have documented the presences of acetaminophen (APAP) in both surface and groundwater and have received attention from government agencies and basic authorities across the globe. The impacts of such pharmaceutical products on non-target organism like fish are underestimated as a result of selected investigation using few biomarkers. We evaluated the sub-chronic impacts of APAP in female catfish (Clarias gariepinus) using multiple biomarkers. The exposure of female catfish to APAP induced oxidative stress. Markers such as superoxide dismutase (SOD), glutathione peroxidase (GPx), and total antioxidant capacity (TAC) were significantly higher in all exposed groups. Exposure of Clarias gariepinus to APAPA caused histological alterations in the gills (fusion and shortening of some filaments, hyperplasia of the epithelial gill cells, aneurism, congestion, and epithelial rupture of the gills), liver (apoptotic hyperplasia, sinusoidal congestion, and necrosis of the hepatocytes), and gonad (degenerated follicles and ovarian apoptosis). Furthermore, multivariate results indicated that there was a distinct response from the acetaminophen-exposed female catfish, with over 95% of the biomarkers significantly contributing to the discrimination between the acetaminophen-exposed female catfish and the control groups. Our research provides evidence supporting the use of a multiple biomarker approach to evaluate the impacts of drugs on the health status of exposed fish.

The benefit of using in vitro bioassays to screen agricultural samples for oxidative stress: South Africa's case

Applied pesticides end up in non-target environments as complex mixtures. When bioavailable, these chemicals pose a threat to living organisms and can induce oxidative stress (OS). In this article, attention is paid to OS and the physiological role of the antioxidant defense system. South African and international literature was reviewed to provide extensive evidence of pesticide-induced OS in non-target organisms, in vivo and in vitro. Although in vitro approaches are used internationally, South African studies have only used in vivo methods. Considering ethical implications, the authors support the use of in vitro bioassays to screen environmental matrices for their OS potential. Since OS responses are initiated and measurable at lower cellular concentrations compared to other toxicity endpoints, in vitro OS bioassays could be used as an early warning sign for the presence of chemical mixtures in non-target environments. Areas of concern in the country could be identified and prioritized without using animal models. The authors conclude that it will be worthwhile for South Africa to include in vitro OS bioassays as part of a battery of tests to screen environmental matrices for biological effects. This will facilitate the development and implementation of biomonitoring programs to safeguard the South African environment.

Ecotoxicological impacts of environmentally relevant concentrations of aspirin in the liver of Labeo rohita: Biochemical and histopathological investigation

Aspirin is one of the emerging pharmaceutical contaminants in the aquatic environment and thus it could impart toxicity to non-target organisms including fish. The present study aims to investigate the biochemical and histopathological alterations in the liver of the fish, Labeo rohita exposed to environmentally relevant concentrations of aspirin (1, 10, and 100 μg/L) for 7, 14, 21, and 28 days. The biochemical investigation revealed a significant (p < 0.05) decrease in the activity of antioxidant enzymes such as catalase, glutathione peroxidase, glutathione reductase; and reduced glutathione content in a concentration and duration dependent manner. Further, the decrease in the activity of superoxide dismutase was in a dose dependent manner. The activity of glutathione-s-transferase, however, increased significantly (p < 0.05) in a dose dependent manner. The lipid peroxidation and total nitrate content showed a significant (p < 0.05) increase in a dose and duration dependent manner. The metabolic enzymes such as acid phosphatase, alkaline phosphatase, and lactate dehydrogenase showed a significant (p < 0.05) increase in all three exposure concentrations and durations. The histopathological alterations in the liver such as vacuolization, hypertrophy of the hepatocytes, nuclear degenerative changes, and bile stagnosis increased in a dose and duration dependent manner. Hence, the present study concludes aspirin has a toxic impact on fish, which is evidenced by its profound effect on biochemical parameters and histopathological analysis. These can be employed as potential indicators of pharmaceutical toxicity in the field of environmental biomonitoring.

Role of Polyamines in the Response to Salt Stress of Tomato

Plants irrigated with saline solutions undergo osmotic and oxidative stresses, which affect their growth, photosynthetic activity and yield. Therefore, the use of saline water for irrigation, in addition to the increasing soil salinity, is one of the major threats to crop productivity worldwide. Plant tolerance to stressful conditions can be improved using different strategies, i.e., seed priming and acclimation, which elicit morphological and biochemical responses to overcome stress. In this work, we evaluated the combined effect of priming and acclimation on salt stress response of a tomato cultivar (Solanum lycopersicum L.), very sensitive to salinity. Chemical priming of seeds was performed by treating seeds with polyamines (PAs): 2.5 mM putrescine (PUT), 2.5 mM spermine (SPM) and 2.5 mM spermidine (SPD). Germinated seeds of primed and non-primed (controls) were sown in non-saline soil. The acclimation consisted of irrigating the seedlings for 2 weeks with tap water, followed by irrigation with saline and non-saline water for 4 weeks. At the end of the growth period, morphological, physiological and biochemical parameters were determined. The positive effects of combined treatments were evident, when primed plants were compared to non-primed, grown under the same conditions. Priming with PAs improved tolerance to salt stress, reduced the negative effects of salinity on growth, improved membrane integrity, and increased photosynthetic pigments, proline and enzymatic and non-enzymatic antioxidant responses in all salt-exposed plants. These results may open new perspectives and strategies to increase tolerance to salt stress in sensitive species, such as tomato.

Molecular and Biochemical Evidence of the Toxic Effects of Terbuthylazine and Malathion in Zebrafish

Our research sought to determine the molecular and biochemical effects of environmentally relevant exposure to commonly used chloro-s-triazine herbicide terbuthylazine and organophosphate insecticide malathion on zebrafish. To this aim, mature zebrafish were exposed to 2 and 30 µg L−1 terbuthylazine and 5 and 50 µg L−1 malathion alone and in combination for 14 days. Aside from the accumulation of TBARS and protein carbonyls, a decrease in antioxidants and succinate dehydrogenase activity, an increase in oxidized glutathione, and enhanced apoptosis via Caspase-3 and BAX overexpression were observed. Furthermore, terbuthylazine and malathion induced mitochondrial swelling (up to 210% after single exposure and up to 470% after co-exposure) and lactate dehydrogenase leakage (up to 268% after single exposure and up to 570% after co-exposure) in a concentration-dependent manner. Significant upregulation of ubiquitin expression and increased cathepsin D activity were characteristics that appeared only upon terbuthylazine exposure, whereas the induction of IgM was identified as the specific characteristic of malathion toxicity. Meanwhile, no alterations in the zebrafish hypothalamic-pituitary-thyroid axis was observed. Co-exposure increased the adverse effects of individual pesticides on zebrafish. This study should improve the understanding of the mechanisms of pesticide toxicity that lead to fish impairment and biodiversity decline.

Alterations in the Expression of Antioxidant Enzyme Genes in Response to Pesticide Exposure During Embryonic Development in the Native Reptile Species Caiman latirostris

The aim of this study was to quantify the expression levels of Catalase (cat) and copper, zinc Superoxide dismutase (Cu, Zn-sod) genes involved in the antioxidant response in Caiman latirostris (broad-snouted caiman) blood, after embryonic exposure to the formulations cypermethrin (CYP), chlorpyrifos (CPF), glyphosate (GLY), and their binary and ternary mixtures. Experimental groups were: negative control (NC-distilled water), vehicle control (VC-ethanol), GLY-2%, CYP- 0.12%, CPF- 0.8%, a ternary mixture of them (TM), and three binary mixtures. The applications were made on the nest material in contact with the eggs at the beginning of the incubation period. After hatching, RNA was isolated from blood and expression levels analyzed through qPCR. The results showed downregulation in the expression of sod and cat genes in the three binary mixtures studied, compared to the controls. In addition, we found a possible antagonistic effect between different pesticides in the TM on the expression of both genes.

Pesticide Pollution: Detrimental Outcomes and Possible Mechanisms of Fish Exposure to Common Organophosphates and Triazines

Pesticides are well known for their high levels of persistence and ubiquity in the environment, and because of their capacity to bioaccumulate and disrupt the food chain, they pose a risk to animals and humans. With a focus on organophosphate and triazine pesticides, the present review aims to describe the current state of knowledge regarding spatial distribution, bioaccumulation, and mode of action of frequently used pesticides. We discuss the processes by which pesticides and their active residues are accumulated and bioconcentrated in fish, as well as the toxic mechanisms involved, including biological redox activity, immunotoxicity, neuroendocrine disorders, and cytotoxicity, which is manifested in oxidative stress, lysosomal and mitochondrial damage, inflammation, and apoptosis/autophagy. We also explore potential research strategies to close the gaps in our understanding of the toxicity and environmental risk assessment of organophosphate and triazine pesticides.

Commonly used surfactants sodium dodecyl sulphate, cetylpyridinium chloride and sodium laureth sulphate and their effects on antioxidant defence system and oxidative stress indices in Cyprinus carpio L.: an integrated in silico and in vivo approach

The present study evaluated the homology modelling, in silico prediction and characterization of Cyprinus carpio cytochrome P450, as well as molecular docking experiments between the modelled protein and the surfactants sodium dodecyl sulphate (SDS), sodium laureth sulphate (SLES) and cetylpyridinium chloride (CPC). Homology modelling of cytochrome P450 was performed using the best fit template structure. The structure was optimized with 3D refine, and the ultimate 3D structure was checked with PROCHEK and ERRATA. ExPASy's ProtParam was likewise used to analyse the modelled protein's physiochemical and stereochemical attributes. To establish the binding pattern of each ligand to the targeted protein and its effect on the overall protein conformation, molecular docking calculations and protein-ligand interactions were performed. Our in silico analysis revealed that hydrophobic interactions with the active site amino acid residues of cytochrome p450 were more prevalent than hydrogen bonds and salt bridges. The in vivo analysis exhibited that exposure of fish to sublethal concentrations (10% and 30% of 96 h LC₅₀) of SDS (0.34 and 1.02 mg/l), CPC (0.002 and 0.006 mg/l) and SLES (0.69 and 2.07 mg/l) at 15d, 30d and 45d adversely affected the oxidative stress and antioxidant enzymes (CAT, SOD, GST, GPx and MDA) in the liver of Cyprinus carpio. As a result, the study suggests that elicited oxidative stress, prompted by the induction of antioxidant enzymes activity, could be attributable to the stable binding of cytochrome P450 with SDS, CPC and SLES which ultimately leads to the evolution of antioxidant enzymes for its neutralization.

Ecotoxicity of chlorpyrifos on earthworm Eisenia fetida (Savigny, 1826): Modifications in oxidative biomarkers

Chlorpyrifos (CPF; O, O'-diethyl-3, 5, 6-trichloro-2-pyridyl phosphorothionate) as an organophosphate compound with moderate toxicity that entered the soil in 1965, is widely used as an active substance of many insecticides. CPF may affect some biochemical mechanisms, particularly through disrupting pro- and anti-oxidant balance and inducing free radical-induced oxidative stress. Expired pesticides, if present in ecosystem, may pose new issues of toxicological concern. In the current study, modifications in the oxidative stress (OS) hallmarks including the content of lipid peroxidation (LPO/MDA) and the activities of antioxidant enzymes catalase (CAT) and glutathione S-transferase (GST) in the whole body extract and total antioxidant capacity (TAC), in the coelomic fluid (CF) of earthworm Eisenia fetida were evaluated spectrophotometrically after exposure to different concentrations (1/20th, 1/10th, and 1/5th of LC₅₀) of fresh and expired CPF for 4 and 8 days. First, LC₅₀ for both fresh and expired CPF were determined by using probit method as ≤192 and ≤ 209 mg/kg dry soil, respectively. Our results also revealed that both fresh and expired CPF could be toxic to earthworms via inducing OS at higher concentrations. Here, CPF-induced OS was determined by a significant elevation (p < 0.05) in LPO content, CAT and GST activities and also a meaningful decrease (p < 0.05) in TAC value. Briefly, CPF may exhibit toxic effects in earthworms in the fresh and expired forms via changing oxidative balance and modifying some biochemical markers in the whole body. Further unraveling is needed to elucidate CPF-related impairments in soil organisms.

DNA Damage and Expression Profile of Genes Associated with Nephrotoxicity Induced by Butralin and Ameliorating Effect of Arabic Gum in Female Rats

Nephrotoxicity induced by exposure to environmental pollution, including herbicides, is becoming a global problem. Natural products are the prime alternative scientific research as they express better medicinal activity and minor side effects compared with a variety of synthetic drugs. This study was performed to evaluate the nephroprotective proficiency of Arabic gum against butralin-induced nephrotoxicity. Adult female rats were supplemented with Arabic gum (4.3 g/kg b.wt) and/or butralin (312 mg/L) in drinking water for 30 days. The results found that markers of serum kidney function, oxidative stress biomarkers, DNA damage, and expression of kidney specific genes (Acsm2, Ace, and Ace2) as well as histopathological examination in treated rats were conducted. Butralin-treated rats showed a rise in serum creatinine (41%), BUN (47.3%), and MDA (140.9%) as well as decrease in activity of the antioxidant markers (CAT (-21%); GPx (-70.7%); and TAC (43.2%)) in comparison with the control group. In addition, butralin treatment increased the DNA damage (221%); altered the expression levels of Acsm2, Ace, and Ace2 (-51.6%, 141.6%, and 143% respectively); and elevated histopathological lesions in the kidney tissues. Pretreatment of Arabic gum prevented butralin-prompted degenerative changes of kidney tissues. The results suggested that the protective effect provided by Arabic gum on renal tissues exposed to the herbicide butralin could be attributed to enhancement of antioxidants and increase the free radical scavenging activity in vivo.

Ameliorative effect of Fennel (Foeniculum vulgare) essential oil on chlorpyrifos toxicity in Cyprinus carpio

Chlorpyrifos (CPF) is an organophosphate pesticide that is frequently and widely used to control both agricultural and domestic pests worldwide. In this study, the protective effect of Fennel (Foeniculum vulgare) essential oil (FEO) was investigated in carp (Cyprinus carpio) exposed to CPF. The fish were divided into six groups that one control group (no treatment) and five experimental groups (FEO (3ml/100g diet) group, CPF₁ (0.023 mg/l) group CPF₂ (0.046 mg/l) group, CPF₁ (0.023 mg/l) plus FEO (3ml/100g diet) group, CPF₂ (0.046 mg/l) plus FEO (3ml/100g diet) group). Blood and tissue (liver, kidney, gill, and brain) samples were taken from the fish at the end of 14 days of application. Hemoglobin (Hb) level, nitoblue tetrazolium (NBT) activity, and total immunoglobulin (TI) level were measured in blood samples of fish. Acetylcholinesterase (AChE) activity was determined in brain tissue while malondialdehyde (MDA) level, reduced glutathione (GSH) level, catalase (CAT), and glutathione peroxidase (GPx) activity were determined in liver, kidney, and gill tissues. The results showed that there was a significant decrease in Hb level, NBT activity, and TI levels in CPF-treated fish compared to the control group. In addition, increased in MDA levels and significant decreases in GSH level, AChE, CAT, and GPx activities were observed in CPF-treated groups. However, FEO-treated was showed a significant improvement in all parameters except AChE activity compared to CPF groups. These study findings showed that FEO could improve CPF-induced toxicity in C. carpio, except inhibition of AChE activity.

Morpho-Functional Alterations in the Gills of a Seawater Teleost, the Ornate Wrasse (Thalassoma pavo L.), after Short-Term Exposure to Chlorpyrifos

Chlorpyrifos (CPF) is an organophosphorus insecticide commonly used for domestic and agricultural purposes. The risk posed by environmental contamination from CPF is well acknowledged, and it has been detected worldwide in aquatic habitats and coastal areas. In addition, due to its slower degradation in seawater compared to freshwater, CPF is of particular concern for marine environments. Here, we investigated for the first time the morpho-functional alterations induced by CPF on the gills of Thalassoma pavo, a widespread species in the Mediterranean Sea. We tested the effects of two sublethal concentrations (4 and 8 µg/L) after 48 and 96 h. Our study demonstrates that the alterations induced by CPF are dose and time-dependent and highlight the harmful properties of this insecticide. After exposure to the low tested concentration, the more frequent alteration is an intense proliferation of the primary epithelium, whereas after exposure to the high concentration, the primary epithelium proliferation is less extensive, and the most evident effects are the thinning of secondary lamellae and the ectopia of chloride and goblet cells. CPF also modulated the expression of Na⁺/K⁺-ATPase. Dilation of lamellar apical tips, pillar cell degeneration, and appearance of aneurysms are often observed.

Acute exposure to the fungicide penconazole affects some biochemical parameters in the crayfish (Astacus leptodactylus Eschscholtz, 1823)

Penconazole is one of the most widely used fungicides all over the world, and since it spreads to large environments, its toxic effects on non-target organisms are of great concern. The toxic effects of penconazole on crayfish (Astacus leptodactylus), which is a bioindicator in freshwater ecosystems and consumed economically, are not known. Therefore, in this study, the purpose was to contribute to the literature on the potential harmful effects of penconazole on a non-target species, Astacus leptodactylus. For this aim, the acute toxicity (96 h) of penconazole was examined. The 96-h LC₅₀ value of penconazole was detected as 18.7 mg L^-1. Four concentrations of penconazole (18.7 mg L^-1, 9.35 mg L^-1, 4.68 mg L^-1, 2.34 mg L^-1) were applied to crayfish for 96 h. The results showed that penconazole had destructive effects on esterase mechanisms by inhibiting acetylcholinesterase (AChE) and carboxylesterase (CaE) activities. Significant increases were observed in all antioxidant parameters (superoxide dismutase (SOD), glutathione peroxidase (GPx), glutathione reductase (GR), glutathione S-transferase (GST), reduced glutathione (GSH), malondialdehyde (MDA)) in all doses except the lowest concentration (2.34 mg L^-1). All adenosine triphosphatase (ATPase) activities (Na⁺/K⁺-ATPase, Mg²⁺-ATPase, Ca²⁺-ATPase, total ATPase) had significant dose-related inhibition in both gill and muscle tissues. In summary, our findings show that acute penconazole administration to crayfish causes significant toxic effects on esterase, antioxidative parameters, and metabolic enzymes.

Biochemical responses of a freshwater fish Cirrhinus mrigala exposed to tris(2-chloroethyl) phosphate (TCEP)

Freshwater fish Cirrhinus mrigala were exposed to tris(2-chloroethyl) phosphate (TCEP) with three different concentrations (0.04, 0.2, and 1 mg/L) for a period of 21 days. During the study period, thyroid-stimulating hormone (TSH), triiodothyronine (T3), and thyroxine (T4) levels were significantly (p < 0.05) inhibited. The superoxide dismutase (SOD), catalase (CAT), glutathione S-transferase (GST), and lipid peroxidation (LPO) levels were increased significantly (p < 0.05) in gills, liver, and kidney tissues, whereas glutathione (GSH) and glutathione peroxidase (GPx) (except liver tissue) activities were inhibited when compared to the control group. Likewise, exposure to TCEP significantly (p < 0.05) altered the biochemical (glucose and protein) and electrolyte (sodium, potassium, and chloride) levels of fish. Light microscopic studies exhibited series of histopathological anomalies in the gills, liver, and kidney tissues. The present study reveals that TCEP at tested concentrations causes adverse effects on fish and the studied biomarkers could be used for monitoring the ecotoxicity of organophosphate esters (OPEs).

Heavy metals, parasitologic and oxidative stress biomarker investigations in Heterotis niloticus from Lekki Lagoon, Lagos, Nigeria

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Occurrence of parasites in fish could bio accumulate heavy metals by as much as 200 % more than values present in fish tissues.

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Parasitic infection in fish is positively skewed towards male fish.

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Parasitism in fish alters histological structures of vital fish organs.

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Combined effects of parasitism and heavy metal pollution in fish elicits antioxidant response in fish.

Heavy metal toxicity in aquatic life as a result of human activities poses a grave health threat to water quality, aquatic and human life. Parasites may serve as indicators of heavy metal pollution. This research investigated the health status of the fish Heterotis niloticus viz-a-viz quality of the water and sediments in Lekki lagoon, parasitic infection, presence of heavy metals and oxidative stress response in the liver and intestine of the fish. Parasites recovered were also analyzed for the extent of bioaccumulation of heavy metals. The metals in water, sediments, parasites, and fish were analyzed using Atomic Absorption Spectrometry. Heavy metal concentrations in the surface water were generally below regulatory limits of World Health Organization. Sediment had high levels of aluminium (124.78 mg/kg) and iron (327.41 mg/kg); other heavy metals were below regulatory limits. Tenuisentis niloticus, an acanthocephalan, was the only parasite recovered. Seventy (70) out of 100 fish sampled were infected with the parasite. T. niloticus bioaccumulated Cd, Ni, and Pb between 65 to 100 times more than the liver and 12 to 200 times more than the intestine. Other metals bioaccumulated from the host tissues by the parasite had the magnitude between 1 to 12 times as the liver and 1 to 30 times as the intestine. There were significant differences in the activities of antioxidant enzymes between the parasitized and non-parasitized fishes. Fish tissues also showed histological alterations, ranging from mild infiltration of inflammatory cells to moderate inflammation and haemorrhagic lesions. Human activities that introduce stressors into the lagoon should be controlled.