Sub-lethal toxicity of chlorpyrifos alone and in combination with polyethylene glycol to common carp (Cyprinus carpio)

The toxicity effects of imidacloprid and chlorpyrifos on oxidative stress and blood biochemistry in Cyprinus carpio

This study aimed to assess the toxicity effects of chlorpyrifos and imidacloprid, alone and in combination, on oxidative biomarkers and blood biochemistry of Cyprinus carpio. A total of 324 common carp (Cyprinus carpio) were distributed among 27 tanks and exposed to concentrations of 0.0, 100, and 200 μg L-1 of chlorpyrifos and 0.0, 10.0, and 20.0 μg L-1 of imidacloprid for 28 days. Changes in enzyme activities in the plasma of fish exposed to chlorpyrifos depended on the dose. In contrast, aspartate aminotransferase (AST), alanine aminotransferase (ALT), alkaline phosphatase (ALP), lactate dehydrogenase (LDH), creatine phosphokinase (CPK), gamma-glutamyl transferase (GGT) activities were significantly increased in fish exposed to imidacloprid, alone and in combination with chlorpyrifos. However, the activity of butyrylcholinesterase (BChE) was significantly decreased. Exposure to imidacloprid and chlorpyrifos, alone and in combination, increased glucose, urea, cholesterol, triglycerides, and creatinine levels, whereas total protein and albumin levels were significantly decreased. The activity of superoxide dismutase (SOD), glutathione peroxidase (GPx), glutathione S-transferase (GST), and catalase (CAT) was significantly increased, while glutathione reductase (GR) was significantly decreased. Additionally, although the total antioxidant capacity (TAN) was significantly decreased, malondialdehyde (MDA) levels increased after exposure to imidacloprid and chlorpyrifos, alone and in combination. In conclusion, exposure to imidacloprid and chlorpyrifos, alone and in combination, induced oxidative stress and altered blood biochemistry in carp fish. Moreover, imidacloprid and chlorpyrifos had synergistic effects on some oxidative and biochemical biomarkers.

Risk Assessment of Fenpropathrin: Cause Hepatotoxicity and Nephrotoxicity in Common Carp (Cyprinus carpio L.)

The synthetic pyrethroid pesticide fenpropathrin (FEN) is extensively used worldwide and has frequently been detected in biota and the environment, whilst the negative effects and toxicological mechanisms of FEN on non-target organisms are still unknown. In the present study, healthy immature common carp were treated with FEN (0.45 and 1.35 μg/L) for a duration of 14 days, and the negative impacts and possible mechanisms of FEN on fish were investigated. Biochemical analyses results showed that FEN exposure altered the levels of glucose (GLU), total cholesterol (T-CHO), triglyceride (TG), albumin (ALB), alkaline phosphatase (ALP), alanine transaminase (ALT), and aspartate transaminase (AST) in carp serum, and caused histological injury of the liver and kidney, indicating that FEN may cause hepatotoxicity and nephrotoxicity in carp. In addition, FEN also altered the activities of superoxide dismutase (SOD) and catalase (CAT) in carp serum, upregulated the levels of reactive oxygen species (ROS), and elevated the levels of malondialdehyde (MDA) in the liver and kidney. Meanwhile, tumor necrosis factor-α (TNF-α) and interleukin-1β (IL-1β) levels were also upregulated, indicating that oxidative stress and inflammatory reaction may be involved in the hepatotoxicity and nephrotoxicity caused by FEN. Furthermore, RNA-seq analysis results revealed that FEN treatment induced a diverse array of transcriptional changes in the liver and kidney and downregulated differentially expressed genes (DEGs) were concentrated in multiple pathways, especially cell cycle and DNA replication, suggesting that FEN may induce cell cycle arrest of hepatocytes and renal cells, subsequently inducing hepatotoxicity and nephrotoxicity. Overall, the present study enhances our comprehension of the toxic effects of FEN and provides empirical evidence to support the risk assessment of FEN for non-target organisms.

Non-lethal biomarkers as promising tools for fish health assessment: In situ exposure to bifenthrin as a case study

Non-lethal biomonitoring should provide an innovative approach to establish bioethical protocols for the management of both aquaculture and wild fisheries resources. We aimed to assess non-lethal biomarkers in Piaractus mesopotamicus caged in a rice field during a bifenthrin (BF) application. We analyzed parameters related to the immune system, energy metabolism and oxidative stress in fish skin mucus and blood plasma. Fish exposed to BF showed a significant increase in skin mucus glucose levels and the enzymatic activities of protease, alkaline phosphatase and superoxide dismutase. Regarding plasmatic parameters, BF increased the levels of glucose, total protein and albumin, but decreased triglycerides. In addition, increased activities of lysozyme and alkaline phosphatase were found in the blood plasma of exposed fish. Our results indicated an increased energy demand, altered immune function and a mild oxidative stress response in fish exposed in situ to BF. We have shown that skin mucus and blood plasma are very promising matrices for the development of non-lethal biomarkers to assess fish health in a stressed environment.

Ecological impacts and management strategies of pesticide pollution on aquatic life and human beings

Pesticide contamination has become a global concern. Pesticides can sorb onto suspended particles and deposit into the sedimentary layers of aquatic environments, resulting in ecosystem degradation, pollution, and diseases. Pesticides impact the behavior of aquatic environments by contaminating organic matter in water, which serves as the primary food source for aquatic food webs. Pesticide residues can increase ammonium, nitrite, nitrate, and sulfate in aquatic systems; thus, threatening ecological environment and human health. Several physical, chemical, and biological methodologies have been implemented to effectively remove pesticide traces from aquatic environments. The present review highlights the potential consequences of pesticide exposure on fish and humans, focusing on the (epi)genetic alterations affecting growth, behavior, and immune system. Mitigation strategies (e.g., bioremediation) to prevent/minimize the detrimental impacts of pesticides are also discussed. This review aims to shed light on the awareness in reducing the risk of water pollution for safe and sustainable pesticide management.

Toxicity of water-soluble polymers polyethylene glycol and polyvinyl alcohol for fish and frog embryos

Personal Care Products (PCPs) have been one of the most studied chemicals in the last twenty years since they were identified as pseudo-persistent pollutants by the European Union in the early 2000s. The accumulation of PCPs in the aquatic environment and their effects on non-target species make it necessary to find new, less harmful, substances. Polyethylene glycol (PEGs) and polyvinyl alcohol (PVAs) are two polymers that have increased their presence in the composition of PCPs in recent years, but little is known about the effect of their accumulation in the environment on non-target species. Through embryotoxicity tests on two common models of aquatic organisms (Danio rerio and Xenopus laevis), this work aims to increase the knowledge of PEGs and PVAs' effects on non-target species. Animals were exposed to the pollutant for 96 h. The main embryotoxicity endpoint (mortality, hatching, malformations, heartbeat rate) was recorded every 24 h. The most significant results were hatching delay in Danio rerio exposed to both chemicals, in malformations (oedema, body malformations, changes in pigmentation and deformations of spine and tail) in D. rerio and X. laevis and significant change in the heartbeat rate (decrease or increase in the rate) in both animals for all chemicals tested.

Toxic effects of aniline in liver, gills and kidney of freshwater fish Channa punctatus after acute exposure

Aniline (C6H5NH2) is one of the hazardous aromatic amine where an amino group -NH2) is connected to phenyl ring (C6H5). Based on the evaluation of the 96-hour LC50 of aniline, two sublethal concentrations (4.19 mg/l and 8.39 mg/l) were selected for acute exposure tests in freshwater fish Channa punctatus. The liver, gills and kidney of fish being the principal sites of xenobiotic material accumulation, respiration, biotransformation, and excretion are the focus of the present study. Throughout the exposure time, the comet assay revealed increased tail length and tail DNA percentage indicating maximum damage to liver, gills and kidney of treated group after 96 h. After acute exposure, there was a significant (p ≤ 0.05) increase in the enzymatic activity of glutathione-S-transferase (GST) and acetylcholinesterase (AChE), whereas decline in superoxide dismutase (SOD) and catalase (CAT) activity was observed. Meanwhile, levels of malondialdehyde (MDA) increased over the exposure period for both concentrations. After 96 h of exposure, degree of tissue change (DTC) was evaluated in liver, gill and kidney of aniline exposed fish. Additionally, light microscopy revealed multiple abnormalities in liver, gills and kidney of all the treated groups. Significant changes were observed in the levels of biochemical markers viz., glucose, triglyceride, cholesterol, aspartate transaminase, alanine transaminase and urea following a 96-hour exposure to aniline. Studies using ATR-FTIR and transmission electron microscopy (TEM) revealed changes in biomolecules and structural abnormalities in several tissues of the aniline-exposed groups in comparison to the control group respectively.

Combined effects of polyethylene terephthalate and abamectin on enzymatic activity and histopathology response in juvenile zebrafish (Danio rerio)

One of the most pressing global environmental issues is the widespread abundance and distribution of microplastics (MPs). MPs can act as vectors for other contaminants in the environment making these small plastic particles hazardous for ecosystems. The presence of MPs in aquatic environments may pose threats to aquatic organisms that ingest them. This study examined effects of abamectin (ABM) and polyethylene terephthalate (PET) MP fragments on histopathological and enzymatic biomarkers in zebrafish (Danio rerio). Zebrafish were exposed for 96 h to pristine PET-MPs at concentrations of 5 mg/L and 10 mg/L, ABM alone at 0.006 mg/L, and the same concentration of ABM in the presence of PET-MPs in aquaria. Histopathological analysis revealed tissue content changes in liver and kidney in the presence of ABM individually and in combination with MPs. Results of enzymatic analysis showed that MPs increased the bioavailability and toxicity of pesticides due to inhibition of catalase (CAT) and acid phosphatase (ACP) enzymes. However, MPs did not affect the toxicity of ABM for glutathione s-transferase (GST) enzyme. Despite the inhibition of acetylcholinesterase (AChE) in MPs or ABM treatments, and some neurotoxicity, no change in activity of this enzyme and neurotoxicity was observed in the combined MPs and ABM treatments, although toxicity effects of MPs and ABM on zebrafish require more detailed studies.

From Personal Care to Coastal Concerns: Investigating Polyethylene Glycol Impact on Mussel's Antioxidant, Physiological, and Cellular Responses

Pharmaceutical and personal care products (PPCPs) containing persistent and potentially hazardous substances have garnered attention for their ubiquitous presence in natural environments. This study investigated the impact of polyethylene glycol (PEG), a common PPCP component, on Mytilus galloprovincialis. Mussels were subjected to two PEG concentrations (E1: 0.1 mg/L and E2: 10 mg/L) over 14 days. Oxidative stress markers in both gills and digestive glands were evaluated; cytotoxicity assays were performed on haemolymph and digestive gland cells. Additionally, cell volume regulation (RVD assay) was investigated to assess physiological PEG-induced alterations. In the gills, PEG reduced superoxide dismutase (SOD) activity and increased lipid peroxidation (LPO) at E1. In the digestive gland, only LPO was influenced, while SOD activity and oxidatively modified proteins (OMPs) were unaltered. A significant decrease in cell viability was observed, particularly at E2. Additionally, the RVD assay revealed disruptions in the cells subjected to E2. These findings underscore the effects of PEG exposure on M. galloprovincialis. They are open to further investigations to clarify the environmental implications of PPCPs and the possibility of exploring safer alternatives.

Effects of Environmental Hypoxia on Serum Hematological and Biochemical Parameters, Hypoxia-Inducible Factor (hif) Gene Expression and HIF Pathway in Hybrid Sturgeon (Acipenser schrenckii ♂ × Acipenser baerii ♀)

Hypoxia is a globally pressing environmental problem in aquatic ecosystems. In the present study, a comprehensive analysis was performed to evaluate the effects of hypoxia on physiological responses (hematology, cortisol, biochemistry, hif gene expression and the HIF pathway) of hybrid sturgeons (Acipenser schrenckii ♂ × Acipenser baerii ♀). A total of 180 hybrid sturgeon adults were exposed to dissolved oxygen (DO) levels of 7.00 ± 0.2 mg/L (control, N), 3.5 ± 0.2 mg/L (moderate hypoxia, MH) or 1.00 ± 0.1 mg/L (severe hypoxia, SH) and were sampled at 1 h, 6 h and 24 h after hypoxia. The results showed that the red blood cell (RBC) counts and the hemoglobin (HGB) concentration were significantly increased 6 h and 24 h after hypoxia in the SH group. The serum cortisol concentrations gradually increased with the decrease in the DO levels. Moreover, several serum biochemical parameters (AST, AKP, HBDB, LDH, GLU, TP and T-Bil) were significantly altered at 24 h in the SH group. The HIFs are transcription activators that function as master regulators in hypoxia. In this study, a complete set of six hif genes were identified and characterized in hybrid sturgeon for the first time. After hypoxia, five out of six sturgeon hif genes were significantly differentially expressed in gills, especially hif-1α and hif-3α, with more than 20-fold changes, suggesting their important roles in adaptation to hypoxia in hybrid sturgeon. A meta-analysis indicated that the HIF pathway, a major pathway for adaptation to hypoxic environments, was activated in the liver of the hybrid sturgeon 24 h after the hypoxia challenge. Our study demonstrated that hypoxia, particularly severe hypoxia (1.00 ± 0.1 mg/L), could cause considerable stress for the hybrid sturgeon. These results shed light on their adaptive mechanisms and potential biomarkers for hypoxia tolerance, aiding in aquaculture and conservation efforts.

Chlorella vulgaris algae ameliorates chlorpyrifos toxicity in Nile tilapia with special reference to antioxidant enzymes and Streptococcus agalactiae infection

BACKGROUND

Chlorpyrifos (CPF) is a widely used pesticide in the production of plant crops. Despite rapid CPF biodegradation, fish were exposed to wastewater containing detectable residues. Recently, medicinal plants and algae were intensively used in aquaculture to replace antibiotics and ameliorate stress impacts.

METHODS AND RESULTS

An indoor experiment was conducted to evaluate the deleterious impacts of CPF pollution on Nile tilapia health and the potential mitigation role of Chlorella vulgaris algae. Firstly, the median lethal concentration LC50 - 72 h of CPF was determined to be 85.8 µg /L in Nile tilapia (35.6 ± 0.5 g body weight) at a water temperature of 27.5 °C. Secondly, fish were exposed to 10% of LC50 - 72 h for six weeks, and tissue samples were collected and examined every two weeks. Also, Nile tilapia were experimentally infected with Streptococcus agalactiae. Exposed fish were immunosuppressed expressed with a decrease in gene expressions of interleukin (IL) 1β, IL-10, and tumor necrosis factor (TNF)-α. Also, a decline was recorded in glutathione peroxidase (GPx), superoxide dismutase (SOD), and catalase (CAT) gene expression in the head kidney tissue. A high mortality rate (MR) of 100% was recorded in fish exposed to CPF for six weeks and challenged with S. agalactiae. Fish that received dietary C. vulgaris could restore gene expression cytokines and antioxidants compared to the control. After six weeks of CPF exposure, fish suffered from anemia as red blood cell count (RBCs), hemoglobin (Hb), and packed cell volume (PCV) significantly declined along with downregulation of serum total protein (TP), globulin (GLO), and albumin (ALB). Liver enzymes were significantly upregulated in fish exposed to CPF pollution, alanine aminotransferase (ALT) (42.5, 53.3, and 61.7 IU/L) and aspartate aminotransferase (AST) (30.1, 31.2, and 22.8) after 2, 4, and 6 weeks, respectively. On S. agalactiae challenge, high MR was recorded in Nile tilapia exposed to CPF (G3) 60%, 60%, and 100% in week 2, week 4, and week 6, and C. vulgaris provided a relative protection level (RPL) of 0, 14.29, and 20%, respectively.

CONCLUSIONS

It was concluded that CPF pollution induces immunosuppressed status, oxidative stress, and anemic signs in Nile tilapia. In contrast, C. vulgaris at a 50 g/kg fish feed dose could partially ameliorate such withdrawals, restoring normal physiological parameters.

Unveiling the multilevel impact of four water-soluble polymers on Daphnia magna: From proteome to behaviour (a case study)

The ubiquitous presence of water-soluble polymers (WSPs) in freshwater environments raises concerns regarding potential threats to aquatic organisms. This study investigated, for the first time, the effects of widely used WSPs -polyvinyl alcohol (PVA), polyvinylpyrrolidone (PVP), polyacrylic acid (PAA), and polyethylene glycol (PEG)- using a multi-level approach in the freshwater biological model Daphnia magna. This integrated assessment employed a suite of biomarkers, evaluation of swimming behaviour, and proteomic analysis to investigate the effects of three environmentally relevant concentrations (0.001, 0.5, and 1 mg/L) of the tested WSPs from molecular to organismal levels, assessing both acute and chronic effects. Our findings reveal that exposure to different WSPs induces specific responses at each biological level, with PEG being the only WSP inducing lethal effects at 0.5 mg/L. At the physiological level, although all WSPs impacted both swimming performance and heart rate of D. magna specimens, PAA exhibited the greatest effects on the measured behavioural parameters. Furthermore, proteomic analyses demonstrated altered protein profiles following exposure to all WSPs, with PVA emerging as the most effective.

Mitigation of haemato-genotoxic and stress response effects in Cyprinus carpio via silymarin dietary supplementation following deltamethrin exposure

The study examined the potential of Silymarin, a blend of bioactive flavonolignans extracted from the milk thistle Silybum marianum, to mitigate Deltamethrin-induced toxicity in the blood of Cyprinus carpio. Fish were exposed to Deltamethrin (0.66 μg/L), the plant extract, or a combination of both for a duration of thirty days. Various parameters, including serum biochemical markers, erythrocytic abnormalities, and genotoxicity endpoints, were assessed. Results indicated a significant (p < 0.05) increase in the levels of AST, ALT, ALP, blood urea nitrogen, creatinine, glucose, cholesterol, and TLC in the fish exposed to the pesticide. Conversely, total protein, TEC, and Hb showed a notable decrease. There was also a notable rise in micronuclei and erythrocytic abnormalities such as acanthocytes, microcytes, and notched cells. Under ultrastructural examination, phenotypic deformities like spherocytosis, discocytes, and clumped erythrocytes were observed. However, dietary supplementation of silymarin (1 g/kg) significantly restored the biochemical, genetic, and cellular parameters, resembling those of the control group. This suggests the potential of this plant extract in protecting the common carp, Cyprinus carpio, from Deltamethrin-induced damage by scavenging free radicals and reducing DNA oxidative stress.

To be or not to be plastics? Protein modulation and biochemical effects in zebrafish embryos exposed to three water-soluble polymers

Water-soluble polymers (WSPs) are a particular category of polymers that, due to their capability to be soluble in water, come out of the classic definition of plastic and therefore also from its regulation and control, representing a possible new environmental problem considering the number of consumer products in which they are contained. For this reason, the aim of this study was to evaluate the possible adverse effects of three of the most used WSPs (polyacrylic acid - PAA, polyethylene glycol - PEG, polyvinylpyrrolidone - PVP), administered at relevant environmental concentrations (0.001, 0.5 and 1 mg/L) to Danio rerio (zebrafish) embryos up to 120 h post fertilization. To assess the WSP toxicity at the molecular, cellular and organism level we used an integrated ecotoxicological approach of both biomarkers and high-throughput technology based on gel-free proteomics. The main results showed how all the three WSPs up-regulated many proteins (up to 74 in specimens exposed to 1 mg/L PVP) with a wide range of molecular functions and involved in numerous cellular pathways of exposed specimens. On the other hand, the measurement of biomarkers showed how PAA and PVP were able to activate the antioxidant machinery following an over-production of reactive oxygen species, while PEG produced no significant changes in the biomarkers measured. Based on the obtained results, the use and application of WSPs should be revised and regulated.

Environmental impacts of chlorpyrifos: Transgenerational toxic effects on aquatic organisms cannot be ignored

Chlorpyrifos (CPF) has been extensively used in the world and frequently found in natural environments, might cause a range of environmental issues and pose a health risk to aquatic species. However, investigation of its toxic effects on offspring after parental exposure has been neglected, especially for aquatic organisms such as fish. In the current study, the effects of chronic CPF exposure (3 and 60 μg/L) on adult zebrafish (F0) was investigated to determine its influence on adult reproductive capacity and offspring (F1 and F2). The results showed the existence of CPF both in F0 ovaries and F1 embryos and larvae, indicating that CPF could be transferred directly from the F0 adult fish to F1 offspring. After 90 d exposure, we observed that F0 female fish showed increased proportion of perinucleolar oocyte in the ovaries, decreased proportion of mature oocyte, and decreased egg production, but not in F1 adult. The transcriptomic analysis revealed that the disruption of metabolism during oocyte maturation in the CPF treatment zebrafish might interfere with F0 oocytes development and quality and ultimately influence offspring survival. For the larvae, the parental CPF exposure distinctly inhibited heart rate at 72 and 120 hpf and increased the mortality of F1 but not F2 larvae. The changes of biochemical indicators confirmed a disturbance in the oxidative balance, induced inflammatory reaction and apoptosis in F1 larvae. Furthermore, the changing profiles of mRNA revealed by RNA-seq confirmed an increased susceptibility in F1 larvae and figured out potential disruptions of ROS metabolism, immune system, apoptosis, and metabolism pathways. Taken together, these results show that chronic CPF treatment can induce reproductive toxicity, and parental transfer of CPF occurs in fish, resulting in transgenerational alters in F1 generation survival and transcription that raising concerns on the ecological risk of CPF in the natural environment.

Effect of different slaughter/stunning methods on stress response, quality indicators and susceptibility to oxidation of large yellow croaker (Larimichthys crocea)

This study aimed to investigate the effects of different slaughter methods (immersion in ice/water slurry, T1; gill cut, T2; CO2 asphyxia, T3; percussion (hit on the head with a stick), T4; Melissa officinalis L. essential oil + CO2, T5) on physiological stress, oxidative stress, and muscle quality in large yellow croaker. In terms of physiological stress, the levels of glucose (GLU), lactate dehydrogenase (LDH), and catalase (CAT) in CO2 asphyxia samples were significantly lower than those in other samples (p < 0.05). The level of cortisol (COR) in T1 sample was 1.25-1.84 times higher than that of other samples. The GLU level of T1 group was 3.2 times higher than that of T3 sample, and significantly higher than that of other samples. The creatine phosphokinase (CPK) and CAT levels of T2 samples were the highest (2.03 ng/mL and 8.34 U/mL, respectively). Furthermore, the superoxide dismutase (SOD) and glutathione peroxidase (GPx) analysis revealed that T3 and T4 samples could maintain good antioxidant enzyme activity during cold storage. The T3 samples maintained the stability of the protein (the lowest carbonyls and surface hydrophobicity) and reduced lipid oxidation (lower TBARS). In addition, the analysis of pH and water-holding capacity (WHC) revealed that T3 samples had better muscle quality. The muscle of T2 samples kept better color due to bloodletting treatment. The samples obtained after addition of Melissa officinalis L. essential oil had poorer indexes in all aspects compared to the T3 samples, which might be caused by the long anesthesia time of the essential oil.

Dose-dependent stress response of esfenvalerate insecticide on common carp (Cyprinus carpio): Evaluating blood parameters and gene expression

Esfenvalerate is a pyrethroid insecticide used primarily in the agriculture sector for insect management. Esfenvalerate is effective against a wide range of harmful insects, including flies, cockroaches, locusts, and many other types of bugs. It is also known that esfenvalerate has toxic effects on aquatic organisms and poses significant environmental concerns. In this study, the aim is to subchronically examine the effects of sublethal concentrations of esfenvalerate insecticide on common carp (Cyprinus carpio) by assessing changes in blood parameters and resulting gene expression. For this purpose, common carp (Cyprinus carpio) were divided into 5 groups and exposed to 0.025, 0.05, 0.1, and 0.15 μg/L concentrations of esfenvalerate for a period of 14 days. Blood and liver tissue samples were collected from the fish that underwent weight and length measurements. The effects on gene expression levels of immune, antioxidant, and stress-related genes in the liver tissue, including SOD, GST, Cortisol receptor, HSP70, H+-ATPase, Na+/K+-ATPase, Catalase, and GpX, were evaluated, as were the hematological and serum biochemical parameters. Significant decreases were observed in the levels of hematocrit, hemoglobin, erythrocytes, triglycerides and total protein and catalase, H+-ATPase, and GpX gene expression. Glucose, cholesterol, alanine aminotransferase, aspartate aminotransferase, lactate dehydrogenase (LDH) and alkaline phosphatase (ALP), SOD, Cortisol receptor, Na+/K+-ATPase gene expression levels increased. As a result, it has been revealed that esfenvalerate insecticide causes oxidative stress in carp at all dose ranges.

Investigations of hemato-biochemical and histopathological parameters, and growth performance of walking catfish (Clarias batrachus) exposed to PET and LDPE microplastics

Fish inhabiting various trophic levels are affected differently as the presence of microplastic (MP) in the water column and their ingestion by fish varies. Walking catfish (Clarias batrachus) inhabits the bottom of the water bodies. To understand the effects of MP, we exposed C. batrachus to two types of MP - polyethylene terephthalate (PET) and low-density polyethylene (LDPE) for 60 days. After exposure, hematological indices, mainly red blood cells and hemoglobin levels decreased, and white blood cells increased significantly compared to the control group (p < 0.05). A significant increase in the levels of blood urea and glucose was observed, and serum glutamic pyruvate transaminase and serum glutamyl oxaloacetic transaminase activity remained elevated (p < 0.05). Histopathological examination of the liver, kidney, intestine, and gills showed morphological alterations. Moreover, MP exposure caused growth retardation (p < 0.05) in C. batrachus. Widespread pollution of water bodies by MP may impose serious ecological risks to bottom-feeding fish in Bangladesh.

Single and Combined Effects of Chlorpyrifos and Glyphosate on the Brain of Common Carp: Based on Biochemical and Molecular Perspective

Chlorpyrifos (CPF) and glyphosate (GLY) are the most widely used organophosphate insecticide and herbicide worldwide, respectively; co-occurrence of CPF and GLY in aquatic environments occurs where they inevitably have potential hazards to fish. However, the potential mechanisms of CPF and GLY to induce toxicity have not been fully explored. To identify the adverse impacts of CPF and GLY on fish, either alone or in combination (MIX), CPF (25 μg/L) and GLY (3.5 mg/L) were set up according to an environmentally relevant concentration to expose to common carp for 21 days. After exposure, CPF and GLY decreased the activities of acetylcholinesterase and Na+/K+-ATPase, altered monoamine oxidase levels, decreased antioxidant enzyme activities (superoxide dismutase, catalase, glutathione S-transferase and glutamic reductase), and induced the accumulation of malondialdehyde in the carp brain. The parameters in the MIX groups had a greater impact compared to that in the CPF or GLY group, suggesting that both single and combined exposure could affect neurological signaling systems and cause oxidative stress and lipid peroxidation damage in carp brains, and that MIX exposure increases the impact of each pollutant. RNA-seq results showed that single or combined exposure to CPF and GLY induced global transcriptomic changes in fish brains, and the number of differentially expressed genes in MIX-treated carp brains were globally increased compared to either the CPF or GLY groups, suggesting that the effects of co-exposure were greater than single exposure. Further analysis results revealed that the global transcriptomic changes participated in oxidative stress, immune dysfunction, and apoptosis of fish brains, and identified that the P13k-Akt signaling pathway participates in both single and combined exposure of CPF- and GLY-induced toxicity. Taken together, our results demonstrated that the interaction of CPF and GLY might be synergic and provided novel insights into the molecular mechanisms of fish brains coping with CPF and GLY.

Effects of cadmium chloride and biofertilizer (Bacilar) on biochemical parameters of freshwater fish, Alburnus mossulensis

Fish in wild are often faced with various types of xenobiotics, that may display synergistic or antagonistic effects. In this study, we aim to examine how exposure to agrochemical compound (Bacilar) and cadmium (CdCl₂) alone and in combination affect biochemical parameters (lactate dehydrogenase, aspartate aminotransferase, alkaline phosphatase, gamma-glutamyl transferase, alanine aminotransferase; creatine phosphokinase (CKP), cholinesterase) and oxidative stress (total antioxidant capacity, catalase, malondialdehyde and protein carbonyl concentrations) of freshwater fish Alburnus mossulensis. Fish were exposed to two concentrations of Bacilar (0.3, and 0.6 mL L^-1) and to 1 mg L^-1 cadmium chloride alone and in combination for 21 days. Results showed that fish accumulate Cd in their body, with the highest rate in individuals exposed to Cd in combination with Bacilar. Both xenobiotics in fish liver induced the activation of liver enzymes suggesting hepatotoxic effects, with the greatest impact in co-exposed groups. A significant decrease in the hepatocyte's total antioxidant capacity indicates the collapse of the antioxidant defense in fish exposed to Cd and Bacilar. A decrease in the antioxidant biomarkers was followed by increased oxidative damage of lipids and proteins. We also reported altered function in the muscle of individuals exposed to Bacilar and Cd seen as decreased activities in CKP and butyrylcholinesterase. Overall, our results point to the toxicity of both Bacilar and Cd on fish but also to their synergistic effects on Cd bioaccumulation, oxidative stress, and liver and muscle damage. This study highlights the need for evaluating the use of agrochemicals and their possible additive effects on non-target organisms.

Environmentally relevant concentrations of butyl benzyl phthalate triggered oxidative stress and apoptosis in adult zebrafish (Danio rerio) liver: Combined analysis at physiological and molecular levels

Butyl benzyl phthalate (BBP), a typical phthalate plasticizer, is frequently detected in aquatic environments, but its possible effects on fish liver are unknown. In this study, adult zebrafish were exposed to 5-500 μg/L BBP and cultured for 28 days. The toxicity mechanism of environmentally relevant concentrations of BBP in the liver was explored using integrated biomarker response (IBR), molecular docking, and histopathological analysis, based on the tests of oxidative stress, apoptosis, and tissue damage, respectively. The results revealed that exposure to 500 μg/L BBP caused lipid peroxidation and DNA damage and induced inflammatory responses in the liver and intestinal tissues. The accumulation of reactive oxygen species (ROS) is the primary manifestation of BBP toxicity and is accompanied by changes in the activities of antioxidant and detoxification enzymes. Notably, the pro-apoptotic genes (p53 and caspase-3) were still significantly upregulated in the 50 μg/L and 500 μg/L treatment groups on day 28. Moreover, BBP interfered with apoptosis by forming a stable complex with apoptosis proteins (P53 and Caspase-3). Our findings are helpful for understanding the toxicity mechanisms of BBP, which could further promote the assessment of the potential environmental risks of BBP.

Polystyrene microparticles can affect the health status of freshwater fish - Threat of oral microplastics intake

Plastic waste pollution is considered one of the biggest problems facing our planet. The production and use of these materials has led to huge amounts of plastic waste entering the aquatic environment and affecting aquatic life. In our experiment, the effect of polystyrene microparticles (PS-MPs; 52.5 ± 11.5 μm) on individual juvenile rainbow trout (Oncorhynchus mykiss) was tested at three different dietary concentrations of 0.5, 2 and 5 % for six weeks. At the end of the experiment, various health parameters of exposed organisms were compared with the control group. The haematological profile revealed an immune response by a decrease in lymphocyte count with a concurrent increase in the number of neutrophil segments at the highest concentration of PS-MPs (5 %). Biochemical analysis showed significant reductions in plasma ammonia in all tested groups, which may be related to liver and gill damage, as determined by histopathological examination and analysis of inflammatory cytokines expression. In addition, liver damage can also cause a significant decrease in the plasma protein ceruloplasmin, which is synthesized in the liver. PS-MPs disrupted the antioxidant balance in the caudal kidney, gill and liver, with significant changes observed only at the highest concentration. In summary, PS-MPs negatively affect the health status of freshwater fish and represent a huge burden on aquatic ecosystems.

Biomarkers of imidacloprid toxicity in Japanese quail, Coturnix coturnix japonica

The in vivo effect of the oral sublethal doses of 3.014 mg kg^-1 of IMI (1/25 LD₅₀) for 1, 7, 14, and 28 days every other day on Japanese quail was investigated. The results revealed that certain biomarkers in the selected tissues of the quail such as acetylcholinesterase (AChE), butyrylcholinesterase (BuChE), aminotransaminases (alanine aminotransferase, ALT, and aspartate aminotransaminase, AST), phosphatases (acid phosphatase, ACP, and alkaline phosphatase, ALP), lactate dehydrogenase (LDH), adenosine-triphosphatase (ATPase), glutathione-S-transferase (GST), lipid peroxidation (LPO), and blood glucose showed significant inductions, while significant reductions in the levels of glutathione-reduced (GSH), deoxyribonucleic acid (DNA), and ribonucleic acid (RNA) were noticed. In this study, the molecular mechanisms of the toxic effects of imidacloprid on quails were elucidated regarding neurotoxicity, hepatotoxicity, oxidative stress, lipid peroxidation, antioxidant activity, and genotoxicity. Because IMI induced alterations in the levels of these biomarkers in Japanese quail; therefore, Japanese quail as a wild avian can be used as a suite bioindicator to detect imidacloprid toxicity.

Biochemical and histopathological responses in Nile tilapia exposed to a commercial insecticide mixture containing dinotefuran and lambda-cyhalothrin

The indiscriminate use of pesticides has led to an increased risk of environmental contamination and pest resistance worldwide, favoring the development of less hazardous formulations. The commercial insecticide ZEUS® (Ihara, Brazil) combining dinotefuran and lambda-cyhalothrin was recently formulated in order to meet the environmental sustainability and food security. However, little is known about the potential toxic effects of ZEUS® to aquatic species. Thus, we report, for the first time, the biochemical and histological responses in tilapia (Oreochromis niloticus) following 96 h exposure to 0.01 mg/L, 0.05 mg/L and 0.1 mg/L ZEUS®. Different biochemical endpoints, including acetylcholinesterase (AChE), gamma-glutamyltransferase (GGT) and alkaline phosphatase (ALP), were assessed as potential biomarkers of insecticide effects. Glutathione S-transferase (GST) was evaluated as a marker of phase II biotransformation, and histopathological changes were measured to indicate gill alterations following ZEUS® exposure. After 96 h exposure, ZEUS® treatment increased GST activity in the liver of fish exposed to the highest concentration, while the intermediate dose increased both renal GGT and hepatic ALP activities. These findings reflect the importance of the liver and kidneys in the detoxification of ZEUS® and highlight the need to understand further toxicity effects. Likewise, the histopathological analysis of gills provided evidence that ZEUS® caused moderate damages. Despite biomarkers alterations reported for O. niloticus following ZEUS® exposure, by comparing our findings with data on toxicity of individual compounds, the commercial ZEUS® mixture seems to present similar or even lower adverse effects on freshwater fish.

Dietary Arthrospira platensis in Rainbow Trout (Oncorhynchus mykiss): A Means to Reduce Threats Caused by CdCl2 Exposure?

The rainbow trout (Oncorhynchus mykiss) is one of the most commercially sought-after freshwater fish species and one of the most farmed in the world. On the other hand, aquaculture breeding frequently results in outbreaks of infectious diseases and pests, and compromises the production and welfare of fish. Arthrospira platensis (known as "Spirulina") has been used as a supplement in diets to enhance fish welfare in recent years because of its beneficial properties. This study aimed to assess the possible protective effects of Arthrospira platensis on rainbow trout specimens exposed to three different doses of the toxicant CdCl₂. The experiment was carried out using five experimental treatments of 40 individuals each: control group; group II (0.2 mg CdCl₂ per kg of commercial fish feed); group III (0.2 mg Kg^-1 of CdCl₂ plus 2.5 g per kg of A. platensis); group IV (0.2 mg Kg^-1 of CdCl₂ plus 5 g per kg of A. platensis); group V (0.2 mg Kg^-1 of CdCl₂ plus 10 g per kg of A. platensis). During the experiment, dietary supplementation of A. platensis normalized all serum and blood parameters altered by the presence of CdCl₂. A. platensis also had a protective effect on markers of oxidative stress.

Toxic effects of polyethylene microplastics on transcriptional changes, biochemical response, and oxidative stress in common carp (Cyprinus carpio)

Aquatic ecosystems have become a place for accumulating microplastics (MPs). MPs can directly or indirectly damage organisms. Although studies of the toxicity of MPs, there are insufficient literature reports on the effects of MPs on freshwater aquatic life. Therefore, this study aimed to evaluate the effect of MPs toxicity on Cyprinus carpio. In this study, biochemical parameters, oxidative biomarkers, and gene expression were assayed in fish exposed to 0, 175, 350, 700, and 1400 μg L^-1 of MPs for 30 days. MPs were detected in the liver and intestine of fish using FTIR-analysis. Mt1, Ces2, and P450 mRNA expression were enhanced in the hepatocytes of fish exposed to MPs, while Mt2 gene expression was significantly decreased. After exposure to MPs, MDA and carbonyl protein levels were higher than those of the reference group. The antioxidant capacity and glycogen contents in the hepatocytes significantly declined. MPs significantly inhibited glutathione reductase (GR), glucose 6-phosphate dehydrogenase (G6PDH), and catalase (CAT) activities. However, superoxide dismutase (SOD) and glutathione peroxidase (GPx) activities increased. MPs decreased the total protein, globulin levels, and butyrylcholinesterase (BChE) activity in blood. In contrast, aspartate aminotransferase (AST), alanine aminotransferase (ALT), gamma-glutamyl transferase (GGT), lactate dehydrogenase (LDH), alkaline phosphatase (ALP), and creatine phosphokinase (CPK) activities increased in treated-fish with MPs. Glucose, creatinine, cholesterol and triglyceride concentrations in fish exposed to MPs were significantly higher than that of the reference group. Consequently, MPs exposure could disrupt biochemical homeostasis, oxidative stress and alter the expression of genes involved in detoxification.

Blood biomarkers as diagnostic tools: An overview of climate-driven stress responses in fish

Global climate change due to anthropogenic activities affects the dynamics of aquatic communities by altering the adaptive capacities of their inhabitants. Analysis of blood provides valuable insights in the form of a comprehensive representation of the physiological and functional status of fish under various environmental and treatment conditions. This review synthesizes currently available information about blood biomarkers used in climate change induced stress responses in fish. Alterations in informative blood-based indicators are used to monitor the physiological fitness of individual fishes or entire populations. Specific characteristics of fish blood, such as serum and plasma metabolites, cell composition, cellular abnormalities, cellular and antioxidant enzymes necessitate adapted protocols, as well as careful attention to experimental designs and meticulous interpretation of patterns of data. Moreover, the sampling technique, transportation, type of culture system, acclimation procedure, and water quality must all be considered for valid interpretation of hemato-biochemical parameters. Besides, blood collection, handling, and storage time of blood samples can all have significant impacts on the results of a hematological analysis, so it is optimal to perform hemato-biochemical evaluations immediately after blood collection because long-term storage can alter the results of the analyses, at least in part as a result of storage-related degenerative changes that may occur. However, the scarcity of high-throughput sophisticated approaches makes fish blood examination studies promising for climate-driven stress responses in fish.

Chlorpyrifos stimulates ABCC-mediated transport in the intestine of the rainbow trout Oncorhynchus mykiss

The organophosphorus pesticide chlorpyrifos, detected in water and food worldwide, has also been found in the Río Negro and Neuquén Valley, North Patagonia, Argentina, where the rainbow trout, Oncorhynchus mykiss, is one of the most abundant fish species. We analyzed whether chlorpyrifos affects the transport activity of the ATP-binding cassette protein transporters from the subfamily C (ABCC), which are critical components of multixenobiotic resistance. We exposed ex vivo O. mykiss middle intestine strips (non-polarized) and segments (polarized) for one hour to 0 (solvent control), 3, 10, and 20 μg L^-1 and to 0, 10, and 20 μg L^-1 chlorpyrifos, respectively. We estimated the Abcc-mediated transport rate by measuring the transport rate of the specific Abcc substrate 2,4-dinitrophenyl-S-glutathione (DNP-SG). In addition, we measured the enzymatic activity of cholinesterase, carboxylesterase, glutathione-S-transferase, and 7-ethoxyresorufin-O-deethylase (EROD, indicative of the activity of cytochrome P450 monooxygenase 1A, CYP1A). We also measured lipid peroxidation using the thiobarbituric acid reactive substances method and the gene expression of Abcc2 and genes of the AhR pathway, AhR, ARNT, and cyp1a, by qRT-PCR. Chlorpyrifos induced the DNP-SG transport rate in middle intestine strips in a concentration-dependent manner (49-71%). In polarized preparations, the induction of the DNP-SG transport rate was observed only in everted segments exposed to 20 μg L^-1 chlorpyrifos (40%), indicating that CPF only stimulated the apical (luminal) transport flux. Exposure to chlorpyrifos increased GST activity by 42% in intestine strips and inhibited EROD activity (47.5%). In addition, chlorpyrifos exposure inhibited cholinesterase (34-55%) and carboxylesterase (33-42.5%) activities at all the concentrations assayed and increased TBARS levels in a concentration-dependent manner (71-123%). Exposure to 20 μgL^-1 chlorpyrifos did not affect the mRNA expression of the studied genes. The lack of inhibition of DNP-SG transport suggests that chlorpyrifos is not an Abcc substrate. Instead, CPF induces the activity of Abcc proteins in the apical membrane of enterocytes, likely through a post-translational pathway.

First biomonitoring of microplastic pollution in the Vaal river using Carp fish (Cyprinus carpio) "as a bio-indicator"

Fish inhabiting freshwater environments are susceptible to the ingestion of microplastics (MPs). Knowledge regarding MPs in freshwater fish in South Africa is very limited. In this study, the uptake of MPs by common carp (Cyprinus carpio) in the Vaal River in South Africa was assessed. MPs were detected in all of the twenty-six fish examined, 682 particles of MPs were recovered from the gastrointestinal tracts of the fish with an average of 26.23 ± 12.57 particles/fish, and an average abundance of 41.18 ± 52.81 particles/kg. The examination of the physical properties of MPs revealed a predominance on fibers (69%), small-sized particles of less than 0.5 mm (48%), as well as prevelance of coloured MPs (94%), mostly green, blue, and black. Using Raman Spectroscopy, the following plastic polymers were identified: high density polyethylene (HDPE), low density polyethylene (LDPE), polypropylene (PP), polyethylene terephthalate (PET), and polytetrafluoroethylene (PTFE). To the best of our knowledge, this study, is the first to report MPs uptake by freshwater biota in the Vaal River using common carp as a target organism. It provided evidence of MP contamination in the Vaal.

First record of microplastic occurence at the commercial fish from Orontes River

Freshwater environments are more sensitive to anthropogenic influences and usually contain higher concentrations of pollutants than marine environments. Microplastic pollution causes additional stress on freshwater animals; yet, studies evaluating the microplastic occurrence in freshwater biota are still limited. In this study, microplastic occurrence in the gastrointestinal tracts (GIT) and gill of commercial fish species (Prussian carp Carassius gibelio (Bloch, 1782); Abu mullet Planiliza abu (Heckel, 1843); Common carp Cyprinus carpio Linnaeus, 1758; European ell Anguilla Anguilla (Linnaeus, 1758); North African catfish Clarias gariepinus (Burchell, 1822); Goldfish Carassius auratus (Linnaeus, 1758) were reported from Orontes River. MPs abundance in the GIT and gill of six species were found as 5.1 ± 2 MPs fish^-1 and 4.4 ± 2 MPs fish^-1 with an occurrence of 95% and 74%, respectively. The majority of extracted microplastics were fiber, black and less than 1000 μm in size. FTIR analysis determined the main polymer types as polyester (50%), high-density polyethylene (HDPE) (10%), polypropylene (PP) (8%) and polyethylene terephthalate (PET) (5%). High MPs abundance and frequency of occurence indicate the exposure of microplastic pollution in freshwater biota which could threat the health of both individuals and consumers. Results obtained in this study will increase the acknowledgement of MPs pollution in the Orontes River. Also, this study will provide data to the administrators to set up necessary legislations in freshwater ecosystems.

Protective effect of protexin concentrate in reducing the toxicity of chlorpyrifos in common carp (Cyprinus carpio)

The present study aimed to evaluate the protective effect of protexin supplementation against chlorpyrifos-induced oxidative stress and immunotoxicity in Cyprinus carpio. After 21 days, the activity of superoxide dismutase (SOD), glutathione peroxidase (GPx) and glutathione reductase (GR), and total antioxidant levels significantly decreased in hepatocytes of fish exposed to chlorpyrifos, while malondialdehyde (MDA) increased. Treatment with protexin was able to reverse the decrease in SOD and GR and significantly reduce MDA levels. Exposure to chlorpyrifos also induced alterations in blood biochemical parameters and caused immunosuppression. Dietary protexin return some parameters (aspartate aminotransferase, lactate dehydrogenase, and γ-glutamyltransferase activities, and glucose, cholesterol, total protein, creatinine, and complement C4 levels) to values similar to those of the control group. Based on the results, it can be concluded that protexin exerted protective effects against chlorpyrifos exposure in C. carpio reducing oxidative damage, and ameriorating blood biochemical alterations and the immunosuppression.

Assessing the toxic effects of bisphenol A in consumed crayfish Astacus leptodactylus using multi biochemical markers

Bisphenol A (BPA), an endocrine-disrupting chemical (EDC), has strong potential for daily exposure to humans and animals due to its persistence and widespread in the environment, so its effects directly concern public health. Although invertebrates represent important components of aquatic ecosystems and are at significant risk of exposure, there is little information about the biological effects of EDCs in these organisms. Astacus leptodactylus used in this study is one of the most consumed and exported freshwater species in Europe. In this study, the 96-h effect of BPA on A. leptodactylus was examined using various biomarkers. The LC₅₀ value of BPA was determined as 96.45 mg L^-1. After 96 h of exposure to BPA, there were increases in superoxide dismutase (SOD), glutathione peroxidase (GPx), glutathione S-transferase (GST), alanine aminotransferase (ALT), aspartate aminotransferase (AST) and lactate dehydrogenase (LDH) activities and levels of malondialdehyde (MDA), and total oxidant status context (TOSC), and there were decreases in the activity of glutathione reductase (GR), carboxylesterase (CaE), acetylcholinesterase (AChE), Na⁺/K⁺ ATPase, Mg²⁺ ATPase, Ca²⁺ ATPase, and total ATPase and the total antioxidant context (TAC). From the results of this study, it can be concluded that BPA has significant toxic effects on A. leptodactylus based on the selected biochemical parameters of antioxidant, cholinergic, detoxification, and metabolic systems in crayfish even at low doses. Thus, it can be said that BPA can seriously threaten the aquatic ecosystem and public health.

A systematic review on the metabolic effects of chlorpyrifos

Organophosphate (OP) pesticides, including chlorpyrifos (CPF), can alter metabolic hemostasis. The current systematic study investigated blood glucose, lipid profiles, and body weight alterations in rodents and fish exposed to CPF. The systematic review was performed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) Guidelines, querying online databases, including Web of Science, PubMed, and Scopus and also search engine including Google Scholar, through January 2021. Studies on rodent and fish exposed to CPF assessing metabolic functions were selected. All studies were in the English language, with other languages being excluded from the review. Two investigators independently assessed each of the articles. The first author's name, publication date, animal model, age, sample size, gender, dose, duration, and route of exposure and outcomes were extracted from each publication. The present review summarizes findings from 61 publications on glycemic, lipid profile, insulin, and body weight changes in rodents and fish exposed to CPF exposure. Most of the studies reported hyperglycemia, hyperlipidemia, and decreased insulin levels and body weight following exposure to CPF. Additionally, we confirmed that the CPF-induced metabolic alterations were both dose- and time-dependent. Our findings support an association between CPF exposure and metabolic diseases. However, more studies are needed to identify the metabolic-disrupting effects of CPF and their underlying mechanisms.

Long-term exposure to polyethylene microplastics and glyphosate interferes with the behavior, intestinal microbial homeostasis, and metabolites of the common carp (Cyprinus carpio L.)

Polyethylene microplastics (PE-MPs) and glyphosate (GLY) occur widely and have toxic characteristics, resulting in increased research interest. In this study, common carp were used to assess the individual and combined toxicity of PE-MPs (0, 1.5, or 4.5 mg/L) and GLY (0, 5, or 15 mg/L) on the brain-gut axis. After 60 days of exposure, the developmental toxicity, blood-brain barrier (BBB), locomotor behavior, intestinal barrier (physical barrier, chemical barrier, microbial barrier), and intestinal content metabolism of common carp were evaluated. Results showed that 15 mg/L of GLY exposure significantly reduced the mRNA expression of tight-junction genes (occludin, claudin-2, and ZO-1) in the brain, and acetylcholinesterase (AChE) activity was clearly inhibited by high concentrations of GLY. However, different concentrations of PE-MPs had no significant effect on the activity of AChE. Furthermore, the free-swimming behavior of common carp was distinctly inhibited by treatment with a combination of 15 mg/L GLY and 4.5 mg/L PE-MPs. Histological studies indicated that PE-MPs alone and in combination with GLY could disrupt the physical and chemical intestinal barriers of common carp. Additionally, the abundance and diversity of gut microbiota in common carp were significantly changed when exposed to a combination of PE-MPs and GLY. Metabolomics further revealed that PE-MPs combined with GLY triggered metabolic changes and that differential metabolites were related to amino acid and lipid metabolism. These findings illustrate that exposure to PE-MPs or GLY alone is toxic to fish and results in physiological changes to the brain-gut axis. This work offers a robust analysis to understand the mechanisms underlying GLY and MP-induced aquatic toxicity.

Advances in organophosphorus pesticides pollution: Current status and challenges in ecotoxicological, sustainable agriculture, and degradation strategies

Organophosphorus pesticides (OPPs) are one of the most widely used types of pesticide that play an important role in the production process due to their effects on preventing pathogen infection and increasing yield. However, in the early development and application of OPPs, their toxicological effects and the issue of environmental pollution were not considered. With the long-term overuse of OPPs, their hazards to the ecological environment (including soil and water) and animal health have attracted increasing attention. Therefore, this review first clarified the classification, characteristics, applications of various OPPs, and the government's restriction requirements on various OPPs. Second, the toxicological effects and metabolic mechanisms of OPPs and their metabolites were introduced in organisms. Finally, the existing methods of degrading OPPs were summarized, and the challenges and further addressing strategy of OPPs in the sustainable development of agriculture, the environment, and ecology were prospected. However, methods to solve the environmental and ecological problems caused by OPPs from the three aspects of use source, use process, and degradation methods were proposed, which provided a theoretical basis for addressing the stability of the ecological environment and improving the structure of the pesticide industry in the future.

Effect of microplastics on Yersinia ruckeri infection in rainbow trout (Oncorhynchus mykiss)

Exposure to microorganisms such as Yersinia ruckeri can significantly affect bacterial infections in fish. Microplastics (MPs) may predispose fish to infection and act as carriers in pathogen transmission. Therefore, this study is designed to evaluate MPs' effect on damage caused by exposure to Y. ruckeri in rainbow trout. In this study, blood biochemical parameters and hepatic oxidative biomarkers as clinical signs were measured in the fish co-exposed to Y. ruckeri (5 and 10% the median lethal dose (LD₅₀)) and MPs (500 and 1000 mg Kg^-1) for 30 days. There were no significant changes in the creatinine, triglyceride, cholesterol levels, and glutamic-pyruvic transaminase activity in the blood of fish infected with Y. ruckeri. In contrast, exposure to MPs had a significant effect on most clinical parameters. The total protein, albumin, globulin, total immunoglobulins, high-density lipoprotein, low-density lipoprotein, cholesterol levels, and γ-glutamyltransferase activity decreased, whereas glucose, triglyceride, and creatinine levels, and glutamic-oxaloacetic transaminase, glutamic-pyruvic transaminase, alkaline phosphatase, and lactate dehydrogenase activities increased in the plasma of fish after co-exposure to MPs and Y. ruckeri. Dietary MPs combined with a Y. ruckeri challenge decreased catalase and glutathione peroxidase activities, and total antioxidant levels. However, superoxide dismutase activity and malondialdehyde contents increased in the hepatocyte of fish co-exposed to MPs and Y. ruckeri. This study suggests that fish exposure to MPs and simultaneous challenge with Y. ruckeri could synergistically affect clinical parameters.

Modulations of blood biochemical parameters of golden mahseer, Tor putitora following exposures to single and mixed organophosphate

Increasing pesticide application is a serious threat to human health and biodiversity. In nature, pesticides prevail in mixtures; therefore the joint effects of pesticides should be taken into consideration due to their priority in toxicity research when aiming at realistic evaluations. In this study, individual and mixture toxicity of the commonly used organophosphate insecticides- chlorpyrifos and dichlorvos was explored. Healthy and clinically active juveniles of golden mahseer (Tor putitora) were exposed to sub-lethal doses (10% of the 96 h-LC₅₀) of the chlorpyrifos, dichlorvos, and their mixture. Blood sampling was conducted after 24 h and 96 h of exposure, followed by a 1 week recovery period. Among the examined biochemical parameters; blood glucose in dichlorvos treatment; alanine aminotransferase and alkaline phosphatase in chlorpyrifos and dichlorvos treatments; and aspartate aminotransferase and urea in mixture pesticide treatments were elevated. In contrast, blood albumin and triglycerides were diminished in mixture pesticide treatments. Vital organs like kidney and liver of the tested animals were compromised to different magnitudes in different pesticide treatments. Kidney was found to be more sensitive than liver in terms of pesticide toxicity during this short exposure experiment. This study revealed that most of the biomarkers were mainly affected at a later exposure phase (after 96 h) and steadily recovered during the depuration period.

Effect of petroleum wastewater treated with gravity separation and magnetite nanoparticles adsorption methods on the blood biochemical response of mrigal fish (Cirrhinus cirrhosus)

Drainage of treated wastewater to surface water is a severe threat to the health of aquatic organisms. This study aimed to evaluate the effects of 0.5 and 1% water-soluble fractions of crude oil (WSFO), WSFO treated with magnetic nanoparticles of Fe₃O₄ (TWSFO-Fe₃O₄) and with the gravity separation method (TWSFO-GSM) on Cirrhinus cirrhosis for 21 days. The rate of erythrocyte hemolysis in fish exposed to untreated 0.5 and 1% WSFO were significantly high. The activities of alanine aminotransferase (ALT), gamma-glutamyl transferase (GGT), alkaline phosphatase (ALP) were significantly increased in the groups exposed to TWSFO-GSM compared to the control group, while lactate dehydrogenase (LDH) was reduced. No significant differences in LDH, ALT, ALP, and GGT activities were observed in the fish treated with TWSFO-Fe₃O₄. The aspartate aminotransferase activity was significantly increased after exposure to TWSFO-Fe₃O₄ (1%) and TWSFO-GSM. The levels of triglyceride were decreased, whereas glucose, cholesterol, and cholinesterase activity increased in fish after both treatments. The total protein and albumin contents significantly decreased in fish under exposure to both doses of TWSFO-Fe₃O₄ and TWSFO-GSM. The globulin level decreased in fish exposed to TWSFO-Fe₃O₄ (1%) and TWSFO-GSM. Glutathione peroxidase, catalase, glucose-6-phosphate dehydrogenase activities, and total antioxidant levels were significantly reduced in the hepatocytes of fish exposed to TWSFO-Fe₃O₄, TWSFO-GSM, and WSFO, while superoxide dismutase activity and malondialdehyde content were increased. This study showed that despite removing oil drips from the WSFO, the xenobiotics present in the effluent treated by gravitational or nano-magnetite methods caused changes in biochemical parameters and induced oxidative stress. Therefore, it is recommended to prevent the discharge of treated effluent from the oil and petrochemical industries to aquatic ecosystems.

Environmentally Relevant Concentrations of Triclosan Induce Cyto-Genotoxicity and Biochemical Alterations in the Hatchlings of Labeo rohita

Xenobiotic Triclosan (TCS) is of great concern because of its existence in a variety of personal, household and healthcare products and continuous discharge in water worldwide. Excessive use of TCS-containing sanitizers and antiseptic products during the COVID-19 pandemic further increased its content in aquatic ecosystems. The present study deals with the cyto-genotoxic effects and biochemical alterations in the hatchlings of Labeo rohita on exposure to environmentally relevant concentrations of TCS. Three-days-old hatchlings were exposed to tap water, acetone (solvent control) and 4 environmentally relevant concentrations (6.3, 12.6, 25.2 and 60 µg/L) of TCS for 14 days and kept for a recovery period of 10 days. The significant concentration-dependent decline in cell viability but increase in micronucleated cells, nucleo-cellular abnormalities (NCAs) and DNA damage parameters like tail length, tail moment, olive tail moment and percent of tail DNA after exposure persisted till the end of recovery period. Glucose, triglycerides, cholesterol, total protein, albumin, total bilirubin, uric acid and urea (except for an increase at 60 µg/L) showed significant (p ≤ 0.05) concentration-dependent decrease after 14 days of exposure. The same trend (except for triglycerides, albumin and total bilirubin) continued till 10 days post exposure. In comparison to control, transaminases (alanine and aspartate aminotransferases) increased (p ≤ 0.05) after exposure as well as the recovery period, while a decline in alkaline phosphatase after exposure was followed by a significant increase during the recovery period. The results show that the environmentally relevant concentrations of TCS cause deleterious effects on the hatchlings of L. rohita.

Polyethylene glycol acute and sub-lethal toxicity in neotropical Physalaemus cuvieri tadpoles (Anura, Leptodactylidae)

Although many polymers are known by their toxicity, we know nothing about the impact of polyethylene glycol (PEG) on anurofauna. Its presence in different products and disposal in aquatic environments turn assessments about its impact on amphibians an urgent matter. Accordingly, we tested the hypothesis that short-time exposure (72 h) of tadpoles belonging to the species Physalaemus cuvieri (Anura, Leptodactylidae) to PEG induces oxidative stress and neurotoxicity on them. We observed that polymer uptake in P. cuvieri occurred after exposure to 5 and 10 mg/L of PEG without inducing changes in their nitrite levels neither at the levels of substances reactive to thiobarbituric acid. However, hydrogen peroxide and reactive oxygen species production was higher in animals exposed to PEG, whose catalase and superoxide dismutase levels were not enough to counterbalance the production of these reactive species. Therefore, this finding suggests physiological changes altering REDOX homeostasis into oxidative stress. In addition, the increased activity of acetylcholinesterase and butyrylcholinesterase, and reduction in superficial neuromasts, confirmed PEG's neurotoxic potential. To the best of our knowledge, this is the first report on PEG's biological impact on a particular amphibian species. The study has broadened the understanding about ecotoxicological risks associated with water pollution by these polymers, as well as motivated further investigations on its impacts on amphibians' health and on the dynamics of their natural populations.

Multibiomarker responses and bioaccumulation of fipronil in Prochilodus lineatus exposed to spiked sediments: Oxidative stress and antioxidant defenses

Fipronil is a current use pesticide, widely used in many crops, commonly adsorbed to sediments of aquatic environments. The purpose of this study was to evaluate the biomarker responses and fipronil distribution pattern in different matrixes (fish, sediment and water) after juveniles P. lineatus exposure at two environmental concentrations (5.5 and 82 μg kg^--1) of fipronil-spiked sediments. The levels of oxidized proteins (PO), lipid peroxidation (LPO), and enzymatic activity of superoxide dismutase (SOD), reduced glutathione content (GSH), antioxidant capacity against peroxyls (ACAP) and acetylcholinesterase (AChE) were evaluated in liver, gills and brain. Concentrations of fipronil and its metabolites (f. desulfinyl, f sulphpHide and f. sulfone) were quantified by GC-ECD. F. desulfinyl was the major metabolite found in all matrixes, followed by f. sulphide in sediments, while f. sulfone was mainly accumulated in fish. Fipronil promoted oxidative stress in P. lineatus, as evidenced by the increases in LPO and PO levels and the decrease brain AChE activity. Fish exposed at both concentrations showed significant decrease in antioxidant capacity. Alterations in the antioxidant defenses system was evidenced in all organs. These results suggest that the occurrence of fipronil in aquatic environments can generate oxidative stress at different levels in P. lineatus, showing that this species is highly sensitive to the deleterious effects of fipronil and metabolites.

Uptake of Pb(II) onto microplastic-associated biofilms in freshwater: Adsorption and combined toxicity in comparison to natural solid substrates

In the present study, microplastic-associated biofilms were cultivated in an urban lake and a reservoir using virgin expanded polystyrene (PS). The uptake of Pb(II) onto both natural (suspended particles and surficial sediment) and anthropogenic (virgin microplastics and microplastic-associated biofilms) solid substrates was investigated and compared as a function of contact time, pH, and ionic strength in batch adsorption experiments. The adsorption isotherms revealed that biofilms enhanced the adsorption capacity of Pb(II) onto microplastics; however, natural substrates still exhibited a higher capacity. Ionic strength and pH significantly influenced the adsorption of Pb(II) onto all of the solid substrates. Under neutral conditions, competitive adsorption of Pb(II) was observed between anthropogenic solid substrates and natural substrates, which may further alter the distribution of Pb(II) among these solid substrates. The combined toxicity tests of Pb(II) and each solid substrate were carried out using Daphnia magna, the results indicated biofilm enhanced the combined toxicity of Pb(II) and microplastics. Therefore, biofilms not only intensified the vector role of microplastics in the migration of heavy metals in freshwater, but also enhanced their combined toxicity, which may have further potential ecological risks to freshwater ecosystems.

Vitamin C rescues inflammation, immunosuppression, and histopathological alterations induced by chlorpyrifos in Nile tilapia

Chlorpyrifos (CPF) is an extensive environmental contaminant and disrupts the physiological status of living organisms. CPF is found to hinder the health of aquatic organisms and ecological function in aquatic systems. The current study aimed at evaluating the protective effects of vitamin C (VC) on the immune response, hematological parameters, and histopathological alterations in Nile tilapia exposed to CPF. Nile tilapia were exposed to waterborne CPF (15 μg/L) for 30 days. Fish were divided into control group: received basal diet; CPF group: received basal diet and exposed to waterborne CPF; VC group: received basal diet plus 0.8 mg VC/kg; and CPF/VC group: received basal diet plus 0.8 mg VC/kg and exposed to waterborne CPF. Blood samples were taken after 15 days and 30 days of the treatment. Liver, gills, and intestine tissues were collected on the 30th day of treatment. CPF showed a deleterious effect on fish's growth performance; it decreased the weight gain by 6%, while VC increased it by 17-23% compared to the control group. CPF group recorded the lowest survival rate (83%), while VC achieved survivability of 96.7% and 93.3% in VC and CPF/VC groups, respectively. The blood picture revealed moderate changes in the CPF group, where the marked alteration was in the hemoglobin concentration and white blood cells. CPF disrupted the hepatic and renal function. Serum lysozyme activity, phagocytic activity, and phagocytic index displayed a dramatic decline in the CPF group but enhanced in VC and CPF/VC groups. An upregulation was observed in antioxidant genes (catalase and glutathione peroxidase), heat shock protein 70, caspase-3, and the cytokines interleukin 1β, interleukin 8, and interferon-gamma in the CPF group. Simultaneously, moderate or normal levels were shown in the VC and CPF/VC groups. CPF altered the histoarchitecture of gills, intestine, and hepatopancreas with apparent degenerative changes possibly resulted from the oxidative stress. At the same time, VC retained the normal structure of the studied tissues. This study raises concerns about the safety of CPF and its impact on the aquatic environment. VC has a high potential to restore the normal physiology of fish exposed to CPF.

Manifestations of oxidative stress and liver injury in clothianidin exposed Oncorhynchus mykiss

This investigation was conducted to evaluate the effects of clothianidin, a neonicotinoid insecticide, on hepatic oxidative stress biomarkers, biochemical indices of blood serum and liver integrity in juvenile Oncorhynchus mykiss following 7, 14 and 21 days of application to environmentally relevant concentrations of 3, 15 and 30 μg/l. The observed hypertrophy caused elevation in hepatosomatic index, a significant increase in serum glucose and a decrease in tissue protein level with extended period of exposure were determined. The treatment resulted in a marked induction in the activities of antioxidant enzymes which were accompanied with simultaneous elevation in MDA and protein carbonyl level reflecting loss of membrane integrity and protein function. Histopathological examination showed liver injury manifested as hepatocellular degeneration, fibrosis, vacuolation, congestion, necrosis, steatosis and pyknosis proceding with the concentration. The stressful condition triggered hyperglycemic and hypoproteinemic conditions which might be proposed as general adaptive response. Moreover, altered liver histology reveals the hepatotoxic potential of clothianidin via oxidative stress as a common pathological mechanism leading to liver injury.

Genotoxicity, oxidative stress, and biochemical biomarkers of exposure to green synthesized cadmium nanoparticles in Oreochromis niloticus (L.)

The considerable increment in the use of Nanoparticles in the industry has been recognized as an environmental concern today. Therefore, this study aimed to investigate the toxicity effects of green synthesized cadmium nanoparticles [Cd]^NPs using Moringa oleifera leaves extract on multi-biomarkers in Oreochromis niloticus after four weeks of exposure. The results showed that LC₅₀ values of [Cd]^NPs for 24, 48, 72 and 96 h were 2.17, 1.75, 1.49 and 1.22 mg l^-1, respectively. There was a significant decrease in the number of white and red blood cells, hemoglobin, hematocrit, mean corpuscular hemoglobin concentration value in fish exposed to [Cd]^NPs. The mean corpuscular volume and neutrophils were increased. [Cd]^NPs exposure to fish has led to cytotoxic and genotoxic changes in the erythrocytes. Significant changes were observed in the cortisol, triiodothyronine, and thyroxine levels of the fish exposed to [Cd]^NPs. The activities of aspartate aminotransferase and alanine aminotransferase increased. Glucose, total lipids, urea, and creatinine levels increased in the serum of fish exposed to [Cd]^NPs, whereas total protein contents and alkaline phosphatase activity decreased. A significant reduction was observed in glycogen, total antioxidant levels, and superoxide dismutase, catalase and glutathione S-transferase activities of fish exposed to [Cd]^NPs. In contrast, the [Cd]NPs exposure resulted in a significant increase in DNA fragmentation percentages, lipid peroxidation, and carbonyl protein levels in different tissues. The results of the present study confirmed that [Cd]^NPs has the toxicity potential to cause Cyto-genotoxicity, oxidative damages, changes in the hematological and biochemical changes, and endocrine disruptor in the fish.

Assessing the combined toxicity of carbamate mixtures as well as organophosphorus mixtures to Caenorhabditis elegans using the locomotion behaviors as endpoints

Carbamate pesticides (CMs) and organophosphorus pesticides (OPs) have been widely used in agriculture and toxicologically affect non-target organisms. Although there are many reports about their toxicities, the combined behavioral toxicities of CM/OP mixtures on Caenorhabditis elegans have rarely been studied. In this study, body bend inhibition (BBI), head thrash inhibition (HTI), and swimming speed inhibition (SSI) by CMs and OPs were chosen as the toxicity endpoints. The locomotion behavioral toxicities of individual pesticides (carbofuran (CAR), methomyl (MET), chlorpyrifos (CPF), and triazophos (TAP)) and their binary mixtures on C. elegans were determined systematically and the toxicological interaction profiles of various CM/OP mixture rays constructed using the combination index. It was shown that four pesticides and their binary mixture rays have significant inhibitory effects on the locomotion behavior of C. elegans; that is, they produce locomotion behavioral toxicities and the toxicity of two OPs is higher than those of two CMs. The toxicological interactions in the binary CM and OP mixtures are different from each other. For example, one mixture ray (CAR-MET-R1) in the CM system on the SSI endpoint exhibits synergism at all concentration levels, another ray (CAR-MET-R3) displays low-dose synergism and high-dose additive action on BBI and HTI endpoints, and weak synergism at high-dose on SSI, and other rays perform additive action. Two rays (CPF-TAP-R1 and CPF-TAP-R2) in the OP mixture system display low-dose additive action and high-dose antagonism on the three endpoints. Another ray (CPF-TAP-R3) shows the additive action at all concentration levels. It can be concluded that it is not sufficient to evaluate the combined toxicity of binary CM/OP mixtures using only one concentration ratio ray and that it is necessary to examine multiple concentration ratios.

Tissue-specific toxicity of clothianidin on rainbow trout (Oncorhynchus mykiss)

This study was performed to investigate the tissue-specific effects of clothianidin on Oncorhynchus mykiss by evaluating the biochemical and histological alterations following 21 days of treatment to environmentally relevant concentrations of 3, 15, and 30 µg/L. The emerged behavioral changes in feeding and swimming performance were considered as adaptive responses to avoid the chemical. The toxic effect of pesticide on nervous system and osmoregulation was evidenced with the inhibition of AChE and Na⁺K⁺-ATPase. The sustained lipid peroxidation, ranging from muscle (196%) > brain (154%) > gill (140%) > kidney (129%), might be suggested as a mechanism mediating the inhibition of membrane-bound enzymes. Histological evaluation showed clothianidin-induced lesions appearing as necrosis, atrophy, and edema in muscle, hyperplasia, and hypertrophy causing shortening and fusion of the secondary lamellae in gill, vacuolization, and hydropic degeneration in brain, degeneration of tubular epithelium, and existence of melanomacrophage centers in kidney. The pronounced degenerative changes observed in gill indicate the vulnerability of tissue possibly due to its role as first contact and entry point for the pesticide. Consequently, clothianidin exerted its toxic effects by altering normal behavior, causing neurotoxicity and disturbing osmoregulation. Moreover, the imposed stress was responded in a tissue-specific manner and histological lesions become more severe with increasing concentration. The findings clearly reveal the potential threat caused by environmentally relevant concentrations of clothianidin to early life stages of fish.

Acetylcholine esterase and antioxidant responses in freshwater teleost, Channa punctata exposed to chlorpyrifos and urea

We aimed to understand the toxic effects of two crop protecting agents, organophosphate pesticide, chlorpyrifos (CPF) and fertilizer, urea (U), and their binary mixtures at sublethal concentrations for 28-d in a freshwater fish Channa punctata with a battery of biochemical biomarkers in gill and liver. The study has practical value as such mixtures, so often present together in water in the agro-intensive areas, might be predicted to cause cocktail effects. Both CPF and U inhibited AChE, augmented SOD, CAT, GPx activities, and caused lipid peroxidation and depletion in tissue macromolecules in a concentration and duration-dependent manner. While U alone had less severe effects compared to CPF treatments, complex interactions were observed for three combination doses (1CPF + 1U, 2CPF + 1U, 1CPF + 2U). In their mutual effects, antagonism prevailed over other interactions when CPF and U were in equal proportion in the mixture, while synergism was observed for AchE and key antioxidant enzymes when more U was in the mixture. The present study concluded that urea in water bodies might impart adverse effects in combination with pesticides in non-target aquatic organisms such as fish, and there should be a restriction in its excessive usage.

Effects of microplastic exposure on the blood biochemical parameters in the pond turtle (Emys orbicularis)

The accumulation of microplastics (MPs) is a growing problem in aquatic ecosystems. Despite increased research on MPs in the last decade, their potential threat to freshwater ecosystems remains an open question. In the present study, the negative impacts of MPs were investigated on blood biochemical parameters in the European pond turtle (Emys orbicularis). Pond turtles were distributed into three experimental groups (n = 9 for each group) and were fed diets containing 250, 500, and 1000 mg MPs (PE100 polyethylene) per kg of food for 30 days, and a control group fed with a standard uncontaminated diet. The results indicated that exposure to 500 and 1000 mg kg^-1 MPs caused a significant increase in the activities of alanine and aspartate aminotransferases, and in the levels of cholesterol, glucose, creatinine, urea, and calcium (Ca⁺²) compared with the control group. On the contrary, the activity of gamma-glutamyl transferase and the levels of total protein, albumin, total immunoglobulins, and phosphorus were significantly reduced in E. orbicularis exposed to 500 and 1000 mg kg^-1 MPs when compared with the controls. In all the MP-exposed groups, the activity of lactate dehydrogenase and globulin and magnesium (Mg⁺²) levels were significantly reduced; while creatine phosphokinase and alkaline phosphatase activities were increased with respect to the control turtles. A significant decrease in triglyceride levels was reported in E. orbicularis exposed to 1000 mg kg^-1 MPs. MPs intake induced notable alterations in blood biochemical parameters of E. orbicularis. These results suggest that changes in the blood biochemical parameters could be an appropriate bio-indicator to evidence the existence of tissue damage in E. orbicularis.

Integrated ecotoxicological assessment of the complex interactions between chlorpyrifos and glyphosate on a non-target species Cnesterodon decemmaculatus (Jenyns, 1842)

Pesticide mixtures are frequent in freshwaters systems around the world, threatening the biota exposed to these conditions. The aim of this study was to determine the single and joint effect of two widely used pesticides in southern South America on a widely distributed fish species. In a 96-h assay, individuals of Cnesterodon decemmaculatus were exposed to 0.84 nL/L and 8.4 nL/L of Clorfox and 0.2 mg/L and 2 mg/L of Roundup Max, commercial formulations of chlorpyrifos and glyphosate, respectively. Also, there were four mixture treatments with all the possible combinations of both pesticides. A multi-level approach was carried out to assess their effects covering the following relevant biomarkers: behavior (immobile time, line crossings and average speed), somatic conditions (Fulton condition factor and hepatosomatic index), serum parameters (cortisol levels, lactate dehydrogenase (LDH), and creatine phosphokinase activity (CPK)), brain and muscle acetylcholinesterase and cytological characteristics (micronuclei frequency and nuclear abnormalities in erythrocytes). Our results showed that Clorfox exposures affect behavioral parameters, serum cortisol, and nuclear characteristics of erythrocytes. Roundup Max affects only the cortisol levels whereas mixture treatments have an effect on behavioral parameters, cortisol levels, LDH and CPK activities, and nuclear characteristics of erythrocytes. Potentiation was the main interaction at the lowest concentrations of both pesticides whereas antagonism occurred at the highest concentrations of both pesticides. These results are highly significant since they arise from an integrated ecotoxicological assessment at several levels of biological organization but even more important is that the potentiated effects of the mixtures we registered are environmentally relevant concentrations.

Combined effects of exposure to sub-lethal concentration of the insecticide chlorpyrifos and the herbicide glyphosate on the biochemical changes in the freshwater crayfish Pontastacus leptodactylus

Glyphosate is an herbicide that inhibits the growth of weed plants, while chlorpyrifos is an insecticide commonly applied to control the pests' population. This study aimed to investigate the combined effects of chlorpyrifos and glyphosate on biochemical, immunological parameters, and oxidative stress biomarkers in freshwater crayfish Pontastacus leptodactylus for 21 days. The experimental design of this study was factorial (3 × 3), including 0.0, 0.4, and 0.8 mg L-1 glyphosate and 0.0, 2.5, and 5 µg L-1 chlorpyrifos. The exposure to chlorpyrifos, glyphosate alone and a mixture of them significantly decreased acetylcholinesterase, alkaline phosphatase, phenoloxidase activities, and total protein levels. The lactate dehydrogenase, glutamic-pyruvic-transaminase, and catalase activities, the contents of glucose, and malondialdehyde levels were increased in the crayfish. No significant changes were detected in glutamic-oxaloacetic-transaminase (SGOT) activity, triglyceride, and total antioxidant (TAO) levels in the crayfish treated with 0.4 mg L-1 glyphosate and the control group. Co-exposure of crayfish to chlorpyrifos and glyphosate increased SGOT activity and TAO levels. Although chlorpyrifos combined with glyphosate decreased the γ-Glutamyltransferase (GGT) activity, the GGT activity was significantly increased in the P. leptodactylus exposed during 21 days to 5 µg L-1 chlorpyrifos alone and 0.8 mg L-1 glyphosate alone. In comparison with the reference group, no significant changes were evidenced in the cholesterol levels in the P. leptodactylus treated with 2.5 µg L-1 chlorpyrifos, but its levels were significantly increased in the other treatment groups. In conclusion, the mix of glyphosate and chlorpyrifos exhibited synergic effects on the different toxicological biomarkers in the narrow-clawed crayfish. Co-exposure to pesticides may result in disruption of homeostasis in the crayfish by altering the biochemical and immunological parameters.