Immunotoxicological, biochemical, and histopathological studies on Roundup and Stomp herbicides in Nile catfish (Clarias gariepinus)

Toxicological assessment of bromoxynil and 2-methyl-4-chlorophenoxyacetic acid herbicide in combination on Cirrhinus mrigala using multiple biomarker approach

The widespread application of herbicides raises concerns about their impact on non-target aquatic organisms. This study aimed to evaluate the toxicity of a commercially available herbicide formulation containing Bromoxynil+MCPA (2-Methyl-4-chlorophenoxyacetic acid) on Cirrhinus mrigala (economically significant fish). A total of 210 juvenile fish were subjected to a triplicate experimental setup, with 70 fish allocated to each replicate, exposed to seven different concentrations of herbicide: 0 mg/L, 0.133 mg/L, 0.266 mg/L, 0.4 mg/L, 0.5 mg/L, 0.66 mg/L, and 0.8 mg/L, respectively, for a duration of 96 h. The median lethal concentration (LC50) was determined to be 0.4 mg/L. Significant hematological alterations were observed, including decreases in RBC counts, hemoglobin, hematocrit, and lymphocyte counts, along with an increase in erythrocyte indices. Biochemical analysis revealed elevated levels of neutrophils, WBCs, bilirubin, urea, creatinine, ALT, AST, ALP, and glucose in treated groups. Morphological abnormalities in erythrocytes and histopathological changes in gills, liver, and kidneys were noted. Pathological alterations in gills, liver and kidneys including epithelial cell uplifting, lamellar fusion, hepatolysis, and renal tubule degeneration were observed. Oxidative stress biomarkers such as TBARS (Thiobarbituric Acid Reactive Substance), ROS (Reactive Oxygen Species), and POD (Peroxides) activity increased, while antioxidant enzymatic activities decreased as toxicant doses increased from low to high concentrations. The study reveals that Bromoxynil+MCPA significantly disrupts physiological and hematobiochemical parameters in Cirrhinus mrigala, which highlights the substantial aquatic risks. In conclusion, the herbicide formulation induced significant alterations in various fish biomarkers, emphasizing their pivotal role in assessing the environmental impact of toxicity. This multi-biomarker approach offers valuable insights regarding the toxicological effects, thereby contributing substantially to the comprehensive evaluation of environmental hazards.

Effects of Exposure to a Glyphosate-Based Herbicide on Haematological Parameters, Plasma Biochemical Indices and the Microstructure of Selected Organs of the Common Carp ( Cyprinus carpio Linnaeus, 1758)

Contamination of water environments with herbicides is a common problem nowadays. The aim of the current study was to evaluate the effects of Roundup on common carp ( Cyprinus carpio) after 1, 3 and 10 days of exposure. The used concentrations corresponded to 1 and 5 mg/l of the active ingredient (glyphosate potassium salt). The haematological analysis performed showed a decrease of the RBC count, as well as an increase of the other erythrocyte indices (Hb, MCV, MCH, MCHC). Most of these changes were dependent on the concentration and time. An increase of the WBC count and the percentage of immature neutrophils occurred, thus indicating the presence of inflammation. In the studied blood biochemical parameters, only minor and temporary changes were observed. The histopathological analysis revealed no alterations in the gills, liver and kidney. Thus, the results of the present study suggest that the haematological parameters are more sensitive and reliable markers of the common carp's exposure to Roundup than the other parameters that were tested.

Dinitroaniline herbicides: a comprehensive review of toxicity and side effects on animal non-target organisms

The widespread use of herbicides has increased concern about the hazards and risks to animals living in terrestrial and aquatic ecosystems. A comprehensive understanding of their effective action at different levels of biological organization is critical for establishing guidelines to protect ecosystems and human health. Dinitroanilines are broad-spectrum pre-emergence herbicides currently used for weed control in the conventional agriculture. They are considered extremely safe agrochemicals because they act specifically on tubulin proteins and inhibit shoot and root growth of plants. However, there is a lack of toxicity information regarding the potential risk of exposure to non-target organisms. The aim of the present review is to focus on side effects of the most commonly used active ingredients, e.g. pendimethalin, oryzalin, trifluralin and benfluralin, on animal non-target cells of invertebrates and vertebrates. Acute toxicity varies from slightly to high in terrestrial and aquatic species (i.e. nematodes, earthworms, snails, insects, crustaceans, fish and mammals) depending on the species-specific ability of tested organisms to adsorb and discharge toxicants. Cytotoxicity, genotoxicity and activation of oxidative stress pathways as well as alterations of physiological, metabolic, morphological, developmental and behavioural traits, reviewed here, indicate that exposure to sublethal concentrations of active ingredients poses a clear hazard to animals and humans. Further research is required to evaluate the molecular mechanisms of action of these herbicides in the animal cell and on biological functions at multiple levels, from organisms to communities, including the effects of commercial formulations.

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.

Genotoxic, biochemical and histological biomarkers of subacute concentrations of paraquat and glyphosate in Nile Tilapia

The use of herbicides for increased food production may pose risk to non-target organisms. This study evaluated the acute toxicity, genotoxic, biochemical, and histological biomarkers of subacute concentrations of paraquat and glyphosate in Oreochromis niloticus (Nile Tilapia) for 28 days following standard methods. Glyphosate (96 hLC50 value-1.23 mg/L) was 9x more toxic than paraquat (96 hLC50 value-11.20 mg/L) against O. niloticus. Average micronucleated cells were significantly higher in the erythrocytes of O. niloticus exposed to the higher (1.12 mg/L) concentration of paraquat at day 14, both subacute concentrations of paraquat at day 28, and lower concentration (0.01 mg/L) of glyphosate at days 14 and 28 compared to the other treatments and controls. Biochemical biomarkers (MDA and GST) activities were significantly higher at both subacute concentrations of the herbicides in the exposed fish compared to the controls at day 28 only. GSH activity was significantly higher in the 0.11 mg/L paraquat concentration while SOD activity was significantly lower at both subacute concentrations of glyphosate in exposed fish compared to controls at day 28. Histological alterations observed were mild to severe shortening of the gill primary lamellar and hepatic portal inflammation of exposed fish compared to the controls. This study demonstrates the risk to non-target organisms due to herbicides’ run-off from agricultural farmlands into aquatic ecosystems at environmentally relevant or subacute concentrations. Sensitization on the responsible use of pesticides is recommended to promote responsible consumption and production and sustain life below water (United Nations Sustainable Development Goals 12 and 14 respectively).

Clinicohematological, Mutagenic, and Oxidative Stress Induced by Pendimethalin in Freshwater Fish Bighead Carp (Hypophthalmichthys nobilis)

Currently, aquatic and terrestrial ecosystems are continuously and chronically polluted by cocktails of countless chemical compounds. The susceptibility to infections is tremendously increasing in a variety of organisms due to exposure to environmental pollutants. Pendimethalin, an herbicide, is continuously used in agriculture to remove unwanted broadleaf weeds across the globe. Therefore, this study investigates the mechanisms of toxicity of pendimethalin in freshwater fish bighead carp upon exposure to low and environmentally relevant concentrations. For this purpose, 48 fish without any clinical abnormalities were kept in a glass aquarium in different experimental groups (T0, T1, T2, and T3). These groups were treated with pendimethalin at 0.00, 0.25, 0.50, and 0.75 mg/L, respectively. Four fish were randomly picked from each experimental group and killed at 72, 96, and 120 hours of the trial to study hematobiochemical parameters and visceral tissues including the brain, liver, heart, gills, and kidneys for histopathology. Herbicide-treated fish indicated various physical and behavioral abnormalities including hypersecretion of mucus, erratic swimming, operculum movement, air gulping, tremors of fins, loss of equilibrium, and increased surface breathing. Histopathologically, gills tissues of treated fish indicated atrophied lamellae, uplifting of secondary lamellae, necrosis of primary and secondary lamellar epithelial cells, telogenesis, congestion, and lamellar fusion. Histopathological examination of liver tissues of treated fish showed mild to moderate congestion, necrosis of hepatocytes, and atrophy of hepatocytes while kidneys revealed degeneration of renal tubules, glomerular atrophy, ceroid, and necrosis of renal tubules. The erythrocyte counts, monocyte and lymphocyte counts, and hemoglobin values were significantly (P < 0.05) reduced in pendimethalin-treated fish. Results on serum biochemistry showed that the biomarkers of kidneys, heart, and liver were significantly higher in fish of treated groups. In addition, values of different biochemical reactions like reactive oxygen species (ROS), thiobarbituric acid reactive species (TBARS), total proteins, and quantity of different antioxidant enzymes including reduced glutathione (GSH), catalase, and superoxide dismutase (SOD) were significantly different when compared to untreated fish. Moreover, the percentile of different nuclear abnormalities in red blood cells and frequency of DNA damage increased significantly in treated fish. It can be concluded from the findings that pendimethalin causes its toxic effects via disruption of physiological and hematobiochemical reactions of fish.

Trends in science on glyphosate toxicity: a scientometric study

As part of the most used herbicides, glyphosate is the most successful ingredient of agrochemical companies. The main objective of this study was to demonstrate research trends related to the glyphosate toxicity and its main effects on human and environmental health. For this purpose, 443 articles published, from 1995 to 2020, on the platform Web of Science™ Thomson Reuters were selected. The main toxicity results related in literature are genotoxicity, cytotoxicity, and endocrine disruption. The environmental effects come mostly from the contamination of groundwater and soils. Several studies have concluded that herbicide concentrations right below the official safety limits induced toxic effects. The results presented a highlighted harmful effect of glyphosate on both human and environmental health. It has been observed that countries where publish the most about the glyphosate toxicity are great investors in large-scale agriculture. It is important to ponder that these countries are in a route of ecosystem exploitation that includes not only fauna and flora, but also human beings. Unfortunately, science does not provide concise data for these pesticide disapproval in the global consumer market. It is necessary to search sustainable global interest alternatives to increase agriculture production based on peoples' food sovereignty.

Glyphosate-based herbicides affect behavioural patterns of the livebearer Jenynsia multidentata

Roundup® is one of the most widely marketed glyphosate-based herbicides in the world. There are many different formulations of this brand that differ from each other in glyphosate concentration, salts and adjuvants, including surfactants, which are labelled as "inert" compounds. Several studies have shown that these formulations are highly toxic to fish, even compared with pure glyphosate. However, mechanisms underlying this toxicity are not fully understood. In this context, this study evaluated the effects of exposure to Roundup Original® (RO), Roundup Transorb® (RT), and Roundup WG® (RWG) on the behavioural patterns of the livebearer Jenynsia multidentata. This fish naturally inhabits agricultural areas in southern Brazil and Argentina where glyphosate is used extensively. In the experiment, animals were exposed to the herbicides for 96 h, at the environmentally relevant concentration of 0.5 mg/L of glyphosate. Swimming performance, anxiety, aggressiveness, long-term memory and male sexual activity were recorded. The formulation RWG negatively affected swimming performance, thigmotaxia and long-term memory consolidation. Conversely, RT reduced the sexual performance of males. These results confirm that Roundup® formulations are extremely harmful and also that they have different targets of toxicity, affecting behaviours that are essential for fish survival.

Growth, Hemato-Biochemical Parameters, Body Composition, and Myostatin Gene Expression of Clarias gariepinus Fed by Replacing Fishmeal with Plant Protein

Simple Summary

The costs of feed ingredients in the aquaculture sector are one of the main problems impacting the success or failure of a business. The key ingredient in aquafeeds and the costliest among them is fish meal (FM). Therefore, great consideration was given to the use of different types of plant protein (PP) meals in aquafeeds (soybean and sunflower meal). In this study, fish were divided into five groups, with each group in triplicate (30 fish/group; 10 fish/replicate). Group 1 was fed the control diet consisting of 15% FM and 41% soybean meal. The other four groups (D1, D2, D3, and D4) were fed experimental diets, where FM was replaced gradually by plant protein sources (33, 50, 66, and 100% soybean meal and sunflower meal) for 60 days. In conclusion, partial or total replacement of FM with a plant protein source (soybean and sunflower meal) showed similar growth performance and body composition with greater economic efficiency.

Abstract

In this study, we evaluated the consequences of replacement of fishmeal with plant protein sources (soybean and sunflower meal) on fish growth parameters, haemato-biochemical factors, body composition, and myostatin gene expression of Clarias gariepinus. A total of 150 C. gariepinus were organized in glass aquaria into five investigational groups, with each group in triplicate (30 fish/group; 10 fish/replicate). Group 1 was fed a control diet (15% fishmeal). The other groups were fed diets where fishmeal was replaced gradually with plant protein, with 10% fishmeal in the second group (D1), 7.5% fishmeal in the third group (D2), 5% fishmeal in the fourth group (D3), and 0% fishmeal in the fifth group (D4). There were no significant differences regarding growth performances and body composition among the groups, except that the feed conversion ratio was improved in D4. The different diet types did not affect hematologic parameters and blood indices. Serum growth hormone and amylase levels also revealed no significant (p = 0.09 and 0.55, respectively) differences among the groups, while serum lipase levels decreased significantly (p = 0.000) due to partial (D2) or complete (D4) substitution of fishmeal with plant protein. The replacement of fishmeal had no effects on liver (p = 0.51) and kidney functions (p = 0.34). However, D4 showed the best profit and economic efficiency compared to the other groups. Altogether, we concluded that substitution of fishmeal with plant protein sources is economically beneficial and may be without any adverse effects on growth parameters, body composition, or hematologic and biochemical parameters, but with the addition of synthetic amino acids.

Hematological and immunological responses in the African catfish Clarias gairepinus exposed to sublethal concentrations of herbicide Ronstar®

The aim of the study was to investigate the effects of sublethal concentrations (0.3, 0.6 and 1.2 mg L^-1) of the herbicide Ronstar on the hematology and some immune parameters in Clarias gariepinus juvenile (mean weight and length 58.72 ± 2.46 g and 27.60 ± 1.62 cm, respectively). The hematological and some immune parameters were studied for 21 days in a static renewal bioassay system in which the water and the herbicide were changed daily. The erythrocyte count, hemoglobin concentration (Hb), and packed cell volume (PCV) were significantly (p < 0.05) reduced in the treatment groups. When compared with the control, there were significant (p < 0.05) leucocytosis, lymphocytosis, neutropenia and monocytopenia in the treatment groups. Both the mean corpuscular hemoglobin (MCH) and mean corpuscular volume (MCV) were reduced ((p < 0.05) in the Ronstar-exposed fish. The result showed that the treated fish suffered hypochromic microcytic anemia. The total immunoglobulin and phagocytic indices (phagocytic capacity and phagocytic index) were significantly (p < 0.05) reduced in the treatment groups. while the respiratory burst was significantly (p < 0.05) increased in the treatment groups. The result showed that exposure to Ronstar had adverse effects on the hematology and immunocompetency of the fish.

Effects of p-nitrophenol on enzyme activity, histology, and gene expression in Larimichthys crocea

p-Nitrophenol (PNP) is one type of environmental pollutant, which is difficult to degrade and soluble in water. To investigate the effects of PNP on economically important marine fish species, we subjected Larimichthys crocea juvenile to five different concentrations of PNP for 96 h, and the semi-lethal concentration (LC50) was 6.218 mg/L. Then we collected the liver, kidney, and gill tissues to determine enzyme activity and gene expression levels, and analyzed histological changes. In histological analysis, the gills showed curling of lamella, epithelial lifting and hyperplasia; the parenchymal structure of hepatocytes was significantly damaged, with severe vacuolation and loss of original structure. The renal cells were damaged too, with congestion and renal tubular necrosis. Catalase and superoxide dismutase both showed an up- and down-tendency with the rise of concentration in the three tissues, and GSH-px had similar trend in the kidney, which decreased at 8 mg/L in the liver but showed no significant differences in the gills. Malondialdehyde of three tissues was increased with an increase in PNP concentration. The expression of four detoxification (cyp450, gst, gpx, hsp70) and one immune-related (mhc II) genes was induced at low PNP concentrations but inhibited at high PNP concentrations in the kidney. In liver, cyp450, hsp70 and mhc II showed similar trend but gst and gpx didn't increase at low PNP concentrations. Our results indicate that the fish possesses the ability to detoxify PNP; however, at high concentrations, PNP still causes serious damage to them. Our data not only help in understanding the ability of L. crocea to detoxify PNP but also should serve as a basis for the study of toxic effects of nitrobenzenes on marine fish.

Biochemical and molecular impacts of glyphosate-based herbicide on the gills of common carp

Glyphosate (GLY)-based herbicide, one of the most widely used herbicides, might cause a series of environmental problems and pose a toxicological risk to aquatic organisms. However, data on the potential hazard and toxicity mechanism of GLY to fish gills are relatively scarce. In this study, a subacute toxicity test of common carp (Cyprinus carpio L.) treated with commercial GLY at 52.08 and 104.15 mg L-1 for 7 d was conducted. The results revealed that GLY exposure significantly inhibited Na+/K+-ATPase and increased AST and ALT activities in the fish gills. The biochemical assays results revealed that GLY treatment remarkably altered the transcriptional levels of HSP70 and HSP90; inhibited the activities of SOD, CAT, GPx, GR, and T-AOC; reduced the contents of GSH, but remarkably promoted MDA and PC contents, suggesting that GLY exposure induced oxidative stress and lipids and proteins damage in the carp gills. Further research revealed that GLY exposure also promoted expression of NF-κB, iNOS, IL-1β, IL-6, IL-8, and TNF-α; altered the levels of IL-10 and TGF-β, indicating that GLY exposure induced inflammatory response in the fish gills. Additionally, we found that GLY exposure activated apaf-1 and bax and inhibited bcl-2, induced caspase-9 and caspase-3 expression and caused remarkable histological damage in the fish gills. These results may further enriches the toxicity mechanistic theory of GLY to fish gills, which may be useful for the risk assessment of GLY and aquatic organism protection.

Toxicological impact of oxyfluorfen 24% herbicide on the reproductive system, antioxidant enzymes, and endocrine disruption of Biomphalaria alexandrina (Ehrenberg, 1831) snails

Oxyfluorfen (Goal 24%EC) herbicide is widely used in agriculture for weed control. Biomphalaria alexandrina snails can be used as bioindicator of the chemical pollution in the aquatic environment. The objective of this study was to evaluate the molluscicidal activity of this herbicide on Biomphalaria alexandrina snails and how it affected its biological system. The present study revealed a molluscicidal effect of oxyfluorfen 24%EC on these snails at LC₅₀ 5.9 mg/l. After exposure of snails to the sub-lethal concentrations (LC₀, LC₁₀, or LC₂₅) of this herbicide, the survival rates, reproductive rate (R₀), and fecundity (M_x) of adult B. alexandrina snails were significantly decreased in comparison with the control group. Also, levels of testosterone and estradiol were decreased significantly. It caused alterations in the antioxidant system, where exposure to sub-lethal concentration of this herbicide caused significant increases in levels of lipid peroxide malondialdehyde (MDA), catalase (CAT), and superoxide dismutase (SOD), while it significantly decreased glutathione transferase (GST). Histopathological changes in the digestive gland included severe damage in the digestive cells, where, they lost their tips and some were degenerated, while the secretory cells increased in number. Regarding the hermaphrodite gland, there were losses of the connective tissues, irregular sperms, and the eggs degenerated. These findings concluded that B. alexandrina snails can be used as a bioindicator for pollution with pesticide in the aquatic environment.

Hematological, physiological and genotoxicological effects of Match 5% EC insecticide on Biomphalaria alexandrina snails

Freshwater snails are used as brilliant biomarkers of aquatic ecosystem pollution by chemical compounds. The objective of this study is to highlight the ecotoxicological impacts of the insecticide Match 5%EC (its active ingredient is lufenuron 5% EC) on Biomphalaria alexandrina snails the intermediate host of Schistosoma mansoni in Egypt. The present investigation recorded a remarkable molluscicidal effect of lufenuron 5% EC on these snails and there was a decrease in total number of their hemocytes after exposure. Three morphologically distinct populations of circulating hemocytes were identified (round small cells, granulocytes and hyalinocytes) and results showed that some hyalinocytes had a shrunk nucleus and some were degenerated. Significant increase of transaminases (ALT and AST), while, a decrease of the total protein and albumin content in hemolymph was recorded. The results of alkaline comet assay in the present study demonstrated that lufenuron 5% EC has a genotoxic effect especially when its concentration increases. It can be concluded that Biomphalaria alexandrina snails can be used as bio monitor to screen the deleterious effects of lufenuron 5% EC insecticide as a cause of the environmental pollution, and this insecticide can be used in controlling schistosomiasis because of its molluscicidal effects on B. alexandrina snails.

Glyphosate and Roundup® alter morphology and behavior in zebrafish

Glyphosate has become the most widely used herbicide in the world, due to the wide scale adoption of transgenic glyphosate resistant crops after its introduction in 1996. Glyphosate may be used alone, but it is commonly applied as an active ingredient of the herbicide Roundup®. This pesticide contains several adjuvants, which may promote an unknown toxicity. The indiscriminate application poses numerous problems, both for the health of the applicators and consumers, and for the environment, contaminating the soil, water and leading to the death of plants and animals. Zebrafish (Danio rerio) is quickly gaining popularity in behavioral research, because of physiological similarity to mammals, sensitivity to pharmacological factors, robust performance, low cost, short spawning intervals, external fertilization, transparency of embryos through larval stages, and rapid development. The aim of this study was evaluate the effects of glyphosate and Roundup® on behavioral and morphological parameters in zebrafish larvae and adults. Zebrafish larvae at 3days post-fertilization and adults were exposed to glyphosate (0.01, 0.065, and 0.5mg/L) or Roundup® (0.01, 0.065, and 0.5mg/L) for 96h. Immediately after the exposure, we performed the analysis of locomotor activity, aversive behavior, and morphology for the larvae and exploratory behavior, aggression and inhibitory avoidance memory for adult zebrafish. In zebrafish larvae, there were significant differences in the locomotor activity and aversive behavior after glyphosate or Roundup® exposure when compared to the control group. Our findings demonstrated that exposure to glyphosate at the concentration of 0.5mg/L, Roundup® at 0.065 or 0.5mg/L reduced the distance traveled, the mean speed and the line crossings in adult zebrafish. A decreased ocular distance was observed for larvae exposed at 0.5mg/L of glyphosate. We verified that at 0.5mg/L of Roundup®-treated adult zebrafish demonstrated a significant impairment in memory. Both glyphosate and Roundup® reduced aggressive behavior. Our data suggest that there are small differences between the effects induced by glyphosate and Roundup®, altering morphological and behavioral parameters in zebrafish, suggesting common mechanisms of toxicity and cellular response.