96-h LC50 Research Articles

Degeneration in Renal Cells of Freshwater Fish (Channa punctata) under Exposure of Nigrosine Black (Acid Black-2), a Tanning Industry Dye

Nigrosine Black (Acid Black-2) is popularly used in tanning industries and a huge amount of this dye comes out with effluent of tanning industries, this dye reached near water bodies, and what impact produced on their aquatic life not reveal yet, Hence a study was plan to find out the impact of Nigrosine black dye on the renal cell of freshwater fish Channa punctata. Sub-acute and chronic exposure to Nigrocine Black produced significant renal cellular degeneration in fish C. punctata. The 1/20th LC50 (96h) of the Nigrocine Black produced degenerating changes in the kidney tissues of fish. Renal corpuscles were revealing swollen and contained some degenerated RBC and thmbrocytes, which appeared to be cellular debris in Bowman space, due to the rapid destruction of the nuclei of erythrocytes. The liberated hemoglobin and other cytoplasmic materials were also observed, while 1/20th of LC50 (96hr) of Nigrosine Black produced renal degeneration in Bowman’s capsule and swelling in the glomerulus in the intoxicated fish along with renal tubules atrophy, degeneration as compared to the control group of fish. The low dose of Nigrosine Black Toxicity in fish produced nephropathy, and nephrosis. While the high dose of Nigrosine black dye produces Glomerulonephritis in experimental fish. The kidney cells of experimental fish are damaged by both doses of Nigrosine Black. The physico-chemical property of aquarium water was kept constant during whole duration of experiment.

Antiparasitical efficacy of sophoraflavanone G isolated from Sophora flavescens against parasitic protozoa Ichthyophthirius multifiliis

Ichthyophthirius multifiliis, a global distributed protozoan parasite, causes “White spot disease” and leads to serious mortality of freshwater fish in aquaculture. The present study was conducted to assess the anti-I. multifiliis efficacy of active compound isolated from Sophora flavescens. The isolated active compound was identified as sophoraflavanone G (SG) with ESI-MS and NMR. In vitro tests, SG at concentrations of 0.5 mg/L and 2 mg/L resulted in death of all theronts and tomonts, respectively; SG at concentrations of 0.125 mg/L and 0.25 mg/L notably decreased theronts infectivity (p < 0.05). Additionally, the in vivo test results showed that a cumulative delivery of SG at concentration of 2 mg/L for 7 days protected fish from I. multifiliis infection. The 96-h LC50 (median lethal concentration) and safety concentration of SG to grass carp were 46.6 mg/L and 11.3 mg/L, respectively. The present work indicated that SG was a potential safe and effectively therapeutic agent in treating I. multifiliis.

Combined effects of S-metolachlor and benoxacor on embryo development in zebrafish (Danio rerio)

It is necessary to study the combined toxicity of an herbicide and its safener because the two are often used in combination. S-metolachlor and its safener benoxacor have been detected in aquatic environments and can individually damage the oxidative stress system in zebrafish embryos (Danio rerio). However, only their separate toxicity in zebrafish (Danio rerio) embryo development has been reported. This study assessed the combined toxicity of benoxacor and S-metolachlor in zebrafish embryo development, including acute toxicity, developmental toxicity, oxidative damage, and cell apoptosis. The 96-h LC50 values were higher in mixtures of benoxacor and S-metolachlor than in benoxacor alone. The treatments included S-metolachlor, Mix-1 (0.1 mg/L benoxacor + 0.1 mg/L S-metolachlor), Mix-2 (0.1 mg/L benoxacor + 0.3 mg/L S-metolachlor) and benoxacor alone. Embryos exposed to Mix-1 and Mix-2 had lower developmental toxicities, superoxide dismutase (SOD) activity, osx and cat expression levels than those exposed to benoxacor alone. Moreover, glutathione S-transferase (GST), catalase (CAT), glutathione reductase (GR), glutathione peroxidase (GPx) activities, and the expressions of tbx16, nrf2, bcl2, and caspase9 were higher in the mixtures than in the benoxacor group. High-throughput RNA sequencing revealed that benoxacor had a greater effect on gene regulation than Mix-1 and Mix-2. The malformation rate, different enrichment gene numbers, and gene expression levels of hatched embryos were higher in Mix-1 than in Mix-2. The results indicate that a mixture of S-metolachlor and benoxacor has antagonistic effects in the early stage of embryo development. The mixtures can break the reactive oxygen species balance, causing abnormal cell apoptosis and developmental malformation in embryos. Besides investigating the combined toxicity of benoxacor and S-metolachlor in zebrafish embryo development, this study provides a risk assessment basis for a herbicide combined with its safener.

Toxic Effects of Organophosphorus and Organochlorine Pesticides on Testudineus (Bloch)

Now-a-day modern techniques employed in agriculture and newer chemicals used have contributed much to environmental pollution, particularly to water pollution. This can result in local effects on the environment. The killing of fish by pesticides is quite common. In the present paper, an attempt has been made to evaluate the impact of 48-h LC 50 concentration of Organphosphors (Cythion and Metacid) and Organochlorine (DDT and Lindane) on the coagulation time (CT) and the total Thrombocyte count (THC) of male and female Anabas testudineus used animal. The study reveals towards pathological disturbances involiving injury and haemorrhage in tissues of the test fish with significant lowered CT value and higher THC count at different levels of the ‘t’ value. Therefore, gradual phasing out of pesticides in fishery resources in fishery resources is suggestive. Further in order to check the use and accidental entry of pesticides in the water bodies, a number of alternative pest control methods have been developed but a complete success has not yet been achievd and thus more needed in this direction.

Is there a common mechanism of neonicotinoid resistance among insects? Preliminary results show that F1 larvae of pre-exposed Chironomus xanthus are more tolerant to imidacloprid

Imidacloprid (IMI) belongs to the group of the first generation of neonicotinoids, known for their toxic effects to non-target invertebrate species. Neonicotinoids have a specific mode of action that mimics acetylcholine, impairing the cholinergic neurotransmission, ultimately affecting the survival of organisms. This research aimed to determine the effects of a commercial formulation based on IMI on survival, and life traits parameters to larvae of parental (P) and F1 generations of the non-target insect Chironomus xanthus. C. xanthus is a bioindicator species of environmental change of great ecological relevance in tropical freshwater systems. The 48-h LC50 of IMI was 23.72 µg/L. Environmentally relevant concentrations of IMI impaired the development of larvae, delayed emergence and diminished the fecundity and fertility rates. However, a physiological adaptation of C. xanthus larvae from the parental generation to the filial generation can be suggested. This finding seems to be a key factor determining the resistance to neonicotinoids in pest species. Further biochemical studies should be carried out to unravel possible physiological adaptations focused on detoxification processes and variability of nicotinic receptors that allow the increase of resistance over generations of insect species of interest.

Toxicity of mefentrifluconazole enantiomers on multiple stages of zebrafish (Danio rerio)

Mefentrifluconazole is a new chiral triazole fungicide with high efficiency and broad spectrum. Zebrafish embryos, larvae and adults were exposed to mefentrifluconazole racemate and enantiomers to investigate aquatic toxicity of mefentrifluconazole at the enantiomer level. Acute toxicity tests were conducted to determine the lethality of mefentrifluconazole. The developmental toxicity of mefentrifluconazole to embryos and larvae was also assessed during acute exposure. Besides, the growth parameters of adults were evaluated after 14 days’ exposure. The 96-h LC50 ranges of rac-, R-(−)- and S-(+)-mefentrifluconazole to all zebrafish life-stages were 0.753–1.198, 1.092–2.022 and 0.583–1.056 mg/L respectively. Larvae were the most sensitive to mefentrifluconazole in terms of lethality, followed by embryos and adults. During acute exposure, morphological deformities caused by mefentrifluconazole, such as yolk sac edema and pericardial edema in embryos, as well as pericardial edema and spinal curvature in larvae were discovered. Besides, mefentrifluconazole induced significant developmental defects, including inhibited heartbeat and reduced body length in both embryos and larvae. After 14 days’ mefentrifluconazole exposure, severe growth inhibition in adult zebrafish was observed. Mefentrifluconazole shows enantioselective toxicity in all stages of zebrafish, and the order of toxicity is S-(+)-mefentrifluconazole > rac-mefentrifluconazole > R-(−)-mefentrifluconazole. Further study is required to explore the specific enantioselective mechanism. Our findings enable a better understanding of the potential risk of mefentrifluconazole to aquatic ecosystems at the enantiomer level.

Behavior and toxicity assessment of copper nanoparticles in aquatic environment: A case study on red swamp crayfish

With the wide use of copper nanoparticles (CuNPs) in various industrial and commercial applications, they inevitably enter the aquatic environment. However, their behavior in the aquatic environment and potential toxicity to aquatic organisms remain little known. In this study, we investigated the behavior of CuNPs in freshwater, as well as the toxicity and bioaccumulation of CuNPs and copper sulfate (CuSO4), used as a positive control for copper ions toxicity, in red swamp crayfish (Procambarus clarkii). The results showed that CuNPs released copper ions into freshwater and aggregated rapidly in freshwater, and their release of copper ions and aggregation slowed down at a higher concentration of CuNPs. The calculated 72-h LC50 values for crayfish were 1.18 and 0.54 mg/L for CuNPs and CuSO4, respectively. Cu accumulation in the gill and hepatopancreas from CuSO4 treatments was significantly higher than that from CuNPs, and the highest Cu bioaccumulation level in crayfish was found in the gill, followed by hepatopancreas and muscle with the exposure of copper. The activities of the antioxidative enzymes in the crayfish significantly decreased after exposure to CuNPs for 48 h, compared to the control (without CuNPs or CuSO4). Histological examination revealed that there was no significant alteration of hepatopancreas in the crayfish exposed to CuNPs. Meanwhile, the growth of crayfish was not significantly inhibited by CuNPs. These results suggested that CuNPs exposure can induce oxidative stress in the crayfish, gill is the main tissue for their accumulation, and their toxicity is mainly caused by the released copper ions.

Toxic effect of triphenyl phosphate (TPHP) on Cyprinus carpio and the intestinal microbial community response

Triphenyl phosphate (TPHP) is a kind of organophosphorus flame retardants, and its use is increasing annually. However, the toxic effect associated with exposure to it has not been adequately investigated. Therefore, in this study, we determined the toxic dose of TPHP in the economic fish species, Cyprinus carpio. Acute and subacute toxicity tests were conducted, and the enrichment of TPHP in the gills, brain, intestines, and liver were determined by Liquid Chromatography-Mass Spectrometry, and the response of carp gut microbial community to TPHP stress was determined using 16 S rRNA gene high-throughput sequencing. Results showed that the 96-h LC50 of TPHP in carp was 7 mg/L. At the 7 d, the order of TPHP absorption was as follows (from highest to lowest): gills > intestine > liver > brain, but at the 28 d and the purification period, the order of TPHP absorption was brain > gills > intestine > liver. TPHP exposure at 3.5 mg/L decreased α-diversity of the intestinal microbial community (p < 0.05), and altered community composition, in particular the relative abundance of dominant microbial populations. Functional profiles of the microbial communities predicted based on 16 S rRNA gene data showed upregulation in the degradation of exogenous substances and energy metabolism of the TPHP-treated groups (p < 0.05), suggesting that intestinal microbial taxa play a role in reducing TPHP toxicity. The results provide insights that could facilitate risk assessments of TPHP pollutants in aquatic environments and the management of associated water pollution.

Isolation and screening of sulfur-oxidizing bacteria from coast of Bhavnagar, India, and formulation of consortium for bioremediation.

Reduced sulfur compounds are a nuisance in coastal industries causing heavy economical as well as ecological loss. One such compound, hydrogen sulfide, is proven toxic to aquatic animals as it interferes with their respiration and metabolism as well as overall development, thereby causing direct increase in mortality. Typically, 96-h LC50 values to freshwater and marine fishes are 0-25µM and 525-700µM, respectively. Management of sulfide and other reduced sulfur compounds from aquaculture water and sediment using bioremediating sulfur-oxidizing bacteria as probiotics has attracted attention in recent decades due to its efficiency and minimized environmental effects. In the present study, 201 native and indigenous probiotic candidates were isolated, from various coastal environments. The prospective candidates were screened based on pH reduction and 19 sulfur-oxidizing bacteria were selected and tested for salt tolerance. Further screening was done based on biosafety, ability to produce sulfate by oxidizing thiosulfate, and 16S rRNA-based identification to obtain nine probiotic candidates. Three strains (Enterobacter ludwigii HS1-SOB, Pseudomonas stutzeri B6-SOB, and Cytobacillus firmus C8-SOB) exerting highest sulfate-ion production were selected for formulating a probiotic consortium using mixture design matrix. The optimal composition was determined to be equal ratios of the three isolates that yielded 0.083mM of sulfate from thiosulfate broth medium at room temperature in 7days. This is a standalone report of sulfur-oxidizing probiotic consortium composed of the said bacteria. The consortium may be used as a strong tool for remediation of reduced sulfur in aquaculture and associated coastal environments.

HISTOPATHOLOGICAL ALTERATIONS OF THE GILL, LIVER AND IDNEY OF THE FISH CATLA CATLA (HAMILTON) EXPOSED TO DICHLORVOS 76% EC (NUVAN)

The fish, Catla catla exposed to an organophosphate Dichlorvos 76% EC (Nuvan) in the laboratory for 10 days in sublethal concentration as 1/10th of 96h LC50 value (1.445 µg/l). The architectural damages of the entry point of the gill, the respiring organ was damaged that impairs the process of respiration. As heterotrophic organisms, the fish depend on the respiring gas for the metabolism which is effected and as a result the growth can be curtailed. The liver the site of metabolism because of its devastating manifestation in it as lesions, all the biochemical interactions are impeded. The exit point of the toxicant, the excretory organ kidney when was defaced in its internal structure, the aminotellic excretory aspect was effected.

Behavioral, physiological, and inflammatory responses of Oreochromis niloticus fish exposed to thallium and/or supplementation with Astragalus membranaceus polysaccharides

The present study was conducted to investigate the behavioral, biochemical, and molecular responses of Oreochromis niloticus fish exposed to sublethal concentration of thallium (T1; 1/10th of 96-h LC50 = 41.9 μg/L) for 60 days. The beneficial role of Astragalus membranaceus polysaccharides (ASP) as a dietary supplement (0.15% and 0.30% diet) in attenuating the resulted alterations was also studied. T1 increased the agressive behaviuor of fish in asociasion with reduction of brain levels of serotonine, GABA and amino acids neurotransmitters. Moreover, the activities of Na+/K+-ATPase and acetylcholine esterases (AchE) were reduced following exposure to T1. T1 also diminsh the catalase (CAT) activity in the brain while elevated the content of oxidative stress markers (protein carbonyl; PC and malondialdhyde; MDA) and DNA damage variables together with overexpressions of the TNF-α, IFN-γ, and IL-1β and stress related genes (P53, Caspase-3 and HSP70) in the brain of fish. In addition, T1 exposure upregulated the expressions of stress related genes, P53, Caspase-3 and HSP70 in the brain. Co-supplementation of ASP (especially at 0.30% diet) with T1 significantly ameliorated the toxic effects of the trace metal. The observasions of the present study indicated the neuroprotective activity of ASP represented by antioxidant, antiapoptotic and anti-inflammatory events evoked by ASP in T1-exposed fish. In conclusion, the supplementation of O. niloticus diet with ASP might be a promising step for reducing the stress of pollution and keeping the behavior pattern and health of the fish.

Evaluation of toxic effect of insecticide, herbicide and fungicide as single and mixture on Gammarus lacustris using biochemical markers

ABSTRACT In the present study, the acute toxic effects of single, double, and triple mixtures of imidacloprid, azoxystrobin, and glyphosate on Gammarus lacustris were investigated. Initially, the 96-hour median lethal dose (LC50) values for imidacloprid, azoxystrobin, and glyphosate were determined as 157, 1.92, and 4.33 mg L−1, respectively. The animals were exposed to one-fiftieth of the 96-h LC50 concentration for 24 or 96 h. The activity of glutathione S-transferase (GST), glutathione reductase, acetylcholinesterase, carboxylesterase (CaE), and superoxide dismutase enzymes as biological markers were examined to determine the non-lethal effects of the pesticides tested. Significant changes were observed in GST and CaE activities especially in detoxification compared to control and between different applications. The results of this study show the potential for increased toxicity in organisms exposed to pesticide mixtures.

Physicochemical characteristics and toxicity studies of crude oil, dispersant and crude oil-- dispersant test media to marine organisms

In this study, the physicochemical characteristics of crude oil, dispersant and crude oil-dispersant test systems and their toxicities on representative marine organisms in a simulated marine ecosystem was assessed. Mechanically dispersed crude oil-in-water test system (MDO) and its water accommodated fraction (WAF) alone, and in combination with a third generation dispersant (D) (Ecobest®), which gave rise to chemically dispersed crude oil-in-water test system (CDO) and its water accommodated fraction (CEWAF), as well as a reference toxicant, sodium dodecyl sulphate (SDS) were used to evaluate toxicities on selected marine organisms (Fish – Tilapia guineensis, Crustacean – Palaeomontes africanus, and Bacteria – Total heterotrophic bacteria and hydrocarbon utilizing bacteria). Physicochemical characteristics were done using standard methods. The static with renewal bioassay option was employed for toxicity tests involving Fish and Crustacean, while the static without renewal option was used for microbial bioassays. Marine organisms were exposed to the following concentrations: 1000, 500, 250, 125, 62.5 and 0 mg/L of MDO, CDO, D, WF and CEWAF, respectively. The LC50 (lethal concentration that resulted in 50% mortality) at 96h and toxicity factors were determined. Results for physicochemical characteristics of the test systems showed that the pH, dissolved oxygen levels were sufficient for sustaining aquatic habitation. Lead metal was present in high amounts in the dispersant test system, but relatively low in chemically dispersed test systems. Cd and Ni were also present at relative amounts that could be toxic to aquatic lives. Toxicity data showed that the new dispersant, Ecobest® was non-toxic to the tested marine organisms relative to the reference toxicant (SDS), which was moderately toxic. The 96h LC50 of MDO, CDO, D, WAF, CEWAF and SDS were 89.8, 225.6, 1891.8, 683.9, 528.1 and 1.37 for T. guineensis, and 275.5, 137.7, 3800.9, 76.1, 168.3 and 9.99 for P. africanus, and 1658.5, 944.1, 17221.9, 228641.0, 1036319.3 and 3.84 for total heterotrophic bacteria. The reference toxicant, SDS, was the most toxic of the toxicants, but the dispersant reduced the toxicity y several folds. However, with the presence of some heavy metals, notably Pb, Cd and Ni, and some levels of polycyclic aromatic hydrocarbons in the test media water, there may be likelihood for bioaccumulation to occur in the tissues of marine organisms.

Acute toxicity of tire wear particles, leachates and toxicity identification evaluation of leachates to the marine copepod, Tigriopus japonicus

Tire wear particles (TWPs) have been characterized as microplastics in recent years, and many of these TWPs will be eventually deposited in coastal areas, leading to adverse effects to marine organisms. Results of the acute toxicity test in this study showed that the 96-h LC50 values of the particles and leachate were 771.4 mg/L (95% CI = 684.4–869.6 mg/L) and 5.34 g/L (95% CI = 4.75–6.07 g/L), respectively. The chemical constituents of TWP and the leachate are very complex, and little research has been conducted to determine which of these constituents contribute to the toxicity of TWP leachate to marine organisms. Therefore, the composition of the TWP and leachate was analyzed, and a variety of chemicals were identified, including metals (Mn, Zn, etc.) and organic compounds (cyclohexanthiol, 4-ethyl-1,2-dimethylbenzene, benzothiazole, stearic acid, N-(1,3-dimethylbutyl)-N′-phenyl-p-phenylenediamine, etc.). In addition, the marine copepod Tigriopus japonicus was applied as a model species in the toxicity identification evaluation study to characterize, identify and confirm the toxicity-causing substances in the TWP leachate. Zn was identified and confirmed as the main toxicant contributing to the toxicity. Furthermore, Zn concentrations in the leachate over time were investigated. The release of Zn from TWPs to the aquatic environment was slow, and conformed to a parabolic model with a release constant k of 2.06. The organic component, benzothiazole, exhibited an antagonistic effect with zinc in the acute toxicity of the TWP leachate.

Accumulation, Chronicity, and Induction of Oxidative Stress Regulating Genes Through Allium cepa L. Functionalized Silver Nanoparticles in Freshwater Common Carp (Cyprinus carpio).

Green evolutionary products such as biologically fabricated nanoparticles (NPs) pose a hazard to aquatic creatures. Herein, biogenic silver nanoparticles (AgNPs) were synthesized by the reaction between ionic silver (AgNO3) and aqueous onion peel extract (Allium cepa L). The synthesized biogenic AgNPs were characterized with UV-Visible spectrophotometer, XRD, FT-IR, and TEM with EDS analysis; then, their toxicity was assessed on common carp fish (Cyprinus carpio) using biomarkers of haematological alterations, oxidative stress, histological changes, differential gene expression patterns, and bioaccumulation. The 96h lethal toxicity was analysed with various concentrations (2, 4, 6, 8, and 10mg/l) of biogenic AgNPs. Based on 96h LC50, sublethal concentrations (1/15th, 1/10th, and 1/5th) were given to C. carpio for 28days. At the end of experiment, the bioaccumulations of Ag content were accumulated mainly in the gills, followed by the liver and muscle. At an interval of 7days, the haematological alterations showed significance (p < 0.05) and elevation of antioxidant defence mechanism reveals the toxicity of biogenic synthesized AgNPs. Adverse effects on oxidative stress were probably related to the histopathological damage of its vital organs like gill, liver, and muscle. Finally, the fish treated with biogenic synthesized AgNPs were significantly (p < 0.05) downregulates the oxidative stress genes such as Cu-Zn SOD, CAT, GPx1a, GST-α, CYP1A, and Nrf-2 expression patterns. The present study provides evidence of biogenic synthesized AgNPs influence on the aquatic life through induction of oxidative stress.

Combined effects of the pesticide spinetoram and the cyanobacterium Microcystis on the water flea Daphnia pulex.

Spinetoram is one of the most worldwidely used pesticides for its high insecticidal efficacy and low human toxicity. Following the large usage of spinetoram, the ecotoxicity and environmental risks to aquatic ecosystems have call for urgent study. In the present study, we investigated the combined effects of spinetoram and the harmful alga Microcystis aeruginosa in freshwater, on survival and reproduction of Daphnia pulex. Acute toxicity test of spinetoram resulted in negative effects on survival, with a 48-h LC50 value of 37.71μg L-1. Under the long-time exposure to environmentally relevant concentrations (0.18 and 0.35μg L-1) of spinetoram and a low composition of Microcystis (30%) in the diet, D. pulex showed both shorter longevity and lower fecundity; the time to first brood also increased. At population level, carrying capacity was highly decreased by spinetoram and Microcystis, whereas a significant decrease of intrinsic growth rate was observed at 0.35μg L-1 spinetoram with 30% Microcystis as food. The present study highlighted that pesticide spinetoram had highly toxic effects on D. pulex and could reduce the tolerance of D. pulex to M. aeruginosa, causing great effects on D. pulex population in natural waterbodies.

Assessing the potential toxicity of paint industry effluents to aquatic organisms using the whole effluent testing (WET) approach.

Point source effluent discharges from industries are major sources of pollutants in aquatic ecosystems. In this study, the whole effluent testing approach was used to assess the toxicity of paint industry effluents to fish. Effluents were collected from three paint industries at point of discharge into the environment. Bioassay procedures were used to assess the toxicity of the effluents to fish. Effluent B was the most acutely toxic to the fish with a 96h LC50 value of 3.50% dilution (v/v). The acute toxicity ranking of the effluents to the fish was B > C > A. Analysis of the biochemical parameters of fish exposed to sublethal dilutions of the effluents showed that the three effluents significantly (p < 0.05) enhanced the activities of liver function enzymes and oxidative stress enzymes in exposed fish. The levels of malondialdehyde, a substrate of oxidative stress, was also significantly (p < 0.05) higher in fish exposed to the effluents (3.87 ± 0.40, 4.99 ± 0.45, and 3.22 ± 0.57 U mg-1 protein for effluents A, B, and C, respectively) compared to levels in control (1.24 ± 0.31 U mg-1 protein). Results from this study have established that untreated or poorly treated paint industry effluents can be highly toxic to aquatic organisms, having the potential to disrupt normal functioning of organisms at low concentrations. The study highlights the advantages of whole effluent testing as a method that accurately predicts the toxic potentials of industrial effluents. This is vital for the adequate protection aquatic ecosystems.

Silica nanoparticles acute toxicity alters ethology, neuro-stress indices, and physiological status of African catfish (Clarias gariepinus)

Silica nanoparticles (SiNPs) are a new class of nanomaterials with unique properties due to their nanoscale size. Currently, SiNPs constitute a potential value in aquaculture; nonetheless, misuse induces toxicity to fisheries and ecosystems. Hence, the present prospective is a pioneer study that illustrates the acute toxicity of SiNPs to African catfish, Clarias gariepinus (B.) and the behavioral response in a renewal static system. Moreover, the influence of SiNPs on neuro-related, stress, immune-related, and oxidative stress indices was investigated. Fish groups of average body weights (73.09 ± 2.20 g) were exposed to 96-h of various concentrations of SiNPs including 0, 50, 100, 150, 200, 250, and 300 mg L−1 without water exchange. The value of 96-h LC50 of SiNPs was computed using Finney's probit analysis. Here we show that the exposure of fish to SiNPs resulted in remarkable ethological alterations such as lethargic, surfacing, inactive, slow swimming manner, and nervousness. By increasing the SiNPs concentration, the behavior scores and mortalities reached the upper limit of top values. The comparison with the control revealed a significant dose-dependent effect by increasing in the activity of 8-hydroxy-2-deoxyguanosine (8-OHdG) and malondialdehyde (MDA) with a concomitant elevation in the stress-controlled parameters (cortisol and nor-epinephrin) of all the fish groups undergone the SiNPs exposure. In contrast, there was a clear reduction in the acetylcholine esterase (AChE) level, immunological biomarkers (lysozymes and nitric oxide), and antioxidant enzymes (glutathione peroxidase (GPX) and superoxide dismutase (SOD)) of the exposed groups and the reduction elevated by increasing the SiNPs exposure concentration in comparison to the control group. Based on the study outcomes, the 96-h LC50 of SiNPs recorded 144.54 mg L−1 in C. gariepinus. We anticipate our assay to be a starting point for further applying the one-tenth of 96-h LC50- as an alternative safe treatment in therapy after considering the acute toxicity to preserve the aquaculture production and sustain human health. Additionally, it was approved that, the toxicity by the exposure to SiNPs observed clear alterations in fish behavior, neurological activity, immune and oxidative responses reflecting physiological disturbance.

Alterations in hematological parameters and the structure of peripheral erythrocytes in Nile tilapia (Oreochromis niloticus) exposed to profenofos.

The burden of pesticide use from agricultural intensification lies in the fact that pesticides may end up in aquatic ecosystems and have pernicious effects on non-target organisms, including fish. Different blood biomarkers, including hemato-biochemical indices, erythrocytic nuclear abnormalities (ENA), and erythrocytic cellular abnormalities (ECA), were observed in Nile tilapia (Oreochromis niloticus) after exposure to varying sub-lethal concentrations (0%, 5%, 10%, 20%, and 40% of 96-h LC50) of profenofos at different time intervals (7, 14, 21, and 28days). The results revealed that glucose and white blood cell (WBC) levels significantly increased, while hemoglobin, red blood cell (RBC), and packed cell volume (PCV) significantly decreased in a time- and concentration-dependent manner. Aberrant erythrocytic morphology-derived ENA, such as nuclear degeneration, micronuclear formation, binuclear development, nuclear budding, and karyopyknosis, significantly increased with time in profenofos-exposed groups compared to controls. Between the treatment and control groups, a significant execution was discerned for teardrop and fusion type ECA. For other cellular aberrations of erythrocytes, including elongated, twin, and spindle, a significant difference appeared only at the beginning of the experiment (day 7). This study concludes that the presence of widely used profenofos in aquatic systems has a pernicious effect on Nile tilapia.

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

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