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Pyrogallol, a botanical hydrolysable tannin, has diverse medical and industrial applications. Its impact on aquatic ecosystems and fish health has been previously studied, revealing histopathological, immunological, biochemical, and haematological alterations in African catfish (Clarias gariepinus). In this study, the neurotoxic potential of pyrogallol was assessed through a 15-day exposure of catfish to concentrations of 1, 5, or 10 mg/L. Enzyme activities such as acetylcholinesterase (AchE), monoamine oxidase (MAO), aldehyde oxidase (AO), and nitric oxide (NO) were measured in serum and brain, along with histopathological examinations in the brain and heart. Pyrogallol exposure led to decreased AchE activity in the brain and serum, increased serum MAO activity, elevated AO in both brain and serum, and suppressed NO levels. Morphological abnormalities and dose-dependent pathological alterations were observed in the brain and heart, including neuropile deformities, shrunken Purkinje cells, cardiomyocyte degeneration, and increased collagen fibers. This suggests that pyrogallol induces adverse effects in fish., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Published by Elsevier B.V.)

Endocrine disruptors are synthetic or natural chemicals that can agonize/antagonize hormone receptors or can interfere with the production and secretion of hormones, leading to altered tissue histology and physiology. Pyrogallol is a contaminant widely distributed in aquatic environments that presents health risks to both humans and animals. However, the potential for endocrine disruption by pyrogallol, particularly in fish, are lacking. The purpose of this study was to shed light on how pyrogallol may affect hormone signalling, histopathology, and reproductive outcomes in African catfish Clarias gariepinus. To investigate this, African catfish were exposed to one sublethal concentration of pyrogallol at either 0, 1, 5 or 10 mg/L for 15 days. We then assessed the effects of pyrogallol on the thyroid gland as well as the reproductive system by measuring sex hormone, seminal quality, gonadal histopathology, and histochemistry. Thyroid stimulating hormone and thyroxine showed notable decreases in catfish, and triiodothyronine was decreased with 10 mg/L pyrogallol. Unlike luteinizing hormone, follicle-stimulating hormone was significantly reduced in fish following exposure to pyrogallol relative to controls. Testosterone was also decreased in fish following pyrogallol exposure, whereas 17β-estradiol increased in catfish exposed to pyrogallol. Additionally, in response to pyrogallol toxicity, sperm quality indices, including count, spermatocrit, motility, and sperm viability were adversely affected in a concentration-dependent manner. Pyrogallol exposure also induced several changes in the gonad following exposure to 1, 5, or 10 mg/L. Deformed tubular structures, vacuolation, thickening of the basement membrane, hypertrophy of the seminiferous tubules, intense melanomacrophage localization, spermatozoa loss, and necrosis were all observed in the testes. In the ovary, atretic follicles, deteriorated mature oocytes, degenerated yolk globules, and an increase in perinucleolar oocytes were observed in catfish exposed to pyrogallol. These findings suggest that pyrogallol may act as endocrine disrupting substance in aquatic environments. Further research on the mechanisms by which pyrogallol impairs endocrine systems, particularly in fish, is recommended., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Pyrogallol promotes free radicals leading to oxidative stress and toxicity. There are however a lack of studies on oxidative stress and the antioxidant system of fish following exposure to pyrogallol. This study measured oxidative stress markers, antioxidant responses, and histological changes in catfish exposed to pyrogallol. Fish were divided into one of four experimental groups: control only, or 1, 5 or 10 mg/L pyrogallol. After 15 days, glutathione-S-transferase in the serum was decreased in fish exposed to either 5 or 10 mg/L pyrogallol relative to controls while superoxide dismutase and total antioxidant capacity were decreased significantly in fish exposed to 1, 5, or 10 mg/L pyrogallol. Conversely, catalase was increased in serum of fish exposed to 1, 5, or 10 mg/L pyrogallol compared to controls. The liver of fish treated with 1, 5, or 10 mg/L pyrogallol had significantly higher levels of oxidative stress markers (malondialdehyde, lipid peroxidation, hydroperoxide content, oxidised protein content, and DNA fragmentation %) that varied with concentration. Catfish exposed to either 1, 5, or 10 mg/L pyrogallol presented with notable histological alterations in the intestine, kidney, and muscles with prominent fibrosis, as intense deposition of collagen fibre was observed by Masson's trichrome staining. Overall, endpoints related to oxidative stress and antioxidant defence enzymes in fish may be early biomarkers of pyrogallol exposure and contamination in aquatic ecosystems. Additional studies should characterize oxidative stress indicators for their utility as biomarkers of effect., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier Ltd. All rights reserved.)

Pyrogallol is a naturally occurring polyphenol derived from natural plants, such as Acer rubrum and Eucalyptus sp. The current study was designed to evaluated pyrogallol-mediated toxicity at sublethal levels (1, 5, and 10 mg/L), derived from 96 h-LC 50 values previously determined for African catfish (Clarias gariepinus). Immunotoxicological indices, histological, histochemical, and ultrastructural alterations in C. gariepinus were evaluated following a 15-day pyrogallol exposure. Pyrogallol decreased immune parameters [lysozyme activity (LYZ), immunoglobulin M (IgM), and phagocytic activity] and increased pro-inflammatory cytokines, interleukin-1 beta (IL-1β), interleukin-6 (IL-6) in the serum of C. gariepinus. In addition, histopathology analysis demonstrated that exposure to pyrogallol induced injury in the liver and spleen of fish. Cellular changes in the liver include hepatocyte hydropic degeneration, melanomacrophage, vacuolated hepatocytes, congested blood, severe structural deformation, and hemorrhage. In the spleen, ellipsoid structures, melanomacrophage centers, and infiltration of inflammatory cells were evident. Together, a high frequency of histopathological lesions was scored in both the liver and spleen of C. gariepinus, which showed a dose-dependent relationship between pyrogallol exposure and histopathological indices. Our data suggest that dysfunction in the immune system may be mediated by pyrogallol-induced changes in cytokines., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier Ltd. All rights reserved.)

Pyrogallol is widely used in several industrial applications and can subsequently contaminate aquatic ecosystems. Here, we report for the first time the presence of pyrogallol in wastewater in Egypt. Currently, there is a complete lack of toxicity and carcinogenicity data for pyrogallol exposure in fish. To address this gap, both acute and sub-acute toxicity experiments were conducted to determine the toxicity of pyrogallol in catfish (Clarias gariepinus). Behavioral and morphological endpoints were evaluated, in addition to blood hematological endpoints, biochemical indices, electrolyte balance, and the erythron profile (poikilocytosis and nuclear abnormalities). In the acute toxicity assay, it was determined that the 96 h median-lethal concentration (96 h-LC 50 ) of pyrogallol for catfish was 40 mg/L. In sub-acute toxicity experiment, fish divided into four groups; Group 1 was the control group. Group 2 was exposed to 1 mg/L of pyrogallol, Group 3 was exposed to 5 mg/L of pyrogallol, and Group 4 was exposed to 10 mg/L of pyrogallol. Fish showed morphological changes such as erosion of the dorsal and caudal fins, skin ulcers, and discoloration following exposure to pyrogallol for 96 h. Exposure to 1, 5, or 10 mg/L pyrogallol caused a significant decrease in hematological indices, including red blood cells (RBCs), hemoglobin, hematocrit, white blood cells (WBC), thrombocytes, and large and small lymphocytes in a dose-dependent manner. Several biochemical parameters (creatinine, uric acid, liver enzymes, lactate dehydrogenase, and glucose) were altered in a concentration dependent manner with short term exposures to pyrogallol. Pyrogallol exposure also caused a significant concentration-dependent rise in the percentage of poikilocytosis and nuclear abnormalities of RBCs in catfish. In conclusion, our data suggest that pyrogallol should be considered further in environmental risk assessments of aquatic species., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier Ltd. All rights reserved.)

The present study described the most recent findings concerning the abundance and distribution of plastic in water, sediment, and fauna in the Nile River of Upper Egypt as an interesting research point. The findings revealed that plastics were abundant in the water, sediments, fish, and crayfish throughout the sites. The Nagaa Hammadi site has the highest abundance of meso- and macroplastics in its water and sediment. African catfish had the highest abundance of meso- and macroplastics compared to the other species, while Nile tilapia had no meso- or macroplastics in its alimentary canal or gills in all sites. The Edfu site has the highest abundance of mesoplastics in the alimentary canals of African catfish, while the Nagaa Hammadi site has the highest abundance of mesoplastics in the gills, and macroplastics appeared only in the alimentary canal of African catfish from the El-wasta site. Only mesoplastics were found in the crayfish's alimentary canal, with the Nagaa Hammadi site having the highest abundance. No macroplastics were detected in the crayfish's gills or alimentary canal. Additionally, this work lets us understand how plastics behave in freshwater environments, and it is a step toward decision-makers taking appropriate measures to reduce their risk., (© 2023. The Author(s).)

This study records the extent of microplastics (MPs) in the surface water, sediments, and fishes of the Mediterranean and Red seas in Egypt. In sediment and water samples, the Ras Gharib station in the Red sea and Damietta and Port Said stations in the Mediterranean sea exhibited the highest microplastic abundance, while the lowest concentration was found in the Ain Sukhna station in the Red Sea and Marsa Matruh station in the Mediterranean sea. Rayon and polyethylene terephthalate were the most frequently found polymers in fishes. The results highlighted the abundant existence of microplastics in sediments, water, and fishes of the Mediterranean and Red seas, thereby improving our understanding of the environmental risks posed by microplastics to fisheries and marine ecosystems and the need for measures to diminish the flux of plastics to the marine settings., (Copyright © 2021 Elsevier Ltd. All rights reserved.)

This study aims to assess the impact of microplastics (MPs) on erythrocytes using eryptosis (apoptosis) and an erythron profile (poikilocytosis and nuclear abnormalities), considered to be novel biomarkers in Nile tilapia ( Oreochromis niloticus) . In this study, four groups of fish were used: The first was the control group. In the second group, 1 mg/L of MPs was introduced to the samples. The third group was exposed to 10 mg/L of MPs. Finally, the fourth group was exposed to 100 mg/L of MPs for 15 days, following 15 days of recovery. The fish treated with MPs experienced an immense rise in the eryptosis percentage, poikilocytosis, and nuclear abnormalities of red blood cells (RBCs) compared with the control group in a concentration-dependent manner. Poikilocytosis of MP-exposed groups included sickle cell shape, schistocyte, elliptocyte, acanthocyte, and other shapes. Nuclear abnormalities of the MPs-exposed groups included micronuclei, binucleated erythrocytes, notched, lobed, blebbed, and hemolyzed nuclei. After the recovery period, a greater percentage of eryptosis, poikilocytotic cells, and nuclear abnormalities in RBCs were still evident in the groups exposed to MPs when crosschecked with the control group. The results show concerning facts regarding the toxicity of MPs in tilapia., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2021 Hamed, Osman, Badrey, Soliman and Sayed.)

Although microplastics (MPs) have received increasing focus and currently have become an emerging area of research, there is limited knowledge about their effect on whole body histology of fish. In this study, tilapia (Oreochromis niloticus) early juveniles were exposed to 1, 10, or 100 mg/L of MPs for 15 days and 15 days post-exposure, after which whole body histological examinations were performed. Histological analysis of kidney revealed congestion of blood capillaries, inflammatory cells, loss of basophilic cytoplasm in several tubules, vacuolated tubules, shrinking of convoluted tubules, widening of intertubular space, complete deformation, glomerular atrophy, vacuolated glomerular cells, and signs of fatty tubules. The liver tissue exhibited vacuoles, hydropic degeneration, necrotic area, severe deformation of hepatocytes, pyknotic nuclei, and dilation and congestion of blood sinusoids. The pancreatic tissue revealed shrunken and degenerated acini with pyknotic nuclei, hemorrhage, necrotic area, inflammatory cells, fatty cells, and congested blood capillaries. In the muscle tissue, fiber core dissociation, edema, necrosis, segmented fibers, and inflammatory cells were detected. The gill tissue demonstrated dilation and congestion of blood vessels, complete lamellar fusions, lifting of epithelium, shortening and degeneration of secondary lamellae, hyperplasia, and deposition of MPs between primary lamellae. In the spinal cord and notochord, the effects were degeneration and protrusion of meninges, deformation and deviation of notochord from its central axis, edema, degeneration of notochord (disappearance of vacuolar cells), deviation of spinal cord from the central axis, and loss of vacuolar cells in notochord. The intestinal tissue exhibited degeneration of basement membrane, inflammatory cells, goblet cells, atrophy of submucosa, pyknotic nuclei, hemorrhage, and vacuolization of mucosal cells. The histopathological changes in different organs were noticed even post-exposure in fish exposed to MPs compared to those in control fish and these changes were concentration dependent. In conclusion, these data together with our previous data suggest that MPs can cause different changes, ranging from biochemical alterations in single cells to lesions in the entire tissue, which can affect the vitality and life of fish., (Copyright © 2021 Elsevier Ltd. All rights reserved.)

Recently, research on the biological effects of microplastics (MPs) has grown exponentially. However, effects of MPs on freshwater fishes and the mechanisms of the biological effects of MPs were limited. So, the purpose of the current study was to clarify the effects of microplastics on oxidative stress response, DNA fragmentation, and proteinogram of the early juvenile stage of Nile Tilapia (Oreochromis niloticus). The fishes were assigned into four groups: one control, three MPs-exposed groups as 1 mg/L of MPs, 10 mg/L of MPs, and 100 mg/L of MPs respectively for 15 days and 15 days of recovery. The activities of superoxide dismutase, catalase, total peroxides, and oxidative stress index (OSI), as well as lipid peroxidation and DNA fragmentation, increased in groups exposed to MPs compared to the control group in a dose-dependent manner. In contrast, the activity of total antioxidant capacity decreased in groups exposed to MPs compared to the control group in a dose-dependent manner. The electrophoretic pattern of muscle proteins revealed alteration in the proteinogram in the MPs-exposed groups compared to control. After the recovery period, the activities of superoxide dismutase, catalase, total peroxides, total antioxidant capacity, lipid peroxidation, DNA fragmentation, and the electrophoretic pattern of muscle proteins returned to normal levels in 1 mg/L of MPs-exposed group. Combined with our previous work, these results suggest that MPs cause the overproduction of reactive oxygen species (ROS) and alters the antioxidants parameters, resulting in oxidative stress and DNA damage. The present study fosters a better understanding of the toxic effects of MPs on Tilapia as a freshwater model. Graphical Abstract.

There is a scarcity of knowledge about the impacts of microplastics (MPs) on the early juvenile stage of freshwater fish. The current study aims to inspect the exposure and post-exposure recovery of microplastics (MPs) on accumulation and blood biomarkers of Nile Tilapia (Oreochromis niloticus) early juvenile. Four groups of fishes were used; the first group was the control group, the second group was exposed to (1 mg/L of MPs), the third group was exposed to (10 mg/L of MPs), and the fourth group was exposed to (100 mg/L of MPs) for 15 days and 15 days of recovery. The results showed that significantly higher numbers of microplastics were observed in microplastics-exposed groups compared to control group. Biochemical parameters (creatinine, uric acid, AST, ALT, ALP, glucose, cholesterol, total protein, albumin, globulin, and A/G ratio) showed significant increment after exposure to microplastics for 15 days compared to control group in dose dependent manner. The hematological indices (RBC's count, Hb, Ht, MCHC, Platelets, WBC's count, and monocytes) showed a significant decline after exposure to microplastics for 15 days compared to control group, while MCV and MCH showed a significant increase after exposure to microplastics for 15 days. After the recovery period, microplastics accumulations, hemato-biochemical alterations were still detected in microplastics exposed groups compared to the control group except for WBC's count and MCV which return to normal levels. MPs caused anemia and perturbations in hemato-biochemical parameters which may cause mortality of tilapia early juvenile and should be considered in a program for monitoring hazard materials in the ecosystem., (Copyright © 2019 Elsevier Ltd. All rights reserved.)

Fish as an aquatic organism could be harmed by various levels of solar ultraviolet radiation (UVA). The present study aimed to characterize UVA (20, 60 and 180 min for 3 days) irradiation-induced hematological and biochemical changes in Oreochromis niloticus. Hematological parameters such as the red blood cell (RBC) count, hemoglobin (Hb) level and hematocrit (Hct) value were significantly (p < 0.05) reduced in fish exposed to different doses of UVA. Also, the leukocyte (WBC) count was significantly reduced (p < 0.05). However, the differential counts of WBCs - lymphocytes, eosinophils and monocytes - increased significantly in the exposed fish compared to the control fish. Many morphological and genotoxic alterations in erythrocytes were observed in the present work. The glucose level showed a significant decrease, but cholesterol and triglycerides showed a significant increase after exposure to UVA. Total protein levels of the fish showed a significant increase (p < 0.05) in the exposed groups. Also, concentrations of urea and creatinine increased significantly as fish were exposed to increasing UVA radiation, compared to the control fish. Finally, the activities of alanine aminotransferase (ALT, U l-1) and aspartate aminotransferase (AST, U l-1) exhibited a significant increase (p < 0.05) with increasing UVA doses.

Groupers are coral fish species of prime ecological and economic significance. The interactions among them and other coral reefs organisms aid the healthiness and species balance in this fundamental marine niches. Also, groupers are among the top priced fisheries species. The Egyptian habitats of the Red Sea are lacking genetic studies that assess species diversity for the final goal of conservation and fisheries management. Moreover, morphological similarities among these organisms sometimes hinder a proper species identification. Hence, more accurate groupers authentication methods are crucially required. Sixteen grouper species belonging to the genera Epinephelus, Anyperodon, Cephaolopholes, Aethaloperca, Variola, and Plectropomus, present in the Red Sea in Egypt, were investigated for species authentication through mitochondrial DNA variations, applying cytochrome oxidase subunit I (COI) and 12srRNA genes sequencing. GenBank comparisons, phylogenetic analyses and comparisons of pairwise distances were carried out. All these analyses aimed to species authentication and identifying their relations at the international scale. The results exhibited >98% identity with E. fasciatus, A. rogaa, C. oligosticta, E. areolatus, V. louti, P. areolatus, E. malabaricus, C. sexmaculata, E. summana, E. chlorostigma, E. polyphekadion, C. miniataus, A. leucogrammicus, E. tauvina, C. argus, C. hemistiktos. Pairwise distances showed a clear increase upon raising comparison level from among species to among-genera. Combined 12srRNA and COI genes sequencing resulted in an accurate tool for Egyptian Red Sea grouper species unambiguous discrimination. This can provide vital aid to the active efforts for these species conservation and fisheries management in Egypt and the world., (Copyright © 2018 Elsevier B.V. All rights reserved.)

In the current study, African catfish, Clarias gariepinus, was exposed to a sublethal concentration of carbofuran (CF) to investigate its negative effects on biochemical and oxidative stress biomarkers. Also, the putative role of lycopene (LYC) administration in alleviating these negative effects was evaluated. Fish were divided into six groups in triplicates as follows: group I was without treatment, group II was orally administered corn oil, group III was orally administered 18 mg LYC/kg body weight, group IV was exposed to 0.121 mg CF/L, group V was orally administered 9 mg LYC/kg body weight and exposed to 0.121 mg CF/L, and group VI was orally administered 18 mg LYC/kg body weight and exposed to 0.121 mg CF/L for 4 weeks. At the end of this period, blood and tissue (liver and kidney) samples were collected and biochemical and oxidative stress biomarkers were analysed. Also, histopathological changes were determined. Carbofuran caused significant increments of glucose, cortisol, aspartic amino transferase, alanine amino transferase, cholesterol, urea, and creatinine; meanwhile, serum acetylcholinesterase, total protein, albumin, and total lipids were significantly reduced. Significant increments in hepatic and renal malondialdehyde (MDA) and superoxide dismutase (SOD) levels and marked reduction in hepatic and renal catalase (CAT), glutathione (GSH), and total antioxidant capacity (TAC) levels were observed in CF-exposed fish comparing to the control group. Treatment with LYC attenuated the CF-induced oxidative stress, and this improvement was more pronounced in fish received the high LYC dose (18 mg/kg body weight). Further, congestion of the central vein with infiltration of mononuclear inflammatory cells, vacuolar necrosis, and haemorrhage was observed in the livers of CF-exposed fish. Oral administration of LYC reduced behavioural changes and histopathological alterations. All the altered biochemical parameters and antioxidant biomarkers were also restored to be near the normal levels. The obtained results evoked that LYC administration alleviated the destructive effects of carbofuran and reduced its toxicity effect on African catfish.

This work is part of a wider eco-toxicological study proposed to evaluate the biological impact of contaminants along the whole course of the river Nile, Egypt. Here we present data on the presence of DNA strand-breaks and apoptotic cells assessed by use of comet and diffusion assays in erythrocytes of Nile tilapia (Oreochromis niloticus niloticus) and African catfish (Clarias gariepinus). The results showed high degrees of DNA damage and increased frequencies of apoptotic nuclei in blood of fish collected from downstream compared with those sampled from upstream river Nile. Qualitative analysis revealed a shift in the frequency of DNA-damage classes towards higher damage levels correlating with the increasing pollution gradient. The degree of DNA damage measured by use of comet assay and diffusion assay exhibited seasonal variations. Both fish species showed significant increases in DNA damage during the summer. The results of our study indicated that the alkaline comet assay seems to be a useful technique for in situ genotoxic monitoring. At the same time the diffusion assay is sensitive enough to detect low frequencies of apoptotic nuclei. The results reveal species-specific differences in sensitivities, suggesting that Nile tilapia may serve as a more sensitive test species compared with the African catfish. Based on the outcome of the comet and diffusion assays, it can be concluded that the water quality of the river Nile with respect to the presence of genotoxic compounds needs to be improved, especially in its estuaries. As far as we know this is the first time that the comet and diffusion assays are used for genotoxic monitoring of the river Nile., (Copyright © 2012 Elsevier B.V. All rights reserved.)