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The discharge and accumulation of malachite green dye in water can pose several risks. This research focuses on studying the safety use of Rhodotorula mucilaginosa MH298827 in the remediation of polluted water with malachite green. Twenty-four Clarias gariepinus fish that acclimatization for 4 weeks in a lab setting were divided into four groups, each group was exposed to 0.25mg/1 for 15 days to one of the following treatment (control without any treatment, malachite green, remediation water by Rhodotorula mucilaginosa MH298827 and Rhodotorula mucilaginosa MH298827). Different Parameters were measured in Clarias gariepinus fish after exposure: The Microbiota (bacterial loads and fungal percentage of occurrence) was examined and counted on one gram of Clarias gariepinus's skin, gills, and intestine. The hematological and biochemical characteristics were measured by drawing blood from the caudal vein of six fish from each group which were chosen randomly and given ice anesthesia. The levels of the liver antioxidant indicators superoxide dismutase, Catalase, and glutathione S-transferase were determined after keeping liver tissue at − 80 °C, homogenized in phosphate buffer (0.1 M pH 7.4), then filtrated, the supernatant was used for analysis after centrifuging for 10 min at 4 °C and 1600 rpm. The erythrocytes with abnormalities and altered morphology were recognized and counted in five fields (about 1500 cells of each fish group) after fixed the smears were in absolute methanol for ten seconds and allowed to dry at room temperature, and the slides were dehydrated in progressively higher alcohol grades and then blood stained with hematoxylin and eosin Ultimately, DPX permanently mounted the slides after they had been cleaned with xylene.

Microalgae have well-established health benefits for farmed fish. Thus, this study aims to explore the potential protective effects of Spirulina platensis, Chlorella vulgaris, and Moringa oleifera against pyrogallol-induced hematological, hepatic, and renal biomarkers in African catfish (Clarias gariepinus), as well as the histopathological changes in the liver and kidney. Fish weighing 200 ± 25 g were divided into several groups: group 1 served as the control, group 2 was exposed to 10 mg/L of pyrogallol, and groups 3, 4, and 5 were exposed to the same concentration of pyrogallol, supplemented with S. platensis at 20 g/kg diet, C. vulgaris at 50 g/kg diet, and M. oleifera at 5 g/kg diet, respectively, for 15 days. Exposure to pyrogallol led to decreased packed cell volume (PCV) and lymphocyte count, but these effects were alleviated by microalgae interventions. C. vulgaris and M. oleifera equally restored PCV and increased lymphocyte counts. Supplementation with C. vulgaris and M. oleifera successfully normalized both neutrophil and eosinophil counts. Pyrogallol intoxication engenders an increase in glycemic status, but C. vulgaris and M. oleifera effectively mitigated this rise. Pyrogallol-exposed fish exhibited signs of renal dysfunction, with increased serum creatinine and total cholesterol levels. A significant decrease in both erythrocytic cellular and nuclear abnormalities was observed following supplementation with microalgae. C. vulgaris and M. oleifera showed promise in decreasing serum glucose and creatinine levels, and improving hematological parameters, while S. platensis exhibited limited efficacy in this regard. Exposure to pyrogallol led to a notable decrease in serum superoxide dismutase activity and total antioxidant capacity (TAC), accompanied by an increase in serum malondialdehyde (MDA) levels. Diets enriched with C. vulgaris and M. oleifera effectively restored these parameters to normal levels, whereas S. platensis did not induce significant changes. None of the microalgae improved TAC except for M. oleifera, which significantly enhanced it. MDA levels returned to control levels equally and significantly across all groups. Interleukin-6 levels did not exhibit significant differences between any of the groups. Collectively, the histopathological changes induced by pyrogallol were most prominently alleviated in the pyrogallol + C. vulgaris and pyrogallol + M. oleifera groups, and to a limited degree in the pyrogallol + S. platensis group. While the tested microalgae did not cause hepatic or renal dysfunction, they did lead to metabolic abnormalities. The incorporation of microalgae into the diet holds significant importance in mitigating the metabolic and histological toxicity of pyrogallol and should be considered in the formulation of fish feed.

Abstract Since its identification in the vitreous humour of the eye and laboratory biosynthesis, hyaluronic acid (HA) has been a vital component in several pharmaceutical, nutritional, medicinal, and cosmetic uses. However, little is known about its potential toxicological impacts on aquatic inhabitants. Herein, we investigated the hematological response of Clarias gariepinus to nominal doses of HA. To achieve this objective, 72 adult fish were randomly and evenly distributed into four groups: control, low-dose (0.5 mg/l HA), medium-dose (10 mg/l HA), and high-dose (100 mg/l HA) groups for two weeks each during both the exposure and recovery periods. The findings confirmed presence of anemia, neutrophilia, leucopoenia, lymphopenia, and eosinophilia at the end of exposure to HA. In addition, poikilocytosis and a variety of cytomorphological disturbances were observed. Dose-dependent histological alterations in spleen morphology were observed in the exposed groups. After HA removal from the aquarium for 2 weeks, the groups exposed to the two highest doses still exhibited a notable decline in red blood cell count, hemoglobin concentration, mean corpuscular hemoglobin concentration, and an increase in mean corpuscular volume. Additionally, there was a significant rise in neutrophils, eosinophils, cell alterations, and nuclear abnormalities percentages, along with a decrease in monocytes, coupled with a dose-dependent decrease in lymphocytes. Furthermore, only the highest dose of HA in the recovered groups continued to cause a significant increase in white blood cells. White blood cells remained lower, and the proportion of apoptotic RBCs remained higher in the high-dose group. The persistence of most of the haematological and histological disorders even after recovery period indicates a failure of physiological compensatory mechanisms to overcome the HA-associated problems or insufficient duration of recovery. Thus, these findings encourage the inclusion of this new hazardous agent in the biomonitoring program and provide a specific pattern of hematological profile in HA-challenged fish. Further experiments are highly warranted to explore other toxicological hazards of HA using dose/time window protocols.

Abstract Fluconazole (FCZ), an antifungal from the azole family, causes several detrimental effects in fish. In recent times, there has been a notable surge in interest regarding the utilization of Moringa oleifera (Mo) as a dietary antioxidant. This research aimed to evaluate the potential protective effects of dietary Moringa oleifera (MO) against the adverse impacts of fluconazole in the African catfish (Clarias gariepinus). The fish were allocated into four groups as follows: a control group fed a basal diet, an FCZ - exposed (200 ng/L) fed basal diet, 1% MO fed through basal diet, and an FCZ-exposed (200 ng/L) and 1% MO fed through basal diet fed group. The results showed that FCZ exposure decreased superoxide dismutase, total antioxidant capacity, and acetylcholine esterase levels. On the other hand, FCZ exposure increased malonaldehyde and cortisol levels as compared to control (P

Abstract The joint impact of tadalafil (Cilais) as a pharmaceutical residue and microplastics on fish is not well comprehended. The current study examined haematological, biochemical, and antioxidant parameters, along with immunohistochemical and histological indications in tilapia (Oreochromis niloticus) after being exposed to tadalafil, polyethylene microplastics (PE-MPs), and their mixtures for 15 days. The fish were distributed into 1st group control group (The fish was maintained in untreated water without any supplements); 2nd group exposed to 10 mg/L PE-MPs;3rd group exposed to 20 mg/l tadalafil (Cilais); 4th group exposed to 20 mg/l tadalafil (Cilais) + 10 mg/LPE-MPs (in triplicate). The levels of creatinine, uric acid, glucose, AST, ALT, and albumin in fish treated with tadalafil alone or in combination with PE-MPs were significantly higher than those in the control group. Fish exposed to PE-MPs, tadalafil, and tadalafil plus PE-MPs showed significantly lower levels of RBCs, Hb, Ht, neutrophils, and lymphocytes compared to the control group. Serum levels of total antioxidant capacity and reduced glutathione (GSH) were notably lowered in fish groups subjected to PE-MPs, tadalafil, and tadalafil + PE-MPs combinations in comparison to the control group. Malondialdehyde (MDA) serum levels were notably elevated in fish groups subjected to PE-MPs, tadalafil, and tadalafil + PE-MPs combinations compared to the control group. The most severe impact was observed in the tadalafil + PE-MPs combination group. Interleukin-6 (IL-6) levels were significantly increased in liver tissues following exposure to both tadalafil and microplastics compared to tissues exposed to only one substance or the control group. Changes in the gills, liver, and renal tissues were seen following exposure to PE-MPs, tadalafil, and tadalafil + PE-MPs combination in comparison to the control group of fish. Ultimately, the mixture of tadalafil and PE-MPs resulted in the most detrimental outcomes. Tadalafil and PE-MPs exhibited showed greater adverse effects, likely due to tadalafil being absorbed onto PE-MPs.

Abstract Polystyrene nanoplastic (PS-NPs) and Engine oil (EO) pose multiple ecotoxic effects with increasing threat to fish ecosystems. The current study investigated the toxicity of 15 days exposure to PS-NPs and / or EO to explore their combined synergistic effects on Nile tilapia, Oreochromis niloticus (O. niloticus). Hematobiochemical parameters, proinflammatory cytokines, and oxidative stress biomarkers as well as histological alterations were evaluated. The experimental design contained 120 acclimated Nile tilapia distributed into four groups, control, PS-NPs (5 mg/L), EO (1%) and their combination (PS-NPs + EO). After 15-days of exposure, blood and tissue samples were collected from all fish experimental groups. Results indicated that Nile tilapia exposed to PS-NPs and / or EO revealed a significant decrease in almost all the measured hematological parameters in comparison to the control, whereas WBCs and lymphocyte counts were significantly increased in the combined group only. Results clarified that the combined PS-NPs + EO group showed the maximum decrease in RBCs, Hb, MCH and MCHC, and showed the maximum significant rise in interleukin-1β (IL-1β), and interleukin-6 (IL-6) in comparison to all other exposed groups. Meanwhile, total antioxidant capacity (TAC) showed a significant (p

Abstract Petroleum aromatic hydrocarbons are considered one of the most dangerous aquatic pollutants due to their widespread across water bodies, persistence, and extension to the food chain. To our knowledge, there hasn’t been any research investigating the hepatorenoprotective effects of Spirulina platensis (SP) against toxicity induced by these environmental toxicants in fish. Thus, we decided to explore its potential safeguarding against benzene and toluene exposure in adult Clarias gariepinus. To achieve this objective, fish were divided into five groups (60 per group; 20 per replicate). The first group served as a control. The second and third groups were intoxicated with benzene and toluene at doses of 0.762 and 26.614 ng/L, respectively for 15 days. The fourth and fifth groups (SP + benzene and SP + toluene, respectively) were challenged with benzene and toluene as previously mentioned following dietary inclusion of SP at a dose of 5 g/kg diet for 30 days. The marked increase in liver metabolizing enzymes, glucose, total protein, albumin, globulin, albumin/globulin ratio, and creatinine confirmed the hepato- and nephrotoxic impacts of benzene and toluene. These outcomes were coupled with cytopathological affections and excessive collagen deposition. The incorporation of SP in ration formulation, on the contrary, restored the previously mentioned toxicological profile due to its antioxidant and cytoprotective attributes. Regardless of SP intervention, the renal tissues still displayed histo-architectural lesions, because of insufficient dose and timeframe. Additional research will be required to identify the ideal SP remediation regimen.

Despite numerous studies on microplastics, the biological impacts of polypropylene microplastics (PP-MPs) and its toxicity on freshwater fish have yet to be fully revealed. The purpose of this research was to look at the potentially harmful effects of PP-MPs in freshwater African catfish Clarias gariepinus and bioremediation using Spirulina. After acclimatization to laboratory conditions, 108 fish (125 ± 3 gm and 27 ± 2 cm) were assigned into triplicate six experimental groups (12 fish/group), a control group, Spirulina group (SP), PP-MP-treated groups (0.14 and 0.28 mg/l PP-MPs), and PP-MP + Spirulina-treated groups (0.14 mg/l PP-MPs + 200 mg/L SP and 0.28 mg/l PP-MPs +200 mg/L SP) for 15-day exposure and 45-day recovery after that. The hematological parameters exhibiting significance (RBCs, Hct, Hb, and MCV) or non-significance (MCH and MCHC) either decreased with the increase in PP-MP doses from 0.0 in the control to 0.28 mg/L red blood cells (RBCs), hematocrit (Hct), mean corpuscular hemoglobin (MCH), mean corpuscular hemoglobin concentration (MCHC), hemoglobin (Hb) and platelets or increased with such an increase in doses (mean corpuscular volume (MCV)). The liver enzyme activity, aspartate aminotransferase (AST), alkaline phosphatase (ALP), and alanine aminotransferase (ALT) exhibited non-significant (p ≥ 0.05) or significant (p < 0.05) increases in (0.14 and 0.28 mg/L) PP-MP-exposed groups, respectively, except ALP. Furthermore, there was a significant (p < 0.05) or non-significant (p ≥ 0.05) increase in 0.14 and 0.28 mg/l PP-MP +200 mg/L-exposure groups, respectively, compared to the control group and the same exposure group without Spirulina. In comparison to the control group, PP-MPs (0.14 and 0.28 mg/L) induced a significant (p < 0.05) increase in the percentage of poikilocytosis and nuclear abnormalities of RBCs. The liver tissue from fish exposed to PP-MPs exhibited varying degrees of pathological changes. These results indicated that these pathological changes increased with PP-MP concentration, suggesting that the effect of PP-MPs was dose-dependent. After 45 days of recovery under normal conditions, it was obvious that there was a significant improvement in the percentage of poikilocytosis and nuclear abnormalities of RBCs, as well as a non-significant improvement in hemato-biochemical parameters and liver tissue.

Ethidium bromide (EtBr) is one of the contaminants recorded in aquatic environments whose effects have been investigated; however, there is still limited knowledge about its remediation. This study examined the potential protective effects of Spirulina platensis (SP) against the effects of EtBr toxicity in the Nile tilapia (Oreochromis niloticus) fry. Fry were divided to five groups, viz., a control and four treatment groups of low-dose EtBr (10 μg/L), low-dose EtBr with SP (10 μg/L EtBr + 200 mg/L SP), high-dose EtBr (100 μg/L), and high-dose EtBr with SP (100 μg/L EtBr + 200 mg/L SP); the exposure period was 2 weeks. Low and high doses of EtBr induced alterations in some hematological, biochemical, and histopathological parameters. Necrotic hepatocytes, degenerated area, vacuolated hepatocytes, pyknotic nuclei, constricted and dilated blood sinusoids, and infiltration of inflammatory cells were observed. Lipid peroxidation concentration was not significantly different in groups exposed to low doses of EtBr and EtBr with SP, but it was increased in groups exposed to high doses of EtBr and EtBr with SP, compared with the control group. After feeding with SP, most histological and histochemical parameters restored to normal values. Therefore, SP may possess the ability to preserve the structural integrity of the hepatic and renal membranes.

Abstract Microplastics are widely distributed in aquatic ecosystems along with other chemical pollutants. Therefore, it is vital to study the health-hazardous effects of MPs in combination with 4-nonylphenol (4-NP), which is a highly abundant industrial waste and a critical alkylphenol endocrine disruptor. We investigated the effects of the exposure to polyethylene microplastics (PE-MPs), 4-NP, and their combination on blood biomarkers in Cyprinus carpio juveniles. Four study groups were treated for 15 consecutive days: (1) control group, (2) 10 mg/L PE-MP group, (3) 10 mg/L PE-MPs + 200 µg/L 4-NP group, and (4) 200 µg/L 4-NP group, followed by 15 days of recovery. Biochemical analyses showed that creatine kinase, lactate dehydrogenase, glucose, liver enzymes, total protein, and A/G ratios were significantly increased after exposure to PE-MPs, 4-NP, and the combination. Hematological parameters (RBC's, Hb, Ht, neutrophil percentage, and WBC's) were significantly decreased in the three exposure groups, whereas mean corpuscular volume and lymphocyte percentages were significantly increased. The 15-day recovery period improved most hematobiochemical parameters and PE-MP accumulation indices. Taken together, we demonstrated the hazardous effects of PE-MP and 4-NP combinations on C. carpio blood parameters and highlighted their potential risk to human health.

Trace elements such as titanium, zirconium, thorium, and uranium, are found in black sand (BS) after weathering and corrosion. Precious metals are not the only valuable elements in black sand, rare earth elements are also found. The aquatic life in lakes and reservoirs is negatively affected by lithophilic elements such as lithium, uranium, and tin. Accordingly, intensive experiments were conducted on Nile tilapia (Oreochromis niloticus) after exposure to isolated black sand. Blood biomarkers, antioxidant balance, morpho-nuclear erythrocyte’s alterations, and histopathological signs have been investigated after fish exposure for 15 days to a 6.4 g BS/kg diet, 9.6 g BS/kg diet, and 2.4 g BS/kg diet. The blood profile, including platelets and white blood cells, was pronouncedly decreased as a result. Functions of the liver and kidneys were impaired. An increase in serum-antioxidant enzymes such as catalase activities and superoxide dismutase was recorded. Also, exposure to black sand induced cellular and nuclear abnormalities in the erythrocytes. In conclusion, the black sand isolated from the Red sea beach influenced Oreochromis niloticus’s hematology, biochemistry, and antioxidant parameters. Poikilocytosis and RBC nuclear abnormalities were also associated with exposure to black sand. The resulting erosion of rocks and rocks’ access to water forces us to consider the seriousness of climatic change on the aquatic ecosystem.

Abstract Due to its prevalence in aquatic environments and potential cytotoxicity, 4-nonylphenol (4-NP) has garnered considerable attention. As a medicinal plant with numerous biological activities, Nigella sativa (black seed or black cumin) seed (NSS) is widely utilized throughout the world. Consequently, this study aimed to examine the potential protective effects of NSS against 4-NP-induced hepatotoxicity in African catfish (Clarias gariepinus). To achieve this objective, 18 fish (351 ± 3 g) were randomly divided into three equal groups for 21 days. The first group serves as a control which did not receive any treatment except the basal diet. The second and third groups were exposed to 4-NP at a dose of 0.1 mg L−1 of aquarium water and fed a basal diet only or supplemented with 2.5% NSS, respectively. The histological, histochemical, and ultrastructural features of the liver were subsequently evaluated as a damage biomarker of the hepatic tissue. Our results confirmed that 4-NP was a potent hepatotoxic agent, as 4-NP-intoxicated fish exhibited many lesions. Steatohepatitis, ballooning degeneration, sclerosing cholangitis, and coagulative necrosis of melanomacrophagecenters (MMCs) were observed. Hemosiderin, lipofuscin pigments, and proliferation of fibroblasts, kupffer cells, and telocytes were also demonstrated in the livers of 4-NP-intoxicated fish. In addition, decreased glycogen content and increased collagen deposition were observed in the hepatic tissue. Hepatocytes exhibited ultrastructural alterations in the chromatin, rough endoplasmic reticulum, smooth endoplasmic reticulum, mitochondria, lysosomes, and peroxisomes. Co-administration of 2.5% NSS to 4-NP-intoxicated fish significantly reduced these hepatotoxic effects. It nearly preserved the histological, histochemical, and ultrastructural integrity of hepatic tissue.

Microplastics (MPs) are an emerging threat to freshwater ecosystems with several ecotoxicological ramifications for fish. Microplastics (MPs) can adsorb heavy metals on their surfaces and increase their availability to aquatic organisms. The combined impact of lead and microplastics on fish has only been studied seldom utilizing a variety of markers. The present study aimed to evaluate the hematological, biochemical, and inflammatory signals (cytokines), as well as antioxidant enzymes in African catfish (Clarias gariepinus) exposed to lead (Pb) and MPs individually and combined for 15 days (acute toxicity experiment). The fish were split into four groups, the first of which was the control group. The second group received exposure to 1 mg/L of lead nitrate [Pb(NO3)2]. The third group was given 100 mg/L of MPs. A solution containing 100 mg/L of MPs and 1 mg/L of lead nitrate [Pb(NO3)2] was administered to the fourth group (the combination group). According to the findings, when MPs and Pb were combined for 15 days, the red blood cells (RBCs), thrombocytes, and lymphocytes were significantly reduced in comparison to the control fish. When compared to the control fish, the fish exposed to MPs and Pb alone or together showed a significant rise in blood interleukin-1β (IL-1β) and interleukin-6 (IL-6) cytokines. Both MPs and Pb exposure in catfish resulted in significant changes in the plasma electrolytes. The fish treated with MPs and Pb individually or in combination showed significant reduction in superoxide dismutase (SOD) and total antioxidant capacity (TAC) levels compared to the control group. The fish exposed to the combined action of MPs and Pb showed a considerable modification in all biochemical markers. The difference in the mean concentration of Pb (mg/L) between the fish exposed to Pb alone and the fish subjected to Pb and MPs combination was not statistically significant. In conclusion, according to this investigation, exposure to Pb caused an insignificant increase in Pb accumulation when MPs were present. However, co-exposure may result in anemia, cellular harm, extremely high levels of oxidative stress, and an inflammatory reaction.

Harness® is a commercial herbicide that contains acetochlor at a concentration of 84% as an active ingredient. Ubiquitous, persistent, and substantial uses of Harness® in agricultural processes have resulted in the pollution of nearby water sources, posing a threat to various aquatic biotas, including fish. The effects of Harness® toxicity on fish health are little known. So, this study aimed to describe the impact of herbicide Harness® on the oxidative stress and reproductive and thyroid performance of male and female tilapia (Oreochromis niloticus) and also investigate the prospective role of the natural antioxidant lycopene supplementation in dismissing the adverse properties of Harness®. Antioxidant enzyme (catalase, superoxide dismutase, and total antioxidant capacity) and hormone measurements (T, E2, T3, and T4) were carried out, and gonadal and thyroid follicle histological sections were examined as a method to investigate the effects of Harness® toxicity on fish. Male and female tilapia were exposed to 10 μmol/L and 100 μmol/L of Harness® and treated with 10 mg lycopene/kg for 15 days of exposure. Our results demonstrated that the antioxidant enzyme activity was altered by Harness exposure and serum T for both males and females dropped; also, female E2 levels decreased, but male E2 increased. Exposure to higher dose of Harness® induced elevation in both T3 and T4 levels, although the low exposure dose stimulated T4 levels. Harness® exposure prompted histological variations and degenerative changes in testicular, ovarian, and thyroid follicle tissues. Lycopene supplement administration diminished oxidative stress induced by Harness®, alleviating its endocrine disparaging effects by neutralizing T3, T4, T, and E2 and ameliorating the histological structure of gonadal and thyroid tissues. In conclusion, lycopene supplementation was preformed to normalize the alterations and oxidative damage caused by Harness® in Nile tilapia, suggesting that lycopene-supplemented diet functioned as potent antioxidants and had the ability to alleviate oxidative stress and thyroid and reproductive toxicity caused by herbicide Harness®. Moreover, it is crucial to take appropriate care when consuming herbicides to defend the aquatic environment.

Contamination of the environment with nano- and microplastic particles exerts a threatening impact on the aquatic ecosystems and sustainable catfish aquaculture. The presence of nanoplastics has been found to have a detrimental impact on both aquatic and terrestrial ecosystems. The present study examines the effect of polystyrene nanoplastics (PS NPs) on the DNA, erythrocytes, oxidative status and renal histology of catfish, in addition to the potential protective effects of Chlorella vulgaris bioremediation and selenium to hinder this effect. Six equal groups of fish were used as follows: Group 1 served as a control group and received water free from PS NPs; Group 2 was exposed to PS NPs at a concentration of 5 mg/L; Group 3 was exposed to PS NPs (5 mg/L) + selenium (1 mg/kg diet); Group 4 was exposed to PS NPs (5 mg/L) + C. vulgaris (25 g/kg diet); Group 5 was supplemented with C. vulgaris (25 g/kg diet); and Group 6 was supplemented with selenium (1 mg/kg diet). The exposure period was 30 days. The results indicated that PS NPs induced oxidative stress by significantly elevating malondialdehyde activities and slightly reducing antioxidant biomarkers, resulting in DNA damage, increased frequency of micronuclei, erythrocyte alterations, and numerous histopathological alterations in kidney tissue. Selenium and C. vulgaris significantly ameliorated the oxidative/antioxidant status, reducing DNA damage, micronucleus frequency, erythrocyte alterations, and improving the morphology of kidney tissue. Nevertheless, further research is needed for a profound understanding of the mechanism behind the toxicity of nano-microplatics in aquatic systems.

Micro- or nanoplastics, which are fragmented or otherwise tiny plastic materials, have long been a source of environmental worry. Microplastics (MPs) have been well documented to alter the physiology and behavior of marine invertebrates. The effects of some of these factors are also seen in larger marine vertebrates, such as fish. More recently, mouse models have been used to investigate the potential impacts of micro- and nanoplastics on host cellular and metabolic damages as well as mammalian gut flora. The impact on erythrocytes, which carry oxygen to all cells, has not yet been determined. Therefore, the current study aims to ascertain the impact of exposure to various MP exposure levels on hematological alterations and biochemical indicators of liver and kidney functions. In this study, a C57BL/6 murine model was concentration-dependently exposed to microplastics (6, 60, and 600 μg/day) for 15 days, followed by 15 days of recovery. The results demonstrated that exposure to 600 μg/day of MPs considerably impacted RBCs’ typical structure, resulting in numerous aberrant shapes. Furthermore, concentration-dependent reductions in hematological markers were observed. Additional biochemical testing revealed that MP exposure impacted the liver and renal functioning. Taken together, the current study reveals the severe impacts of MPs on mouse blood parameters, erythrocyte deformation, and consequently, anemic patterns of the blood.

The alkaline rocks are known for enriching rare lithophilic elements, including lithium, uranium, and tin, which negatively impact aquatic life. This study offers an intensive investigation of the influence of alkaline rocks on Nile Tilapia (Oreochromis niloticus). The variation in blood profile, the induction of antioxidant enzymes, morphological erythrocyte, and histological structure have been conducted for the fish after 15 days of exposure to alkaline rocks powder with a dose of 100 μg/L. As a result, there was a pronounced decrease in blood profiles, such as platelets and white blood cell counts. There was a failure in the liver and kidney functions. Moreover, it shows an increase in superoxide dismutase (SOD) and catalase (CAT) activities as antioxidant biomarkers. Also, exposure to alkaline rocks induced DNA mutation and erythrocyte distortion. We concluded that the bulk alkaline rocks induced changes in the hemato-biochemical and antioxidant parameters of Nile tilapia. Additionally, exposure to bulk alkaline rock compounds also caused poikilocytosis and nuclear abnormalities of RBCs. This draws our attention to the seriousness of climatic changes, the erosion of rocks, and their access to water.

Plastic particles have the ability to transfer harmful chemical pollutants due to their high adsorption capacity. Therefore, this study aimed to investigate the effects of combined exposure to polyethylene microplastics (PE-MPs) and 4-nonylphenol (4-NP) on juvenile common carp (Cyprinus carpio) using histopathological and histochemical biomarkers. Fish were separated into a control group and three treatment groups (10 mg/L PE-MPs; 10 mg/L PE-MPs + 200 µg/L 4-NP; 200 µg/L 4-NP) for a two-week continuous exposure experiment followed by two weeks of recovery. The three treatment groups showed histopathological changes compared to the control. These alterations included severe edema, lifting of the outer epithelium, interlamellar fusion and vacuolation, secondary lamellar shortening and complete fusion, increased mucous cell numbers in the gill tissue, enlargement of inner layer stratum periventricular, cell degeneration with pyknotic nuclei, increased blood capillaries, spongiosis in the brain tissue (optic tectum), central vein hemorrhage, shrunken and fatty degeneration of hepatocytes, rosette shapes around small congested blood sinusoids, vacuoles, necrosis, and severe glycogen reduction in the liver tissue. Some tissue changes improved during the two-week recovery period but did not return to normal. In conclusion, the mixture exposure of the PE-MPs and 4-NP on fish carp induced some histological alterations in most studied tissues and post-exposure made improvement in cellular and tissue structure.

Using common carp as a model, we assessed the effects of polyethylene (PE) plastics on the brain. We measured activity of acetylcholinesterase (AChE), monoamine oxidase (MAO), and the content of nitric oxide (NO) in carp brain following exposure to 100 mg/L of either macroplastics (MaP), microplastics (MPs), or nanoplastic (NPs) for 15 days compared to an unexposed group. Following exposure, each biochemical biomarker was reduced 30–40%, with a higher magnitude of change corresponding to the smaller size of the particles (NPs > MPs > MaPs). In the carp tectum, exposure for 15 days to plastic particles caused varying degrees of necrosis, fibrosis, changes in blood capillaries, tissue detachment, edema, degenerated connective tissues, and necrosis in large cerebellar neurons and ganglion cells. In the carp retina, there was evidence for necrosis, degeneration, vacuolation, and curvature in the inner layer. Here we provide evidence that exposure to plastic particles can be associated with neurotoxicity in common carp.

Dexamethasone (glucocorticoid) was recently shown to be a life-saving drug for the treatment of SARS-CoV-2 disease. Water and sediments can be contaminated by sewage treatment plants when this product is widely used. Accordingly, we evaluated the effects of dexamethasone as pharmaceutical residue on Clarias gariepinus, following exposure and post-exposure recovery on blood biochemical, antioxidant, and cytokine markers. Three experimental groups were examined. Control, fish exposed to 0.3 mg/L of dexamethasone, and fish exposed to 3 mg/L of dexamethasone for 7 days, followed by a 15-days recovery period. Hematological indices, such as red blood cell number, hemoglobin (Hb), platelets, mean corpuscular hemoglobin concentration, and large lymphocytes, were significantly declined following the exposure to dexamethasone compared to control. In contrast, hematocrit (Ht), mean corpuscular volume, monocytes, small lymphocytes, and mean corpuscular hemoglobin increased significantly depending on the dose–concentration. Liver and kidney functions, other biochemical parameters (albumin and globulin), cortisol, and cytokine (IL-1β and IL-6) concentrations increased significantly after exposure to dexamethasone compared to control. Antioxidants and acetylcholinesterase enzymes were significantly decreased in catfish treated with dexamethasone cumulatively with doses. After a recovery period, blood biochemical, antioxidant, and cytokine markers were still elevated compared with the control group. In conclusion, dexamethasone at concentrations present in water bodies causes deleterious effects on blood biomarkers, biochemical, and antioxidant as well as immune upregulation in catfish until after depuration period.

In the present study, the neutral comet assay was applied for determination DNA double strand breakage in the African catfish Clarias gariepinus exposed variable concentrations and size of silver nanoparticles and ions. The parameters, tail % DNA; tail length, tail area; tail intensity; tail moment, olive tail moment, head mean intensity exhibited variability in the treatment and recovery periods. The silver small sized nanoparticles affect significantly (P 10–20%), moderate damaged (%TDNA ≥20–40%) and sever damaged (%TDNA ≥ 40%). The undamaged DNA exhibited more or less decline with Ag and AgNPs whereas the damaged DNA increased with fluctuation especially with Ag and all concentration of AgNPs except for 40 nm/100 µg/L. After 15-day recovery, fluctuation in undamaged and damaged DNA was evident due to insufficient period of DNA repair with individual variations. No hedgehogs (%TDNA

A few studies assessed how natural products can protect fish from the neurotoxic effects of Microplastics (MPs). Therefore, the goal of this study was to look into the neurotoxicity of PE-MPs on the brain tissue of African catfish (C. gariepinus), and whether dietary feeding on Chlorella, citric acid, and lycopene could help alleviate their toxicity. Five groups of fish were used: The first group received a standard diet (control). The second group was fed 500 mg/kg PE-MP. The third group was fed PE-MP + lycopene (500 mg/kg diet). The fourth group was fed PE-MP + citric acid (30 g/kg diet). And the fifth group was fed PE-MP + Chlorella (50 g/kg diet) for 15 days. The activities of Acetylcholinesterase (Ach), Monoamine Oxidase (MAO), Aldehyde Oxidase (AO), and Nitric Oxide (NO), and the histological effect on brain tissues were then assessed. The activity of the four neurological biomarker enzymes investigated was altered significantly in fish subjected to PE-MP alone compared with the control group. For fish exposed to PE-MP with lycopene, citric acid, or Chlorella, the activities of these neurological enzymes significantly improved particularly with Chlorella compared with fish fed PE-MP individually. Histological investigations illustrated that being subjected to PE-MPs effected cellular alterations in the telencephalon, including diffuse distorted and degraded neurons, encephalomalacia, aggregated neuroglial cells (gliosis), as well as deformed and necrotic neurons, neuropil vacuolation (spongiosis), aggregated neuroglial cells (gliosis), pyknotic neurons, and shrunken Purkinje cells which were found in the cerebellum. Most histological alterations induced by exposure to PE-MP feeding were restored by dietary feeding on Chlorella, citric acid, and lycopene. Accordingly, this study recommends using citric acid, lycopene, and Chlorella as a natural remedy against MP neurotoxicity particularly with Chlorella.

Although, the effects of 4-non-ylphenol (4-NP) on fish’s reproductive hormones were assessed in several studies using adult models, however, the effect of this endocrine disruptor on immature fish’s reproductive hormones was not addressed commonly. We aimed to study the apoptosis induction, hematotoxicity, reproductive toxicity, and the recovery associated with 4-NP exposure in juvenile African catfish [Clarias garepinus) using some hormones [17β-estradiol (E2), testosterone (T), follicle-stimulating hormone (FSH), and luteinizing hormone (LH)] and gonad histology as biomarkers. The toxic effects of 4-NP have been studied in many animal models, but there is still limited knowledge about the dose-dependent damage caused by 4-NP exposure in juvenile Clarias gariepinus. A healthy juvenile C. gariepinus was categorized into four groups (n = 3/group; three replicates in each group). The first group was the control, and the other three groups were subjected to 4-NP concentrations as 0.1, 0.2, and 0.3 mg/L for 15 days; they were left for a recovery period of another 15 days. The reproductive hormones of C. gariepinus exposed to 4-NP for 15 days exhibited significant variations between the treatment groups and the control (P < 0.05), which were evident in E2 and T-values, whereas FSH, LH, total protein, and lipid peroxidation values showed non-significant differences among all groups at P < 0.05. Such a situation referred to the fact that the 15-day recovery period was insufficient to remove the impacts of 4-NP doses in concern. The trend of dose-dependent increase/decrease was recorded for T, E2, FSH, and LH. The histopathological alterations of 4-NP treated in gonad tissues were recorded in juvenile C. gariepinus, reflecting their sensitivity to 4-NP estrogenic-like effects. Overall, our results investigate that recovery has improved the reproductive toxicity caused by 4-NP in juvenile C. garepinus. Significant variations between the treated groups and the control group (P < 0.05) were evident in hematological parameters except for hemoglobin (Hb), mean corpuscular volume (MCV), mean corpuscular hemoglobin (MCH), and mean corpuscular hemoglobin concentration (MCHC). The parameters exhibiting significance decreased with such increased doses [red blood cells (RBCs), hematocrit (Hct), and white blood cells (WBCs)]. Similar patterns of significant variations toward the increase or decrease were recorded following the 15-day recovery period. Apoptotic frequency in erythrocytes and brain cells has increased significantly with increased 4-NP exposure, indicating that 4-NP caused cytotoxic effects, such as apoptosis in a dose-dependent manner. However, these cellular alterations greatly decreased after the 15-day recovery period.

This study was conducted to explore the protective potential of three different antioxidant supplements, lycopene, citric acid, and Chlorella, against reproductive injuries induced by microplastics (MPs) in freshwater mature male catfish. A total of 150 mature male African catfish (Clarias gariepinus) were assigned to five treatment groups as follows: control group fish were fed with control diet, the second group fish were fed with 500 mg/kg MP diet, and the remaining three groups of fish were fed with 500 mg/kg MP diet plus lycopene (500 mg/kg diet), citric acid (30 g/kg diet), and Chlorella (50 g/kg diet), respectively, for 15 days. Ingestion of MPs significantly decreased serum luteinizing hormone, follicle-stimulating hormone, sex steroid (testosterone and estradiol) levels and sperm count, spermatocrit, motility, and viability. It also induced histological alterations and degenerative changes in testicular tissues. Administration of lycopene and Chlorella with MP diets maintained hormone levels comparable to those in the control group, enhanced sperm quality, and decreased testicular histological damage. Chlorella was more effective in enhancing sperm quality, and lycopene was more efficient in alleviating testicular tissue damage. Citric acid supplementation was irrelevant in mitigating MP-induced injury. This study indicated that both lycopene and Chlorella ameliorated the MP-induced reproductive dysfunction by improving reproductive hormonal levels, sperm parameters, and histological configuration, whereas the citric acid dose used in this study was not effective in ameliorating the MP-induced reproductive stress. Additional research and monitoring of MP-induced pollution in freshwater ecosystems are required to avoid the severity of reproductive toxicity in freshwater fish.

Morphological alterations and nuclear abnormalities in fish erythrocytes have been used in many studies as bioindicators of environmental mutagens including ionizing radiation. In this study, adult Japanese medaka (Oryzias latipes) were irradiated with gamma rays at a low dose rate (9.92 μGy/min) for 7 days, giving a total dose of 100 mGy; and morphological alterations, nuclear abnormalities, and apoptotic cell death induced in peripheral erythrocytes were investigated 8 h and 7 days after the end of the irradiation. A variety of abnormalities, such as tear-drop cell, crenated cell, acanthocyte, sickled cell, micronucleated cell, eccentric nucleus, notched nucleus, and schistocyte, were induced in the peripheral erythrocytes of the wild-type fish, and a less number of abnormalities and apoptotic cell death were induced in the p53-deficient fish. These results indicate that low dose-rate chronic irradiation of gamma rays can induce cytotoxic and genotoxic effects in the peripheral erythrocytes of medaka, and p53-deficient medaka are tolerant to the gamma-ray irradiation than the wild type on the surface.

Negative impacts of chemicals are documented in the environment, but a shortage exists in bioremediation studies for residues of such chemicals in aquatic systems. This study focused on the effects of Ethidium Bromide (EtBr) on fry of Oreochromis niloticus and the role of Spirulina platensis (SP) as a bioremediation agent. Five groups of fish were divided into (1) control, and four treatment groups: (2)10 µg L − 1 EtBr, (3)10 µg L − 1 EtBr with 200 mg L − 1 SP, (4)100 µg L − 1 EtBr, and (5)100 µg L − 1 EtBr with 200 mg L − 1 SP for 15 days. Antioxidant biomarkers–total antioxidant capacity; TAC, Superoxide dismutase; SOD, and catalase; CAT–were assessed. Exposure to EtBr led to a decrease in TAC after exposure to 100 µg L − 1 EtBr and 100 µg L − 1 EtBr +200 mg L − 1 SP. No significant change in SOD and CAT activity was observed compared with control fish, except for fish treated with 100 µg L − 1 EtBr. This treatment induces an increase in activity of SOD and CAT. DNA fragmentation increased significantly after exposure to EtBr alone and this increase was counteracted by combined exposure to SP. Exposure to EtBr induced alteration in antioxidant capacity and DNA damage. SP protects against these negative impacts.

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.

The current study investigates the hepatotoxic effects of two acute doses of silver nanoparticles (AgNPs) and silver nitrate (AgNO3) on African catfish (Clarias garepinus) using biochemical, histopathological, and histochemical changes and the determination of silver in liver tissue as biomarkers. AgNPs-induced impacts were recorded in some of these characteristics based on their size (20 and 40 nm) and their concentration (10 and 100 μg/L). Concentrations of liver enzymes (Aspartic aminotransferase; AST, Alanine aminotransferase; ALT), alkaline phosphatase (ALP), total lipids (Tl), Glucose (Glu) and Ag-concentration in liver tissue exhibited a significant increase under stress in all exposed groups compared to the control group. The total proteins (Tp), albumin (Al), and globulin (Gl) concentrations exhibited significantly decrease in all treated groups compared to the control group. At tissue and cell levels, histopathological changes were observed. These changes include proliferation of hepatocytes, infiltrations of inflammatory cells, pyknotic nuclei, cytoplasmic vaculation, melanomacrophages aggregation, dilation in the blood vessel, hepatic necrosis, rupture of the wall of the central vein, and apoptotic cells in the liver of AgNPs-exposed fish. As well as the depletion of glycogen content in the liver (feeble magenta coloration) was observed. The size and number of melanomacrophage centers (MMCs) in liver tissue showed highly significant difference in all exposed groups compared to the control group. Recovery period for 15 days led to improved most alterations in the biochemical, histopathological, and histochemical parameters induced by AgNPs and AgNO3. In conclusion, one can assume liver sensitivity of C. garepinus for AgNPs and the recovery period is a must.

The current study aims at evaluating the toxicity of hydroxychloroquine (HCQ) as a pharmaceutical residue in catfish (Clarias gariepinus) and the protective role of Spirulina platensis (SP). Four groups were used in this study: (1) a control group, (2) a group exposed to 3.16 mg/l of HCQ, (3) a group exposed to 3.16 mg/l of HCQ + 10 mg/l of SP, and (4) a group exposed to 3.16 mg/l of HCQ + 20 mg/l of SP for 15 days of exposure. The HCQ-treated group showed a significant decline in the hematological indices and glucose, total protein, and antioxidant levels in relation to the control group, whereas the HCQ-treated group showed a significant increase in the levels of creatinine, uric acid, aspartate aminotransferase (AST), and alanine aminotransferase (ALT) as well as the percentage of poikilocytosis and nuclear abnormalities of RBCs in relation to the control group. The histopathological evaluation of the liver indicated dilation of the central vein, vacuolization, degeneration of hepatocytes and pyknotic nuclei, as well as reduction of glomeruli, dilation of Bowman’s space, and degeneration of renal tubules in the kidney of the HCQ-treated group. Spirulina platensis (SP) rendered the hematological and biochemical indexes as well as antioxidant levels and the histological architecture to normal status in a dose-dependent manner. Accordingly, the current study recommends the use of SP to remedy the toxic effects of HCQ.

The potential toxicity of five selected herbicides i.e. bispyribac-sodium, penoxsulam, haloxyfop-p-ethyl, pinoxaden, and tralkoxydim, and a pyrethriod insecticide deltamethrin was determined on the early 4th instar larvae (after 24, 48 and 72-h exposure) and pupae (after 24 and 48-h exposure) of Culex pipiens L. in the laboratory. As a result, deltamethrin was count as the most toxic compound on the early 4th instar larvae and pupae of Cx. pipiens compared with all tested herbicides after exposure times. For the tested herbicides, pinoxaden was the most potent herbicide against both tested developmental stages followed by bispyribac-sodium and penoxsulam, which exhibited a moderate toxicity; while haloxyfop-p-ethyl and tralkoxydim were deemed to be the lowest toxic compounds among all tested pesticides after exposure times. In addition, the toxicity of all pesticides against larval and pupal stages of mosquito was increased gradually as exposure time increased especially after 72-h exposure for larvae and 48-h exposure for pupae. In conclusion, this is the first report on the side toxicity effects of haloxyfop-p-ethyl, tralkoxydim, penoxsulam and bispyribac-sodium on immature stages (larvae and pupae) of Cx. pipiens mosquitos in Egypt.

The role of the liver is the major site of detoxification and metabolism, so it was considered as a target organ in toxicological studies. The present study investigates the potential protective effects of Amphora coffeaeformis extract against hepatotoxic effects in African catfish, Clarias gariepinus induced by arsenic. The fish Clarias gariepinus was exposed to sub-lethal concentrations of arsenic; 19.2 and 38.3 mg/L (1/8 and 1/4 of 96h-LC50 value, 153.17 mg/L) for 15 days. Histopathological alterations of the liver were analyzed under light and transmission electron microscope (TEM). Using the light microscope, the alterations were hypertrophy and hyperplasia of hepatocytes, necrosis, melanomacrophage accumulation, lymphocytic aggregation and congested blood vessels as well as depletion in glycogen content. TEM investigation resulted in alterations in perichromatin granules that increased and progressively formed small clusters closely related with patches of heterochromatin. Also fractionation, dilation, and vesiculation of rough endoplasmic reticulum were observed in addition to mitochondrial hyperplasia, hypertrophy and cristolysis. Significant main effects were reported for glutathione and malondialdehyde levels (P< 0.05) after arsenic exposure. This arsenic-induced hepatotoxicity was improved with the dietary supplementation of Amphora. We concluded that Amphora extract can be used as a hepato-protective agent on arsenic-induced fish due to its biologically active components.

This study investigates the effects of silver nanoparticles (AgNPs) and silver nitrate (AgNO3) on gills and muscles in African catfish (Clarias garepinus). Changes in bioaccumulation, histopathological, and histochemical were used as biomarkers. The effects of AgNPs were recorded in some of these properties based on their size (20 and 40 nm) and their concentration (10 and 100 µg/L). The concentrations of silver (Ag) in gills and muscles tissues showed significant variations in all exposed groups compared to the control group. At tissue and cell levels, histopathological changes were observed. These changes include aneurism, collapse, subepithelial edema, epithelium lifting and hyperplasia of interlammellar epithelium, curling of secondary lamellae, epithelial cell necrosis, hypertrophy and proliferation of erythrocytes, bifurcation and fusion of filament, an increase in the number and size of mucous cells in the gills tissues. In addition, degeneration of muscle bundles, infiltration of inflammatory cells, focal areas of necrosis, splitting of muscle fibers, broken myofibrils, thickening of muscle bundles, dislocated striated muscles and shortening of muscle bundles in muscle tissues of fish exposed to AgNPs were exporated to evaluate the changes. Also, depletion of carbohydrates of the gill tissues and the muscle fibers with an increase in the number and size of mucous cells that condense in the secondary lamellae were observed. The 15-day recovery period improved most of the modifications in histopathological and histochemical parameters caused by AgNPs and AgNO3. In conclusion, one can assume the sensitivity of the gills and muscles of C. garepinus to AgNPs and recovery strategy is a must. Keywords: AgNPs, Clarias garepinus, Bioaccumulation, Histopathology, Histochemical, Gills, Muscles

Heavy metals have different adverse impacts on different life stages of fish species with attempts to use natural antioxidants to counteract their effects. So, the present study investigated the potential protective effects of Amphora coffeaeformis extract against arsenic-induced hemato-biochemical alterations in African catfish, Clarias gariepinus. The fish exposed to sub-lethal concentrations of arsenic; 19.2 and 38.3 mg/L (1/8 and 1/4 of 96h-LC50 value, 153.17 mg/L) for 15 days. The main effect of arsenic was recorded in some blood parameters such as RBC’s count, hematocrit, mean corpuscular volume, mean corpuscular hemoglobin, and white blood cells. As for biochemical parameters, the main effect of arsenic was significant for alkaline phosphatase, glucose, uric acid, creatinine, albumin, globulin, and albumin/globulin. Also, the residue of arsenic in fish muscles showed significant effects. The majority of these arsenic-induced parameters were improved with dietary supplements of the diatom A. coffeaeformis. So, Amphora extract can be used as detoxification factor on fishes induced by arsenic due to its biologically active components providing protections like antioxidant, antiviral, antibacterial, and anti-inflammatory. Besides, they have excellent contents of proteins and carbohydrates which are supposed to enhance the effect of these compounds.

Although many studies on the hematological and biochemical parameters in fishes have been done, still there are some shortage in the estimation and evaluation of the baseline’s values of marine and freshwater fishes. Recently, the use of hematology and biochemistry of fishes in toxicology, aquaculture, environmental pollution, feeding, and antioxidants studies has been increased. In this study we introduced the importance of those parameters and their importance as biomarkers in fish toxicology from previous literature and as new findings. Hemato-biochemical parameters were widely used in fish toxicological studies. Many researches have used the protein electrophoresis as a valid tool to determining intra and inter-specific variation among species. Protein profile was extensively used in determining the health of fish, as indicators of anemia or other diseases provide information about the existence of the disease, and in the diagnosis of disease. So, to carry out the aim of this study, we reported one of the more advanced techniques used SDS-PAGE as molecular biomarker for protein profile analysis in fish with shedding the light on the importance of hematological and biochemical parameters in fish toxicological studies. Keywords: Fish, Hematology, Biochemistry, Liver, SDS-PAGE

The present study was carried out to investigate the histological and histochemical changes in the retina on different developmental stages of Egyptian toad Bufo regularis. Our experiment started when tadpoles begin to feed. The adapted embryos are divided into 3 large tanks of 200 embryos each, collections of samples started from feeding age every three days. Both histological and histochemical results showed that the general architecture of the retina organ is correlated with the state of development. Therefore, it displayed different characteristic features depending on the investigated developmental stage starting from the larval stage (feeding began, stage 44) and ending with the post-metamorphic stage 66. Also, the present work aimed to study the chronic effects of UVA on the retina structure of B. regularis during development and metamorphosis for the first time.

The present study aims to investigate the effects of methyltestosterone on monosex farmed tilapia, Oreochromis niloticus by detection of apoptosis, micronucleus and alterations of erythrocytes. Fishes were obtained from four localities (Assiut as a control and Beheira, Alexandria and Kafr EL-Sheikh; three farms from each governorate as farmed monosex produced using methyltestosterone). Blood smears were processed for Hematoxylin and eosin technique. The major alterations recorded in the red blood cells were as swelled cells (Sc), tear drop-like cells (Tr), and sickle cells (Sk). Also, a significant difference (P ⩽ 0.001) between three governorates and Assiut was recorded in the micronucleus test, apoptosis and altered erythrocytes. These alterations are considered as an indication for performance and health of fish in the monosex culture medium indicating the side effects of overdose induction of MT.

The use of steroid-treated feeds as 17 α-methyltestosterone for the production of all-male populations is widespread in tilapia aquaculture. The aim of the present study was to investigate the misuse effects of methyltestosterone on monosex farmed Nile tilapia, Oreochromis niloticus by evaluation of hematological and biochemical values. The fishes were obtained from four localities (Assiut as a control, Beheira, Alexandria and Kafr el-Sheikh: three farms from each governorate as farmed monosex produced using methyltestosterone). The total erythrocyte count, hemoglobin rate, hematocrit percentage, mean corpuscular hemoglobin (MCH), mean corpuscular hemoglobin concentration (MCHC), mean corpuscular volume (MCV), white blood cell count, blood platelets, lymphocyte, monocyte, neutrophils and basophils were determined. The results showed that there were changes in the erythrocytic series and in the defense white blood cells. Activities of aspartate aminotransferase (AST), alanine aminotransferase (ALT) and alkaline phosphatase (ALP), glucose, cholesterol, total protein, uric acid and creatinine were determined for biochemical study. These alterations are considered an indication for performance and health of fish in the monosex culture medium indicating the side effects of overdose induction of MT.

Synthesis of bi functionally substituted thieno[2,3-c]pyrazole compounds was carried out by a new method. The substituted group at position five is namely (carbonitrile, carboxamide, N-(substitutedphenyl) carboxamide and benzoyl group). Chloroacetylation of the amino thieno[2,3-c]pyrazolecarboxamide compound afforded the chloroacetyl amino derivative. The chemical structure of the newly synthesized compounds was established by elemental and spectral analysis including IR, 1H NMR spectra in addition to 13C NMR and mass spectra for most of them. In the present work, we assessed the role of the new synthesized thieno[2,3-c]pyrazole compounds as antioxidants against the toxicity of the 4-nonylphenol on the red blood cells of the most economically important Nile fishes namely African catfish (Clarias gariepinus). The erythrocytes alterations were used as biological indicators to detect those effects. After exposure to 4-nonylphenol, the erythrocytes malformations (swelled cells, sickle cells, tear drop like cells, acanthocytes, and vacuolated cells) were recorded in highest number in comparison with other groups control and those injected with thieno[2,3-c]pyrazole compounds. So, the new thieno[2,3-c]pyrazole compounds can be used as antioxidants against toxicity of 4-nonylphenol on fishes.