The antioxidant defense capacities and histological alterations in the livers and gills of two fish species, Oreochromis niloticus and Clarias gariepinus, as indicative signs of the Batts drain pollution.

The impacts of the Batts drain on two chronically exposed fish (O. niloticus and C. gariepinus) were assessed using multiple biomarkers. Concentrations of metals in water and sediments (Cu, Zn, Fe, Cd, Pb, and Al) showed significant elevations near the Batts discharges (site 2) compared to the reference site (site 1). The liver and gills of fish collected from site 2 showed marked elevations in the catalase, superoxide dismutase, glutathione peroxidase, and thiobarbituric acid reactive substance levels. In addition, significant reductions in glutathione-reduced contents were also recorded. Tissue and species-specific antioxidant responses were associated with excessive generations of reactive oxygen species, which were visualized fluorescently. Various histological alterations were observed in the gills and livers of both species. These alterations varied between compensatory responses (ex: epithelial thickening and lifting) and irreversible damage (ex: necrotic degeneration). Based on the level of lipid peroxidation and the frequency of histopathological modifications, O. niloticus demonstrated greater resistance to the same level of pollution than C. gariepinus. Using integrated biomarkers to evaluate the real impacts of untreated discharges of the Batts drain is applied for the first time on the selected fish species at the studied sites.

Metal Accumulation and DNA Damage in Oreochromis niloticus and Clarias gariepinus After Chronic Exposure to Discharges of the Batts Drain: Potential Risk to Human Health.

The present work showed the impact of long-term exposure to the Batts drain's discharges on O. niloticus and C. gariepinus fish species. The accumulation level of Cu, Zn, Fe, Cd, Pb and Al in five vital tissues was markedly elevated near the Batts drain (site2) compared to the samples from the reference site (site 1). At the same site, C. gariepinus displayed the highest accumulation capacities when compared to O. niloticus. Based on the metal pollution index, livers and kidneys, followed by gills, showed the maximum overall metal load. The degree of DNA damage (assessed by comet and diphenylamine assays) was relative to the accumulated metals in tissues with species and site specification. The values of the hazard index for human consumption showed that the studied metals were within safe values at normal consumption rates. While harmful health consequences were observed at the habitual consumption level at site 2.

The Potential Use of Orange and Banana Peels to Minimize the Toxicological Effects of Silver Nanoparticles in Oreochromis Niloticus.

To evaluate the effectiveness of orange peels (OP) and banana peels (BP) in reducing the toxicity of silver nanoparticles (Ag-NPs), Oreochromis niloticus were exposed to Ag-NPs, Ag-NPs + OP, and Ag-NPs + BP for 24, 48, and 96 h. Time-dependent toxicological impacts of Ag-NPs were recorded. The maximum Ag accumulation was in hepatic and renal tissues after 96 h. A marked decrease in red blood cell count, hemoglobin content, hematocrit ratio, and mean corpuscular hemoglobin concentration was observed after 48 and 96 h of Ag-NPs exposure. Silver accumulation resulted in severe histological alterations (ex: congestion, vacuolization, and necrotic degeneration) in gills, livers, and kidneys. The adsorptive capacity of both peels could reduce the bioavailability of Ag-NPs as indicated by decreased Ag content in tissues, insignificant change in the hematological parameters with control groups, and regressive histological alterations based on the frequency of alterations' existence and the extent of affected parts.

Long-Term Exposure to the Water of Wadi El-Rayan Lakes Induced Testicular Damage and Endocrine Disruption in Mugil cephalus.

This study aimed to investigate the testicular function of Mugil cephalus that inhabit Wadi El-Rayan lakes. Testes of fish inhabiting the upper lake (site 2) and the lower lake (site 3) of Wadi El-Rayan showed significant decreases in gonadosomatic index, high accumulation levels of six metals, and eight organochlorine pesticide residues. Compared to reference fish, high percentages of histological alterations as testicular degeneration, germ cell reduction, testicular inflammation, vacuolization, and loss of tubular arrangement were observed in sites 2 and 3. Moreover, endocrine disruption signs were recorded based on the percentage of ovotestis appearance and the ovotestis severity index values. The maximum defective testicular antioxidant mechanisms were recorded in site 3 as indicated by sharp decreases in catalase, superoxide dismutase, glutathione reduced levels, and high thiobarbituric acid reactive substances. Finally, long-term exposure to Wadi El-Rayan water may impair the reproductive health of fish via testicular oxidative damage and endocrine disruption.

Silver Nanoparticles Induce Time- and Tissue-Specific Genotoxicity in Oreochromis niloticus: Utilizing the Adsorptive Capacities of Fruit Peels to Minimize Genotoxicity.

Fish were exposed to a sub-lethal concentration of silver nanoparticles with and without orange and banana peels water treatment for 24, 48, and 96 h. The adsorption of AgNPs on both peels was recognized by scanning electron microscopic, energy dispersive X-ray spectroscopy, and laser ablation imaging. The % of DNA damage in liver and muscle tissues (comet assay) showed significant elevations in all studied groups with the maximum level in liver tissues after 24 h. DNA damage was markedly decreased after 48, and 96 h signifying the presence of an effective repairing mechanism. Micronucleus and nine nuclear anomalies were recorded in the peripheral blood cells. All anomalies were observed in all studied groups with a maximum induction rate after 96 h. of exposure. Based on the % of DNA damage and the frequencies of nuclear anomalies, water treatment with orange and banana peel succeeded to reduce AgNPs-induced genotoxic damage.

Evaluation of Nephrotoxicity in Oreochromis niloticus After Exposure to Aluminum Oxide Nanoparticles: Exposure and Recovery Study.

Nephrotoxic impacts of Al2O3 nanoparticles (NPs) were studied in Oreochromis niloticus after seven days of exposure and fifteen days of recovery periods. Fish were classified as group I (dechlorinated water); group II (2 mg/L Al2O3NPs); group III (4 mg/L Al2O3NPs); group IV (8 mg/L Al2O3NPs). Blood creatinine and uric acid levels showed marked increases in groups III and IV. A dose-dependent disturbance in renal antioxidant components was recorded as indicated by elevated catalase, superoxide dismutase, thiobarbituric acid reactive substances levels, and decreased glutathione reduced concentration. Renal histopathology was recorded with the highest % of appearance in group IV. A reduction in renal Al content, kidney function biomarkers (excepting group IV), and enhanced antioxidant status were observed after applying a recovery strategy. Several structural damages were identified following the recovery period, but the alteration frequencies indicated regressive histopathological changes. The Al2O3NPs-induced nephrotoxicity can be reduced after applying a suitable recovery period.

Assessment of Hepatotoxicity Induced by Aluminum Oxide Nanoparticles in Oreochromis niloticus Using Integrated Biomarkers: Exposure and Recovery.

The hepatotoxic impacts of 2, 4, and 8 mg/L of Al2O3 nanoparticles (31.4 ± 4.8 nm) were evaluated in Oreochromis niloticus after 7 days of exposure and 15 days of recovery periods. The biochemical analysis of aspartate aminotransferase, alanine aminotransferase, and alkaline phosphatase in plasma showed significant increases in both 4 and 8 mg/L Al2O3 NPs exposed groups. The antioxidant biomarkers showed concentration-dependent elevations in catalase, superoxide dismutase, glutathione peroxidase activities, and thiobarbituric acid reactive substances levels. Glutathione reduced contents showed significant reductions in both 4 and 8 mg/L Al2O3 nanoparticles exposed groups. Several hepatic histopathological alterations were recorded ranging from adaptive responses (e.g. melanomacrophages aggregation) to permanent damage (e.g. necrosis). The recovery period using toxicant-free water led to an obvious reduction in the Al content in liver, liver and antioxidant enzymes in addition to regressive histopathological alterations based on the frequency of alterations occurrence and the extent of affected areas.

Does the adsorbent capacity of orange and banana peels toward silver nanoparticles improve the biochemical status of Oreochromis niloticus?

Silver nanoparticles (Ag NPs) have wide medical and industrial applications; therefore, their release into aquatic environments is a problematic issue. The present study aims to evaluate the removal efficiency of Ag NPs from water using orange peel (OP) and banana peel (BP) to moderate their toxicity on Oreochromis niloticus. Fish were divided into 4 groups: control group (dechlorinated tap water), Ag NPs (4 mg/L) exposed group, Ag NPs (4 mg/L) + OP (40 mg/L) group, and Ag NPs (4 mg/L) + BP (40 mg/L) group for 24 h, 48 h, and 96 h. The adsorptive ability of both peels was confirmed by scanning electron microscope and energy-dispersive X-ray spectroscopy after the exposure processes. The biochemical results revealed a gradual elevation in plasma glucose, total proteins, globulin, liver enzymes (AST, ALT, and ALP), creatinine, and uric acid after Ag NPs exposure, while albumin and total lipid concentrations were significantly decreased. The recorded antioxidant biomarkers in gills, and liver tissues after Ag NPs exposure showed severe oxidative damages (maximally after 96 h) as indicated by marked elevations in thiobarbituric acid reactive substances, glutathione peroxidase, catalase, and superoxide dismutase values, and decreased glutathione reduced content. All studied parameters restored more or less to that of control groups after OP and BP water treatment. The adsorbent abilities of both peels could reduce Ag NPs bioavailability and moderate their toxicological impacts.

Assessment of metal pollution impacts on Tilapia zillii and Mugil cephalus inhabiting Qaroun and Wadi El-Rayan lakes, Egypt, using integrated biomarkers.

Qaroun and Wadi El-Rayan lakes are exposed to a huge amount of discharges from different sources and numerous anthropogenic activities. Therefore, the present work aimed to evaluate the impacts of metal pollution on two wild fish species; Tilapia zillii and Mugil cephalus collected from lake Qaroun (eastern and western parts) and Wadi El-Rayan lakes (upper and lower lakes). Accumulation of metals (Cu, Zn, Cd, and Pb) in water, sediment, and five vital tissues as well as metal pollution index (MPI), contamination factor (CF), and pollution load index (PLI) were integrated as metal pollution biomarkers. Generally, these integrated endpoints had the same trend and indicated that the eastern part of lake Qaroun was the most polluted site followed by the lower lake of Wadi El-Rayan. To assess the environmental genotoxicity, the percentage DNA damage in different tissues of both fish species was estimated using the comet assay technique. The percentage of DNA damages showed tissue-, species- and site-specification. Hazard index (HI) has been used as an evaluation index for human health associated with fish consumption at the studied sites. This index showed that all metals were in the safe limits at normal consumption levels while adverse health effects are expected to occur at the subsistence consumption level. The safe HI for each metal at normal consumption level does not neglect that the combined cumulative risk impact of all metals is a sign of warning and the health of fish consumers nearby contaminated sites is threatened.

The Long-Term Exposure to Discharges of Sabal Drain Induces Genotoxic Effects on Oreochromis niloticus.

To study the genotoxic impacts of Sabal discharges, three sites around Sabal drain were selected and compared to a reference site (site1). Site2 was at the southern part of the main canal, site3 was at the main canal outlet, and site4 at the northern part of the main canal. Compared to the reference fish, the recorded micronuclei and other nuclear anomalies showed marked (p < 0.05) increases with different frequencies in the studied sites. The induction of nuclear deformations was as following site3 > site4 > site2 > site1. The analysis of comet assay data showed that the DNA damage (based on the percentage of tail DNA) was significantly increased and the levels of damage were associated with the distance from the main discharge point. Moreover, DNA damages showed variable percentages among the studied tissues. The gills and liver tissues collected from site3 showed the highest DNA damage compared with low muscular DNA damage.

Comparative Assessment of Genotoxic Impacts Induced by Zinc Bulk- and Nano-Particles in Nile tilapia, Oreochromis niloticus.

Fish were separately exposed to 1/2 LC50/96 h values of bulk-Zn and nano-Zn for 7, 14, and 28 days. The induction of micronuclei (MN) and other eight nuclear abnormalities in erythrocytes showed marked time and size dependence. The frequencies of all nuclear anomalies were progressively elevated (p < 0.05) with increasing the time of exposure to both bulk-Zn and nano-Zn. Throughout the study periods, fish exposed to nano-Zn showed the maximum elevation in all studied nuclear anomalies. Based on the fragmented DNA values, both Zn forms induced tissue-specific DNA damage as following gills > liver > muscles. Moreover, nano-Zn exposed groups revealed a maximum percentage of DNA damage among all studied groups, especially after 14 days. The percentage of DNA damage was decreased in all tissues on the 28th day, which reflected the presence of an effective repair mechanism. Finally, nano-Zn exhibited more genotoxic effects than that of its bulk counterparts.

The Chronic Exposure to Discharges of Sabal Drain Induces Oxidative Stress and Histopathological Alterations in Oreochromis niloticus.

To study whether the effluents of Sabal drain could affect the health status of Oreochromis niloticus; site2 (south part of main canal), site3 (at the canal outlet), site4 (north part of main canal) and site1 (reference site) were selected. Compared to the reference fish, activities of superoxide dismutase and glutathione peroxidase in addition to glutathione reduced and thiobarbituric acid reactive substances concentrations of the gills showed significant (p < 0.05) increase with different levels in all studied sites. Whereas, catalase activities revealed significant (p < 0.05) decrease in all studied sites with maximum decrease in site3. The recorded histopathological lesions were correlated with the distance from discharge point. Gills, liver and kidney of site3 had the worst histopathological conditions based on the frequency of alterations appearance and size of the affected areas. While, the regressive alterations that recorded in site2 and site4 suggest the onset of adaptive histological mechanisms.

Antioxidant Responses and Nuclear Deformations in Freshwater Fish, Oreochromis niloticus, Facing Degraded Environmental Conditions.

Two sites of collection along river Nile, nearby metal-related factories (site2) and 7 km downstream (site3) were compared to unpolluted reference fish farm (site1). Metals concentration (Cu, Zn, Pb, Fe, Mn and Cd) in water and sediment samples showed highly significant (p < 0.01) differences among sites. According to contamination factor and pollution load index values, overall pollution was ordered as site2 > site3 > site1. Compared with Oreochromis niloticus of site1, activities of superoxide dismutase, catalase and glutathione-S-transferase as well as malondialdehyde formation were significantly (p < 0.01) increased in both liver and gills of fish collected from metal contaminated sites. This increment showed a tissue-specific pattern with higher rate of increment in liver than in gills. While reduced glutathione level was sharply decreased in site2 and site3. Micronucleus test was assessed as an environmental genotoxic endpoint in erythrocytes. Assessment of eight nuclear deformations showed gradient frequencies related to the distance from the industrial discharges.