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.

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.

Effect of the change in energy reserves on the entomopathogenic nematode efficacy.

The free-living infective juveniles of the entomopathogenic nematodes are non-feeding, so the stored energy reserves in these juveniles are of great importance. The relationship between the energy reserves and the efficacy of the entomopathogenic nematodes of genera Heterorhabditis and Steinernema was studied. New progenies of S. riobrave and H. bacteriophora (ISK-2 strains), were obtained using the continuous culturing method of nematode juveniles (IJs), for the several cycles under the optimum condition of the temperature (25 degrees C) and nematode density (20 IJs/ larva), inside the host Galleria mellonella. Thus, the nematode efficacy was maximized with a high conservation of energy reserves. The results showed that there was an increase in the penetration rate and the virulence through the new progenies of S. riobrave and H. bacteriophora than in the original progenies, with an increase in the energy reserves.