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Heavy metals (HM) are widespread contaminants of water affecting aquatic organisms and aquatic ecosystems. Indian lotus, Nelumbo nucifera (Gaertn.), is a beneficial medicinal plant that exhibits several pharmacological properties. It is hypothesized that incorporation of Indian lotus leaf (ILL) powder may be able to alleviate toxic effects exerted by a mixture of lead (Pb), cadmium (Cd), mercury (Hg), and zinc (Zn) in Nile tilapia, Oreochromis niloticus (L.). A total of two hundred and forty fish were randomly allocated into eight groups in triplicate, in a bifactorial design (4 ILL levels × 2 HM exposures). The fish in the first four groups were fed on a basal diet (39.9% crude protein) that was enriched with 0.0, 0.1, 0.2, and 0.4% ILL (in G1–G4, respectively), with no HM exposure. In the remaining four groups, fish were fed with the same diets and, in addition, were exposed to 1/20 of the 96 h-LC50 of Pb, Cd, Hg, and Zn mixture (in G5–G8, respectively), for 45 days. The HM exposure significantly elevated the levels of serum alanine and aspartate aminotransferases, creatinine, urea, malondialdehyde, and activities of catalase (CAT), superoxide dismutase (SOD), and glutathione peroxidase (GPX). The expression level of hepatic metallothionein (MT) was up-regulated as well as high residual levels of HM in fish musculature were recorded in the HM-exposed fish. Two-way ANOVA revealed that all the studied variables were significantly affected by the ILL supplementation, HM exposure, and their interaction. Moreover, levels of MDA, CAT, SOD, and MT showed significant positive correlations with HM concentrations. Moreover, necrosis and degeneration of hepatopancreatic cells with congestion, hyperplasia, and fusion of gills lamellae were observed in HM-exposed fish. Interestingly, ILL supplementation, especially in the fish fed with 0.2 and 0.4% ILL, was observed to reduce the HM concentration in the fish body, resulting in the reduction of its toxic effects on the biochemical and antioxidant activities. These results demonstrated that dietary ILL supplementation could protect Nile tilapia against the toxic effects of HM, and therefore, may serve as a beneficial feed additive for application in the aquaculture industry.

The present study investigated the possible effect of profenofos (PFF) on hepato-renal functions, non specific-immunity, and oxidants/antioxidants status in common carp, Cyprinus carpio (L.), and the supportive role of geranium (Pelargonium graveolens) essential oil (GEO). A static 96-h acute toxicity test was performed to determine the 96-h LC50 of PFF in common carp fingerlings and it was found to be 47.46 μg L−1 calculated by Finney probit analysis. One hundred and twenty fish were randomly allocated into four groups in triplicate. The first served as control and second groups were fed on basal diets that were enriched with 0.0 and 400 mg kg−1 of diet GEO, respectively without PFF exposure. The third and fourth groups were fed on the same diets and in addition, were exposed to 1/10 of the 96 h-LC50 of PFF (4.74 μg L−1), respectively for 60 days. The results revealed that the PFF exposure induced marked increases in the levels of serum alanine and aspartate aminotransferases (ALT and AST), alkaline phosphatase (ALP), lactate dehydrogenase (LDH), creatinine, urea, cholesterol, triglycerides (TG), and malondialdehyde (MDA). Meanwhile, the serum total protein (TP), globulins, glucose, lysozyme activity, complement3 (C3), nitric oxide (NO), and hepatic antioxidant enzyme activities as well as the reduced glutathione (GSH) content were markedly declined in the PFF-exposed fish compared to the control group. Additionally, vacuolation, pyknosis, and degeneration of hepatocytes and epithelial cells of renal tubules with mononuclear cell infiltration were observed. A strong caspase-3 and weak BCL-2 immunohisto-reactivity in the liver and kidney tissues of PFF-exposed fish were noted respective to the control. Interestingly, GEO supplementation improved these variables with nearly restoring to control values with improving the histological architecture of liver and kidney tissues. The apoptotic condition of the examined tissues was markedly restricted in the combination group than PFF-exposed group. These results concluded that GEO has ameliorative influence against toxic impacts of PFF on hepato-renal functions, immunological parameters, and oxidative stress in common carp, and therefore, maybe a valuable candidate as a dietary supplement in aquaculture.