الفهرس 
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Abstract
In the present study 90 specimens of Clarias gariepinus were used to determine the adverse effects of two sub lethal concentrations of arsenic (19.2 and 38.3 mg/L) on behavioral changes, blood constituents (Red blood cells, hemoglobin, hematocrit, mean corpuscular volume, mean corpuscular hemoglobin, mean corpuscular hemoglobin concentration and white blood cells) and biochemical parameters (Aspartic amino transferase, Alanine amino transferase, Alkaline phosphatase, lactate dehydrogenase, glucose, total protein, albumin, globulin, creatinine and uric acid) in addition to the estimation of the arsenic residue in fish muscles. Liver malondialdehyde and antioxidant biomarkers (Superoxide dismutase and glutathione) measurements were studied after arsenic exposure. Also the adverse effects of arsenic on the morphology and morphometric analysis of erythrocytes were studied beside the degree of DNA damage in the red blood cells which investigated by using the comet assay. The histopathological and histochemical characteristics of the liver, kidney and gills were studied in addition to electron microscopic observations of the hepatocytes. The validity of Amphora extract (7% and 10% of the fish meal) for detoxification of arsenic toxicity was testified.
The results can be summarized in the following points:
Behavioral changes
After exposure to arsenic, most of the fishes exhibited loss of equilibrium. Reduction in the feeding activity, fins hemorrhage and skin alterations were also recorded in those exposed to arsenic. The mortality rate (60%) was recorded in aquarium with 38.3 mg/L arsenic. On the other hand, fish groups exposed to the same doses of arsenic in combination with amphora didn’t show such abnormal behavior and didn’t show any mortality.
Hemato-biochemical parameters
The significant 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 regards the biochemical parameters, the arsenic main effect 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. These arsenic-induced parameters were improved with the dietary supplemented Amphora.
Antioxidant and oxidative stress biomarkers
The main effect of arsenic was highly significant on glutathione (GSH) level (p<0.0001) and significant on malondialdehide (MDA) level (P< 0.05) while insignificant on superoxide dismutase (SOD) level. Amphora main effect and the arsenic-amphora interaction were significant (P< 0.05) only for SOD level.
Morphology, morphometry and genotoxicity of erythrocytes
The erythrocytes showed morphologically different patterns of deformed cells include swelled cells, teardrop-like cells, sickle cells, echinocyte, acanthocyte, and elliptocyte. The arsenic main effects of the damaged and undamaged erythrocytes were highly significant (P<0.0001). For the blood morphometric parameters, the main effect of arsenic was highly significant (p<0.0001) in all measurements except for the nuclear axis ratio. The degree of DNA damage measured by comet assay showed significant main effect (P<0.001) of arsenic for all comet parameters except comet height, head diameter, head area, head intensity, and head mean intensity. The majority of this arsenic-induced toxicity was improved with the dietary supplemented Amphora.
Histopathological and histochemical studies
Examination of liver sections after exposure to arsenic showed the hepatocytes lost their normal polygonal shape and showed degeneration in the form of disintegration in most cytoplasmic contents. Melanomacrophage centers and lymphocytic aggregation were also observed close to the blood vessels. Marked hypertrophy of hepatocytes with the ruptured cell membrane and lysed nucleus were also observed. The histochemical investigation revealed that there was a fluctuation in the polysaccharide materials. This arsenic-induced hepatotoxicity was improved with the dietary supplementation of Amphora.
Kidney tissues of arsenic-exposed fish displayed tubular edema and necrosis, hematopoietic degeneration, melanomacrophage aggregates, Bowman’s capsule edema and glomerulus shrinkage while gill tissues of arsenic-exposed fish revealed lamellar rupture, lamellar aneurysm, epithelial edema and hypertrophy and mucous cell hyperplasia. PAS response revealed consumption in the polysaccharide materials in the kidney and gills in the arsenic group in contrast with control. These arsenic-induced changes in kidney and gill tissues were improved with the dietary supplementation of Amphora.
Electron microscopic observations
The Electron microscopic observations of liver cell 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. Some ultrastructure changes in liver hepatocytes of arsenic-induced fish were ameliorated by Amphora supplementation.