The use of steroid-treated feeds as 17 a-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. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http:// creativecommons.org/licenses/by-nc-nd/4.0/).

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-LC 50 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.

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