• Ananth A
• Keerthika V
• M R Rajan

Abstract: Selenium is an important micronutrient for animals including fishes. Selenium exhibit toxicity when it accumulate at higher level in the animal. To date toxicity of selenium in inland aquatic system is poorly understood. So the objectives of this work are to study Sub-lethal concentration of selenium and its impact on behavioural, biochemical and enzymatic changes of Oreochromis mossambicus. Median lethal concentration (LC50 96h) of selenium of Oreochromis mossambicus was 7.6 mg/l. Then the effect of sub-lethal concentration of selenium to fishes was analyzed by exposing fishes to different concentration of 1/100 (T1), 1/50 (T2) and 1/10 (T3) of LC50 values and one control (T0) without selenium for 14 days. Behavioural abnormalities like circular swimming, jerk movement, continuous opercular movement, frequent surface respiration, chafing, excess mucus secretion and hyper activity was observed among selenium exposed fishes and there is no such changes in control. Biochemical parameters such as protein, carbohydrate and lipids in gills, liver and muscles decreased significantly as the concentration of selenium increased. Enzymes like Aspartate transaminase (AST), Alanine transaminase (ALT) and Lactate dehydrogenase (LDH) in serum increased significantly with increasing concentration of selenium. So alteration of these parameters in fishes can be used as bioindicators for assessing selenium toxicity.

Key words: Selenium, LC50, Sub-lethal concentration, Oreochromis mossambicus, Biochemical and Enzymes

"Behavioural, Biochemical and Enzymatic changes of freshwater fish Oreochromis mossambicus exposed to sub-lethal concentration of Selenium", International Journal of Emerging Technologies and Innovative Research (www.jetir.org), ISSN:2349-5162, Vol.6, Issue 6, page no.254-261, June-2019, Available :http://www.jetir.org/papers/JETIR1906D86.pdf

"Behavioural, Biochemical and Enzymatic changes of freshwater fish Oreochromis mossambicus exposed to sub-lethal concentration of Selenium", International Journal of Emerging Technologies and Innovative Research (www.jetir.org | UGC and issn Approved), ISSN:2349-5162, Vol.6, Issue 6, page no. pp254-261, June-2019, Available at : http://www.jetir.org/papers/JETIR1906D86.pdf