Bioassay to Determine the Copper Toxicity Effects in Catla Fish

Abstract

Fish are relatively sensitive to changes in their surrounding environment including an increase in pollution. Fish health may thus reflect, and give a good indication of the health status of a specific aquatic ecosystem. Common Carp (Catla catla) is an important commercial species around the world to feed populations and is as an economic rather than an ornamental fish. Certain heavy metals are necessary for specific body functions due to their nutritional value. High concentrations of these metals can however cause a toxic effect within an organism. Copper is an essential trace metal in small concentrations for several fish metabolic functions. Essentiality of copper arises from its specific incorporation into a variety of enzymes, which play important roles in physiological processes (e.g. enzymes involved in cellular respiration, free radical defense, neurotransmitter function, connective tissue biosynthesis and other functions), as well as, into some structural proteins (WHO, 1998). Although the crucial role of copper in several enzymatic processes, this heavy metal can exert adverse toxicological effects, when present in high concentrations in water. In the present study enzyme and biochemical changes have been related to copper. It can be concluded that muscle alterations as a result of heavy metal exposition of fish may serve as a sensitive biomarker for the toxicity of sublethal concentrations of metals as well as other pollutants. However, complementary studies are necessary for a better understanding of its deleterious effects.