LEVELS OF DIETARY COPPER ON GROWTH PERFORMANCE OF NILE TILAPIA

摘要

The mineral copper is considered essential for fish for being component of several enzymes and to participate in important reactions of organism (WATANABE, 1997). Thus, it is supplemented on fish diets, and its requirement for teleosts were determinedbetween 3 - 10 mg kg"1 (CLEARWATER et al., 2002), and according to Ferrari et al. (2004) Nile tilapia (Oreochromis niloticus) requires 4 mg kg''. Levels beyond requirement can either affect negatively growth performance. Levels bellow can affect severalorgans and tissues, such as hematopoietic, cardiac and nervous systems (DEVLIN, 1998). Fish exposed at high levels of copper, either on diet or water, can causes serious consequences of toxicity on animals. This effects must be investigated due to sulphate of copper is largely used to prevent boom of algae in aquaculture, and it can drastically affect fish production. Therefore, the objective of this study was to evaluate the effects of feeding diets containing graded levels of copper on growth performance of Nile tilapia.