Effects of dietborne copper on accumulation in the tissues and organs, growth and feed utilization of rainbow trout (Oncorhynchus mykiss, Walbaum, 1792) juvenile.

The present experiment was conducted to study effects of elevated dietary Cu and establish upper limits of Cu in fish feed. Accumulation and growth of dietborne copper in the gill, muscle tissue, digestive system and whole body of rainbow trout (Oncorhynchus mykiss, Walbaum). Four experimental isonitrogenic (460 g kg-1) and isolipidic (200 g kg-1) diets were formulated. Diets were prepared by adding 0 (control), 0.1, 0.4 or 1.6 g kg-1 CuSO4.5H2O feed, respectively. Each diet was randomly assigned to triplicate groups of 576 juvenile fish whose average weight 19.97±0.048 g. Fish were fed to satiation for experimental period. After 15, 30, 45 and 60 days, the fish were sampled and Cu accumulation in the gill, muscle tissue and the digestive system were determined. The data were presented in ?g of sample Dry Weight (DW). At the end of the trial, with increasing dietary Cu concentration, Cu accumulation of gill, muscle tissue, liver and the digestive system were increased. However, accumulation of gill were not significant (p>0.05) in the fish fed with 0.4 (D 3) and 1.6 (D 4) g kg-1 CuSO4.5H2O diets. Accumulation of muscle tissue were not significant (p>0.05) in the fish fed with 0 (D 1) and 0.1 (D 2) g kg-1 CuSO4.5H2O diets. The accumulation of Cu in the digestive system increased with increasing dietary Cu concentration and at periyot were significant (p<0.05) in group fed with the highest Cu concentration diet