The objective of this study was to analyze the body yield and the chemical composition of catfish (jundia), Rhamdia quelen, reared in net-tanks and fed with diets containing different levels of protein and energy. An initial density of 70 fish/m³, in 18 net-tanks (5.0 m³) was used, for 324 days. A randomized complete design was used, with two factors: Crude Protein (CP) at three levels, 25, 30 and 35%; and Digestible energy (DE) at two levels, 3,250 and 3,500 kcal, and three replications. The diet was given freely, but it was measured daily. At the beginning of the experiment, one group of fish was killed to determine the body and chemical parameters. Every 28 days, two individuals of each experimental unit were killed and measured: total and standard length, total weight, liver, gonads, head, clean torso (CT) and visceral fat weight, respectively. Subsequently, the hepatosomatic index, gonadosomatic index, head percentage, carcass and clean torso yield were calculated. The fillet yield and the sex of the individuals were also registered from June/2006 on. Analyses of humidity, crude protein, lipids and mineral matter were conducted for the chemical composition of the jundia meat. Feed with 30% CP provided fish with better clean torso yield. The muscle composition was not influenced by the tested diets. The best result was obtained using diets containing 30% CP and 3,250 kcal digestible energy/kg.
body yield; catfishc; chemical analyses
