Rendimento de carcaça em surubim ("Pseudoplatystoma" spp.) avaliado por ultra-som

The parameters of carcass trait of alive surubim (Pseudoplatystoma spp.) evaluated by ultrasound were estimated in this trial. A total of 34 fish was divided into two groups according to average body weight: group 1 = 2.7 kg e group 2 = 1.5 kg. The fish were measured for total, head and standard lengths. Ultrasound images of four defined points were obtained: 1 - anterior insertion of dorsal fin; 2 - posterior insertion of dorsal fin; 3 - anterior insertion of fat fin and 4 - insertion of caudal fin. After, weights of carcass, head, shank fillet and belly fillet were obtained. Correlations of measures obtained by the ultrasound images with carcass yield traits were determined. The point 3 showed the best correlations for yield of group 1 with: carcass (0.91), head (0.86), shank fillet (0.87) and belly fillet (0.91). Carcass yield of group 1 was higher (70.9%) than group 2 (66.9%), probably due to the highest head weight of these animals. The best equations for carcass yield and fillet weight were the ones that considered the measures of point 3 and total length, respectively. Ultrasound for evaluation of carcass traits in alive surubim is a reliable technique, once it can maintains reproducers with great performance inside stock.