Corn granulometry in diets for tambaqui juvenile

SUMMARY This study aimed to evaluate the performance, carcass composition and viability of different corn granulometry (CG) in diets for tambaqui. It was distributed 160 fish (3.86±0.03g) into 20 aquaria (40-L) in a completely randomized design with five treatments and four replications. The treatments consisted of diets with different CG: 150, 300, 500, 710 and 850 µm. As performance parameters were evaluated: feed intake (FI), weight gain (WG), feed conversion rate (FCR), final total length (FTL), final standard length (FSL), height (H), specific growth rate (SGR), specific development rate (SDR) and survival (SUR). For carcass composition were evaluated moisture, crude protein, ether extract and mineral matter. For the economic analysis of diet were analyzed the total cost of production (TCP), cost of feed per kg weight gain (CFK) and the index of economic efficiency (IEE). Data were subjected to analysis of variance at 5% probability and polynomial regression. There was quadratic effect for the variables FI, WG, FCR, FTL, FSL, H, SGR and SDR, obtaining the best results, respectively, for CG estimated at 530.22; 555.40; 597.47; 566.75; 562.07; 557.48; 562.70 e 555.68 µm. There was no influence of CG on the carcass composition. There was quadratic effect for TCP and CFK variables, with higher values for CG estimated at, respectively, 600.44 and 602.11 µm. It is concluded that CG of 500 µm is indicated to tambaqui feed.