Apparent digestibility of energy and protein of tilapia (Oreochromis niloticus) and corvina (Plagioscion squamosissimus) by-product meal, and canela crayfish (Macrobrachium amazonicum) meal for Nile tilapia

The trial was conducted to evaluate the apparent digestibility coefficients (CDa) of gross energy (EB) and crude protein (PB) of tilapia (FT) and corvina (FC) processing by-product meal, and canela crayfish (Macrobrachium amazonicum) meal (FM), for Nile tilapia fingerlings. Forty sexual reverted fishes, with average weight of 40 a, were allotted to 500 L feeding tanks. Feces collection was performed at two 150 L conical tanks. CDa was evaluated by an indirect method, with 0.1% chromic oxide (Cr2O3) as the indicator. Average temperature, dissolved oxygen, pH and conductivity were 8.5 +/- 0.50degreesC, 3.57 +/- 0.12 mg/L, 7.21 +/- 0.03, e 0.18 +/- 0.01 muS/cm, respectively. Digestibility coefficients of PB, EB and MS was 70.67 and 54.45 for FC, 67.09 and 48.52 for FT, 88.79 and 68.38 for FM, respectively; the digestible values of protein (%) and energy (kcal/kg) as fed basis were, 37.50 and 2107.46 for FC, 28.72 and 1927.18 for FT, 53.74 and 2763.23 for FM. The evaluated feedstuffs have potential for utilization on tilapia nutrition, however, it is necessary to determine its inclusion levels in diets for the different rearing phases of this species.