Boscolo et al., 2002. Rev. Bras. Zootec., 31 (2): 539-545

The trial aimed to evaluate the apparent strain digestibility coefficients (aDC) of dry matter (DM), gross energy (GE) and crude protein (CP) of soyabean meal (SBM), maize (M), wheat (W), wheat meal (WM), pearl millet (PM), triticale (TC), cassava meal (CM) and soyabean oil (SBO). 100 sexually reverted Nile tilapia were used; the fishes had a mean weight of 37.614.98g, and were distributed into 2 alimentation (500-litre) mansory tanks; the faeces were collected in modified Guelph system in two 150-litre aquaria. aDC was determined by an indirect method, with 0.1% chromic oxide (Cr2O3) as marker. aDC of DM, CP and GE was 65.49, 89.58 and 71.38 for SBM; 73.22, 93.40 and 76.63 for M; 86.51, 96.30 and 87.07 for W; 66.79, 91.00 and 68.81 for WM; 77.96, 94.91 and 89.12 for PM; 68.51, 94.78 and 80.55 for TC; 91.11, 97.52 and 91.40% for CM, respectively. The GE of SBO was 89.85%; the digestible protein and energy values were 42.19% and 3057.63 kcal/kg for SBM; 7.18% and 3037.03 kcal/kg for M; 11.01% and 3423.66 kcal/kg for W; 13.44% and 2825.88 kcal/kg for WM; 13.88% and 3755.55 kcal/kg for PM; 13.74% and 3230.69 kcal/kg for TC; and 1.76% and 3280.09 kcal/kg for CM. The digestible energy of SBO was 8485.28 kcal/kg. The results showed that the protein and energy of these feeds are efficiently used by Nile tilapia. To formulate complete diets, the digestible protein and energy values must be used.