Evaluation of faba beans (Vicia faba L. var. minuta) as a replacement for soybean meal in practical diets of juvenile Nile tilapia Oreochromis niloticus

We have studied the possible use of faba bean meal (FBM) in juvenile Nile tilapia-practical diets by progressively increasing its inclusion level at the expense of dehulled soybean meal (DSBM) in isonitrogenous (27.5%) and isoenergetic formulated (15.20 kJ g− 1) diets. DSBM was replaced by 12, 24 and 36% of FBM (diets 1, 2 and 3, respectively). A diet without FBM served as the control. Each diet was fed for 75 days to three replicate groups of 30 fish (17.64 ± 0.04 g; mean ± SE), arranged in a completely randomized design in an open circulation system.Survival did not differ among treatments (p > 0.05). The growth and feed conversion ratio (FCR) did not differ significantly (p < 0.05) between fish fed diets1, 2 and the control diet. By contrast fish fed diet 3 showed poorer growth and feed conversion ratio than the other groups. Apparent dry matter digestibility (ADMD) showed a progressive reduction with increasing FBM levels. Apparent protein digestibility (APD) decreases significantly in fish fed diet 3. No significant difference in carcass protein content was found among the treatments, but fish fed diet 3 had higher moisture and lower lipid content in carcass than fish fed in the other diets. Results showed that FBM could be incorporated up to 24% in diets of juvenile Nile tilapia which corresponds to a reduction of 20% DSBM in the control diet without compromising growth or feed conversion ratio.