Evaluation of substituting black seed meal (Nigella sativa L.) as protein source in Nile tilapia diets

The study seeks to evaluate the suitability of Black seed meal (Nigella sativa L.) (BSM) as a protein source in replacing increasingly expensive soybean meal (SBM) in Nile tilapia diets on growth performance, feed utilization body composition and economic evaluation of Nile tilapia, Oreochromis niloticus. Five isonitrogenous and isocaloric diets were formulated to contain different levels of black seed meal (BSM) as an alternative to soybean meal in Nile tilapia diets at different levels (T1, control, 0%, T2, 25%, T3, 50%, T4, 75% and T5, 100% for 60 days. Therefore, the results were conducted that, replacement of SBM by TBM up to 50% did not effect on growth performances (weight gain (NG), feed intake (FI)) and feed utilization (specific growth rate (SGR), relative growth rate (RGR) and protein productive value (PPV). Results: No differences were observed among the control and any other treatment in survival rate. Carcass crude protein did not affected by inclusion black seed meal levels in all experimental treatments. In contrast, ash content showed significant increasing with increase black seed meal levels in diets (P<005). From economic view, it was observed that replacing 50% of SBM by BSM in Nile tilapia diets reduces feed costs by 5.88% while replacing 75% and 100% of SBM by BSM led to increase feed costs by 17.38% and 16.27%, respectively. Inclusion BSM levels more than 50% of SBM in Nile tilapia diets led to decrease growth performance and feed utilization and get negative reflection on economic efficiency of diets.