Evaluation of nutritional quality of moringa (Moringa oleifera Lam.) leaves as an alternative protein source for Nile tilapia (Oreochromis niloticus L.)

摘要

This study was conducted to evaluate the suitability of freeze-dried moringa leaf meal, Moringa oleifera, as an alternative protein source for Nile filapia. Three experimental diets were formulated to contain moringa, leaf meal at levels of 10%, 20% and 30% of the total dietary protein (Diets 2, 3 and 4, respectively) and one diet acting as a control (Diet 1) which included only fish meal and wheat meal as protein sources. All diets were isonitrogenous (35% crude protein) and isoenergetic (20 kJ g(-1)). A 7-week feeding trial was carried out on triplicate groups of seven fish (9-11 g) in 45-1 aquaria connected to a recirculating system. The daily fish ration was calculated at 15-g feed per metabolic body weight (kg(0.8)) per day (about five times maintenance). No feed-related mortality was observed during the whole experimental period. Diets with higher inclusion levels of moringa leaves (Diets 3 and 4) significantly depressed growth performance of the fish (SGR: 2.0% in both groups) compared to Diets 1 and 2 (SGR: 2.7% and 2.4%, respectively). The relatively high total phenolics (0.7% and 1%), nonhaemolytic saponin (1.5% and 2.3%) and phytic acid (0.5% and 0.8%) in Diets 3 and 4, respectively, as well as NDF (3.8% and 5.7%) and ADF (3.0% and 4.5%) in the aforementioned diets may have contributed to the poorer growth performance in these groups. These results suggest that moringa leaf meal can be used to substitute up to 10% of dietary protein in Nile tilapia without significant reduction in growth.