Evaluation of Moringa (Moringa Oleifera) leaves meal as a growth promoter and immune stimulant for Nile Tilapia (Oreochromis niloticus)

One hundred and eighty Nile Tilapia fish (Oreochromis niloticus) with initial body weight (IBW) 28 ± 0.33 grams were used in the present experiment. The experiment was conducted in glass aquariums. Fish were stocked at a rate of 15 fish in each aquarium. Fish were allocated into four experimental groups (Each group includes three replicates) and one of them was used as a control. The control group was fed on a basal diet free from moringa leaves meal (MLM), whereas 2 nd, 3 rd and the 4 th group were fed on diets containing 3.0, 4.4 and 7.4 % MLM, in replacement of 10, 15 and 25 % of soybean meal (SBM), respectively (according to the percentage of crude protein in each). The experimental period lasted for 6 weeks (42 days). Parameters of growth efficiency, blood haematology, immune response, antioxidant status and histopathological changes in internal organs of Nile tilapia were used as indices for the study. The obtained results showed that MLM have high nutritive value. Inclusion of MLM in the fish diet at level 3.0 % or 4.4 %, significantly (P < 0.5) enhanced the growth performance indices of fish, including final live body weight, body weight gain, feed conversion ratio, and survival rate (%) either after three or six weeks of feeding MLM diets compared with those fed the control diet. Fish fed 7.4 % MLM diet recorded the lowest growth performance traits compared with the control and those fed 3.0% or 4.4 MLM diets. The average of feed conversion ratio after 42 days; recorded:1.84, 1.58, 1.50 and 2.13 g feed per g gain, for fish groups fed the control, 3.0 %, 4.4 % and 7.4 % MLM diets, respectively. Survival rate (%) was improved with inclusion of MLM in the diet at level of 3.0 or 4.4 %, while it decreased with 7.4 % MLM diet. Significant improvement of immunity and antioxidant capacity of fish occurred with feeding MLM in the diet, where levels of IgM, lysozymes, RBCs, GPx, platelets (PLT) and nitric oxide (NO) were significantly increased (p < 0.05 or 0.01), with exception that levels of NO and GPx were decreased in blood of fish fed 7.4 % MLM. The levels of WBCs and SOD were not affected significantly by feeding the experimental diets.