Dietary supplementation of Moringa leaf meal for Nile tilapia Oreochromis niloticus: Effect on growth and stress indices

Abstract

The current study investigated the effects of Moringa (Moringa oleifera) leaf meal (MLM) on growth and stress indices of Nile tilapia (O. niloticus). Experimental fish (2.0 ± 0.5 g average body weight) were divided into two groups; one was fed with a diet not supplemented with MLM (control diet), and the other group was fed with a diet supplemented with 1.5% MLM (diet 2) for three-month period. The results showed that MLM incorporation in the diet improved growth indices (body mass gain, specific growth rate, length gain rate and feed conversion ratio) and somatic indices (spleen somatic index, hepatosomatic index and intestine somatic index). Moreover, all hematological indices were also significantly increased. Additionally, stress indices were significantly improved, including antioxidants; superoxide dismutase, glutathione peroxidase, catalase and lipid peroxidase; and biochemical indices including enzymes activities of Aspartate Aminotransferase and Alanine Transaminase, as well as glucose and cortisol concentrations. Also, markedly up-regulated the expression of related genes; Insulin-Like Growth Factor-1 (IGF-1), Transforming Growth Factor-β (TGF-β) and superoxide dismutase (SOD) genes; in fish group fed diet supplemented with MFM as compared with the control group. These results show that MLM effectively alleviated starvation stress through retaining the enhanced growth and stress indices. In conclusion, Moringa supplementation to Nile tilapia has a positive effect as growth promoter and natural anti-stress phyto-therapy. Keywords: Moringa oleifera, Growth, Stress, Antioxidants, Gene expression, Nile tilapia