comparative study on the use of Pennisetum clandestinum and Moringa oleifera as protein sources in the diet of the herbivorous Tilapia rendalli

The efficacy of kikuyu grass and moringa leaves as protein sources in Tilapia rendalli (11.5 ± 1 g) diets was compared. Nine diets (30 % CP 20 MJ kg⁻¹) were formulated by substituting fishmeal (FM) for kikuyu leaf meal (KLM) and moringa leaf meal (MLM). A control diet contained 10 % FM and no leaf meal. FM was replaced at 25, 50, 75 and 100 % by KLM in diets: KLM 25, KLM 50, KLM 75 and KLM 100, and then by MLM in diets: MLM 25, MLM 50, MLM 75 and MLM 100, respectively. Maize and gluten meals were adjusted accordingly. Each diet was fed to triplicate groups of fish for 60 days. The best growth (SGR and TGC) was in the control group. There was no significant (P > 0.05) decrease in SGR and TGC when KLM replaced up to 50 % FM. There was a significant (P < 0.05) decrease when MLM replaced >25 % FM. Kikuyu diets had no effect on villi height. A trend towards shorter villi was evident with increasing MLM. Hepatocyte degradation was higher in fish fed moringa-based diets. Anti-nutrients (tannins and polyphenols) in moringa may have contributed to the poor growth, irritation of the enterocytes and hepatotoxic effects. These results show that replacing up to 25 % FM with KLM is effective in reducing the costs without negatively impacting the growth performance or health of T. rendalli. Adding MLM even at the lowest level (25 %) was expensive and resulted in compromised growth and health.