Comparative nutritional evaluation of raw, methanol extracted residues and methanol extracts of moringa (Moringa oleifera Lam.) leaves on growth performance and feed utilization in Nile tilapia (Oreochromis niloticus L.) W Afuang, P Siddhuraju & K Becker Department of Aquaculture Systems and Animal Nutrition, Institute for Animal Production in the Tropics and Subtropics, University of Hohenheim, Stuttgart, Germany Correspondence: Prof. Dr K Becker, Department of Aquaculture Systems and Animal Nutrition, Institute for Animal Production in the Tropics and Subtropics, University of Hohenheim (480b), D-70593 Stuttgart, Germany. E-mail: kbecker@uni-hohenheim.de Abstract The suitability of raw and methanol-extracted morin- ga ( Moringa oleifera Lam.) leaf meal to replace 10%, 20% and 30% of the total ¢shmeal-based dietary pro- tein in tilapia feeds was tested. Ten isonitrogenous and isocalori¢c feeds (35% crude protein and 20 MJ kg À 1 gross energy), denoted as diets 1 (¢sh- meal-based control), 2, 3, 4 (containing 13%, 27% and 40% raw moringa leaf meal), 5, 6, 7 (containing 11%, 22% and 33% methanol-extracted moringa leaf meal), and 8, 9, 10 (containing methanol-soluble ex- tracts of the raw moringa leaf meal at the same level as would have been present in diets 2,3, 4) were pre- pared. Forty tilapia (16.772.4 g), kept individually, were fed the experimental diets (four ¢sh per treat- ment) at the rate of 15g feed per kg metabolic body weight (kg 0.8 ) per day. A reduction in the growth per- formance was observed with an increasing level of raw moringa leaf meal (diets 2^4), whereas inclusion of methanol-extracted leaf meal (diets 5^7) had no signi¢cant ( Po0.05) e¡ect on the growth perfor- mance compared with the control (diet 1). The growth performance of ¢sh fed diets 8^10 containing methanol extracts of the moringa leaf meal were also similar to the control. The chemical composition va- lues of the gained weight showed that lipid accretion decreased with increased inclusion of moringa leaves, and ash content increased. Dietary moringa methanol extracts reduced protein accretion, but had no e¡ects on lipid and ash contents compared with the control. The inclusion of raw, methanol- extracted residues and methanol extracts of the moringa leaf meal (diets 3 and 4,5,6 and 7, and 8 respectively) reduced the plasma cholesterol content signi¢cantly. Similarly, a signi¢cant reduction in muscle cholesterol was observed in ¢sh fed the diets 4, 8, 9 and 10. It was concluded that the solvent- extracted moringa leaf meal could replace about 30% of ¢shmeal from Nile tilapia diets. Keywords: Moringa oleifera, leaf meal, methanol extraction, Nile tilapia, growth performance, feed utilization Introduction The identi¢cation and utilization of non-conven- tional and lesser-utilized plant protein sources to re- place ¢shmeal, either partially or totally, in practical ¢sh feeds has been an area of focus in aquaculture nutrition research recently (Mart|'nez-Palacios, Gal- va Ø n, Olvera-Novoa & Cha Ø vez 1988; Olvera-Novoa, Martinez-Palacios, Galva Ø n & Chavez 1988; Ng & Wee 1989; Davies, McConnell & Bateson 1990; Gomes, Rema & Kaushik 1995; Hossain, Focken & Becker 2001; Ogunji & Wirth 2001; Siddhuraju & Becker 2003). The products from the Moringa oleifera tree hold considerable potential for becoming animal and ¢sh feed ingredients because of their high Aquaculture Research, 2003, 34, 1147^1159 r 2003 Blackwell Publishing Ltd 1147