The Effects of Substituting Soybean Meal, Wheat Flour and Cassava Flour with Groundnut Cake, Poultry By-product Meal, Brewery Waste and Rice Bran on Growth and Body Composition of Tilapia Fry

An 8-week feeding trial was conducted to evaluate the effects of replacing soybean meal, wheat flour and cassava flour with groundnut cake, poultry by-product meal, brewery waste and rice bran on the growth and body composition of Oreochromis niloticus fry at 3.77 g initial mean weight. Four iso-nitrogenous (35 % CP) experimental diets (1 control, 3 substituted) were prepared and administered. Control diet (Diet 1) has fishmeal, soybean meal, wheat flour, cassava flour and a blend of palm oil and fish oil as macro-ingredients. Soybean meal, wheat flour and cassava flour in the control diet were replaced with groundnut cake, brewery waste, rice bran to form Diet 2. Those three ingredients in the control diet were replaced with poultry by-product meal, brewery waste and rice bran to form Diet 3. Finally, Diet 4 was formulated with a combination of groundnut cake and poultry by-product meal, brewery waste and rice bran to replace the three ingredients above. Value-wise, the best growth performances were observed from the fish fed on Diet 3 but there were no significant differences among all the treatments. Generally, the substitution of soybean meal, wheat flour and cassava flour with groundnut cake, poultry by-product meal, rice bran and brewery waste have no major effect on the body composition of the fish. Meanwhile, the substitution has a positive effect with respect to feed cost in producing a kilogram of feed and a kilogram of fish. The authors suggested that the substitution of soybean meal, wheat flour and cassava flour with groundnut cake or poultry by-product meal or the combination of groundnut cake and poultry by-product meal, brewery waste and rice bran is more cost-effective and economical for Nile tilapia farming.