No abstract

Although net yield directly relates to actual production at harvest, feeding trials aimed at replacing dietary fishmeal in cultured fish have largely ignored the performance indicator. A 16-week experiment aimed at comparing Net Fish Yields in Nile tilapia fed on peanut-based meals as alternatives to dietary fishmeal took place at Busoga University farmland in Eastern Uganda. Earthen ponds of size 4.0 x 3.0 x1.0 for length, width and depth respectively were used for culturing the experimental fish. Each of the 16 pond units were stocked at a density of 48 Nile tilapia fingerlings of initial live weight of 21.95 grams. Iso-nitrogenous diets containing 30% and 25% Crude Protein (CP) for the first 12 and last four weeks respectively, were used during the trial. Dietary treatments included the fishmeal (FM)-based diet and two peanut-based diets. The latter consisted of peanut meal (PNM)-based diet and mixed plant meal (MPM)-based diet in a ratio of 50:50. The commercial feed (CF) for grow-out Nile tilapia containing 25% CP acted as a control diet. NFYs of 5668 and 5624 kilograms per pond unit for Nile tilapia fed on the MPM and FM-based diets respectively, showed no significant difference (p0.05). On the contrary, NFY of 4819 kilograms characteristic to the PNM-based diet was the lowest and significantly poorer (p<0.05) than the two test diets. Basing on the comparable NFYs, the MPM-based meal should substitute the conventional fishmeal in the diet of pond cultured Nile tilapia.