Comparison of net fish yields in pond cultured Nile tilapia (Oreochromis niloticus L.) fed on peanut-based meals as alternatives to dietary fishmeal

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