keywords: Digestibility, proximate composition, duckweed, Lemna paucicostata, Oreochromis niloticus, Nile tilapia
This study evaluated the digestibility of processed duckweed based diets and its effect on proximate composition of Oreochromis niloticus. Blanching and sun-drying were employed as the processing methods to reduce antinutrients in the duckweed meal. The experiment was conducted in two outdoor concrete ponds with an area of 5m x 3.5m (l × b) and a depth of 1.5m each, using 27 Hapa nets measuring 1m2 each. Nine iso-proteinous diets (D1-D9) were formulated using least-cost feed formulation software. Soybean meal was replaced by blanched and sun-dried duckweed meal at 25%, 50%, 75%, and 100% each. A total of 10 fingerlings of O. niloticus (7.46 ± 0.06g) were stocked per Hapa and fed three times a day at 5% biomass for 24 weeks. Indirect method using Chromic oxide was used to determine the digestibility while the fish carcass were analyzed following the standard method of Association of Official Analytical Chemistry.