Suitability of using duckweed as feed and treated sewage as water source in tilapia aquaculture

66 Feasibility of using both treated effluent and duckweed biomass from a pilot-scale UASB-duckweed ponds system treating domestic sewage was evaluated in rearing Nile tilapia (Oreochromis niloticus). The nutritional value of duckweed was compared with wheat bran, used as a local fish feed ingredient, by applying these as the only source of feed for tilapia juveniles weighing 20 grams initial mean body weight. Two sources of water were used for each feed trial, treated-sewage and freshwater. The experiment was conducted in parallel with a conventional settled sewage-fed fishpond stocked with tilapia. Results of growth performance demonstrated that, in case of freshwater ponds specific growth rate (SGR) of tilapia fed on fresh duckweed was significantly ( https://www.w3.org/1998/Math/MathML" display="inline"> p < 0 . 01 ) higher than the SGR in wheat bran fed pond. No significant difference ( https://www.w3.org/1998/Math/MathML" display="inline"> p > 0 . 05 ) was observed between the two feeding regimes in case of treated sewage-fed ponds. The SGR of tilapia reared in the treated sewage-wheat bran-fed pond (TWP) was significantly higher (p