Using Water Meal(Wolffia globosa),Water Fern (Azolla sp.) and Duckweed (Lemna minor) for Nutrient Absorption in Fermented Faeces of Nile Tilapia (Oreochromis niloticus)

Abstract

absorption in fermented faeces of Nile tilapia (Oreochromis niloticus) was studied. The studies on
nutrient concentration of fermented faeces of Nile tilapia were performed at 0.5, 1.0, 1.5 and 2.0 g dry
weight/L for 24 days. The results found that ammonia was decreased to 0 mg/L. Nitrate, total nitrogen,
orthophosphate and total phosphorus were increased to 6.28±0.18, 16.41±0.15, 7.00±0.54 and 8.23±0.28
mg/L, respectively. The studies on the growth and nutrient absorption of water meal, water fern and
duckweed in fermented fecal of Nile tilapia were consequently evaluated at 1.5 g dry weight/L, fermented
for 24 days. The results were suggested water meal, water fern and duckweed could be used to absorb
nutrients in fermented faeces of Nile tilapia. The duckweed showed the highest absorption efficiency and
could decrease nitrate, total nitrogen orthophosphate and total phosphorus to 0.157±0.000, 0.375±0.000,
0.198±0.010 and 0.193±0.010 mg/g fresh weight/d, respectively. The result showed that water meal, water
fern and duckweed could be used to reduce the waste from fermented faeces of Nile tilapia.