Tick Nouanthavong and Preston T R 2011 Effect of biodigester effluent,  duckweed and leaves from Taro (Colocacia esculenta) on growth of Tilapia (Oreochromis niloticus) in open ponds. Workshop on Reducing Greenhouse Gas Emissions from Livestock and Soils (Editors: Reg Preston and Sisomphone Southavong). National Institute of Animal Science, Hanoi, 14-15 November 2011. httm://www.mekarn.org/workshops/GHG-CC/tick.htm