Nutritional Content and Growth Ability of Duckweed Spirodela polyrhiza on Various Culture Media

Abstract

Giant duckweed (Spirodela polyrhiza) is one species of duckweed, distributed cosmopolitanly in stagnant freshwater. The duckweed has several potential uses such as for animal and fish feeds. However, its biological information in Indonesia is rare. A research was conducted in June to July 2019 to explore its nutritional content and growth ability. The growth ability experiment was done with two replications at The Research Center for Limnology, Indonesia Institute of Sciences laboratory. The indoor experiments used 3 types of culture media, namely P (mixture of Urea, NPK, and Gandasil); Q (water waste from catfish cultivation), and R (hydroponic fertilizer). Spirodela polyrhiza has a protein content of 24.10%; fat 1.74%; ash 1.78%, crude fiber 14.47%, and nitrogen-free extract of 57.89%. There were 15 types of amino acids observed in the biomass, made of as much as 13.1% w/w. The highest growth was obtained in R culture media with a specific growth rate (SGR): 8.54-16.53 % and productivity of 15.62-51.32 g/day/m2. Outdoor trials using the R media have a SGR value of 10.17-11.16% and productivity of 54.82-84.1 g/day/m2. Spirodela polyrhiza can be developed and have the potential to be used as an alternative natural feed source for aquaculture or another purpose. Further research is needed.