Oligochitosan for mutual paddy and tilapia growth performance in aquaponics system

Abstract

This study was conducted to evaluate the influence of oligochitosan added to the fish tank to benefit both tilapia and paddy in the aquaponics system. Chitosan was irradiated at 25 kGy to produce low molecular weight chitosan (oligochitosan). The characteristics of chitosan such as molecular weight, solubility, viscosity, and colour were investigated. The low molecular weight chitosan (Mw = 5 kDa), obtained from the radiation degradation by gamma-ray was further used as a dietary supplement for tilapia. Nitrogen, one of the most important macro-nutrients for plant growth and crop productivity was supplied by fish faeces and food waste containing oligochitosan in fish tanks. The addition of oligochitosan could improve growth, and immune responses and alter the bacterial flora in the intestine of tilapia, so as to play a role in promoting the growth of paddy in the aquaponics system.