Production of freshwater infusoria and Blacksoldier fly larvae using various organic substrates as starter feeds for fish larvae

Abstract

Freshwater infusoria were raised on banana peels, potato peels, cabbage leaves and water lettuce for three weeks while Blacksoldier fry larvae (BSFL) raised on goat, pig and cow dung manures for four weeks was later fed to juvenile Nile tilapia as started feeds. Infusoria and BSFL were cultured in twelve plastic containers each 40 liter and nine plastic plates each 0.135 m2 respectively. The density and biomass of infusoria; and water quality parameters were measured. The biomass and abundance of BSFL were determined. The growth performance and survival rates of Nile Tilapia (Oreochromis niloticus) were studied at three inclusion levels of BSFL (25, 75 and 100%) and fed twice a day in twelve polyethene tanks 20 litre each for two months. The mean density and biomass of infusoria were higher in banana peels and lowest in water lettuce leaves, at water temperature ranging from 21.5 ± 0.3 to 22.5 ± 0.5°C. Turbidity was generally highest in Lettuce leaves and lowest in Banana peels. Freshwater infusoria were active within 15 days of the experiment and became inactive with increasing turbidity. The biomass and abundance of BSFL were higher in pig manure and lowest in goat manure, and showed significant differences among inclusion levels (p<0.05). The growth rate of juvenile tilapia was numerically higher in treatment receiving 100% of BSFL (6.63±1.67 g) and lowest at 25% (1.92±31.11g) of BSFL. Results suggest potential of banana peels and pig manure as good substrate and higher inclusion level of BSFL to grow Nile tilapia.