Aquaponics combines the technologies of hydroponics and aquaculture to produce fish and vegetable crops with significantly reduced external fertilizer and water use. The nutrients available to the fish and plants are directly related to the feed given to the fish, making high quality feed essential for effective crop production. The objective of this research is to analyze the effects of Black Soldier fly (Hermetia illucens) meal as a supplemental protein source integrated within existing commercial feed for Nile Tilapia (Oreochromis niloticus) also using freshwater mussels as a biofiltering organism.
Purina Catfish 32 Floating Feed was ground down, and Black Soldier fly meal was added as 15% and 25% the total weight. The feed was re-pelletized, and six aquaponic systems were run for 12 weeks within a greenhouse, each with 40 Nile tilapia and 16 plants of Ethiopian Kale and 16 Georgia Southern Collard Greens within a deep-water growing bed. Two systems were each fed 15% BSFM feed, two fed 25% BSFM feed, and two fed 0% BSFM feed. They each were fed 1% daily of the average total system fish weight, taken weekly. Freshwater mussels were added to the system to filter feed on algae and suspended organic material before the water entered the biofilter. Plants were harvested upon reaching maturity and analyzed for leaf length, leaf color, root length, root color, shoot weight, and root weight. Tank and biofilter ammonia, nitrite, and nitrate concentrations were taken weekly.
Results revealed the BSFM supplemented feed to be similar in effect to the pure commercial mix feed. There was no significant difference in tilapia, collard green, or kale yield due to feed type. Feed type similarly had no significant effect on ammonia, nitrite, and nitrate content within the tanks or biofilters.