Feed costs which are one of the biggest costs in aquaculture are reduced significantly in the Aquaponics Africa system. Whilst it is convenient and expensive to use a commercial feed this is replaced by natural feed. Tilapia Rendalli consume a huge range of plant products including banana and mulberry leaves, worms and any waste by-products from the vegetable grow beds.
Chickens and ducks can fit into the system in several ways. Chickens can be put in cages above the fish tanks so that their droppings fall directly into the tank and are consumed by the fish and also find their way to the vegetables. Ducks too can be put into the tanks provided they have a means to get out. They also consume the stalks of the feed that the fish leave behind. Worms can be fed to the fish and the chickens. Luserne can be grown in the hydroponic beds to feed the chickens.
Another exciting food source for the fish being developed commercially at Aquaponics Africa is Lemna or duckweed which is grown from fish waste products utilizing an ABR growing system.
Aerobic Biological Reactors(ABR's) are a key component in the water recycling process of an Aquaponics production system.They provide for the biological conversion of ammonia. This results in an ideal growing medium for Lemna minor which becomes fish food. Lemna is one of natures smallest flowering plants and contains 35-40% crude protein with a high concentrations of essential amino acids, folic acid, minerals and beta carotene pigments that provide a balanced and nutritional diet.
In the integrated tilapia and duckweed recirculating system, the fish and the waters of the tilapia growout ponds provide the nutrients upon which the duckweed will thrive. In turn, the duckweed removes unwanted nutrients and waste products from the system, converting the nutrients into plant biomass. This plant biomass, in turn, becomes a high protein food for the fish. While all this is going on, water within the integrated system is conserved and purified. The entire system is a natural and sustainable approach to aquaculture. The impact of ABR's and Lemna to the system are:
Clean recirculated water returned to the fish reseviour.
Highly effective nitrate conversion.
Complete reduction in the cost of fish feed
Reduction in management and labour efforts and costs