Introduction
Aquaponics, i.e. a synergistic connection of hydroponics and aquaculture, is a young industry in the Czech Republic. The prominent research infrastructure in the country is the Aquaponic hall of the Faculty of Fisheries and Protection of Waters, University of South Bohemia. The Aquaponic hall comprises six recirculating aquaculture systems (5 m3 each), six big-scale mineralization units (1 m3 each), and four types of hydroponic systems (DWC, Media bed, Drip, Aeroponics) with at least six repetitions. The research group is mainly focused on improving the nutrient efficiency of aquaponics through the development of tailored aquaponics feed, integrated pest and diseases management in aquaponics, effective aquaculture sludge valorization, and knowledge transfer to aquaponic adopters. Further research is focused on changes in the amino acid, fatty acid, and sensory characteristics of fish fed with alternative sustainable feedstuffs.
Research fields
For improvement of nutrient efficiency through the development of tailored aquaponic feed, we used a sophisticated multistep approach based on:
Integrated pest and disease management and its bottlenecks in aquaponics were reviewed (Folorunso et al., 2021). Further experiments are focused on the runoff of pesticides into aquaponic water and its effects on fish and nitrifiers in the biofilter. Moreover, since numerous biocontrol agents are commercially available against insect pests, further research aims to develop novel bioagents against common fungal diseases, which are hard to tackle with natural fungicides. These bioagents include several entomopathogenic fungi, which are first tested in vitro (Fig.2.). The best candidate is then tested in situ.
We use several approaches for valorizing aquaculture sludge, including aerobic digestion in continuous big-scale mineralization units or lab-scale batch reactors, vermicomposting aquaculture sludge (Kouba et al., 2018), and/or/or biofloc technology.
Knowledge transfer to aquaponic adopters is based on regular meetings with aquaponic farmers. As most of the aquaponic farms in the Czech Republic were installed by the same company, they all suffer from the same flaws, i.e. undersized water and air pumps and mechanical and biological filters. With the help of national funding agencies, the technologies of two of the farms were already improved, and these farms are profitable.
Since the sustainable feedstuffs in aquafeed can substantially alter the composition of fish flesh, the final product is analyzed for amino acids, fatty acids, and sensory characteristics by certified panelists.
Acknowledgment
The authors would like to thank the Ministry of Education, Youth and Sports of the Czech Republic – the CENAKVA project (LM2018099).
References
Folorunso, E. A., Roy, K., Gebauer, R., Bohatá, A., Mráz, J. (2021). Integrated pest and disease management in aquaponics: A metadata‐based review. Reviews in Aquaculture, 13: 971-995.
Kouba, A., Lunda, R., Hlaváč, D., Kuklina, I., Hamáčková, J., Randák, T., Kozák, P., Koubová, A., Buřič, M. (2018). Vermicomposting of sludge from recirculating aquaculture system using Eisenia andrei: Technological feasibility and quality assessment of end-products. Journal of Cleaner Production, 177: 665-673.
Roy, K., Kajgrová, L., Mráz, J. (2022). TILAFeed: A bio-based inventory for circular nutrients management and achieving bioeconomy in future aquaponics. New Biotechnology, 70: 9-18.
Roy, K., Mráz, J. (2021). Digestibility of protein feeds for Tilapia. Edition of Methodics, University of South Bohemia in České Budějovice, Faculty of Fisheries and Protection of Waters, Vodňany, Czech Republic, 186.