Introduction
Biofloc Technology (BFT) is based on the use of bioflocs. Bioflocs are agglomerates of microbes, algae, protozoa with detritus and organic matter. Water exchange along the ongrowing process of fish and/or crustacean using these biofloc systems is zero or minimal. Organic residues accumulated in biofloc ponds degrade, and ammonia is either nitrified or assimilated by an intensive heterotrophic microbial community. These processes replace the conventional external biofilter of a Recirculation Aquaculture System (RAS) or the high and expensive water exchange of a conventional open flow system, maintaining a high C/N ratio and inducing the uptake of ammonium by the microbial community (Avnimelech et al., 1994; McIntosh, 2000). A by-product of the biofloc is the growth of amicrobial community and the production of microbial protein that can be ingested by fish/crustaceans together with feed. The non-eaten fraction fo the feed is also recycled byt the microbial community and as a consequence a double utilization of the protein by fish/crutstaceans is observed (Avnimelech et al.,1989; McIntosh, 2000; Velasco et al., 1998).
A trial will be conducted at IRTA to compare RAS and BFT with different fish species: Mugil cephalus, Tinca tinca, Anguilla anguilla is presented. For each species the results obtained using both systems in terms of growth rate Feed Conversion Ratio, gut development, enzyme production and intestinal, microbiota composition are compared.
Materials and methods
Fish (1-5 g) will be placed in IRTAmar® units (IRTA, Spain) and BFT using the same identical tanks and environmental conditions (100 L tanks with four replicates, 20±1ºC, 12hL:12hD photoperiod, 500 lux intensity) for two months.
Results
The trial will start on May 2016 and will finish on September 2016. We expect to have all the results to be presented in September during the Congress.
References
Avnimelech et al.,1989; McIntosh, 2000; Velasco et al., 1998
Yoram Avnimelech. 2006. Feeding with microbial flocs by tilapia in minimal discharge bio-flocs technology ponds. Aquaculture 264 (2007) 140 - 147.
Yoram Avnimelech. 2009. Biofloc Technology - A practical guide book. The World Aquaculture Society. Baton Rouge, Louisiana, United States.