User:Cifaxin

= Biofloc Technology =

What is Biofloc?
“Biofloc Technology (BFT)” is an efficient alternative system where nutrients could be continuously recycled and reused. The sustainable approach of such system is based on growth of microorganism in the culture medium, benefited by the minimum or zero water exchange. These microorganisms (biofloc) has two major roles:


 * 1) maintenance of water quality, by the uptake of nitrogen compounds generating “in situ” microbial protein; and
 * 2) nutrition, increasing culture feasibility by reducing feed conversion ratio and a decrease of feed costs.

History of Biofloc
The first Biofloc Technology was developed in the early 1970s at Ifremer-COP (French Research Institute for Exploitation of the Sea, Oceanic Center of Pacific) with different penaeid species including Penaeus monodon, Fenneropenaeus merguiensis, Litopenaeus vannamei and L. stylirostris. In 1980s and beginning of 1990s, Israel and USA (Waddell Mariculture Center) started Research and Development with Tilapia and White shrimp L. vannamei, respectively, in which water limitation, environmental concerns and land costs were the main causative agents that promoted such research.

Regarding to commercial application, in 1988 Sopomer farm in Tahiti (French Polynesia) using 1000m2 concrete tanks and limited water exchange achieved a world record in production (20–25 ton/ha/year with two crops). On the other hand, Belize Aquaculture farm or “BAL” (located at Belize, Central America), probably the most famous case of commercial application in the world, produced around 11-26 ton/ha/cycle using 1.6 ha lined grow-out ponds. Much of know-how of running worldwide commercial scale BFT shrimp ponds is derived from BAL experience. In small-scale BFT greenhouse-based farms, Marvesta farm (located at Maryland, USA), probably is the well-known successful indoor BFT shrimp farm in USA, can produce around 45 ton of fresh never frozen shrimp per year using ~570 m3 indoor race-ways. Nowadays, BFT have being successfully expanded in large-scale shrimp farming in Asia, Latin and Central America, as well as in small-scale greenhouses in USA, South Korea, Brazil, Italy, China, India and others. In addition, many Research centres and Universities are intensifying R&D in Biofloc Technology, mostly applied to key fields such as grow-out management, nutrition, reproduction, microbial ecology, biotechnology and economics.

The role of Microorganisms
In BFT, microorganisms present a key role in nutrition of cultured animals. The macroaggregates (biofloc) is a rich protein-lipid natural source available “in situ” 24 hours per day. In the water column occurs a complex interaction between organic matter, physical substrate and large range of microorganisms such as phytoplankton, free and attached bacteria, aggregates of particulate organic matter and grazers, such as rotifers, ciliates and flagellates protozoa and copepods. This natural productivity play an important role recycling nutrients and maintaining the water quality.

The consumption of biofloc by shrimp or fish has demonstrated innumerous benefits such as improvement of growth rate, decrease of FCR and associated costs in feed. Growth enhancement has been attributed to both bacterial and algae nutritional components, which up to 30% of conventional feeding ration can be lowered due to biofloc consumption in shrimp. More than 29% of daily food consumed for L. vannamei could be biofloc.

Species Compatibility
Not all species are candidates to BFT. Some characteristics seems to be necessary to achieve a better growth performance such as resistance to high density, tolerance to intermediate levels of dissolved oxygen (~3-6 mg/L), settling solids in water (~10 with a maximum of 15 mL/L of “biofloc volume”, measured in Imhoff cones) and N-compounds, presence of filtering apparatus (i.e. tilapia), omnivorous habits and/or digestive system adaptable to better assimilate the microbial particles.