Application of biofloc technology in intensive tilapia farming

Biofloc technology has been widely applied in intensive whiteleg shrimp farming models. Currently, this technology has been applied to commercial tilapia farming with high productivity up to 26 tons/ha/crop.

Principle

The biofloc system allows organic waste and microbial populations to survive in the pond. Through the process of water mixing and aeration to maintain the presence of floc particles, water quality is ensured. Managing a biofloc farming system is not simple, requiring relatively complex techniques necessary to ensure the system operates well and achieves high productivity.

Biofloc systems can operate at very low water exchange rates (about 0.5 - 1%/day). Low water exchange allows for better biofloc growth and activity to enhance the treatment of organic waste and nutrients. In a biofloc system, water exchange to maintain pond water quality is minimized, instead, waste treatment is performed within the system thanks to the role of heterotrophic microorganisms.

Benefit

Biofloc plays an important role in treating organic waste and is a good source of nutrition for tilapia ponds. Using biofloc technology in intensive tilapia farming promotes the growth rate of farmed fish with high productivity, improved feed efficiency, and contributes to reducing pond environmental pollution. In addition, it also improves biosecurity, improves water use efficiency and control, and reduces the impact of weather fluctuations.

Breeding process

Tilapia selected for farming are male monosex fish of Novit 4 strain, size 7 - 10 g/fish, raised at a density of 5 fish/m2. Feeding 2 times/day, with a level of meeting 90% of the demand. Each week, the fish are fasted for 1 day to stimulate the fish to use biofloc biomass in the pond.

The amount of biofloc needed to supply in the first month is 3 - 5 ppm/day. From the second month, when there is a quantity of biofloc available in the system, we only need to add biological products containing microorganisms such as the Bacillus bacteria group to maintain a stable amount of biofloc in the pond. Add molasses with a carbon content of 37.5%, once a week, to provide an additional source of carbon.

During the rearing process, operate the bottom aeration system day and night in combination with the water fan to mix the pond water evenly from the bottom to the surface and create water flow in the pond. In the first 2 months, only run the water fan when adding molasses and biofloc bait. Then use both the bottom aeration and water fan continuously until harvest to maintain oxygen and ensure biofloc is suspended in the water.

Harvest

Applied in Hai Duong with a 5-hectare scale model, after 6 months, the average weight of farmed fish reached 624.2g/fish, productivity reached 26 tons/ha/6-month farming season; the time for fish to reach an average size of 500g/fish was 18 days earlier than conventional intensive farming.

In terms of economic efficiency, the total investment for 1 hectare of intensive commercial tilapia farming using biofloc is about 542 million VND; total revenue is 689 million VND; net profit is 147 million VND; profit/capital ratio is 27.1% for a 6-month farming cycle. However, according to the research and experimental application group, this model is suitable for farming facilities that are capable of investing in infrastructure and technology.

According to Thuysanvietnam.com.vn