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 water quality in the pond 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 environmental pollution in the pond. 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 is done twice a 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 be supplied in the first month is 3 - 5 ppm/day. From the second month, when there is a sufficient amount of biofloc in the system, we only need to add biological products containing the microbial component of 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 a water fan to mix the pond water evenly from the bottom layer to the surface layer and create a water flow in the pond. In the first 2 months, only run the water fan when adding molasses and biofloc bait. Then use both bottom aeration and water fans 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 624.2 g/fish, the yield reached 26 tons/ha/6-month farming season; the time for fish to reach an average size of 500 g/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