Application of biofloc technology in intensive tilapia farming.

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

Principle

Biofloc systems allow organic waste and microbial populations to thrive in the aquaculture pond. Through water mixing and aeration to maintain the presence of floc particles, water quality is ensured. Managing a biofloc aquaculture system is not simple; it requires relatively complex techniques to ensure the system operates well and achieves high productivity.

Biofloc systems can operate with very low water exchange rates (approximately 0.5 - 1%/day). Low water exchange promotes better biofloc growth and function, enhancing the processing of organic waste and nutrients. In biofloc systems, water changes to maintain pond water quality are minimized; instead, waste treatment takes place within the system thanks to the role of heterotrophic microorganisms.

Benefit

Biofloc plays a crucial role in treating organic waste and is a good source of nutrients for tilapia ponds. Using biofloc technology in intensive tilapia farming promotes faster growth rates, higher yields, improved feed efficiency, and reduced pond pollution. Furthermore, it enhances biosecurity, improves water use and control efficiency, and reduces the impact of weather fluctuations.

Farming process

The tilapia selected for farming were monosex male Novit 4 strain, weighing 7-10 g/fish, raised at a density of 5 fish/m2. They were fed twice daily, meeting 90% of their nutritional needs. Each week, the fish were fasted for one day to encourage them to utilize the biofloc biomass in the pond.

The amount of biofloc needed in the first month is 3-5 ppm/day. From the second month onwards, once biofloc is present in the system, simply add a biological product containing Bacillus bacteria to maintain a stable biofloc level in the pond. Supplement with molasses containing 37.5% carbon once a week to provide additional carbon.

During the rearing process, operate the bottom aeration system day and night in combination with water aerators to thoroughly mix the pond water from the bottom to the surface and create water flow within the pond. For the first two months, only run the water aerators when supplementing molasses and biofloc as bait. After that, use both bottom aeration and water aerators continuously until harvest to maintain oxygen levels and ensure biofloc remains 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, yielding 26 tons/ha/6-month farming cycle; 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 technology is approximately 542 million VND; total revenue is 689 million VND; net profit is 147 million VND; and the profit/capital ratio reaches 27.1% for a 6-month farming cycle. However, according to the research team's observations, based on experimental application, this model is suitable for farms with the capacity to invest in infrastructure and technology.

According to Thuysanvietnam.com.vn