Note when raising shrimp under Biofloc technology

Shrimp farming by Biofloc technology is widely applied and effective in many localities across the country. However, the management of the farming system is not simple, requires relatively complex techniques to achieve high productivity.

Biofloc technology is widely applied Photo: Tran Ut

Choose probiotics

Probiotic is a biological product, is composed of beneficial living microorganisms, helps strengthen the intestinal bacteria system, enhances resistance, helps the host body fight off pathogenic bacteria. According to the research results, the use of probiotics has more effective strains than single strains in improving the growth and health of white shrimp. Commonly used preparations are mixtures containing Lactobacillus pentosus BD6, Lactobacillus fermentum LW2, Bacillus subtilis E20 and Saccharomyces cerevisiae P13.

The process of creating flocs

The pond is lined with the whole pond pond and equipped with 4 water fan rigs (oxygen supply, flow generation), 2 air turbines (ensuring oxygen in the middle of the pond, limiting the deposition of flocs). , 1 automatic feeding and feeding machine. In order to ensure good control of flocs and water quality during the culture process, ponds should be equipped with a siphon tube system, allowing the sediment to be deposited in the middle of the pond periodically or at the time to intervene.

Water treatment

Pond rehabilitation, water collection and treatment stages, water color, microbiological treatment … follow the standard process. In the first time, the amount of organic matter in pond water is still low. The development of Biofloc is not favorable because the density of heterotrophic bacteria can hardly reach high levels. Therefore, maintain a light water color to facilitate shrimp farming. From the second week onwards, it is necessary to supplement Carbon source (C) so that heterotrophic bacteria gradually develop.

If shrimp pond water is reused for the following crop, it is necessary to replenish it right before stocking shrimp. Because at this time the organic matter content in the pond water is very high. When supplemented with C and full of oxygen, flocs will grow well, making food for shrimp.

Fan mode

Water in ponds fed with Biofloc technology needs to be stirred, providing oxygen continuously.

1st month: 1 fan set operating continuously 24 / 24h (can rotate every frame for 6 hours a day; make sure that at any one time, there is 1 fan unit working). From the 15th day on, the morning runs 1 tubing (in the center of the pond) for 1 hour at 9-10h, the afternoon runs 1 hour (14-15h) to disperse the suspended matter in the central area.

2nd month: The first 10 days a fan set runs 24 / 24h. The second set runs from 7pm to 7am the next morning. Flooding increased by one hour each session (9 – 11h and 14-16h). From day 11 onwards, 2 fan units run 24 / 24h. Flooding runs alternately, every 12 hours.

3rd month: 2 daytime aeration and 2 fan units running continuously. From 19h night to morning, run 1 spill and 4 fan units.

Additional mode C and type of substrate C used

Every day, it is necessary to determine TAN (total nitrogen) content at 9 o’clock to calculate the amount of substrate containing C, it is necessary to add (C) according to the following formula:

C (kg) = (TAN – 0.5 mg / L) x 1,000 x V x 20

(Where V is the existing pond water volume)

In the first culture month, if the amount of substrate C calculated according to the above formula, <70% of the feed put into the pond the previous day, then adjust it to the equivalent of 70% of the feed. Also in this month, use only tapioca or rice bran. From the second month onwards, use 80% tapioca or rice bran, 20% molasses. How to use: spread wheat flour or bran all over the pond, separate molasses to mix with water in the fan area.

Feeding

In the first month, shrimp can be fed by hand. However, from the second month onwards, automatic feeding machines should be used. Conduct a daily record of the amount of feed taken into the pond in order to have a basis for calculating the substrate containing C to supplement. In principle, when flocs have developed in ponds, the demand for shrimp pellets will be reduced in part, farmers need to pay attention to make appropriate adjustments. Besides, it is recommended to use foods with a lower protein content than normal.

Source: contom.vn