Recirculating Aquaculture Systems - RAS

PS 1

An indigenous probiotic preparation for the prevention of Vibrios and Luminescent Bacteria (In Hatchery and Grow Out)

Probiotics in shrimp culture have an outstanding positive impact in maintaining general health of the culture system, which includes both the animals and environment. Among the two broad categories of probiotics such as pond probiotics and gut probiotics, pond probiotics are of two categories. First category is the organisms, which are aimed at degrading the waste generated in the pond bottom and provide a healthier environment for the animals. Second category is the antagonistic bacteria, which suppress the pathogenic microbes present in the pond water and maintain a healthy balanced microbial ecosystem for better growth of the animals. Gut probiotics are aimed at modifying the intestinal microbial flora favorably by inhibiting or suppressing pathogenic bacteria such as vibrios. Besides, the probiotic organisms and their products have an immunostimulatory effect also. If properly selected and blended these organisms can participate in the process of food digestion by contributing to the pool of hydrolytic enzymes. But in all such preparations the desirable characteristics have to be selectively engineered and integrated if the expected results were to be obtained under field conditions.

A variety of commercial probiotic preparations are available in market from which selection of an appropriate one turn out to be beyond the capability of farmers. Basically, it has to be realized that probiotic organisms are viable biological entities, which have several specific requirements for growth and multiplication. Most of the probiotic preparations now available in India are the ones developed in other countries and imported as such or produced in India utilizing the organisms isolated from other countries. It is the case with the organisms isolated from unrelated environment say for example freshwater, soil and sewage. Because of these reasons the efficacy of such organisms in Indian aquaculture conditions happens to be much doubtful.

Considering this drawback with the available probiotic preparation this Centre had taken up a comprehensive research programme aiming at developing indigenous probiotics much needed for the Indian aquaculture and especially for shrimp culture. One among such products which the Centre could bring out was the PS –1


PS – 1 is a preparation aimed at fresh, brackish and marine environments. For fresh water application the product will contain Pseudomonas aeruginosa MCCB 102 (Genbank Accession no. EF 062514) for brackish, MCCB 117 (Genbank Accession no.EF 062511) for marine and MCCB 119 (Genbank Accession no. EF 062513) for freshwater systems. All indigenous isolates from Indian waters. The organism produces a bioactive molecule, Pyocyanin, preventing the growth of pathogenic Vibrio present in aquaculture systems. The product is available in 100 and 300-ml bottles, which consists of 109 to 1012 Cells/ml, adequate to exclude luminescent bacteria from hatchery and grow out systems.

  • Produces the antagonistic molecule pyocyanin to suppress growth of vibrios sp both in hatchery and grow outs.
  • Increases survival rate of larvae.
  • Improves overall health of the animal in grow out.
Physical nature and shelf life

PS – 1 is normally pale yellow in colour on storage, attains a green colour on shaking. The preparation has a shelf life of 180 days at room temperature.



In hatchery the application of PS - 1 can be initiated from Nauplius stage onwards at a rate 100-ml/ ton water /day to get 106 cells/ml of culture water.

Grow Out

For effective colonization in a micro-ecosystem, the introduced organism must be in sufficiently large numbers. Economic considerations dictate brewing PS-1 at farm site by the farmers themselves. Accordingly, 300-ml PS-1 containing 109-1012 cfu/ml would be required to obtain sufficient cell count for one-hectare pond by brewing overnight in 100-L medium.



PS-1 300 ml/hectar, Pond water 100 L, Rice bran/wheat bran 100 gm, Shrimp feed (expired) 700 gm.

Brewing Procedure

Filter pond water through muslin cloth, add cooked feed and rice/wheat bran, and empty PS -1 and maintain overnight (12 hours) with occasional stirring or aeration. Dilute the probiotic preparation with adequate quantity of pond water and spray over the pond. Prepare during evening and apply during the morning hours.

Why Recirculating Aquaculture Systems

Aquaculture hatcheries currently use the open larval rearing system. The open larval rearing systems have been found to have certain shortcomings. These are illustrated in the figure below and explained subsequently.

In an open larval rearing system in a hatchery, there is continuous exchange of seawater on a regular basis. The quantum of exchange varies depending on the hatchery and could be as high as 100%. Due to the heavy demand of seawater in the production...


Recirculating Aquaculture Systems (RAS)

Recirculating aquaculture systems, or RAS, are closed-loop production systems that continuously filter and recycle water, enabling large-scale fish farming that requires a small amount of water and releases little or no pollution.

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