Successful bioremediation of nitrogenous toxins in shrimp farming grow-out operations

Indian shrimp aquaculture provides annual foreign exchange of Rs.20,000 crores,  offer job opportunities to the tune of 7 lakh / year in on and off farm sectors and improve the rural economy. The recent research efforts on intensification in shrimp farming have enhanced the productivity and the farm income. However accumulation of nitrogenous wastes in aquaculture ponds due to uneaten feed and host metabolism is one of the drawbacks of high density shrimp farming. Though the permitted levels of ammonia in shrimp culture ponds is <1 ppm, concentrations of ammonia often reach upto 4 ppm leading to stress to the shrimps affecting their growth and survival, which in turn reduces the shrimp yield by 10 -15 %  which may consequently lead to even total crop loss. Maintaining the optimal environmental quality is the key to reduce the economic loss caused by the environmental stress due to nitrogenous wastes.

Successful bioremediation of nitrogenous toxins in shrimp farming grow-out operationsSuccessful bioremediation of nitrogenous toxins in shrimp farming grow-out operations

Several products are available in the market containing consortia of nitrifying and denitrifying bacteria for application in freshwater aquaculture operations. These microbes are highly sensitive to physio-chemical parameters of the culture environment and hence cannot effectively function in brackishwater environments with salinity ranging from 15 to 45 ppt. Through persistent research for a decade on environmentally relevant bacteria, the ICAR-CIBA has enriched consortia of nitrifying and denitrifying bacteria that are well suited for use in brackishwater aquaculture systems in India to manage toxic nitrogenous compounds in brackishwater aquaculture systems. CIBAMOX was developed through enrichment/characterization and development of consortia of naturally occurring chemolithotrophic ammonia oxidizing bacteria (AOB) and nitrite oxidizing bacteria (NOB) and denitrifying bacteria (DNB) from brackishwater ecosystems of India.

Successful bioremediation of nitrogenous toxins in shrimp farming grow-out operationsSuccessful bioremediation of nitrogenous toxins in shrimp farming grow-out operations

The product had successfully completed field trials in 27 ponds in Surat and Navsari districts of Gujarat, 15 ponds in Nellore and Bhimavaram districts of Andhra Pradesh and 40 ponds in Kancheepuram and Thiruvallur districts of Tamil Nadu. Regular application of the product @ of 3 l/ha once in ten days from 45 days of culture onwards till the end of culture has shown to restrict the levels of ammonia below the maximum permissible limits.

Benefits of CIBAMOX

One application of the product (@ 5 l/ha) removes ammonia, nitrite and nitrate and regular application (@ 3 l/ha) prevents the build-up of nitrogenous wastes in culture ponds. The product is effective under wide range of salinity (15 - 45 ppm)  both in grow-out pond and re-circulatory systems.

Economics

Use of this product once in ten days after 45 days of culture will totally require the application for 7 times in a crop of 120 days. Dosage of 3 litres per application leads to a total of 21 l/ha/crop.  If the cost of product is taken as Rs.500/l, the final expenditure works out to be Rs.10,500/ha/crop. The field trials have proved that the application of CIBAMOX can increase the survival rate by 5 - 10%. For farms that stock 60 pieces per square meter, CIBAMOX has ensured an incremental biomass/yield of 900 kg due to increased survival rate which will enhance the economic return by Rs.2.70 lakh/ha.

Commercialization of the technology

The product was released in the 89th Foundation Day of the ICAR on 16th July 2017 at New Delhi and is ready for commercialization. The Agribusiness incubator (ABI) of the ICAR-CIBA will help in the preparation of detailed project report, advisory services to establish production facilities and the technical training for industrial production of the microbes to the potential clients.

(Source: ICAR-Central Institute of Brackishwater Aquaculture (CIBA), Chennai)