Detrodigest
(A tool for Bioremediation of Detritus in Aquaculture)
Bioremediation in aquaculture an emerging technology which opens up new possibilities for better and sustainable production with least disturbance to the surrounding environment. There are two approaches to the process of bioremediation. 1. Biostimulation (stimulating the native microorganisms to perform better) and 2. Bioaugmentation (introduction of new organisms for better activity). In fin and shellfish culture system hypolimnion of pond bottom is the most dynamic micro-ecosystem, which precisely determines the fate of grow outs in terms of production and onset of diseases. During the culture period, this thin sediment water interface is continuously modified with the deposition of un-eaten feed, faecal matter, moults, dead phyto or zooplankton etc. Accumulation of these detritus trough out the pond or in pockets leads to anoxic conditions paving the way for ammonia and hydrogen sulphide production, the two most toxic gases in aquaculture systems. Apart from aerating the water columns, another method to do away with the detritus is to apply highly efficient detritus degrading bacteria so as to prevent the accumulation of the former, avoiding massive dissolved oxygen demand. With this objective, a novel microbial preparation composed of Bacillus sp. has been designed for Indian Aquaculture sector and technically named as ‘DETRODIGEST’.
One of the basic requirements of a successful bio-augmentation is the suitability of the microorganisms concerned in terms of their requirements for establishing in a region and to colonize and perform within a short period. The organism used for the preparation of Detrodigest is Bacillus cereus sensulato MCCB 101 (Genbank Acc. No. EF 062509) isolated from aquaculture fields of Kerala and subjected to rigorous screening procedures. Extensive field level demonstration and validation over a period of five years has been made in Kerala and Tamil Nadu to ascertain its suitability in shrimp culture systems and it has proved to be an appropriate preparation for prolonged and safe detritus management in any aquaculture systems.
An extensive study on the salinity preference of the organism in Detrodigest revealed its euryhaline nature by growing and adequately producing hydrolytic enzymes at all salinities tested ranging from fresh water to seawater (0 – 45 ppt). The organism in Detrodigest is highly versatile with the potential to produce a variety of enzymes such as protease, lipase, chitinase etc. Rapid degradation of detritus as soon as formed by Detrodigest makes more dissolved oxygen available at the pond bottom.As a result of the digestion of detritus, mineralization proceeds at faster rate resulting in phytoplanktion bloom, generally three days after the addition of Detrodigest. The bloom may remain for 10 days and for perpetual blooming repeated addition once in 10 days has been found to be fruitful.
For effective colonization in a micro-ecosystem, the introduced organism must be in sufficiently large numbers. Economic considerations dictate brewing Detrodigest at farm site by the farmers themselves. Accordingly, 300-ml Detrodigest containing 109 -1012cfu/ml would be required to obtain sufficient cell count for one-hectare pond by brewing overnight in 100 L medium. This is provided in a solid for after immobilizing in a mineral base material to facilitate reaching the pond bottom.
Salient features of Detrodigest
- Indigenous – One of the basic requirements of a successful bio-augmentation process is the suitability of the microorganisms concerned in terms of their requirements for establishing in a region and to colonize and perform within a short period. The organism used for the preparation of Detrodigest is Bacillus cereus sensu lato MCCB 101 (Genbank Acc. No. EF 062509) isolated from aquaculture fields of Kerala and subjected to rigorous screening procedures. Extensive field level demonstration and validation over a period of five years has been made in Kerala and Tamil Nadu to ascertain its suitability in shrimp culture systems and it has proved to be an appropriate preparation for prolonged and safe detritus management in any aquaculture systems.
- Euryhaline nature– An extensive study on the salinity preference of the organism in Detrodigest revealed its euryhaline nature by growing and adequately producing hydrolytic enzymes at all salinities tested ranging from fresh water to seawater (0 – 45 ppt).
- Versatility – The organism in Detrodigest are highly versatile with the potential to produce a variety of enzymes such as protease, lipase, chitinase etc. Another outstanding property of the organism is its capability to reduce ammonia, which gets liberated as a result of deamination and excretion by shrimp. This was very much reported during the field level demonstration programme as the ammonia content in all ponds, which received Detrodigest, was below toxic level (<0.01ppm NH3). Rapid degradation of detritus as soon as formed by Detrodigest makes more dissolved oxygen available at the pond bottom. (Eh, Ammonia and nitrite graph)
- Better algal bloom– As a result of the digestion of detritus, mineralization proceeds at faster rate resulting in phytoplanktion bloom, generally three days after the addition of Detrodigest. The bloom may remain for 10 days and for perpetual blooming repeated addition once in 10 days has been found to be fruitful. (Algal graph)
Application
For effective colonization in a micro-ecosystem, the introduced organism must be in sufficiently large numbers. Economic considerations dictate brewing Detrodigest at farm site by the farmers themselves. Accordingly, 300-ml Detrodigest containing 1023-1025 CFU/ml would be required to obtain sufficient cell count for one-hectare pond by brewing overnight in 100 L medium.
PROTOCOL
Contents
Detrodigest 300 ml/hec, 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 Detrodigest 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.
Presentation
Detrodigest is presented in 100mL and 300mL polystyrene bottles sealed with aluminum foil. There are preparations available for fresh, brackish and marine waters. Other than grow out systems the specific preparation can be used for fin and shell fish hatcheries and ornamental fish production centres without brewing to get a final cell count of 1X106 cells/mL rearing water. Brewing is required when it is used in grow out systems only where large volumes of the bio-augmentor is required.
Dr. Prem Kumar, a Senior Scientist in the Finfish Culture Division at the ICAR-Central Institute of Fisheries Education (ICAR-CIFE), is recognized for his contributions to finfish aquaculture and sustainable fish farming practices. His research focuses on advancing breeding, seed production, and grow-out techniques for economically important finfish species, essential for enhancing fish farming efficiency and profitability. Dr. Kumar has been instrumental in developing improved methods for breeding and rearing native fish species, supporting biodiversity conservation while boosting aquaculture productivity in India.
Dr. David Verner-Jeffreys is a Senior Scientist at WorldFish and an esteemed expert in aquatic animal health and aquaculture biosecurity. With a background in fish pathology and disease management, Dr. Verner-Jeffreys has dedicated his career to developing solutions that enhance disease prevention and sustainable health practices in aquaculture systems globally. His research focuses on combating infectious diseases that impact fish farming, particularly in developing countries, where aquaculture plays a crucial role in food security and livelihoods.
Dr. M. Shashi Shekhar, is a distinguished expert in aquatic animal health and environmental management in brackishwater aquaculture. With extensive experience in fish and shrimp health management, his work addresses critical challenges in disease prevention, environmental sustainability, and biosecurity, contributing to the growth and resilience of India’s brackishwater aquaculture sector. By emphasizing biosecurity, environmental monitoring, and eco-friendly health management practices, Dr. Shekhar has contributed to enhancing the resilience and sustainability of shrimp and fish farming.
Dr. K.V. Rajendran is a prominent aquaculture scientist at the ICAR-Central Institute of Fisheries Education (ICAR-CIFE) in India, recognized for his expertise in fish health management and aquatic animal disease control. With a focus on advancing disease diagnostics, biosecurity, and sustainable health practices in aquaculture, Dr. Rajendran’s work has greatly contributed to improving the resilience and productivity of India’s aquaculture sector. His research addresses major challenges related to fish and shellfish health, particularly in diagnosing and managing viral, bacterial, and parasitic diseases that impact farmed species.
Dr. T. Raja Swaminathan is a renowned scientist at the ICAR-Central Institute of Fisheries Technology (ICAR-CIFT) in Kochi, India, with expertise in fish health management, aquaculture biosecurity, and disease diagnostics. His work focuses on addressing challenges related to aquatic animal health, particularly in ensuring sustainable and safe practices in India’s aquaculture industry. Dr. Swaminathan is recognized for his contributions to the detection and control of fish and shellfish diseases, which are critical for enhancing productivity and reducing economic losses in aquaculture.
Dr. Neeraj Sood, a distinguished scientist at the ICAR-National Bureau of Fish Genetic Resources (ICAR-NBFGR) in India, is recognized for his work in fish genetics, conservation, and sustainable aquaculture practices. His research focuses on the genetic characterization and conservation of fish biodiversity, which is critical for protecting valuable genetic resources and promoting sustainable aquaculture. By identifying and cataloging fish species and their genetic diversity, Dr. Sood has contributed to the preservation of native fish species, ensuring that these resources can support resilient and productive aquaculture systems in India.
Dr. B. Santhosh, a leading scientist at the Vizhinjam Regional Centre of the ICAR-Central Marine Fisheries Research Institute (ICAR-CMFRI), is known for his impactful contributions to marine aquaculture and coastal fisheries development in India. His work focuses on advancing sustainable practices in mariculture, particularly in seed production, hatchery technology, and the cultivation of high-value marine species like finfish, shellfish, and sea cucumbers. Dr. Santhosh’s research has played a critical role in supporting livelihood opportunities for coastal communities by promoting aquaculture as a viable and environmentally sustainable industry.
Dr. Victoria Alday-Sanz is a renowned aquaculture expert at National Aquaculture Group (NAQUA) in Saudi Arabia, recognized globally for her work in shrimp health management, biosecurity, and sustainable aquaculture practices. With a background in veterinary science and extensive experience in aquatic animal health, Dr. Alday-Sanz has played a critical role in advancing shrimp farming practices to enhance productivity while maintaining rigorous biosecurity standards. Her work is instrumental in addressing major health challenges in shrimp aquaculture, particularly in the prevention and management of viral and bacterial diseases that can impact large-scale operations.
J.M.P.K. Jayasinghe is a distinguished figure in aquaculture, known for his contributions to sustainable fish farming practices, particularly in Asia. With a focus on innovative aquaculture technologies and resource management, he has dedicated his career to improving the productivity, efficiency, and environmental sustainability of aquaculture systems. Jayasinghe has been involved in developing best practices that help small-scale and commercial farmers enhance yields while minimizing the environmental impact, which is crucial for both economic growth and ecological health.
Dr. Vasant Kripa is the former Secretary of the Coastal Aquaculture Authority (CAA) in Chennai, India, and a highly respected scientist in marine biology, coastal aquaculture, and environmental management. With a career spanning over three decades, Dr. Kripa has been instrumental in developing policies and practices that promote sustainable and responsible coastal aquaculture in India. Her work has focused on balancing the growth of aquaculture with environmental conservation, ensuring that coastal ecosystems remain resilient and productive.
Dr. K.M. Shankar is the Vice Chairman of the Asian Fisheries Society, Indian Branch, and former Dean of the College of Fisheries in Mangalore, India. A highly respected figure in fish health management and aquaculture, Dr. Shankar has contributed significantly to advancing aquaculture science, particularly in aquatic animal health, biotechnology, and sustainable fisheries. His research focuses on pathogen detection, disease management, and biosecurity in aquaculture, addressing key challenges to improve productivity and sustainability in the industry.
Prof. Arun K. Dhar is a Professor and Director of the Aquaculture Pathology Laboratory at the School of Animal & Comparative Biomedical Sciences, The University of Arizona, USA. An expert in aquaculture pathology and virology, Prof. Dhar is highly regarded for his research on diseases affecting shrimp and other aquatic species. His work focuses on identifying, understanding, and managing viral pathogens that pose significant threats to aquaculture industries globally.
Dr. Iddya Karunasagar is a distinguished Indian microbiologist and food safety expert, known for his pioneering work in aquatic microbiology, aquaculture health, and public health. His research focuses on seafood safety and disease management in aquaculture, with significant contributions to understanding and controlling microbial pathogens, such as Vibrio species, which affect marine organisms. His work has helped develop diagnostic tools and strategies that promote sustainability in aquaculture and ensure safer seafood.
Dr. Pramoda Kumar Sahoo is the Director-cum-ICAR National Professor at the Indian Council of Agricultural Research-Central Institute of Freshwater Aquaculture (ICAR-CIFA). A leading expert in fish health management and aquatic animal diseases, Dr. Sahoo’s work focuses on advancing disease control, immunology, and molecular biology in freshwater aquaculture. His research is pivotal in improving the health, resilience, and sustainability of India’s aquaculture industry, which plays a vital role in food security and rural livelihoods.
Dr. Rohana Subasinghe is the Managing Director of FutureFish, a consultancy specializing in sustainable aquaculture and fisheries development. With over 30 years of experience in aquaculture, aquatic animal health, and international fisheries, Dr. Subasinghe is a globally recognized expert dedicated to promoting sustainable practices that support food security, environmental protection, and socioeconomic growth.
Dr. Eduardo Leano is the Director General of the Network of Aquaculture Centres in Asia-Pacific (NACA), an intergovernmental organization focused on sustainable aquaculture development in the Asia-Pacific region. With a strong background in aquatic animal health and pathology, Dr. Leano has dedicated his career to advancing sustainable aquaculture practices, improving disease management, and promoting biosecurity within the industry.