WWW.WAS.ORG • WORLD AQUACULTURE • DECEMBER 2014 27 Biofloc and Shrimp Immunity Kim et al. (2013) studied the effect of biofloc on growth and immune activity of Pacific white shrimp post-larvae and found dense microbial population associated with bioflocs induces a trigger toward the development and maintenance of the shrimp immune system. More than 2,000 bacterial species have been found in well-developed biofloc water. Bioflocs enhance the non-specific immune system of shrimp, based on mRNA expression of six immune-related genes: ProPO1, proPO2, PPAE, ran, mas and SP1. This mechanism may be an important means to protect shrimp against drastic disease outbreaks, which often lead to collapse of shrimp production systems and huge losses. A study at Bogor University, Indonesia and Ghent University, Belgium revealed that the biofloc system contributes to the enhancement of immune response and survival after IMNV challenge, regardless of carbon source. The application of biofloc technology brings about beneficial effect in disease control and management in shrimp culture.1 A workshop on biofloc technology and shrimp diseases was held in Ho Chi Minh City from December 9-10, 2013. Ekasari1 reported higher phenoloxidase activity (an immune indicator) in response to carbon loading in a biofloc system. Avnimelech1 showed significantly lower infection of tilapia by Streptococcus in biofloc compared to clear water system. Wasielesky1 showed that biofloc can be successful in preventing WSSV in southern Brazil. Taw1 presented on possible use of biofloc system as biosecurity in preventing diseases in shrimp culture (Table 3). In summary, the main attributes of biofloc systems that reduce the risk of shrimp disease are: • Low rates of water exchange improve pathogen exclusion (biosecurity). • Continuous aeration provides stable water quality (DO and pH). • A diverse and stable microbial community stimulates the non-specific immune system and limits development of opportunistic species like Vibrio. • Regular removal of accumulated sludge controls biofloc concentration to moderate levels. Notes Nyan Taw, Ph.D, Technical Consultant, Blue Archipelago Berhad, Malaysia nyan.taw@bluearchipelago.com Former Chief Technical Advisor (CTA) and Consultant for FAO of the United Nations taw.nyan@yahoo.com 1 Presentations at ‘Workshop on biofloc technology and shrimp diseases’ held on 9-10 December 2013 in Ho Chi Min City, Vietnam. References Avnimelech, Y., P. DeSchryver, M. Emerciano, D. Kuhn, A. Ray and N. Taw. 2012. Biofloc Technology: A Practical Guidebook. Technion Israel Institute of Technology, Second Edition. World Aquaculture Society. Baton Rouge, LA, USA. Cardona, E., B. Lorgeoux, L. Chim, and J. Goguenheim. 2014. Effect of rearing systems, clear water vs biofloc, on reproductive performances and quality of larvae of the shrimp Litopenaeus stylitostris (Abstract) World Aquaculture 2014 Adelaide, Australia. Kim, S.-K., I.-K. Jang, H.-C. Seo, Y.-R. Cho, T. Samocha and Z. Pang. 2013. Effect of biofloc on growth and immune activity of Pacific white shrimp, Litopenaeus vannamei postlarvae. Aquaculture Research 2013 1-10. Kopot, R. and N. Taw. 2004. Efficiency of Pacific white shrimp culture, current issues in Indonesia. Global Aquaculture Advocate, April 2004. Megahed, M.E. 2010. The effect of microbial biofloc on water quality, survival and crowth of the green tiger shrimp (Penaeus semisulcatus) fed with different crude protein levels, I: Sustainable solution to the dependency on fish oil, fishmeal and environmental problems. Journal of the Arabian Aquaculture Society 5(2):1-24. McIntosh, R. 2001. Changing Paradigms in Shrimp Farming V. Establishment of heterotrophic bacterial communities. Global Aquaculture Advocate, February 2001. Otoshi, C.A., C.M. Holl, D.R. Moss, S.R. Arce and S.M. Moss. 2006. Super-intensive RAS trial yields encouraging shrimp harvest at Ocean Institute. Global Aquaculture Advocate July/August 2006. Samocha, T.M., R. Schveitzer, D. Krummenauer and T.C. Morris. 2012. Recent advances in super-intensive, zero-exchange shrimp raceway systems. Global Aquaculture Advocate November/ December 2012. Taw, N. 2005. Shrimp farming in Indonesia: evolving industry responds to varied issues. Global Aquaculture Advocate, August 2005. Taw, N., H. Fuat and N. Tarigan. 2008. Partial harvest/biofloc system promising for Pacific white shrimp. Global Aquaculture Advocate September/October 2008. Taw, N. 2010. Biofloc technology expending at white shrimp farms; biofloc systems deliver high productivity with sustainability. Global Aquaculture Advocate, November/ December 2010. Taw, N., P.Y. Thoung, L.T. Ming, C. Thanabatra and K.Z. Salleh. 2011. Malaysia shrimp farm redesign successfully; combines biosecurity, biofloc technology. Global Aquaculture Advocate, March/April 2011. Taw, N., U. Saleh and M.S. Bujang Slamat. 2013. Malaysia Shrimp Project scales up for production in biosecure biofloc modules. Global Aquaculture Advocate January/ February 2013. Taw, N. and S. Setio. 2014. Intensive farm in Bali, Indonesia produces shrimp in biofloc system. Global Aquaculture Advocate, January/ February 2014. Biofloc systems—a recent technology—offer a promise of stable and sustainable production, inasmuch as the system is operated without water exchange and so has an enhanced capacity for nitrification within the culture ponds.
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