Biofloc technology is a new revolution to intensive shrimp farming with an alternative for treating in-situ culture water quality without affecting the shrimp production. This means that the water can be regularly checked and treated so as to provide a good condition for the shrimp growth. It is a zero water exchange intensive culture system that improves the water quality, effluent quality and growth performance.
Water quality parameters in biofloc are the main role in the survivability of shrimp cultured, therefore water level needs to be maintained within safe range . Parameters such as dissolved oxygen, pH, ammonia, nitrate, nitrite, alkalinity, settlement solid (SS) are significantly important in biofloc development. The biofloc system needs constant high DO for aeration of the shrimp and also the microbial activity in the water. High SS is the result of increasing biofloc particles inside the water and therefore need to be removed constantly. Avoiding high ammonia levels inside the culture system is one of the most important notes as it can be toxic for shrimp growth. All of these parameters need to be checked regularly so as to maintain the optimum level to avoid mortality.
The effluent from intensive culture of aquatic animals has been one of the contributors to environmental pollution. However, biofloc technology reduces the nitrogen content in the effluent thus making it an eco-friendly system. The conversion of particulate matter into biofloc biomass by heterotrophic bacteria through assimilation has effectively utilized the nitrogen present in the culture water. This is also supported with the nitrification, nitrogen uptake by photoautotroph and denitrification. In the present study, reduction in the effluent nitrogen where the nitrogen waste generation is also reduced with the consumption of biofloc by shrimp which assimilates more nitrogen (Timmons et al. 2002). Thus, in general the overall system has the ability to improve effluent quality.
The growth parameters of P. vannamei in intensive culture systems improves with the use of biofloc technology. This is proved with the biofloc system which has the ability to become the supplementary food source and provider for nutrients such as protein, lipid, mineral and vitamin. The growth promoter compounds needed by shrimp such as carotenoids, chlorophylls, phytosterols, bromophenols and amino sugars are also contained in the biofloc system. These bioactive compounds come together and help to promote enzyme activity in the digestive system thus increasing feed utilization and assimilation.
Figure 1. The shrimp cultured in the biofloc farm has good growth performance with low FCR
Overall, the biofloc system has a significant improvement in the survivability of shrimp P. vannamei. It not only serves to improve water quality but also the growth of shrimp and effluent produced. Thus, biofloc technology is a significant system developed in the aquaculture industry that will contribute to a high intensive culture system around the world.
References
Timmons, M.B., J.M. Ebeling, F.W. Wheaton, S. T. Summerfelt, and B.J. Vinci. 2002. Recirculating Aquaculture Systems, 2nd edition. Northeastern Regional Aquaculture Center. Publication No. 01-002. Cayuga Aqua Ventures. Ithaca, NY. 769 pp.