Biofloc technology: an emerging avenue in aquatic animal healthcare and nutrition

Biofloc is a conglomeric aggregation of microbial communities such as phytoplankton, bacteria, and living and dead particulate organic matter. Biofloc technology involves manipulation of C/N ratio to convert toxic nitrogenous wastes into the useful microbial protein and helps in improving water quality under a zero water exchange system. It may act as a complete source of nutrition for aquatic organisms, along with some bioactive compounds that will enhance growth, survival, and defense mechanisms, and acts as a novel approach for health management in aquaculture by stimulating innate immune system of animals. Nutritionally, the floc biomass provides a complete source of nutrition as well as various bioactive compounds that are useful for improving the overall welfare indicators of aquatic organisms. Beneficial microbial bacterial floc and its derivative compounds such as organic acids, polyhydroxy acetate and polyhydroxy butyrate, could resist the growth of other pathogens, thus serves as a natural probiotic and immunostimulant. The technology is useful in maintaining optimum water quality parameters under a zero water exchange system, thus prevents eutrophication and effluent discharge into the surrounding environment. Moreover, the technology will be useful to ensure biosecurity, as there is no water exchange except sludge removal. The technology is economically viable, environmentally sustainable, and socially acceptable.