Biofilm in Aquaculture Production

Abstract

A biofilm is an assemblage of microbial cells which is irreversibly associated with a surface and enclosed in a matrix of primarily polysaccharide material. It may form on a wide variety of surfaces, including living tissues, medical devices, industrial or potable water system pipe or natural aquatic systems. A well-diversified organism such as algae, bacteria, protozoa, arthropods, etc. may be observed in the biofilm assemblage. The biofilm structure depends on the nature of substratum, hydrodynamics of system, nutrient availability, light and grazing capacity of organism. It has been observed that the introduction of substrata for the development of biofilm in the aquaculture system play a significant role. Biofilm organisms are microscopic and highly nutritious.  The organisms of biofilm may serve as single cell protein and are easily harvested by all size of cultured species in aquaculture as compared to planktonic organism in the water column. Biofilms are considered as good quality protein source (23-30%). Microalgae and heterotrophic bacteria are rich source of immune enhancers, growth promoters, bioactive compounds and dietary stimulants which can enhance growth performance of cultured organism. Substrata minimize the mortality by providing shelter and hiding places to cultured organisms. The attached nitrifying bacteria  contained in biofilm improve the water quality by lowering  ammonia waste from culture system through nitrification process. Biofilm based low cost technology will help resource poor farmers in generating protein rich nutrient in sustainable manner from aquaculture. An attempt has been made to review the role of biofilm in aquaculture.   Key words: Biofilm, fish growth, sustainable, water quality, survival, nutrient quality.