MICROORGANISMS IN AQUACULTURE DEVELOPMENT

ABSTRACT

Microbes found in aquaculture are usually from source water, feeds including augmented live foods. These microbes are found in the gills, intestine, muscles and on the surface of fish, shrimps, crustaceans and other aquatic organisms. Microorganisms in aquaculture play several roles including their use as live food, food supplements, probiotics, in pond aeration and in the purification of aquarium. As food, microbes provide the essential nutrients such as vitamins, enzymes, polyunsaturated fatty acids, amino acids, pigments and steroids; and serve as carbon and nitrogen sources. Microbial diversity in aquaculture depends largely on the quality (physicochemical properties) of the farm water and this has greatly influenced the growth of every aquaculture. Fungi, Bacteria, Protozoa, Helminthes and Microalgae are present in aquaculture, each performing its unique role in the ecosystem. While some are beneficial, others are not. They are used as probiotics to check the growth of some pathogenic microorganisms thereby reducing the incidence of aquarium diseases. Microbial live foods include Bacteria, Fungi, Microalgae and Protozoa. Microbes used as live food include lactic acid bacteria, Bacillus, Chlorella vulgaris, Saccharomyces and Aspergellus. These live foods have the advantage of small size, ease of digestion and ability to stimulate enzyme synthesis. Besides, microbes function in pond purification (biofilters) as well as its bioenergetic cycle. Microalgae, specifically aerate ponds through the release of oxygen during photosynthesis. The beneficial role of microbes has contributed immensely to the growth, development and sustainability of aquaculture.