A review on Spirulina: alternative media for cultivation and nutritive value as an aquafeed

The nutritional value of spirulina in aquafeeds has been studied extensively as a fishmeal replacer or as a functional feed additive to increase growth and health performance of fish in the last decade. Despite increased interest in spirulina research in aquaculture, its increased production cost still limits its use in commercial rations. Zarrouk's medium is the standard substrate used for growing spirulina. Although this medium offers optimal biomass production, it incurs higher costs due to the expensive components needed for concocting the medium. In this regard, development of cost-effective alternative culture medium or techniques is necessary for the industrial-scale production of these microalgae. This paper reviews research on different alternative media for spirulina cultivation and its nutritive value as an aquafeed. Numerous alterations in the composition of Zarrouk's medium with cheaper chemical ingredients have been explored as a potential substitute for cost-effective microalgae cultivation. Industrial and processing wastes and by-products with appropriate nutrient profiles for growing spirulina are also being considered as alternative culture media. The use of rice bran or other cheaper agricultural by-products, as a cost-effective growth medium for commercial-scale spirulina production has yet to be explored extensively in agriculture-based countries, especially in rice-producing Asian countries.