Valorization of the chemical diversity of the tropical red seaweeds Acanthophora and Kappaphycus and their applications in aquaculture: A review

The role that seaweeds play as primary producers and ecosystems engineers in marine coastal ecosystems is widely acknowledged. Seaweeds, however, are also important drivers in the development of the blue bioeconomy due to their vast diversity of unique chemicals with a broad range of industrial and biotechnological applications. In tropical regions, seaweed production has been focused on a few species only, because of their hydrocolloids used in the food industry. There is a strong need to identify new applications of red seaweed species in other sectors such as aquaculture. Therefore, to diversify the culture of red seaweeds, more tropical species need to be investigated for their chemical composition and potential application in aquaculture, and then, to develop a method for a sustainable cultivation of new seaweed candidates and enhance their economic potential. Based on this context, we analyze the potential value of the red edible seaweed Acanthophora spp., an under-valued seaweed species which is naturally abundant in tropical countries, and Kappaphycus spp., a commercially valuable seaweed commonly used for polysaccharide extraction. The vast chemical diversity of seaweeds (polysaccharides, phytohormones, amino acids, and pigments) has led to research on a wide range of applications in aquaculture, including pathogen control, immunostimulant, antioxidant, bioremediation, feed, UV protectants, increase in seafood shelf life, animal colorant, and growth regulator for microalga culture. This review hopes to stimulate the interest among seaweed researchers to investigate other local seaweed species and seek greater added value of their biomass and chemical compounds and their applications in the aquaculture sector. Additionally, this information will help stakeholders to benefit from these two red seaweeds by contributing to the diversification of the blue bioeconomy in tropical countries.