The Quest for Functional Ingredients for Sustainable Aquaculture Feeds in Sub-Saharan Africa.

The aquaculture sector plays a key role in ensuring food and nutritional security as well as fostering economic growth in sub-Saharan Africa (SSA). However, as the sector continues to grow, its future faces economic, environmental, and sustainability challenges. At the core of these challenges are the substantial nutritional and health requirements of the farmed fishes that are cultured semi-intensively and intensively. Nutrient-balanced feed resources like fish meal and soybean are highly indispensable in most aquaculture production systems in SSA. However, these ingredients are limited, expensive, and are also in direct competition with farmed terrestrial animals and humans. Additionally, frequent disease outbreaks, especially due to the impact of climate change, pose viability challenges that are traditionally controlled using chemotherapeutics. But their indiscriminate usage has led to the occurrence of resistant microbes in the environment further adding to the challenges. Functional ingredients (FIs), derived from plants and microbial sources, are emerging as viable options to address both the nutritional and health issues of farmed fish. FIs contribute to fish health, growth performance, and resilience to disease and stress not only through their antioxidant, immunomodulatory, and antimicrobial properties but also by their nutritional benefits. The incorporation of these ingredients, into fish feeds can greatly reduce production costs, ecological footprint, and reliance on finite marine resources and synthetic drugs. However, FIs, with a few exceptions, have not been widely adopted in the aquafeed industry. This review aims to critically examine the reasons behind their limited adoption in the aquafeed industry, identifying key challenges and research gaps that hinder their widespread application. Additionally, it explores and evaluates the potential role of FIs in formulating cost-effective and functional aquafeeds with a low ecological footprint. A particular focus is given to their role in enhancing aquaculture productivity in the SSA region, highlighting opportunities for sustainable growth and the need for further research to optimize their efficacy and commercial viability.