International Journal of Aquaculture, 2025, Vol.15, No.5, 221-228 http://www.aquapublisher.com/index.php/ija 221 Feature Review Open Access Towards Sustainable Aquaculture: A Review on The Use of Microalgae as Functional Feed Ingredients CostaD.S. 1 , Pereira-Júnior J.A. 2, Martins M.L. 3 1 LMM-Marine Mollusc Laboratory, Aquaculture Department, UFSC, Florianópolis, SC, Brazil 2 LCM-Marine Shrimp Laboratory, Aquaculture Department, UFSC, Florianópolis, SC, Brazil. 3 AQUOS-Aquatic Organisms Health Laboratory, Aquaculture Department, UFSC, Florianópolis, SC, Brazil Corresponding authors: domicksonsc@hotmail.com International Journal of Aquaculture, 2025, Vol.15, No.5 doi: 10.5376/ija.2025.15.0021 Received: 19 Jul., 2025 Accepted: 03 Sep., 2025 Published: 18 Sep., 2025 Copyright © 2025 Costa et al., This is an open access article published under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Preferred citation for this article: Costa D.S., Pereira-Júnior J.A., and Martins M.L., 2025, Towards sustainable aquaculture: a review on the use of microalgae as functional feed ingredients, International Journal of Aquaculture, 15(5): 221-228 (doi: 10.5376/ija.2025.15.0021) Abstract Population growth is intensifying the demand for sustainable protein sources, positioning aquaculture as a strategic sector for global food security. However, the industry faces nutritional, economic, and environmental challenges, particularly due to the high cost and ecological impact of fishmeal (FM) and fish oil (FO), which are widely used in commercial feeds. These inputs are rich in essential fatty acids, such as docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA), whose production relies on intensive harvesting of marine species, thereby compromising the sustainability of the supply chain. In this context, microalgae have emerged as promising alternatives due to their high nutritional and functional value, including proteins, long-chain polyunsaturated fatty acids (LC-PUFAs), antioxidants, and bioactive compounds. This review compiles scientific evidence demonstrating that the inclusion of microalgae in fish and shrimp diets can maintain or enhance lipid composition, immunocompetence, pathogen resistance, antioxidant activity, and gut health in cultured organisms. Species such as Schizochytriumsp., Nannochloropsis sp., Chlorella sp., and Spirulina sp. have shown promising results. Although further studies are needed to determine optimal inclusion levels and potential synergies among species, current data support the potential of microalgae to contribute to a more efficient and sustainable aquaculture. Keywords Fishmeal; Fish oil; Antioxidants; Bioactive compounds 1 Introduction The development and growth of the human population have driven a continuous search for alternatives to meet the increasing demand for resources, especially food (Gil et al., 2024). In this context, expanding the production of proteins for human consumption in a safe and sustainable way represents a significant challenge for various sectors, including aquaculture. Aquaculture is an activity focused on the production of aquatic organisms such as fish, crustaceans, mollusks, and algae. This practice plays a strategic role in global food security, since, according to data from the Food and Agriculture Organization of the United Nations (FAO, 2024), aquaculture production has reached 223.2 million tons. Of this total, 185.4 million tons corresponded to the production of aquatic animals, while 37.8 million tons referred to algae production. Furthermore, approximately 89% of aquatic animal production was intended for human consumption. Despite the significant figures achieved by aquaculture, challenges still persist regarding the nutrition of farmed organisms, especially fish and shrimp (Evrendilek, 2024). These issues go beyond technical aspects such as diets formulation, balanced and nutritionally adequate feed, and also encompass economic and environmental concerns, including high production costs and the sustainability of the production system. In this context, it is worth noting that feed accounts for a large portion of the total production costs (Baki and Yücel, 2017) making it one of the main obstacles to the economic viability of aquaculture, especially for small and medium-sized producers. The high cost of aquaculture feed is largely associated with the use of ingredients such as fishmeal (FM) and fish oil (FO), which are valued for their high concentration of polyunsaturated fatty acids (PUFAs), especially docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) (Zhang et al. 2024) which play essential roles in
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