Lemongrass (Cymbopogon citratus) as a Phytogenic Feed Additive in Aquaculture: Effects on Growth Performance, Feed Utilization, Immunity, and Disease Resistance

Abstract

Intensive aquaculture systems have increased production but also raised concerns about disease pressure, stress, and the consequences of prolonged antibiotic and synthetic growth-promoter use. Plant-based feed additives offer one practical route toward more sustainable practices. Lemongrass (Cymbopogon citratus), long valued in traditional medicine and cuisine, contains citral and related compounds that display antimicrobial, antioxidant and immunomodulatory activity. This review draws together experimental findings published up to 2022 on the dietary use of lemongrass leaf powder, aqueous extracts and essential oil in cultured fish. Across tilapia, African catfish and tambaqui, moderate inclusion levels have frequently improved weight gain, specific growth rate and feed conversion, while supporting selected haematological and innate-immune parameters and, in several challenge trials, reducing mortality after bacterial infection. Effective doses generally fall in the range of 0.25–0.50 ml kg⁻¹ for essential oil and 2–10 g kg⁻¹ for leaf powder, although species and product form influence the optimum. Safety appears acceptable within the tested ranges. Remaining gaps include longer-term commercial trials, wider species coverage and clearer mechanistic understanding. Overall, the pre-2023 literature indicates that lemongrass is a low-cost candidate phytogenic additive capable of contributing to growth, health and reduced reliance on conventional chemotherapeutic agents.