Medicinal Plants as Ecological Solutions for Fish Growth and Immunostimulatory Effects in Aquaculture

Abstract

The growing global interest in sustainable aquaculture has led to an increased search for alternatives to synthetic antibiotics and chemical feed additives. Medicinal plants have surfaced as promising ecological solutions, with research showing their potential to improve fish growth, boost immunity, and enhance disease resistance while decreasing the need for antibiotics. Recent studies suggest that supplementing fish diets with medicinal plants may improve survival rates. This supplementation upregulates key immune-related gene responses, including cytokines such as interleukin (IL)-1β and tumor necrosis factor-alpha (TNF-α), as well as lysozyme (LYZ and LZM genes) and immunoglobulins (IgM, IgT, and IgD). As a result, innate and adaptive immune responses can be enhanced depending on the species and dosage. Furthermore, certain plant-derived compounds have shown antimicrobial properties similar to traditional antibiotics, reducing pathogen loads by more than 50%. This review examines the role of medicinal plants in aquaculture, highlighting their effects on immunity, antimicrobial activity, and growth promotion. It delves into the mechanisms involved, such as the modulation of cytokine expression, enhancement of antioxidant defenses, and regulation of gut microbiota. However, challenges like variable phytochemical composition, the need for optimal dosages, and regulatory issues limit their broader use. While previous reviews have addressed the use of medicinal plants in aquaculture, few have thoroughly examined their dual role in both enhancing fish health and contributing to ecological functions such as improving water quality and promoting climate resilience. This review aims to fill that critical knowledge gap by integrating these dimensions highlighting how medicinal plants serve not only as bioactive growth promoters and immune enhancers but also as ecological tools for fostering environmental sustainability in aquaculture systems. Incorporating medicinal plants into aquaculture could potentially reduce antibiotic use by up to 50% by 2050, aligning with global efforts toward sustainable and eco-friendly fish production. Innovations in phytochemical profiling, nanotechnology-based delivery systems, and next-generation sequencing are anticipated to further enhance the effectiveness and standardization of plant-based aquafeeds. This comprehensive framework offers new insights into the development of resilient and environmentally responsible aquaculture practices, particularly in the face of climate change.