Synergistic impacts of probiotics and prebiotics (synbiotics) in fish farming

The aquaculture sector is vulnerable to disease outbreaks, environmental stressors, and antibiotic overuse due to high stocking densities and intensive production practices, necessitating the adoption of sustainable health management strategies. Dietary functional additives such as probiotics, prebiotics, and synbiotics have emerged as promising alternatives to antibiotics in fish farming. Probiotics are live, non-pathogenic microorganisms that confer health benefits to the host, whereas prebiotics are indigestible substrates that selectively stimulate beneficial gut microbiota; synbiotics combine both components to enhance their functional complementarity. The individual effects of probiotics and prebiotics are well-documented. Nevertheless, there is limited integrative knowledge on the optimal dosage and combination strategies. This review critically synthesizes synbiotic supplementation (prebiotics and probiotics) in fish farming, highlighting the underlying mechanisms and the synbiotic dosages that maximize synergistic effects on fish growth, immune response, and disease resistance. By consolidating experimental evidence and identifying knowledge gaps, it offers a practical and research-oriented framework to guide the effective application of synbiotics in sustainable aquaculture.