Biofloc technology and immunological resilience in pacific white shrimp (Litopenaeus vannamei): A mechanistic review

• Biofloc systems enhance immunological resilience in Litopenaeus vannamei through microbiota modulation, innate immune activation, and antioxidant strengthening. • Microbial metabolites and MAMPs within biofloc stimulate hemocyte activity, AMP expression, and pathogen surveillance mechanisms. • Improved water quality and nutrient-rich microbial biomass reduce physiological stress and support stable immune homeostasis. • Variability in BFT performance underscores the need for standardized immune markers, molecular characterization, and long-term monitoring. • Future directions include multi-omics integration, immune-targeted probiotics, biofloc–vaccine synergies, and climate-resilient BFT system innovation. Biofloc Technology (BFT) is recognized as an ecologically sustainable aquaculture method that improves water quality, enhances nutrient recycling, and increases disease resilience in cultured crustaceans, especially Litopenaeus vannamei . Initially designed to mitigate environmental impact and decrease reliance on water exchange, recent findings suggest that biofloc systems have significant immunomodulatory effects, driven by intricate interactions among host, microbes, and the environment. This review consolidates existing mechanistic insights regarding the influence of BFT on immune function in shrimps, focusing on microbiota modulation, innate immune activation, antioxidant enhancement, and exposure to bioactive microbial metabolites. Biofloc systems promote stable and diverse microbial communities that effectively exclude pathogens, enhance beneficial taxa, and provide immunostimulatory microbial-associated molecular patterns (MAMPs) that activate hemocyte and humoral responses. Furthermore, enhanced water quality and nutrient-dense microbial biomass jointly mitigate oxidative stress, promote physiological homeostasis, and bolster resistance to bacterial and viral pathogens, such as Vibrio spp. and white spot syndrome virus. Comparative analyses of biofloc and conventional systems demonstrate the enhanced immunological, nutritional, and environmental efficacy of BFT. However, they also identify significant limitations, such as inconsistent outcomes stemming from variable system management, insufficient long-term immune data, and a limited comprehension of the molecular pathways that regulate host responses. To address these knowledge gaps, standardized immune markers, integrated multiomics analyses, and farm-scale validation are necessary. This review presents a mechanistic framework for enhancing BFT as an immune-focused, climate-resilient approach to sustainable crustacean aquaculture.