Water biofloc microorganism enhance shrimp resistance to microplastics

Microorganisms play a crucial role in modifying the physical-chemical properties and ecotoxicological effects of microplastics (MPs) in aquatic ecosystems. However, existing studies have not been conducted in actual aquaculture environments, which are typically enriched with a variety of microorganisms. To address this, we have investigated the potential of water biofloc to mitigate MPs contamination in Litopenaeus vannamei aquaculture systems. Here, shrimps were subjected to varying concentrations of MPs in clean water and biofloc water. Results showed that clean water group displayed significantly lower survival rate (65.28 % ± 8.67 %) and diminished immune enzymes (i.e., lysozyme and polyphenol oxidase) activities compared to the water biofloc treatment (p < 0.05). Significant differences were observed in the activities of digestive enzymes, antioxidant enzymes and Na⁺/K⁺-ATPase in the clear water and biofloc water treatments (p < 0.05). Notably, biofloc treatments maintained consistent proximate composition and enzymatic activities (p < 0.05), while demonstrating remarkable microbial community stability between aqueous and intestinal habitats that proved resilient to MPs exposure. However, biofloc microorganisms significantly reduced shrimp astaxanthin content (49.24 %), leading to declines in pigmentation, water-holding capacity, and muscle adhesiveness. These findings offer a theoretical foundation for assessing MPs-related risks in aquaculture and advancing ecologically sustainable shrimp farming. In addition, our study provides practical insights for promoting cleaner and more sustainable aquaculture practices.