A Comparison of Physiological Homeostasis and Product Quality Between Recirculating Water and Earthen Pond Culture of Litopenaeus vannamei

Water quality deterioration during the late culture phase remains a key limiting factor for intensive Litopenaeus vannamei farming. This study compared traditional open earthen ponds and recirculating aquaculture systems (RAS) to investigate differences in physiological health, tissue structure, and muscle quality of cultured shrimp between the two culture modes. Using coefficient of variation (CV) as a quantitative metric, we observed that water quality parameters in the RAS group exhibited smaller fluctuation amplitudes, with nitrogenous metabolite concentrations and TCBS-culturable Vibrio-like bacteria loads notably lower than those in open earthen ponds. Shrimp reared in RAS achieved better overall growth performance. In contrast, shrimp in the pond system showed systemic ammonia accumulation across multiple tissues, accompanied by gill lamellar blockage, respiratory epithelial shedding, and disrupted mitochondrial cristae in the hepatopancreas. Histochemical assays further revealed marked glycogen depletion in the hepatopancreas of pond-reared shrimp, along with a “low-protein, high-moisture” muscle profile characterized by porous myofibrillar architecture. Although oxidative stress markers were elevated in the Pond group, plasma lysozyme activity was significantly suppressed. These findings suggest that the superior growth performance and muscle quality observed in the RAS system may be partly associated with lower homeostatic and stress repair costs, which arise from overall differences in rearing conditions between the two culture modes. The present study provides supporting histological and physiological evidence for optimizing shrimp culture strategies and upgrading production models.