Impact of different culture substrates on the water environment and growth performance of Babylonia areolata in a recirculating aquaculture system

Abstract

This study evaluates the effects of different substrates (PVC culture nests, ceramic particles, and sand) on Babylonia areolata's growth performance, water environment, and microbial community in a recirculating aquaculture system (RAS). A RAS, integrating vertical sedimentation tanks, nano-aeration devices, and foam separation equipment with ecological culture nests, was designed to address issues in traditional culture models. Over 180 days, water quality parameters, microbial diversity, growth condition, and enzyme activity of B. areolata were monitored. Water quality remained stable: dissolved oxygen was 5.04–7.98 mg/L, pH 7.26–8.46, ammonia nitrogen 0.05–0.25 mg/L, and nitrite nitrogen 0.021–0.069 mg/L. Different substrates significantly affected snail growth and water environment regulation. The sand group had the highest final shell length (35.46 ± 3.02 mm) and body weight (11.5 ± 1.04 g), while the ceramic particle group showed lower growth rates. Microbial community analysis revealed higher diversity in PVC and sand substrates (Shannon index 6.83–6.91), and the ceramic particle group had significant enrichment of some antibiotic resistance genes (ARGs). Enzyme activity analysis indicated dynamic changes in antioxidant and digestive enzymes. Lipase activity in the ceramic particle group was significantly lower than in other groups (p < 0.05). In conclusion, PVC ecological culture nests combined with the efficient water treatment system can maintain stable water quality and support high - density culture (1500 ind./m²). This study provides a feasible technical solution for B. areolata recirculating aquaculture and scientific insights for substrate selection and ARGs control.