Enhancing sustainable Penaeus vannamei aquaculture: A green duckweed-biofloc multitrophic system for improved culture performance and economic benefits

To advance ecological sustainability and nutrient recovery in biofloc technology (BFT), this study developed an integrated duckweed-biofloc multitrophic system (DBG) for the culture of Penaeus vannamei and compared it with conventional BFT (CG). Under zero-water-exchange operation, DBG achieved apparent removal of nitrate (NO 3 − -N), total nitrogen (TN), soluble reactive phosphate (SRP), total phosphorus (TP), and dissolved organic carbon (DOC) of 10.637 ± 6.312 %, 17.769 ± 5.765 %, 10.778 ± 3.245 %, 8.520 ± 1.999 %, and 37.57 ± 13.94 %, respectively. By the end of the culture period, DBG also maintained lower total suspended solids (TSS) compared with the CG. Improvements in the aquaculture water environment and dietary enrichment also contributed to benefits for the cultured shrimp. Histological examination revealed improved gut morphology in DBG shrimp, accompanied by significantly higher antioxidant capacity and digestive enzyme activities ( p < 0.05). Furthermore, the growth performance, appearance, and muscle quality of shrimp in the DBG improved. Net present value (NPV) analysis confirmed the economic feasibility of the DBG system. Metabolomic analyses of water and shrimp gut revealed elevated levels of flavonoid compounds (e.g., vicenin-2 and isoschaftoside) in the DBG. Integrated metabolomic and transcriptomic analyses further indicated enhanced immunity and attenuated inflammation in DBG shrimp, potentially via the regulation of gut serotonin metabolism. Additionally, dietary enrichment of DBG promoted nutrient assimilation, particularly of chitin, proteins, and vitamins. Overall, the duckweed-biofloc multitrophic system not only improves water quality and nutrient recycling but also enhances shrimp health and productivity, offering a sustainable and economically sound strategy for modern aquaculture. • The accumulation peaks of NO 3 − -N, TN, SRP and DOC in DBG were significantly reduced. • DBG enhances P. vannamei growth, quality, and economic benefits. • Duckweed raises flavonoid levels in water and P. vannamei gut. • DBG improves the metabolism related to inflammation and nutrient absorption.