Oxygen nanobubble-induced hyperoxia: Effects on growth, digestive enzyme activity, intestinal morphology, and biochemical parameters in kuruma prawn (Penaeus japonicus)

Oxygen nanobubble (NB-O 2 ) technology constitutes an efficient and stable approach for the release of dissolved oxygen (DO), frequently leading to a substantial elevation in DO levels within the water. Nevertheless, the potential effects of long-term hyperoxia induced by NB-O 2 exposure in farmed shrimp remain poorly understood. Accordingly, this research aims to investigate the impact of hyperoxia during NB-O 2 treatment on growth performance, digestive enzyme activity, intestinal morphology, muscle proximate composition, and target gene expression in kuruma prawn ( Penaeus japonicus ). The present study employed NB-O 2 as a technical strategy to regulate dissolved oxygen levels and conducted a 40-day aquaculture experiment under DO conditions of 7.45 ± 0.16 mg/L (air treatment) and 15.95 ± 0.11 mg/L (NB-O 2 treatment). The study demonstrated that hyperoxia during NB-O 2 treatment enhances the growth performance of P. japonicus (weight gain rate, specific growth rate, and molting rate), improves intestinal digestive enzyme activity (pepsin, trypsin), and augments muscle proximate components (crude protein, crude fat). Furthermore, the NB-O 2 treatment increased serum biochemical parameters (glucose, total protein, albumin, acid phosphatase, alkaline phosphatase, and lysozyme) and upregulated the expression of digestion and antioxidant genes ( trypsin 1 , peroxidase ), and it significantly reduced the number of pathogenic microorganisms in seawater, demonstrating its effectiveness in water quality purification. In conclusion, long-term hyperoxia induced by NB-O 2 exposure offer potential benefits for the aquaculture of P. japonicus , promoting overall health and stability. • This study is the first to analyze the hyperoxia effects induced by NB-O 2 on Penaeus japonicus aquaculture. • Long-term exposure to NB-O 2 can increase DO and effectively inhibit the total bacterial count and vibrio count in water. • NB-O₂ can improve growth, digestion, muscle approximation, and serum biochemical indicators in Penaeus japonicus . • Long-term exposure to NB-O 2 does not result in any significant adverse effects on the gut morphology of Penaeus japonicus . • This study is exploratory and fills the gap in the research of NB-O 2 in the field of Penaeus japonicus aquaculture.