Abstract: The interactive effects of dissolved oxygen and feeding rates on Jinhu grouper in a recirculating aquaculture system. Four treatment groups were established: the Control group (CK) with a dissolved oxygen level of 6 mg/L and a feeding rate of 2%; the High Feeding Rate group (HFR) with a dissolved oxygen level of 6 mg/L and a feeding rate of 3.5%; the High Dissolved Oxygen group (HDO) with a dissolved oxygen level of 9 mg/L and a feeding rate of 2%; and the Mixed group (MIX) with a dissolved oxygen level of 9 mg/L and a feeding rate of 3.5%. A practical aquaculture experiment was conducted over a period of 60 days. Through the analysis of the intestinal microbiota composition and serum metabolomics of juvenile Jinhu grouper, a weighted correlation network analysis (WGCNA) was employed to investigate the associations between metabolomics and gut microbial genera. The results indicated that the HFR group significantly enhanced both species diversity and abundance of the gut microbiota. Meanwhile, the HDO group maintained abundance while optimizing the evenness of functional structure distribution. The MIX group achieved intestinal homeostasis by moderately upregulating diversity to prevent excessive competition among microbial communities. Metabolomics analysis indicates that both the HDO and HFR groups optimize the primary bile acid synthesis pathway by reducing the abundance of genera such as Cetobacterium and Stenotrophomonas, while simultaneously decreasing the abundance of Pseudomonas to modulate sphingolipid levels and alleviate immune stress. Notably, the MIX group effectively inhibits the proliferation of Vibrio under hyperoxic conditions and enhances serum spermidine levels by regulating the abundances of Acinetobacter, Dubosiella, and Allobaculum, thereby improving the antioxidant capacity. The conclusion indicates that the combined effect of a 3.5% feeding rates and 9 mg/L dissolved oxygen can optimize the intestinal microbiota structure of grouper, inhibit the proliferation of pathogenic bacteria, and enhance the functional activity of beneficial bacteria. The findings provide a theoretical basis for regulating dissolved oxygen levels and feeding parameters in RAS. It is recommended to adopt a combination strategy of a 3.5% feeding rates with 9 mg/L dissolved oxygen for aquaculture practices.

Key words: Jinhu grouper, dissolved oxygen, feeding rates, serum metabolites, Serum metabolites

摘要： 针对循环水养殖系统（RAS）溶氧和投喂率对金虎石斑鱼的交互影响，设置了CK组（溶氧6 mg/L、投喂率2%）、HFR组（溶氧6 mg/L、投喂率3.5%）、HDO组（溶氧9 mg/L、投喂率2%）组和MIX组（溶氧9 mg/L、投喂率3.5%）4个处理组，开展为期60 d的养殖试验。通过对金虎石斑鱼幼鱼肠道微生物组成、血清代谢组学测定，采用加权共表达网络（WGCNA）分析对代谢组与肠道微生物菌属进行关联分析。结果显示：HFR组显著提升肠道菌群物种多样性和丰度，HDO组在维持丰度的同时优化功能结构分布均匀性，MIX组通过适度上调多样性避免菌群过度竞争，实现肠道稳态。代谢组学分析显示，HDO和HFR组通过降低鲸杆菌属、嗜麦芽窄食单胞菌属丰度优化初级胆汁酸合成通路，同时减少绿脓杆菌属丰度调节鞘氨醇水平以缓解免疫应激。值得注意的是，MIX组能抑制高氧条件下弧菌属增殖，并通过调控不动杆菌属、杜氏杆菌属和杆菌属丰度提升血清亚精胺水平，增强机体抗氧化能力。研究表明：3.5%投喂率与9 mg/L溶氧的联合作用可优化石斑鱼肠道菌群结构，抑制病原菌增殖并增强益生菌功能活性。研究结果为RAS溶氧与投喂参数调控提供理论依据。建议采用3.5%投喂率与9 mg/L溶氧组合策略进行养殖。

关键词: 金虎石斑鱼, 溶氧, 投喂率, 肠道微生物, 血清代谢物