Dietary resveratrol alleviates the negative impact of high-level Clostridium autoethanogenum protein on the growth, immunity, transcriptomic response, and intestinal microflora of Litopenaeus vannamei

This study evaluated whether dietary resveratrol (RES) could alleviate the adverse effects of high-level fishmeal (FM) replacement with Clostridium autoethanogenum protein (CAP) in Pacific white shrimp (Litopenaeus vannamei). Four isonitrogenous and isolipidic diets were prepared: a control diet containing FM (C), a high-CAP diet (T), and two CAP-based diets supplemented with 400 mg/kg (TR1) or 800 mg/kg (TR2) RES. After an 8-week feeding trial, high-level CAP replacement significantly reduced growth performance, antioxidant capacity, non-specific immunity, and resistance to Vibrio parahaemolyticus, and also induced hepatopancreatic and intestinal damage as well as intestinal microbial dysbiosis. Compared with group T, RES supplementation significantly improved growth performance and post-challenge survival, enhanced antioxidant and immune-related indices, alleviated tissue injury, and promoted a more favorable intestinal microbial structure by increasing beneficial taxa and reducing potentially harmful bacteria. Transcriptomic analysis further showed that RES reversed CAP-induced dysregulation of genes and pathways associated with metabolism, immunity, detoxification, and stress adaptation. Overall, dietary RES effectively mitigated the negative effects of high CAP inclusion and improved the physiological adaptability of L. vannamei to low-FM diets. These findings support the application of RES as a functional additive in CAP-based aquafeeds.