Luqing Pan

This study investigated the effects of glycerol monolaurate (GML) on the growth performance, physiological efficacy, intestinal structure, and microbiota of hybrid juvenile ♀ Epinephelus fuscoguttatus × ♂ E. lanceolatus. A total of 594 groupers were administered diets supplemented with 0, 2, 4, 6, 8, or 10 g/kg of GML over an 80-day period. The findings indicated that the group receiving 4 g/kg GML supplementation demonstrated significantly enhanced growth performance, as evidenced by increased weight gain, specific growth rate, and a reduced feed conversion ratio compared with the control and other experimental groups. This growth enhancement was associated with elevated catalase and glutathione levels, suggesting improved antioxidant capacity that may contribute to enhanced immune function. Furthermore, fish in the 4 g/kg group exhibited increased digestive enzyme activity and significantly improved intestinal morphology, characterized by thicker muscular layers and a greater fold width and height. Furthermore, compared with the control group, GML supplementation elevated the relative abundance of Proteobacteria while reducing that of Firmicutes at the phylum level. At the genus level, GML markedly suppressed the relative abundance of Mycoplasma and Vibrio. These compositional alterations are potentially linked to improved energy acquisition and a decreased risk of pathogenic infections. Collectively, these results reveal that GML acts as a promising functional feed additive to boost growth performance, optimize digestive capacity, and sustain intestinal structural integrity in hybrid grouper. Based on these results, the optimal GML supplementation dose was determined to be 4 g/kg, providing valuable insights into the role of GML in aquaculture practices for hybrid grouper.

Dietary plant-derived bioactive compounds for enhancing physiological health are becoming a prevalent strategy for antibiotic alternatives. Our study revealed the effects and underlying mechanism of osthole (OST) and OST-tetramethylpyrazine (TMP) compound in Litopenaeus vannamei based on network pharmacology, molecular docking and a 42-d feeding trial verification. The results illustrated that OST and OST-TMP compound significantly improved the survival rate, weight gain rate, specific growth rate and feed conversion ratio, strengthening the growth performance of L. vannamei. Meanwhile, combining the predictive results from network pharmacology and molecular docking, we propose that OST and TMP synergistically enhance the antioxidant defence capacity of shrimp through the synergistic Nrf2 signalling pathway, thereby enhancing the expression of total antioxidant capacity, superoxide dismutase, catalase and glutathione peroxidase. Furthermore, OST-TMP exhibited a significant increase of the immune response in haemocyte and intestine of shrimp, increasing the expression of antimicrobial peptide and lysozyme and suppressing the inflammatory factors, via the synergistic (NF-κB) and complementary targets predicted by network pharmacology. Additionally, gut microbiota composition of L. vannamei was improved, and the dominant genera were correlated with intestinal immune in the compound groups. For the first time, we elucidated the mechanism of plant-derived bioactive compounds mediating physiological health in aquatic animals via a new strategy of network pharmacology-molecular docking-experimental verification and identified the optimal addition amount of OST-TMP in shrimp (150 mg/kg TMP + 20 mg/kg OST), providing a technical safeguard for the animal health and the safety of aquatic products.