Archidendron clypearia extract: Modulating intestinal inflammation and enhancing disease resistance in aquacultured American bullfrogs (Aquarana catesbeiana)

Intestinal inflammation and bacterial infections challenges in the aquaculture of American bullfrogs (Aquarana catesbeiana), impacting their health and productivity. Archidendron clypearia, a traditional Chinese medicinal plant, is known for its analgesic, antibacterial, anti-inflammatory, and antioxidant properties, suggesting its potential as an integrative therapeutic agent in aquaculture. In this study, a short-term feeding experiment (35 days) was designed to explore the effects of A. clypearia extract (AE), on growth, intestinal morphology, antioxidant status, immune function and intestinal flora of bullfrog fingerlings. After feeding, bullfrogs were experimentally infected with Elizabethkingia miricola and monitored for an additional 14 days. Four groups were fed a commercial diet supplied with different AE as 0, 0.2, 1.0, and 5.0 g/kg. Results showed significant improvements in the growth and intestinal morphology of AE-supplied groups compared to the control. Moreover, Dietary supplemented with AE significantly increased expression levels of the tight junction protein–related genes, including zonula occludens-1(ZO-1), zonula occludens-2 (ZO-2), zonula occludens-3 (ZO-3), occludin, and claudin-7. However, the expression of inflammation-related genes, including Interleukin-8 (IL-8), Interleukin-1β (IL-1β), C-X-C Motif Chemokine Ligand 10 (CXCL10), in the liver and intestine were significantly decreased in all AE groups compared to the controls (P < 0.05). Alternatively, no significant impact on blood indices and intestinal microflora in all experimental groups. After challenge, the survival rates in 0, 0.2, 1.0 and 5.0 g/kg groups were 10 %, 50 %, 80 % and 70 %, respectively, suggesting enhancement of the bullfrog resistance in AE groups compared to control. The results suggest the AE positively impacted growth performance and disease resistance, making it a potentially useful functional feed additive in bullfrog breeding. The results suggest that adding 1.0 g/kg AE to the diet positively impacted growth performance and disease resistance, making it a potentially useful functional feed additive in bullfrog breeding.