Cinnamaldehyde treats largemouth bass non-lethal bacterial enteritis by regulating gut morphology, barrier, inflammation, microbiota and serum biochemistry

With the development of aquaculture technology, the scale and density of aquaculture continue to increase, enteritis has become a common and frequent disease worldwide. In order to treat enteritis and prevent the abuse of antibiotics, it is of great significance to develop new and efficient drugs. Cinnamaldehyde is a natural product isolated and extracted from plants such as cinnamon and has a variety of biological functions such as antibac-terial, antifungal, antiviral, antiulcer, anticancer and growth-promoting. The aim of this study was to investigate the therapeutic effect of cinnamaldehyde on Aeromonas hydrophila infection caused by non-lethal enteritis in largemouth bass. Fish were infected with A.hydrophila by intraperitoneal injection, 20 mg/kg, 40 mg/kg and 80 mg/kg cinnamaldehyde were given for 7 days. The results showed that cinnamaldehyde decreased the clinical symptoms and intestinal pathological damage caused by A.hydrophila infection, increased the expression of ZO-1, Occludin and Claudin-1, reduced oxidative damage and enhanced the ability of antioxidant. Cinnamaldehyde up-regulated the expression of TGF-beta 2, IL-10 and IL-11, and down-regulated the expression of TNF-alpha, IL-1 beta, IL-15 and IL-8, regulated the diversity of the intestinal microflora structure, maintained the relative balance of in-testinal microflora to improve intestinal health. Overall, these data clearly indicated that cinnamaldehyde was a potentially effective drug for treatment of A.hydrophila infection caused enteritis in largemouth bass. In conclusion, Cinnamaldehyde is a potential drug for the treatment of non-fatal enteritis in aquaculture.