The combination of matrine and tannic acid protects chickens against intestinal infection caused by Salmonella Typhimurium

The aim of this study was to investigate the effect of the combination of matrine and tannic acid on intestinal infection in chickens with Salmonella Typhimurium. A model of chicken intestinal infection with S. Typhimurium was established to confirm the protective effect of the combination of matrine and tannic acid in vivo. This combination prolonged survival time, promoted growth, and decreased the bacterial burdens of the liver and duodenum in chickens infected with S. Typhimurium, and was superior to matrine or tannic acid monotherapy. The combination of these substances alleviated the changes in organ indices and liver and spleen congestion, decreased intestinal permeability, and alleviated duodenal lesions in chickens caused by S. Typhimurium. The same combination suppressed the transcription of IL-1β and TNF-α in the intestine of chickens infected with S. Typhimurium, possibly through the downregulation of the mRNA expression of TLR-4/p50/NLRP-3/Caspase-1. Moreover, the combination of matrine and tannic acid decreased the levels of intestinal nitrate and iNOS mRNA in the duodenum of chickens infected with S. Typhimurium. Caecal microbiota analysis revealed that this combination improved gut microbiota dysbiosis in chickens infected with S. Typhimurium, as evidenced by alterations in the abundance of microbiota composition at the phylum (Firmicutes and Actinobacteria, Proteobacteria), family (Bifidobacteriaceae and Enterobacteriaceae), and genus (Lactobacillaceae, Escherichia-Shigella, and [Ruminococcus]_torques_group) levels. In conclusion, the combination of matrine and tannic acid is a viable strategy to protect chickens against S. Typhimurium infection, possibly through the suppression of the inflammatory response and the modulation of the intestinal microecology.