Viola yedoensis Makino alleviates lipopolysaccharide-induced intestinal oxidative stress and inflammatory response by regulating the gut microbiota and NF-κB-NLRP3/ Nrf2-MAPK signaling pathway in broiler

Viola yedoensis Makino (Vy) is a well-known traditional Chinese medicine widely used to treat inflammatory diseases. However, the regulatory effects of dietary Vy supplementation on lipopolysaccharide (LPS) -induced intestinal damage in broilers and the underlying molecular mechanisms remain unclear. In this study, broilers were intraperitoneally injected with 1 mg/kg LPS on days 17, 19 and 21 to induce intestinal damage. Vy supplementation at 0. 5, 1. 5 and 4. 5 % in the diet was administered separately for 21 days to investigate the potential protective effects of Vy supplementation against LPS-induced intestinal impairment in broilers. Vy supplementation improved intestinal morphology and restored growth performance. Vy supplementation attenuated intestinal inflammation by regulating the nuclear factor kappa B (NF-κB) / NLR family pyrin domain-containing 3 (NLRP3) signaling pathway and inhibited its downstream pro-inflammatory factor levels. In addition, Vy supplementation relieved intestinal oxidative impairment by regulating the nuclear factor erythroid-2 related factor 2 (Nrf2) / mitogen-activated protein kinase (MAPK) signaling pathway and downstream antioxidant enzyme activity. Vy supplementation reduced LPS-induced mitochondrial damage and apoptosis. Furthermore, Vy supplementation alleviated LPS-induced intestinal inflammation and oxidative damage in chickens by increasing the abundance of protective bacteria (Lactobacillus and Romboutsia) and reducing the number of pathogenic bacteria (unclassifiedfRuminococcaceae, unclassifiedfOscillospiraceae and norankfₙorankₒClostridiaᵥadinBB60group). Overall, Vy supplementation effectively ameliorated LPS-induced intestinal damage by regulating the NF-κB-NLRP3/Nrf2-MAPK signaling pathway and maintaining intestinal microbiota balance. Vy supplementation can be used as a dietary supplement to protect broilers against intestinal inflammation and oxidative damage.