Scutellaria baicalensis extract alleviates salpingitis and enhances egg production in laying hens via suppression of the NF-κB signaling pathway

Scutellaria baicalensis (SB), a traditional Chinese herb known for its bioactive properties, was evaluated for its potential to mitigate salpingitis in laying hens. This study investigated the effect of SB extract (SBE) on salpingitis and explored its underlying mechanisms of action. In vitro, an inflammatory response was induced in HD11 macrophage-like cells using lipopolysaccharide (LPS), followed by treatment with SBE. For the in vivo trial, salpingitis was induced in laying hens via intraperitoneal injection of Escherichia coli and Staphylococcus aureus. Hens were subsequently treated with SBE or amoxicillin over a 21-day period. On day 21 post-infection, hens were humanely euthanized for sample collection. Analytical methods included antimicrobial susceptibility testing, histopathological examination, ELISA, quantitative PCR, and Western blotting. SBE exhibited no cytotoxic effects and ameliorated LPS-induced cytotoxicity in HD11 cells. In vitro, SBE modulated the expression of both pro- and anti-inflammatory cytokines. In vivo, SBE administration significantly improved egg production, with an average yield of 27-32 eggs per hen over 21 days compared to an average of 14 eggs in the infected untreated group. Plasma levels of IL-1β, IL-6, TNF-α, and IFN-γ were significantly reduced, while IL-2 levels were increased. Differential white blood cell counts (neutrophils, eosinophils, and lymphocytes) were restored to levels comparable to those in healthy birds. Gross anatomical and histopathological evaluations revealed reduced oviduct lesions and diminished inflammatory infiltration. Western blot analysis indicated that SBE suppressed NF-κB nuclear translocation from the cytoplasm to the nucleus through enhanced phosphorylation of AKT and IκBα, thereby inhibiting inflammatory signaling. This finding was consistent with in vitro results. Additionally, SBE exhibited direct antibacterial activity against relevant pathogens. These results indicate that SBE effectively alleviates salpingitis in laying hens by inhibiting NF-κB nuclear translocation via IκBα/AKT activation and concurrently improving egg production. The study supports SBE as a promising antibiotic-free alternative for managing salpingitis in poultry.