Lactobacillus plantarum protects broilers against Salmonella Typhimurium infection via modulating TLR4/MyD88/NF-κB signaling pathway and gut microbiota

Aims Salmonella Typhimurium (ST) infection in broilers threatens food security and public health, and antibiotic overuse causes serious side effects. This study aimed to evaluate the protective effects and mechanism of Lactobacillus plantarum (LW) isolated from Tibetan chickens against ST infection in broilers. Methods and Results Eighty 1-day-old Arbor Acres broilers were randomly divided into four groups (n = 20 per group): control (CC), LW supplementation (LW), ST infection (ST), and ST + LW treatment (PR). Broilers in LW and PR groups were orally administered 1 × 10⁸ CFU mL−1 LW from day 4 to day 21, and those in ST and PR groups were challenged with 1 × 10⁸ CFU mL−1 ST from day 15 to day 18. Results showed that LW significantly alleviated ST-induced growth retardation, oxidative stress and intestinal histological injury. Meanwhile, LW inhibited NF-κB pathway to reduce intestinal inflammation, upregulated tight junction proteins to enhance intestinal barrier function, increased the abundance of Lactobacillus and Bacilli to optimize gut microbiota, and maintained taurine levels to regulate taurine and hypotaurine metabolism. Conclusions LW effectively protects broilers from ST infection via regulating intestinal immunity, barrier function, gut microbiota and metabolism. LW can be used as a safe and effective probiotic to prevent ST infection in poultry, thus reducing food safety risks and ensuring public health.