Music intervention mitigates LPS-induced gut barrier disruption and immune stress in broilers via TLR4/NF-κB regulation

Abstract

Immune stress induced by harsh environment in intensive farming can impair broiler intestinal health. Although music as an environmental intervention can alleviate short-term stress injury, its long-term regulatory mechanism on intestinal inflammation has not been clarified. In this study, we investigated the effects of a music-enriched environment on growth performance, intestinal barrier function, and inflammatory responses in lipopolysaccharide (LPS)-induced immunostressed broilers. AA broilers were randomly divided into four groups: control group (CON), music-enriched environment group (MUC), LPS-induced immune stress group (LPS) and music-enriched environment + LPS group (MUC+LPS). On the 14th, 16th and 18th days, the LPS and MUC+LPS groups were injected intraperitoneally with 500 μg of LPS to construct an immune stress model, and the CON and MUC groups were injected with an equal amount of saline. On day 28, the birds were sacrificed to detect the indicators associated with intestinal barrier and inflammation. The LPS group showed a significant decrease in performance from 14 to 28 days, with elevated serum levels of CORT, ACTH, DAO, and d-LA, and a decrease in the activity of intestinal mucosal SOD/GSH-Px, and impaired gut morphology. impaired; music remission significantly alleviated the decline in production performance, reduced the levels of stress hormones and markers of intestinal barrier damage, while elevating jejuno-ileal GSH-Px activity and improving intestinal morphology. Significant inflammatory gene expression characteristics were observed in jejunum and ileum tissues after LPS injection: upregulation of TLR4, NF-κB, TNF-α, IL-1β, and IL-6, and significant suppression of jejunal IL-10 expression. Notably, IL-10 and IFN-γ expression in the ileum did not show statistical differences. Inflammation-related gene expression showed an overall down-regulation trend after the music intervention, but was still significantly different from the control group. Music intervention on the regulation of jejunal MYD88 and ileal TNF-α - the LPS group did not show statistically significant differences in the expression of these two key inflammatory nodes with the LPS+MUS group. Mechanistic studies have shown that LPS triggers an oxidative stress cascade through activation of the TLR4/NF-κB signaling axis, leading to disruption of intestinal barrier integrity. In contrast, music exposure exerts a protective effect through a dual mechanism: on the one hand, it helps to enhance the expression of the tight junction protein ZO-1/Occludin to repair the physical barrier; on the other hand, it inhibits the activation of the TLR4/NF-κB pathway, which can effectively alleviate LPS-induced immunopathological damage.