Maternal supplementation with Lactobacillus reuteri enhances colostrum sIgA secretion and immune function of offspring.

Specific maternal gut microbiota can activate immune responses in the gut-associated lymphoid tissues, driving the secretion of maternal immunoglobulins into the milk and facilitating the passive immunity of the offspring via the entero-mammary axis. This study aims to investigate the distinct gut microbiota profiles between large white (LW) sows and Ningxiang (NX) sows, and to explore probiotic for maternal and offspring intestinal health. Lactobacillus reuteri (LR) was significantly enriched in the feces of NX sows and positively correlated with colostral immunoglobulin (Ig) levels, specifically IgG (r = 0.568, P = 0.014), IgA (r = 0.573, P = 0.013), and IgM (r = 0.721, P = 0.0007). Maternal supplementation with LR isolated from NX pigs enhanced mammary IgA production and elevated secretory IgA (sIgA) levels in both colostrum and the ileum of mice. Importantly, maternal dietary LR supplementation improved immune functions of offspring mice challenged with enterotoxigenic escherichia coli (ETEC), as evidenced by reduced systemic inflammation (TNF-α, IFN-γ) and preserved intestinal barrier function. These results support the potential of NX pig-derived LR as a probiotic to improve the health of maternal and offspring via the gut-mammary axis.