The effect of Lactobacillus on the expression of porcine β-defensin-2 in the digestive tract of piglets

Some probiotic lactobacilli strains are known to confer health benefits to piglets by modulating its immune functions. This study investigates how intestinal mucosal immune responses in the digestive tract of neonatal piglets are influenced by Lactobacillus colonization. L. salivarius B1, isolated from the intestinal mucosa of a healthy piglet, was confirmed to possess excellent probiotic properties, such as strong adhesion to Caco-2 cells and high lactic acid production in vitro. It is hypothesized that early administration of L. salivarius B1 might facilitate colonization and promote intestinal mucosal immune responses in the piglet. The neonatal piglet was used as a model to investigate the in vivo colonization of L. salivarius and the effect on pBD-2 expression in response to L. salivarius B1. Results show that L. salivarius B1 colonizes duodenal mucosa early and upregulates the expression of pBD-2 in a non-inflammatory manner (p < 0.01). Levels of pBD-2 in saliva were observed to increase upon exposure of enterocytes to L. salivarius B1 and were tightly correlated with the administration of successive doses of L. salivarius B1. These findings provided further insight into the effects of probiotic Lactobacillus on the intestinal mucosal immune response of the neonatal piglet and suggest that pBD-2 upregulation may be in part responsible for the immune response induced by L. salivarius.