Spatiotemporal dynamics of mucosa-associated Lactobacillus along the small intestine and its response to 2′-fucosyllactose and galacto-oligosaccharides in piglets

Early-life colonization of <i>Lactobacillus</i> in the gut is crucial for immediate and lifelong health. The intestinal mucosa is a key interface of host-microbiota interaction, but the colonization patterns of <i>Lactobacillus</i> within this niche remain unclear. In this study, nine newborn piglets per litter (ten litters total) were randomly assigned (three piglets per group per litter; <i>n</i> = 30 per group across all litters) to receive daily oral doses of 2'-fucosyllactose (2'-FL, 100 mg/(kg·d)), galactooligosaccharides (GOS, 1 g/(kg·d)), or saline (control) during the 21 day suckling period. The results revealed significant age-associated shifts in <i>Lactobacillus</i> composition, with the higher <i>Lactobacillus</i> abundance observed during the suckling period and decreasing after weaning (<i>P</i> < 0.05). On postnatal day 8, <i>Lactobacillus delbrueckii</i> was the dominant species, followed by <i>Limosilactobacillus reuteri</i>, <i>Limosilactobacillus mucosae</i>, <i>Lactobacillus amylovorus</i>, and <i>Lactobacillus johnsonii</i>. From days 8 to 21, the levels of <i>L</i>. <i>johnsonii</i>, <i>L</i>. <i>amylovorus</i>, <i>L</i>. <i>mucosae</i>, and <i>L</i>. <i>reuteri</i> notably declined on the jejunal mucosa (<i>P</i> < 0.05), whereas the quantities of <i>L. amylovorus</i> increased on the ileal mucosa (<i>P</i> = 0.001). By day 49, <i>L. mucosae</i> showed a lower level on the duodenal and jejunal mucosa (<i>P</i> < 0.05). Compared with the control group, 2'-FL enriched more <i>Lactobacillus</i> (e.g. <i>L</i>. <i>delbrueckii</i> and <i>L. johnsonii</i>) on the jejunal mucosa on day 21 (<i>P</i> < 0.05), and reduced total <i>Lactobacillus</i> on day 49 (<i>P</i> < 0.05). Relative to 2'-FL, the impact of GOS was less significant (<i>P</i> > 0.05). These results highlight the role of 2'-FL and GOS in selectively modulating the development of intestinal <i>Lactobacillus</i>, offering insights into their potential for regulating mucosal function during critical growth phases. These findings provide a mechanistic basis for targeted prebiotic interventions in neonatal piglets.