Abstract:
Early in life and particularly around weaning, piglets are susceptible to infections
because of abrupt social, environmental, and dietary changes. Dietary interventions
with probiotic bacteria have gained popularity because of the increased awareness
of the direct link between diet and health. In this study, piglets received the probiotic
strain Escherichia coli Nissle 1917 (EcN) or a control treatment perorally from day 2
after birth until 2 weeks post-weaning. To investigate spatio-temporal effects of EcN
on the gut microbiota composition, intestinal epithelial gene expression and immune
system, feces, digesta, blood, scraping material and mesenteric lymph node tissue
were collected at different time points. In addition, oral vaccinations against Salmonella
enterica serovar Typhimurium were administered on days 21 and 45 of the study
to assess the immunocompetence. EcN-treated pigs showed a reduced diversity of
taxa within the phylum Proteobacteria and a lower relative abundance of taxa within
the genus Treponema during the pre-weaning period. Moreover, EcN induced T cell
proliferation and Natural Killer cell activation in blood and enhanced IL-10 production
in ex vivo stimulated mesenteric lymph node cells, the latter pointing toward a more
regulatory or anti-inflammatory state of the local gut-associated immune system.
These outcomes were primarily observed pre-weaning. No significant differences were
observed between the treatment groups with regards to body weight, epithelial gene
expression, and immune response upon vaccination. Differences observed during the
post-weaning period between the treatment groups were modest. Overall, this study
demonstrates that the pre-weaning period offers a ‘window of opportunity’ to modulate
the porcine gut microbiota and immune system through dietary interventions such as
EcN supplementation.
