Rearing environment affects development of the immune system in neonates

Abstract

SummaryEarly-life exposure to appropriate microbial flora drives expansion and development of an efficient immune system. Aberrant development results in increased likelihood of allergic disease or increased susceptibility to infection. Thus, factors affecting microbial colonization may also affect the direction of immune responses in later life. There is a need for a manipulable animal model of environmental influences on the development of microbiota and the immune system during early life. We assessed the effects of rearing under low-(farm, sow) and high-hygiene (isolator, milk formula) conditions on intestinal microbiota and immune development in neonatal piglets, because they can be removed from the mother in the first 24 h for rearing under controlled conditions and, due to placental structure, neither antibody nor antigen is transferred in utero. Microbiota in both groups was similar between 2 and 5 days. However, by 12-28 days, piglets reared on the mother had more diverse flora than siblings reared in isolators. Dendritic cells accumulated in the intestinal mucosa in both groups, but more rapidly in isolator piglets. Importantly, the minority of 2-5-day-old farm piglets whose microbiota resembled that of an older (12-28-day-old) pig also accumulated dendritic cells earlier than the other farm-reared piglets. Consistent with dendritic cell control of T cell function, the effects on T cells occurred at later time-points, and mucosal T cells from high-hygiene, isolator pigs made less interleukin (IL)-4 while systemic T cells made more IL-2. Neonatal piglets may be a valuable model for studies of the effects of interaction between microbiota and immune development on allergy.

Probiotics – do they have a role in the pig industry?

“…However, it is possible that piglets born into regularly sterilised farrowing accommodation may acquire a substantially different microbiota from the substrate than they would in an outdoor farrowing situation. This has indeed been shown in recent studies in pigs raised in different high v. low hygiene environments, which showed that such differences significantly affect not only intestinal microbiota composition but also the mucosal innate immune function in neonates, as well as in adult animals (Mulder et al, 2009;Inman et al, 2010).…”

Intrauterine Growth Restriction Impairs Small Intestinal Mucosal Immunity in Neonatal Piglets

“…Additionally, decreases in IL2 and IFN-γ mRNA expression may represent a regional inhibition of the immune status that is associated with MHC-II expression (Zeitz et al 1988;Bravery et al 1995), which is consistent with the lower MHC-II expression detected in the present study (unpublished data). Although the rearing environment affects the development of the immune system in neonates (Inman et al 2010), the process takes time. Piglets in this study were newborn and euthanized shortly after birth without suckling.…”

Interference of Bifidobacterium choerinum or Escherichia coli Nissle 1917 with Salmonella Typhimurium in gnotobiotic piglets correlates with cytokine patterns in blood and intestine

“…In this work, a possible probiotic effect of autochthonous B. choerinum was compared with that of probiotic E. coli Nissle 1917. Gnotobiotic pigs were used to avoid any effect of interindividual variation in intestinal microflora and rearing environment [27]. The distribution of bacteria, their translocation, the protective effect against subsequent infection with virulent Salmonella Typhimurium, the clinical state of experimental piglets and systemic and local production of two inflammatory cytokines – a chemokine, interleukin (IL)‐8, a proinflammatory cytokine, tumour necrosis factor (TNF)‐α and an anti‐inflammatory cytokine, IL‐10, were assessed.…”