Intestinal immune maturation is accompanied by temporal changes in the composition of the microbiota

Abstract

In animals establishment of the intestinal microbial ecosystem is influenced by mucosal immune functions. As mucosal immune functions dynamically change during development of juvenile layer chicken, this study focused on dynamics in the ileal microbiota composition in relation to intestinal immune development. In addition, the levels of immunoglobulin (Ig) in serum and amount of bacteria coated with IgA, a hallmark of intestinal immune maturation, were analysed. The composition of the intestinal microbiota transiently changed at the age of 14-42 days compared to the microbiota composition before and after this period. This temporal deviation in microbiota composition was associated to a temporal increase in transcriptional activity of pro-inflammatory cytokine genes. Furthermore, before week two limited amounts of faecal bacteria were bound by IgM and from week two increasing amounts of bacteria were bound by IgA, reaching a maximal level of 70% of IgA-coated bacteria at 6 weeks of age. These data could indicate that prior to achievement of intestinal homeostasis at 6-10 weeks post hatch, activation of inflammatory pathways cause a temporal disturbance of the microbiota composition. This period of imbalance may be essential for adequate immune development and establishment of intestinal homeostasis.

Training of Primary Chicken Monocytes Results in Enhanced Pro-Inflammatory Responses

“…More research on, for example, cytokine production, metabolic mechanisms, and epigenetic changes will be of great value to understand the mechanisms behind trained innate immunity in chickens. Innate immune training may have potential to improve disease resistance of poultry in a nonspecific manner, especially at a young age when the adaptive immune system has not yet fully developed [13,[45][46][47]. Dietary additives or vaccinations based on β-glucan could potentially be applied in vivo to train innate immune cells and improve resistance to a variety of pathogens.…”

Development of the Ileal Microbiota in Three Broiler Breeds

“…Lu et al (16), found that clone libraries at 3, 7, and 49 d.p.h had a high dissimilarity to those from 14, 21, and 28 d.p.h with Lactobacillus decreasing while Clostridia increased over time. Similarly, den Hartog et al (47) used T-RFLP reads to demonstrate a temporary disturbance in ileal microbiome composition between 14 and 42 d.p.h.…”

Effect of delayed feeding post-hatch on expression of tight junction– and gut barrier–related genes in the small intestine of broiler chickens during neonatal development

“…Mucins provide adhesive sites for IgA and make up the first line of intestinal defense ( Everett et al., 2004 ). IgA is the most abundant immunoglobulin isotype at mucosal sites ( Brandtzaeg, 2010 ) and is an important factor in preventing infection and regulating the composition of microbiota ( Den Hartog et al., 2016 ). In agreement with previous report ( Zhang et al., 2015 ), IgA was poorly expressed during the first week of life and increased during second week of life in both the jejunum and ileum.…”

“…Small intestine of hatched chicks is immature and undergoes dramatic changes during the first days post-hatch ( Uni et al., 2000 ). Immediately after hatch, functional maturation of GIT is triggered by microbiota and dietary antigens ( Den Hartog et al., 2016 ). Similarly to our observation, rudimentary crypts have been found immediately post-hatch in small intestine and only one crypt per villi has been observed ( Uni et al., 2000 ).…”