Studies on microbial programming in formula fed neonatal piglets and their susceptibility to Escherichia coli infection later in life
Final Report Abstract
Hyper-proliferacy in modern pig breeds has resulted in increasing litter sizes, often exceeding the number of active teats or the milk production capacity of the mother and thereby the ability to efficiently rear all life-born piglets. This has resulted in increased use of milk replacers based on bovine milk compounds and (partly) mother-free rearing systems. Based on the current literature and own preliminary results, it was hypothesized that artificially reared piglets may develop an immature-type gut microbiota accompanied with a dysregulation of the developing neonatal gut physiology and immune system. These effects may be even fortified by bovine milk-based formula feeding through the induction of a remodeling of the neonatal gut early in life accompanied by morphological and physiological modifications. This, in turn, promotes the production of high levels of organic acids from excessive lactose fermentation and may selectively favor the proliferation of putative pathogens. Within the project, experiments with neonatal piglets reared by the mother or in artificial rearing units (isolators) and either fed sow milk or bovine milk-based formula for a certain (up to 14 days) time period confirmed, that isolator rearing combined with formula feeding delayed and outbalanced the natural intestinal bacterial colonization as compared to sow-reared littermates. Furthermore, formula-fed piglets were highly colonized by putative pathogens and susceptible to Clostridioides difficile infection accompanied by a high abundance of antibiotic resistance genes as revealed by metagenomic analyses. Additional studies showed that sow milk constitutes a protective effect against pathogen-induced intestinal epithelial reactions. Thus, artificially reared and formula-feed neonatal piglets may not only be more susceptible to pathogen infection but may also contribute to the evolution of farm-related resistomes. With regard to physiological development, not only intestinal morphology and functionality (e.g. brush border membrane disaccharidase activities) but furthermore pancreas and hepatic development were severely affected by isolator rearing combined with formula feeding. For example, we could confirm our preliminary studies showing that reduced small intestinal lactase activity, despite high lactose concentration in the formula, led to high large intestinal concentration of short chain fatty acids and especially lactic acid. Using a back-fostering model where piglets were initially isolator-reared with formula and then moved back to their mothers showed, that e.g. induced differences in organ development might be reversible during an early-life time window. The data show, that maternal environment as well as uptake of mothers’ milk are essential for appropriate intestinal digestive function and cannot be completely replaced by artificial rearing systems and sole feeding concepts based on milk replacers. Microbiome analyses in the experiments with neonatal piglets were accompanied by analysis of several immunological parameters such as peripheral blood mononuclear cell (PBMC) and jejunal intraepithelial immune cell populations, expression of pro- and anti-inflammatory cytokine genes in jejunal tissue as well as serum levels of pro- and anti-inflammatory cytokines. Although e.g. PBMC subsets analyzed according to their cell surface marker expression did not show differences between experimental groups, intracellular staining for inflammatory Th1- type polarization characterized by increased Tbet or IFNg+ expression differed significantly depending on environment and diet. Similarly, differences in the activation of antigen presenting cells likely caused by bacterial colonization patterns were shown. Furthermore, intraepithelial natural killer cells as well as yet less understood NK phenotypes (e.g. CD3+, SLAII+) showed differences between treatment groups. Their role in early-life microbiota-host interplay is worth further investigation. Taken together, the results of the project provide a deeper insight into the nutritional and environmental-induced interplay between the early-life bacterial colonization of the porcine intestinal tract and the concomitant physiological and immunological development. The findings suggest that artificial rearing and formula feeding should be carefully re-considered as on-farm practice for the handling of large litter of hyper-prolific sows.
Publications
- 2018. Formula-feeding predisposes neonatal piglets to Clostridium difficile infection. Journal of Infectious Diseases. 217: 1442-1452
Ł. Grześkowiak, B. Martínez-Vallespín, T.H. Dadi, J. Radloff, S. Amasheh, F.-A. Heinsen, A. Franke, K. Reinert, W. Vahjen, J. Zentek, R. Pieper
(See online at https://doi.org/10.1093/infdis/jix567) - 2019. Impact of early-life events on the susceptibility to Clostridium difficile colonisation and infection in the offspring of the pig. Gut Microbes. 10:251-259
Ł. Grześkowiak, R. Pieper, H.A. Hong, S.M. Cutting, W. Vahjen, J. Zentek
(See online at https://doi.org/10.1080/19490976.2018.1518554) - 2020. Towards a porcine in vivo model resembling the pathogenesis of Tlr5-dependent enteropathies. Gut Microbes. 12:1782163
R. Pieper, N. van Best, K. van Vorst, F. Ebner, M. Reissmann, J. Zentek, M. Hornef, M. Fulde
(See online at https://doi.org/10.1080/19490976.2020.1782163) - 2021. Influence of nutrition and maternal bonding on postnatal lung development in the newborn pig. Frontiers in Immunology. 734153
J. Schlosser-Brandenburg, F. Ebner, R. Klopfleisch, A.A. Kühl, J. Zentek, R. Pieper, S. Hartmann
(See online at https://doi.org/10.3389/fimmu.2021.734153)
