Early post-natal environment and supplementation of B. lactis NCC2818 exert a sustained influence on the developing immune system and on gut microbial co-metabolism in the pig.
Claire A. Merrifield1, Marie C. Lewis2, 3Bernard Berger4, Olivier Cloarec5, Florence Charton4, Lutz Krause6, Swantje Duncker4, Annick Mercenier4, Elaine Holmes1, Mick Bailey2 Jeremy K. Nicholson1.
1Biomolecular Medicine, Department of Surgery and Cancer, Imperial College London, UK; 2Infection and Immunity, School of Clinical Veterinary Science, University of Bristol, Langford House, Langford, North Somerset, UK; 3Food and Nutritional Sciences, School of Chemistry, Food and Pharmacy, University of Reading, Reading, UK; 4Nestlé Research Centre, Vers-chez-les-Blanc, Lausanne, Switzerland; 5Korrigan Sciences Ltd., Maidenhead, UK; 6Queensland Institute of Medical Research, Brisbane, Australia
Introduction
The young piglet is a valuable model for human infants in studies designed to identify interactions between the developing immune system, metabolism and the microbiome in early life. The early postnatal environment, including factors such as weaning and acquisition of the gut microbiota, has been causally linked to the development of later immunological diseases such as allergy and autoimmunity. Here, we show that early-life environment influences development of metabolic and immune phenotype as well as the gut microbiota in a porcine model.
Methods
Piglets were removed to an isolator facility 24 hours after birth, formula fed until 21d at which point they were weaned onto an egg-based diet. Animals were gender and litter-matched to the control group or supplemented with the human probiotic Bifidobacterium lactis NCC2818 from 1d. Animals were sacrificed at 35d and the experiment was repeated with a second batch of piglets under identical husbandry conditions.
Metabolic profiling of serum throughout the experiment and urine at 35d was carried out using 1H Nuclear Magnetic Resonance spectroscopy (NMR). Intestinal barrier function was assessed using immunofluorescence histology and immunoglobulin and cytokine production from various immunological sites was quantified. 16s pyrosequencing was conducted on colonic content and mucosal scrapings.
Results
At one day after birth, metabolic profiling of serum demonstrated significant inter-batch variation which persisted until weaning. However, the urinary metabolic profiles demonstrated that significant inter-batch effects on metabolites including 3-hydroxyisovalerate, trimethylamine-N-oxide and mannitol persisted beyond weaning to at least 35 days. In addition, immunoglobulin and cytokine parameters including mucosal IgA, IgM and IL-10, exhibited batch-dependent changes, as did the composition of colonic microbiota at 35 days. Supplementation with B.lactis NCC818 was not associated with significant differences in microbial composition at the family level but was associated with altered excretion of urinary host-microbial co-metabolites, changes in the immunological phenotype and up-regulation of expression of intestinal tight-cell junction proteins. Significant correlations between the production of certain cytokines and immunoglobulins by mucosal tissues and levels of urinary sarcosine, betaine, lactate and alanine were identified and this suggests the potential for a non-invasive urinary test to assess the development of the mucosal immune system.
Conclusion
We demonstrate that the environment during the first day of life influences development of the microbiota, metabolic phenotype and immune parameters and suggest that nutritional intervention at this early stage of life could be beneficial for at-risk infants who have suffered aberrant initial intestinal colonisation caused by, for example, caesarean section or premature birth.
2