PSI-6 - Temporal analysis of jejunal mucosal proteome reveals profile changes in piglets from birth to early postweaning stage

Abstract: The intestinal mucosa is a dynamic and interactive structure that supports physiological processes essential for maintaining intestinal architecture, epithelial renewal, cellular metabolism, and mucosal immunity. As piglets age, the intestinal mucosa adapts to dietary changes and evolving physiological demands across different growth stages, partly through changes in proteome profiles. However, little is known about the dynamic changes of mucosal proteomes during the preweaning and postweaning stages in piglets. The aim of this study was to investigate temporal changes in jejunal mucosal proteomes during the suckling and early postweaning periods. On postnatal day (PND) 0 (within 24 h after birth), 10, 18, postweaning day (PWD) 7 and 14, six barrows were selected and euthanized for jejunal mucosa collection. Total proteins were extracted from mucosal samples and subjected to liquid chromatography-tandem mass spectrometry for shotgun proteomic analysis. A total of 5,498 proteins were detected across all time points. Principal component analysis and hierarchical clustering were applied to capture features representing the entire proteome across developmental stages. These analyses revealed age-related effects on the jejunal mucosal proteomes. Specifically, mucosal proteomes on PND 10 were distinct from those on PWD 7 and PWD 14, with PND 18 intermediate to PND 10 and postweaning profiles, while samples on PND 0 showed considerable variation. Analysis of the top 50 differentially expressed proteins revealed that mucosal proteins on PND 0 had the highest abundance of alpha-fetoprotein, Ig-like domain-containing proteins, MAM domain-containing 4, neural cell adhesion molecule 1, branched-chain-amino-acid aminotransferase, and melanotransferrin (FDR < 0.05). Additionally, the abundance of proteins involved in stress and antioxidant defense responses, amino acid metabolism, protein translation, and post-translational modifications or function as metabolic enzymes and proteasome components, increased from PND 0 to PWD 14 (FDR < 0.05). Gene ontology enrichment analysis indicated age-related changes in proteins associated with translation, tricarboxylic acid cycle, glycolytic process, positive regulation of cell proliferation, immune response, and carbohydrate metabolic process (P < 0.05). Taken together, the shift in proteomes likely reflects an age-related upregulation of metabolic and stress responses and protein turnover that are critical for maintaining cellular homeostasis and resilience against age-associated oxidative stress. Overall, the findings may indicate age-associated physiological changes during intestinal maturation in piglets, including increases in antioxidant capacity, energy production, protein repair, and maintenance of tissue growth and integrity.