# Integrated Transcriptomics and Targeted Metabolomics Approaches: Comparative Analysis of the Ileum in Neonatal Piglets with Different Birth Weight

## TL;DR

This study finds that high-birth-weight piglets have better intestinal development and energy metabolism at the molecular level compared to low-birth-weight piglets.

## Contribution

The study integrates transcriptomic and metabolomic data to reveal molecular and metabolic differences in ileal development based on birth weight in piglets.

## Key findings

- High-birth-weight piglets showed upregulated genes related to DNA replication and energy metabolism.
- Pyruvic acid concentrations were higher in high-birth-weight piglets, indicating active energy metabolism.
- Differentially expressed genes included RFC3, PCNA, and others involved in cell division and nutrient absorption.

## Abstract

Birth weight is a key determinant of intestinal development and subsequent growth performance in pigs, but the molecular mechanisms remain unclear. We investigated ileal differences between high- and low-birth-weight piglets using integrated transcriptomic and targeted metabolomic analyses. High-birth-weight piglets exhibited upregulated expression of genes related to DNA replication, cell division, and energy metabolism, accompanied by higher pyruvic acid concentrations. These findings suggest that birth weight is associated with molecular indicators involved in cellular proliferation and energy metabolism, and that these molecular and metabolic characteristics may be related to intestinal function, physiological adaptability, and growth potential in neonatal piglets.

This study was conducted to elucidate the molecular and metabolic differences in ileal development according to birth weight in neonatal piglets. A total of 126 neonatal piglets born from Yorkshire × Landrace × Duroc crossbred sows were used, and the top 5% (H group, 1.77 ± 0.02 kg) and bottom 5% (L group, 0.72 ± 0.03 kg) of birth weights were selected for analysis. Ileal tissues were collected for transcriptomic (RNA-seq) and targeted metabolomic (GC–MS) analyses, and selected genes were validated using RT-qPCR. A total of 112 differentially expressed genes (DEGs) were identified, among which RFC3, PCNA, MCM3, MCM10, AURKA, AURKB, CCNB2, CCNA2, CCNF, and SI were significantly upregulated in the H group (p < 0.05). These genes were mainly involved in pathways related to DNA replication, cell division, and nutrient digestion and absorption. In addition, metabolomic analysis revealed that pyruvic acid concentrations were significantly higher in the H group (p < 0.05), indicating the activation of energy metabolic pathways. These results indicate that high-birth-weight piglets possess a genetic foundation for enhanced cellular proliferation and energy metabolism, and they further highlight potential molecular targets for improving growth performance and intestinal development in low-birth-weight piglets.