PHYSIOLOGY AND ENDOCRINOLOGY SYMPOSIUM: Postnatal reproductive development and the lactocrine hypothesis

Area of Science:

• Reproductive Biology
• Developmental Biology
• Animal Science

Background:

• Maternal factors significantly influence offspring development and phenotype beyond birth.
• The lactocrine mechanism, involving signals from mother to offspring via first milk (colostrum), plays a vital role in postnatal development.
• Neonatal uterine development is critical for long-term reproductive health, proceeding independently of ovaries shortly after birth.

Purpose of the Study:

• To investigate the role of lactocrine signaling via colostrum in neonatal porcine uterine development.
• To determine the consequences of disrupted lactocrine signaling on uterine development and adult reproductive performance.
• To identify molecular pathways affected by lactocrine signaling during early uterine development.

Main Methods:

• Comparative analysis of uterine development in piglets fed colostrum versus milk replacer.
• RNA sequencing to assess gene expression differences in the uterus by postnatal day 2.
• Integrated microRNA-mRNA pathway analyses to identify affected biological processes.

Main Results:

• Disruption of lactocrine signaling by milk replacer feeding altered neonatal porcine uterine development.
• Over 800 differentially expressed genes related to cell-cell signaling, ESR1 signaling, and tissue development were identified by postnatal day 2.
• Limited colostrum consumption negatively affected adult reproductive performance.

Conclusions:

• Colostrum consumption and intact lactocrine signaling are essential for establishing a normal uterine developmental program in pigs.
• Lactone signaling is a critical extra-ovarian input for uterine development.
• Early life lactocrine signaling impacts long-term reproductive success.