Associations between foetal size and ovarian development in the pig.

Area of Science:

• Reproductive Biology
• Developmental Biology
• Ovarian Physiology

Background:

• Intrauterine growth restriction (IUGR) affects 25% of piglets, causing impaired postnatal reproductive performance in females.
• The timing of developmental origins for these reproductive deficits during gestation remains unclear.

Purpose of the Study:

• To investigate fetal ovarian development in normal and growth-restricted piglets throughout gestation.
• To identify early gestational markers associated with impaired reproductive potential.

Main Methods:

• Histological analysis of GATA4-stained fetal ovaries at gestational days (GD) 45, 60, and 90.
• Quantification of plasma estradiol concentrations.
• Real-time quantitative PCR (qPCR) to assess mRNA abundance of 12 candidate genes in fetal ovaries.

Main Results:

• Fewer primary follicles were observed in the least-weight fetuses compared to control littermates at GD90 (P ≤ 0.05).
• Lower plasma estradiol concentrations were found in lesser-weight fetuses at GD90 (P ≤ 0.05).
• Differential mRNA expression of genes including PTGFR, KI67, and P53 was noted in ovaries of lesser-weight fetuses at specific gestational days.

Conclusions:

• Ovarian development and gene expression are altered in growth-restricted fetuses early in gestation.
• These prenatal changes indicate programming of postnatal reproductive potential deficits.
• Further research is needed to link prenatal development with postnatal reproductive outcomes.