How does stress affect sow's fertility?

The aims of this project are to gain new knowledge regarding influences of stress and hormonally semi-defined media on oocyte maturation, fertilisation and early embryo development in vitro in the pig.

Stress among our group housed pigs occurs predominantly due to fighting after regrouping, which is commonly performed at a time coinciding with several important reproductive events around ovulation. From earlier studies, plasma from frequent blood samples were collected from sows stressed by ACTH-treatment or fasting, as well as from control sows. The plasma has been analysed for concentrations of cortisol and other reproductive hormones. This well-characterised plasma will be added in the in vitro embryo production media during different time periods of oocyte maturation, fertilisation and early embryo development, as well as in a sequential mode closely following the hormonal oestrous cycle of the pig. The quality of oocytes, zygotes and early embryos will be assessed by several methods, including morphology, immunohistochemistry and confocal laser scanning microscopy.

This project will combine the information and unique material from the earlier studies with abattoir derived oocytes and provide a new and important aspect of the impact of stress on the early pregnancy. Our preliminary results suggest a major negative impact on oocyte fertilisation when plasma from ACTH-treated sows is added during in vitro fertilisation, but not during in vitro maturation.

Financier: Formas
Collaborator: Raquel González Herrero