|Mcguire, William - FORMERLY 5438-01-10|
Submitted to: Life Sciences
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: December 23, 1998
Publication Date: N/A
Interpretive Summary: Pig litter size at birth is reduced due to 30-50% mortality during gestation. In order to increase litter size, it is important to understand factors that limit litter size and those factors important for normal prenatal development. One such factor could be the steroid hormone cortisol. This study was conducted to determine if cortisol is present in very early pig embryos (days 25 and 35 of gestation; term = 114 days). Cortisol's presence is a necessary, but not sufficient, condition for it to influence embryonic development at these ages. Indeed, we found cortisol to be present in day 25 fetuses and to increase eightfold by day 35. At this latter age, cortisol concentrations were significantly and positively associated with embryonic weight. Such a relationship may reflect an ability of cortisol to stimulate growth at this gestational age.
Technical Abstract: A study was conducted to determine the presence of cortisol in body tissue of porcine embryos at days 25 and 35 of gestation. Cortisol concentrations (ng/mg DNA) were low but measurable at day 25 and increased eightfold by day 35 during a time when body weight increased 6.4-fold. At day 35, there was a highly significant positive linear regression of body weight on cortisol concentrations. The source of this embryonic cortisol is not known, but its presence suggests the opportunity for cortisol to influence porcine embryonic development at these early gestational stages.