<p><i>In utero </i>heat stress (<b>IUHS</b>)
is a major concern for realizing full production potential in the swine
industry. Postnatal phenotypes, such as growth performance, post-absorptive
metabolism, and stress response, are negatively altered in pig offspring that
have been exposed to IUHS. With current trends in global temperatures predicting
a continuation of increased temperatures, it is necessary to further
investigate mechanisms driving these altered postnatal phenotypes and to find
mitigation strategies to combat the negative effects of IUHS. In a first study,
postnatal consequences of IUHS in pigs were evaluated and a mitigation strategy
was tested. A second study was conducted to investigate the HPA axis response
to a stress challenge in IUHS pigs. The first study found decreased average
daily gain in IUHS pigs, and that providing a nutrient-dense diet did not
rescue this lost productivity due to a decrease in feed intake for this diet.
These results show the importance of maintaining beneficial gestation
environments to avoid IUHS and the need to continue looking for alternative
strategies to mitigate negative effects of IUHS. In the second study, IUHS pigs
had a decreased change in cortisol response (<b>Δ CORT</b>)
from baseline when subjected to a corticotropin-releasing hormone (<b>CRH</b>)
challenge at 10 wk of age, and 15 wk old pigs had a decreased Δ CORT response when subjected
to a dexamethasone suppression test and a CRH challenge as well as decreased
glucocorticoid receptor expression in both the hypothalamus and anterior
pituitary when compared to 10 wk old pigs. These results show changes in HPA
axis function as young pigs mature and that particular focus may need to be put
on IUHS pigs at a young age when they might be more vulnerable to negative
impacts of stress. Overall, these studies show that IUHS causes a variety of
negative postnatal effects in offspring and that a better understanding of
mechanisms driving these changes along with developing alternative strategies
to combat the incidence of these negative postnatal effects remains of paramount
importance for the swine industry.</p>
| Identifer | oai:union.ndltd.org:purdue.edu/oai:figshare.com:article/14522679 |
| Date | 05 May 2021 |
| Creators | Jacob Michael Maskal (10732173) |
| Source Sets | Purdue University |
| Detected Language | English |
| Type | Text, Thesis |
| Rights | CC BY 4.0 |
| Relation | https://figshare.com/articles/thesis/Evaluating_and_mitigating_the_effects_of_in_utero_heat_stress_on_postnatal_performance_and_stress_response_of_swine/14522679 |
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