Genetic Effects on the Endocrine Maturation of Pig Fetuses

Program: Abstracts - Orals, Featured Poster Presentations, and Posters
Session: SUN 72-87-HPA Axis
Basic
Sunday, June 16, 2013: 1:45 PM-3:45 PM
Expo Halls ABC (Moscone Center)

Poster Board SUN-87
Pierre Mormede*, Elena Terenina, Laure Gress, Yann Labrune, Nathalie Iannuccelli, Laurianne Canario and Laurence Liaubet
INRA, Castanet-Tolosan, France
The adrenocortical (HPA) axis is a major player in fetal maturation and in the genetic influences on piglet survival. Together with the autonomic nervous system and the thyroid axis it has a critical role in metabolic adjustments at birth. The main objectives of pig genetic selection are the increase of prolificacy and the reduction of body fat content. Both reduce physiological maturity of newborns and increase piglet mortality. The aim of the present study is to identify behavioral, physiological and molecular indicators for a better survival at birth, in order to find new biomarkers of piglet maturity for further use in genetic selection.

The present experiment was designed to take advantage of two extreme breeds for piglet maturity, Large White (LW) with an increased neonatal mortality and Meishan (MS) more mature at birth (1). In order to sort apart the respective influence of the maternal and fetal genotype, LW and MS sows were inseminated with mixed semen (LW+MS), giving purebred fetuses in their respective maternal genetic environment and (±) genetically identical F1 fetuses in each maternal environment. Fetuses were delivered naturally (114 days) or by cesarean section at 90 or 110 days of gestation. Cortisol was measured in plasma by radioimmunoassay, total and free T3 and T4 by AIA (automated immunoassay analysis) and catecholamines by HPLC after solvent extraction.

As expected, circulating cortisol levels in fetuses increased largely towards the end of gestation (between 90 and 110 d). However, no genetic difference could be detected at 90 days, and slightly higher levels were found at 110 days in pure MS fetuses. No genetic difference was found in newborns. These results show that the well-documented difference in cortisol levels between MS and LW take place largely during the extra-uterine life. Catecholamine concentrations in arterial plasma show small variations between 90 and 110 days of gestation (noradrenaline level increased and adrenaline level decreased). Only marginal differences were found in thyroid hormone levels.

These results do not reveal critical changes in hormone levels that could explain genetic variation in piglet survival. These hormonal levels will be compared with metabolomic and transcriptomic data obtained in the same animals.

(1) Canario L et al., J Anim Sci 2006; 84:3185.

Nothing to Disclose: PM, ET, LG, YL, NI, LC, LL

*Please take note of The Endocrine Society's News Embargo Policy at http://www.endo-society.org/endo2013/media.cfm

Sources of Research Support: INRA (Institut National de la Recherche Agronomique);Agence Nationale de la Recherche (ANR-09-GENM-005) awarded to LL
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