Session: SUN 72-87-HPA Axis
Poster Board SUN-87
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.
Nothing to Disclose: PM, ET, LG, YL, NI, LC, LL
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