Brandt Y, Einarsson S, Ljung A, Lundeheim N, Rodríguez-Martínez H, Madej A
Department of Clinical Sciences, Division of Reproduction, Swedish University of Agricultural Sciences (SLU), P.O. Box 7054, SE-750 07 Uppsala, Sweden.
Anim Reprod Sci. 2009 Jan;110(1-2):172-85. doi: 10.1016/j.anireprosci.2008.01.008. Epub 2008 Jan 18.
This study investigated the effect of continuous elevated cortisol concentrations during standing oestrus on time of ovulation and patterns of progesterone, oestradiol and luteinising hormone (LH) in sows. The elevation of cortisol concentrations was achieved through repeated intravenous injections of synthetic adrenocorticotropic hormone (ACTH) every 2 h for approximately 48 h, from the onset of the second standing oestrus after weaning. Treatment was terminated when ovulation was detected (monitored by transrectal ultrasonography every 4h) or when the sow had received a maximum of 24 injections. The dose of ACTH (2.5 microg/kg) was chosen to mimic the cortisol concentrations seen during mixing of unfamiliar sows. The sows (n=14) were surgically fitted with jugular vein catheters and randomly divided into a control (C group where only NaCl solution were injected) or an ACTH group. Blood samples were collected every 2 h. In parallel with the blood sampling, saliva samples for cortisol analyses were taken from eight sows before onset of treatment and from four of the sows during treatment. There was no difference in time from onset of standing oestrus to ovulation between the two groups. The interval between the peaks of oestradiol and LH to ovulation was prolonged in the ACTH group compared to the C group (p<0.05), with a tendency towards an earlier decline of oestradiol in the ACTH group. Cortisol and progesterone concentrations were significantly elevated during treatment in the ACTH group (p<0.001), with cortisol peak concentrations occurring between 40 and 80 min after each ACTH injection. Cortisol concentrations in saliva and plasma were highly correlated (p<0.001). In conclusion, elevated cortisol concentrations from the onset of standing oestrus increase progesterone concentrations and prolong the interval between oestradiol and LH peaks to ovulation, the latter possible due to an early decline in oestradiol concentrations and a change of the LH peak outline. The effect these hormonal changes have on reproductive performance need to be further investigated. Saliva samples might be a useful and non-invasive method to assess cortisol concentrations in sows.
本研究调查了在母猪静立发情期持续升高的皮质醇浓度对排卵时间以及孕酮、雌二醇和促黄体生成素（LH）模式的影响。从断奶后第二次静立发情开始，每隔2小时重复静脉注射合成促肾上腺皮质激素（ACTH）约48小时，以实现皮质醇浓度的升高。当检测到排卵（每4小时通过经直肠超声监测）或母猪接受最多24次注射时，终止治疗。选择ACTH的剂量（2.5微克/千克）以模拟陌生母猪混群时出现的皮质醇浓度。母猪（n = 14）通过手术安装颈静脉导管，并随机分为对照组（C组，仅注射NaCl溶液）或ACTH组。每2小时采集一次血样。在采血的同时，在治疗开始前从8头母猪采集唾液样本用于皮质醇分析，在治疗期间从4头母猪采集唾液样本。两组从静立发情开始到排卵的时间没有差异。与C组相比，ACTH组中雌二醇和LH峰值到排卵的间隔延长（p<0.05），ACTH组中雌二醇有更早下降的趋势。ACTH组在治疗期间皮质醇和孕酮浓度显著升高（p<0.001），每次ACTH注射后40至80分钟出现皮质醇峰值浓度。唾液和血浆中的皮质醇浓度高度相关（p<0.001）。总之，从静立发情开始皮质醇浓度升高会增加孕酮浓度，并延长雌二醇和LH峰值到排卵的间隔，后者可能是由于雌二醇浓度过早下降和LH峰值轮廓改变。这些激素变化对繁殖性能的影响需要进一步研究。唾液样本可能是评估母猪皮质醇浓度的一种有用且非侵入性的方法。
