Hawken P A R, Esmaili T, Scanlan V, Blache D, Martin G B
1UWA Institute of Agriculture (Animal Production), The University of Western Australia, 35 Stirling Highway, Crawley, WA 6009, Australia.
Animal. 2009 May;3(5):690-6. doi: 10.1017/S1751731109003954.
Stimuli from a prospective mate increase the secretion of luteinising hormone (LH) in sheep. This 'male effect' in ewes and 'female effect' effect in rams is predominantly mediated by olfactory signals, though it is thought that non-olfactory signals play synergistic or substitutive roles. In this study, we tested whether exposure to visual or audio-visual stimuli from a prospective mate would stimulate an increase in LH secretion in ewes (Experiment 1) and rams (Experiment 2). In Experiment 1, groups of eight Merino ewes were exposed to one of three stimuli midway through a frequent blood-sampling regimen: full ram contact, still images of rams, a video of ewes and rams mating. Control ewes (n = 8) were completely isolated from rams. Exposure to still images of rams appeared to stimulate an increase in mean LH concentrations (P < 0.05) and tended to increase LH pulse frequency (P < 0.1), but the response was significantly smaller than that observed in ewes exposed to rams (P < 0.01). Audio-visual stimuli had no effect on any parameters of LH secretion (P > 0.1). In Experiment 2, Merino rams were allocated to either an Exposure (n = 7) or a Control (n = 7) group. Exposure rams underwent two exposure periods midway through a frequent blood-sampling regimen; exposure to still images of ewes and audio recorded during mating of ewes and rams (audio-visual exposure); exposure to oestrous ewes (ewe exposure). Control rams were sampled at the same frequency but remained isolated from ewe stimuli. Exposure of rams to the audio-visual stimuli did not affect any parameters of LH secretion (P > 0.1). In contrast, exposure to oestrous ewes increased LH pulse frequency (P < 0.05) and advanced the onset of the next LH pulse (P < 0.05). In conclusion, visual signals appear to be involved in eliciting the neuroendocrine response of ewes to rams and are of greater importance to this phenomenon in ewes (male effect) than rams (female effect). However, overall the visual and audio-visual signals used in this study were far less effective than stimulus animals, suggesting that these stimuli are less important than olfactory signals, or a combination of olfactory and audio-visual signals.
来自潜在配偶的刺激会增加绵羊体内促黄体生成素（LH）的分泌。母羊中的这种“雄性效应”和公羊中的“雌性效应”主要由嗅觉信号介导，不过据认为非嗅觉信号也发挥协同或替代作用。在本研究中，我们测试了暴露于来自潜在配偶的视觉或视听刺激是否会刺激母羊（实验1）和公羊（实验2）体内LH分泌增加。在实验1中，八组美利奴母羊在频繁采血方案进行到一半时，分别暴露于三种刺激之一：与公羊充分接触、公羊的静止图像、母羊和公羊交配的视频。对照母羊（n = 8）与公羊完全隔离。暴露于公羊的静止图像似乎刺激了平均LH浓度升高（P < 0.05），并且有增加LH脉冲频率的趋势（P < 0.1），但该反应明显小于暴露于公羊的母羊所观察到的反应（P < 0.01）。视听刺激对LH分泌的任何参数均无影响（P > 0.1）。在实验2中，美利奴公羊被分配到暴露组（n = 7）或对照组（n = 7）。暴露组公羊在频繁采血方案进行到一半时经历两个暴露期；暴露于母羊的静止图像以及母羊和公羊交配时录制的音频（视听暴露）；暴露于发情母羊（母羊暴露）。对照公羊以相同频率采血，但与母羊刺激隔离。公羊暴露于视听刺激对LH分泌的任何参数均无影响（P > 0.1）。相比之下，暴露于发情母羊会增加LH脉冲频率（P < 0.05）并提前下一个LH脉冲的起始时间（P < 0.05）。总之，视觉信号似乎参与引发母羊对公羊的神经内分泌反应，并且在母羊的这种现象（雄性效应）中比公羊的（雌性效应）更重要。然而，总体而言，本研究中使用的视觉和视听信号远不如刺激动物有效，这表明这些刺激不如嗅觉信号或嗅觉与视听信号的组合重要。
