Center for Pheromone Technology, Department of Animal Science, Bharathidasan University, Tiruchirappalli, Tamilnadu, India.
Anim Reprod Sci. 2013 May;138(3-4):163-7. doi: 10.1016/j.anireprosci.2013.02.017. Epub 2013 Mar 5.
Chemo-signals are among the reliable non-invasive methods for estrus detection in mammals. Water buffalo is a silent heat animal and, hence, there is search for chemo-signals which would be effective non-invasive indicators of estrus state. We analyzed the faecal chemical cues during the estrous cycle in buffalo and to find the estrus-specific faecal volatile compounds adopting bull behavior assay. The faecal samples were collected at three phases of the estrous cycle (i.e., proestrus, estrus and postestrus) and subjected to gas chromatography-mass spectrometry analyses. We found 27 volatile compounds in the faeces of buffaloes, of which 4-methyl phenol (4mp) and trans-verbenol (tv) were found only in estrus faeces. The faecal samples of estrus buffaloes and the estrus-specific compound(s) (4mp+tv) at three different concentrations were tested for behavioral responses (flehmen and mounting behavior) in the bull. The bulls exhibited repeated flehmen when exposed to a combination of the two compounds (i.e., 4mp+tv) as compared to the individual compounds or raw faecal sample collected from buffalo when in estrus (P<0.05). However, higher number of mounting behavior was recorded when bulls were exposed to 4mp followed by a combination of the two compounds (4mp+tv) and trans-verbenol (P<0.05), in that order. By contrast, less number of mounting behavior was exhibited by bulls when exposed to the control sample (i.e., Hexadecanoic acid) (P<0.05). As inferred from the bull behavior assay, the present study suggests that the two compounds, 4 methyl phenol and trans-verbenol would be reliable indicators of estrus in buffaloes.
化学信号是哺乳动物发情检测中可靠的非侵入性方法之一。水牛是一种无声发情的动物，因此，人们一直在寻找有效的非侵入性发情状态化学信号指示剂。我们分析了水牛发情周期中的粪便化学线索，并通过公牛行为测定法寻找发情特异性粪便挥发性化合物。在发情周期的三个阶段（即发情前期、发情期和发情后期）采集粪便样本，并进行气相色谱-质谱分析。我们在水牛粪便中发现了 27 种挥发性化合物，其中 4-甲基苯酚（4mp）和反式马鞭草烯醇（tv）仅存在于发情期粪便中。将发情期水牛的粪便样本和发情特异性化合物（4mp+tv）在三个不同浓度下用于公牛的行为反应（嗅闻和交配行为）测试。与单独的化合物或发情期水牛采集的原始粪便样本相比，公牛在暴露于两种化合物（即 4mp+tv）的组合时表现出反复的嗅闻行为（P<0.05）。然而，当公牛暴露于 4mp 后再暴露于两种化合物（4mp+tv）和反式马鞭草烯醇时，记录到更多的交配行为（P<0.05），顺序为 4mp、4mp+tv、trans-verbenol。相比之下，公牛在暴露于对照样本（即十六烷酸）时表现出较少的交配行为（P<0.05）。根据公牛行为测定法，本研究表明，这两种化合物 4-甲基苯酚和反式马鞭草烯醇将是水牛发情的可靠指示剂。
