Minter L J, DeLiberto T J
Utah State University, Department of Fisheries and Wildlife, Logan, UT 84322, USA.
Theriogenology. 2008 May;69(8):946-52. doi: 10.1016/j.theriogenology.2008.01.010. Epub 2008 Mar 21.
The coyote is a seasonally breeding mammal, with most copulations occurring between December and April (depending on location). The objective of this study was to characterize seasonal changes in serum testosterone concentrations, testicular volume, and ejaculate quantity and quality in captive male coyotes. There were seasonal differences in testicular volume, with the greatest volume (20.2+/-5.4cm2), mean+/-S.E.M.) in February, corresponding with peak breeding season. Circulating serum testosterone concentrations peaked (3.31+/-0.9 ng/mL) during January and were positively correlated (P< or =0.001, r=0.413) with testicular volume. Ejaculate volume (1.67+/-0.4 mL) and sperm concentration (549.2 x 10(6)+/-297.7 spermatozoa/mL) both peaked during January and February, consistent with the height of the breeding season. Ejaculate volume and sperm concentrations were positively correlated with testicular size (r=0.679, P< or =0.001 and r=0.499, P< or =0.001, respectively) and with serum testosterone concentrations (r=0.368, P< or =0.01 and r=0.208, P< or =0.05). Progressively motile, viable, and morphologically normal spermatozoa fluctuated seasonally, peaked (90.4+/-4.5, 84.8+/-4.1, and 87.9+/-2.9%) during the breeding season, and then subsequently declined (period of aspermatogenesis). All three of these end points were positively correlated with testicular size (r=0.589, P< or =0.001; r=0.586, P< or =0.001; and r=0.469; P< or =0.001) and serum testosterone (r=0.167, P< or =0.05; r=0.190, P< or =0.05; and r=0.221, P< or =0.01). In conclusion, there were intricate relationships among testosterone concentrations, testicular volume, and the production of both functionally intact and morphologically normal spermatozoa.
郊狼是一种季节性繁殖的哺乳动物，大多数交配发生在12月至4月之间（取决于地理位置）。本研究的目的是描述圈养雄性郊狼血清睾酮浓度、睾丸体积以及射精量和质量的季节性变化。睾丸体积存在季节性差异，2月份体积最大（20.2±5.4平方厘米，平均值±标准误），与繁殖高峰期相对应。循环血清睾酮浓度在1月份达到峰值（3.31±0.9纳克/毫升），且与睾丸体积呈正相关（P≤0.001，r = 0.413）。射精量（1.67±0.4毫升）和精子浓度（549.2×10⁶±297.7个精子/毫升）均在1月和2月达到峰值，与繁殖季节的高峰期一致。射精量和精子浓度与睾丸大小呈正相关（分别为r = 0.679，P≤0.001和r = 0.499，P≤0.001），与血清睾酮浓度也呈正相关（分别为r = 0.368，P≤0.01和r = 0.208，P≤0.05）。进行性运动、存活且形态正常的精子数量季节性波动，在繁殖季节达到峰值（分别为90.4±4.5%、84.8±4.1%和87.9±2.9%），随后下降（无精子生成期）。这三个终点指标均与睾丸大小呈正相关（分别为r = 0.589，P≤0.001；r = 0.586，P≤0.001；r = 0.469，P≤0.001），与血清睾酮也呈正相关（分别为r = 0.167，P≤0.05；r = 0.190，P≤0.05；r = 0.221，P≤0.01）。总之，睾酮浓度、睾丸体积以及功能完整和形态正常精子的产生之间存在复杂的关系。
