Hedia M G, El-Belely M S, Ismail S T, Abo El-Maaty Amal M
Department of Theriogenology, Faculty of Veterinary Medicine, Cairo University, Giza, Egypt.
Department of Theriogenology, Faculty of Veterinary Medicine, Cairo University, Giza, Egypt.
Theriogenology. 2019 Jan 1;123:68-73. doi: 10.1016/j.theriogenology.2018.09.032. Epub 2018 Sep 28.
The present detailed study aimed to establish for the first time reference values for ultrasound measures of testicular dimensions and Doppler measures of blood flow in the testicular artery of rams over a 12-month period, and to investigate a possible association between monthly changes in dynamics of testicular blood flow from one hand and testicular volume, plasma testosterone and estradiol -17β concentrations as well as semen characteristics from the other hand. Five fat-tailed rams weighing 45-60 kg and aging 2-4 years old were subjected to semen collection, jugular blood sampling, ultrasonographic scanning of the testes and Doppler examination of testicular artery twice monthly for a period of one year. The overall mean (±SD) values for testicular volume as well as RI (resistive index) and PI (pulsatility index), respectively were 71.84 ± 5.33 mm, 0.378 ± 0.102 and 0.642 ± 0.208. Average testicular volume was the lowest in June (59.44 ± 5.83 mm) and reached its maximum (84.43 ± 8.52 mm) in November after 42.2% increase (p < 0.01). Mean values of RI were lowest between September and March, increasing significantly (p < 0.01) in April (+53%) reaching highest value in June (0.564 ± 0.158). From the lowest value recorded in October through February, the average PI values increased significantly (p < 0.05) in March (+41%) to reach maximum value in July (0.940 ± 0.368). In parallel with the substantial decrease in Doppler measurements, all parameters analyzed during the breeding season (October-March) were positively affected. In conclusion, the monthly definite changes in the studied parameters evidenced three novel findings: (1) plasma testosterone concentration, which increased significantly (p < 0.05) at late summer (August), was the potential initiator for resuming the breeding season in rams via triggering spermatogenic activity and maximum testicular volume during this period, (2) resulting values of testicular volume and testicular blood flow profiles all year round provide useful reference values for predicting testicular function in rams, (3) the marked increase in testicular blood flow volume, i.e. remarkable decrease in both RI and PI values, during the breeding season could be regulated by the marked increase in testicular volume and plasma estradiol -17β levels during this period.
本详细研究旨在首次确定12个月内公羊睾丸尺寸超声测量值及睾丸动脉血流多普勒测量值的参考值，并研究一方面睾丸血流动力学的月度变化与另一方面睾丸体积、血浆睾酮和雌二醇-17β浓度以及精液特征之间可能存在的关联。选取5只体重45 - 60千克、年龄2 - 4岁的肥尾公羊，在一年时间里每月进行两次精液采集、颈静脉采血、睾丸超声扫描及睾丸动脉多普勒检查。睾丸体积以及阻力指数（RI）和搏动指数（PI）的总体均值（±标准差）分别为71.84 ± 5.33毫米、0.378 ± 0.102和0.642 ± 0.208。平均睾丸体积在6月最低（59.44 ± 5.83毫米），11月达到最大（84.43 ± 8.52毫米），增加了42.2%（p < 0.01）。RI的均值在9月至3月间最低，4月显著增加（p < 0.01）（增加53%），6月达到最高值（0.564 ± 0.158）。从10月至2月记录的最低值开始，平均PI值在3月显著增加（p < 0.05）（增加41%），7月达到最大值（0.940 ± 0.368）。与多普勒测量值的大幅下降同时，繁殖季节（10月至3月）期间分析的所有参数均受到积极影响。总之，所研究参数的月度明确变化证明了三个新发现：（1）血浆睾酮浓度在夏末（8月）显著增加（p < 0.05），是通过在此期间触发生精活动和最大睾丸体积来恢复公羊繁殖季节的潜在启动因素；（2）全年的睾丸体积和睾丸血流曲线结果为预测公羊睾丸功能提供了有用的参考值；（3）繁殖季节期间睾丸血流量显著增加，即RI和PI值显著降低，可能受此期间睾丸体积和血浆雌二醇-17β水平显著增加的调节。
