Laboratory of Animal Reproductive Physiology, University of Vila Velha (UVV), Vila Velha, Espírito Santo, Brazil.
Laboratory of Animal Reproductive Physiology, University of Vila Velha (UVV), Vila Velha, Espírito Santo, Brazil; School of Veterinary Medicine, Campus Curitibanos, Federal University Santa Catarina, Santa Catarina, Brazil.
Theriogenology. 2023 Mar 15;199:131-137. doi: 10.1016/j.theriogenology.2023.01.023. Epub 2023 Jan 30.
This study aimed to evaluate the effects of heat stress (HS) and its duration on semen quality, serum testosterone, pulsatility and resistibility index of the testicular artery of French Bulldogs. Eight male French Bulldogs, 3-7 years old, 12.63 ± 1.8 Kg were adapted and trained for two months. Room temperature was 21 °C. Semen was collected by digital stimulation. The median of four andrological evaluations was T0. Heat was applied to the scrotum using an electrical heat pad at 40 °C for 11 min. Rectal temperature (RT) and scrotum temperature were evaluated using a mercury thermometer and an infrared thermography camera before and after HS. Semen was evaluated immediately (T1) and after seven (T7), 14 (T14), 21 (T21), 28 (T28) and 60 (T60) days after HS. Semen parameters included macroscopic (volume, color and viscosity) and microscopic (sperm motility and vigor, percentage of morphologically normal or defected spermatozoa, sperm concentration and total number of sperm cells) aspects. A pulsed colored doppler ultrasound was performed on the testicular artery at the spermatic cord and epididymis region before and immediately after HS. Serum testosterone was analyzed before, 48 and 96 h after HS. Data was analyzed by ANOVA using SAS. There was a 1.23 °C increase on RT and a 4.98 °C increase on thermograph after HS. Sperm motility decreased at T1 (P < 0.05) and tended to stay lower at T7 (P = 0.056). It improved at T14, but reduced again at T21 (P < 0.05). At T28 and T60 motility was normal. Vigor was lower at T1 (P < 0.05), normal at T7 and T14, but decreased at T21 (P = 0.054), at T28 and T60 it was not different than T0. Sperm concentration was lower at T1 (P < 0.05) and not different from T0 at other timepoints. Volume color and viscosity were not different. Total sperm per ejaculate was reduced at T1 and T7 (P < 0.05) and tended to be lower at T14 (P = 0.057). T21, T28 and T60 were not different than T0. There was a decrease in normal sperm cells and an increase in defected sperm at T7. There was no difference within T14, T21, T28 and T60. The raise in pathologies at T7 was from an increase in minor defects (P < 0.05). There was no difference in serum concentration of testosterone nor pulsatility and resistivity index before and after HS. In conclusion, induction of HS directly to the testis reduces sperm quality in French Bulldog. This impairment is immediately and transitory.
本研究旨在评估热应激（HS）及其持续时间对法国斗牛犬精液质量、血清睾酮、睾丸动脉搏动和阻力指数的影响。8 只 3-7 岁、12.63±1.8kg 的雄性法国斗牛犬经过两个月的适应和训练。室温为 21°C。通过数字刺激采集精液。四次男科评估的中位数为 T0。使用 40°C 的电热垫对阴囊进行 11 分钟的 HS。在 HS 前后使用水银温度计和红外热像仪评估直肠温度（RT）和阴囊温度。立即（T1）和 7 天后（T7）、14 天后（T14）、21 天后（T21）、28 天后（T28）和 60 天后（T60）评估精液。精液参数包括宏观（体积、颜色和粘度）和微观（精子活力和活力、形态正常或畸形精子的百分比、精子浓度和总精子数）方面。在 HS 前后，在精索和附睾区域对睾丸动脉进行脉冲彩色多普勒超声检查。在 HS 前、48 小时和 96 小时后分析血清睾酮。使用 SAS 进行方差分析。HS 后 RT 升高 1.23°C，热图升高 4.98°C。T1 时精子活力下降（P<0.05），T7 时趋于较低（P=0.056）。T14 时有所改善，但 T21 时再次下降（P<0.05）。T28 和 T60 时活力正常。T1 时活力降低（P<0.05），T7 和 T14 时正常，但 T21 时降低（P=0.054），T28 和 T60 时与 T0 无差异。T1 时精子浓度降低（P<0.05），其他时间点与 T0 无差异。体积、颜色和粘度无差异。每次射精的总精子数在 T1 和 T7 时减少（P<0.05），T14 时趋于较低（P=0.057）。T21、T28 和 T60 与 T0 无差异。T7 时正常精子减少，畸形精子增多。T14、T21、T28 和 T60 之间无差异。T7 时病理学的增加来自于轻微缺陷的增加（P<0.05）。HS 前后血清睾酮浓度、搏动和阻力指数无差异。综上所述，直接对睾丸进行 HS 会降低法国斗牛犬的精子质量。这种损伤是即刻和短暂的。
