Abdel-Aziz Swelum Ayman, Saadeldin Islam M, Ba-Awadh Hani, Alowaimer Abdullah N
Department of Animal Production, College of Food and Agriculture Sciences, King Saud University, P.O. Box 2460, Riyadh 11451, Saudi Arabia; Department of Theriogenology, Faculty of Veterinary Medicine, Zagazig University, 44519, Egypt.
Department of Animal Production, College of Food and Agriculture Sciences, King Saud University, P.O. Box 2460, Riyadh 11451, Saudi Arabia; Department of Physiology, Faculty of Veterinary Medicine, Zagazig University, 44519 Zagazig, Egypt.
Theriogenology. 2018 Oct 1;119:18-27. doi: 10.1016/j.theriogenology.2018.06.017. Epub 2018 Jun 21.
This study aimed to evaluate the effects of melatonin implants on the reproductive performances and hormone levels of dromedary (Camelus dromedarius) bulls during the non-breeding and subsequent breeding seasons. Fourteen mature dromedary bulls were divided into a control group (n = 7) and a group that was implanted with melatonin (n = 7) twice, at the beginning of the study and 35 days later. The trial started on the 17th June and continued for 10 weeks during the non-breeding season. Reproductive performances of animals in the control and melatonin groups were evaluated weekly during the non-breeding season [control non-breeding (CNB) and melatonin non-breeding (MNB) groups, respectively] and evaluated again during the subsequent breeding season [control breeding (CB) and melatonin breeding (MB) groups, respectively], which started on the 6th December and continued for 10 weeks. MNB bulls had greater (P ≤ 0.05) scrotum circumference and testicular volume, sexual desire, reaction time and mating ability scores, and serum melatonin and testosterone concentration values (24.91 ± 0.26 cm, 271.00 ± 7.81 cm, 2.31 ± 0.13, 2.03 ± 0.22, 2.26 ± 0.09, 23.90 ± 0.05 pg/mL and 2764.51 ± 137.02 pg/mL, respectively) than the CNB group (23.63 ± 0.05 cm, 199.21 ± 3.27 cm, 1.00 ± 0.00, 0.00 ± 0.00, 1.00 ± 0.00, 9.46 ± 0.08 pg/mL and 1872.41 ± 264.89 pg/mL, respectively). The scrotum and testes, reaction time score, proportion of bulls refusing to mount, and serum melatonin values were significantly higher in MB than CB bulls (P ≤ 0.05). Progressive motility (PM), average pathway velocity, straight-line velocity, curvilinear velocity (VCL), linearity, straightness (STR), wobble, beat cross frequency (BCF), livability, and DNA integrity were significantly higher in MB than CB bulls (P ≤ 0.05). PM, VCL, STR, amplitude of lateral head displacement, BCF, and livability were significantly higher in MNB than CB bulls (P ≤ 0.05). In conclusion, melatonin implants improved the reproductive performance of bulls during the non-breeding and subsequent breeding seasons.
本研究旨在评估褪黑素植入物对单峰驼（骆驼属单峰驼）公牛在非繁殖季及随后繁殖季的繁殖性能和激素水平的影响。14头成年单峰驼公牛被分为对照组（n = 7）和在研究开始时及35天后两次植入褪黑素的组（n = 7）。试验于6月17日开始，在非繁殖季持续10周。在非繁殖季每周评估对照组和褪黑素组动物的繁殖性能（分别为对照非繁殖组和褪黑素非繁殖组），并在随后的繁殖季（分别为对照繁殖组和褪黑素繁殖组）再次评估，繁殖季于12月6日开始，持续10周。与对照非繁殖组相比，褪黑素非繁殖组公牛的阴囊周长、睾丸体积、性欲、反应时间和交配能力评分以及血清褪黑素和睾酮浓度值更高（P≤0.05）（分别为24.91±0.26厘米、271.00±7.81厘米、2.31±0.13、2.03±0.22、2.26±0.09、23.90±0.05皮克/毫升和2764.51±137.02皮克/毫升，对照非繁殖组分别为23.63±0.05厘米、199.21±3.27厘米、1.00±0.00、0.00±0.00、1.00±0.00、9.46±0.08皮克/毫升和1872.41±264.89皮克/毫升）。褪黑素繁殖组公牛的阴囊和睾丸、反应时间评分、拒绝爬跨的公牛比例以及血清褪黑素值显著高于对照繁殖组（P≤0.05）。褪黑素繁殖组公牛的前向运动率（PM）、平均路径速度、直线速度、曲线速度（VCL）、线性度、直线性（STR）、摆动、拍击交叉频率（BCF）、存活率和DNA完整性显著高于对照繁殖组（P≤0.05）。褪黑素非繁殖组公牛的PM、VCL、STR、头部侧向位移幅度、BCF和存活率显著高于对照繁殖组（P≤0.05）。总之，褪黑素植入物改善了公牛在非繁殖季及随后繁殖季的繁殖性能。
