Macedo Gustavo Guerino, Batista Emiliana de Oliveira Santana, Santos Gustavo Martins Gomes Dos, D'Occhio Michael J, Baruselli Pietro Sampaio
Faculty of Veterinary Medicine and Animal Sciences, Federal University of Mato Grosso do Sul, Campo Grande 79070-900, Mato Grosso do Sul, Brazil.
Faculty of Veterinary Medicine and Animal Science, University of Sao Paulo, Sao Paulo 05508-270, Sao Paulo, Brazil.
Animals (Basel). 2021 Apr 25;11(5):1236. doi: 10.3390/ani11051236.
The present study examined whether priming with estradiol benzoate (EB) for 12 h increased both the peak and duration of LH release in response to kisspeptin (KISS1, KP) in cows. In a Latin square design, ovariectomized Nelore cows ( = 8) received: Control, i.m. 4 mL of 0.9% saline; KP, i.m. 4 mg murine KISS1-10; EBKP, i.m. 4 mg KISS1-10 + i.m. 2 mg EB simultaneously; EB12KP, i.m. 4 mg KISS1-10 + i.m. 2 mg EB 12 h before KISS1-10. Concentrations of LH were determined in blood samples obtained at time 0 (treatment), 20, 40, 60, 90, 120, 150, 180, 210 and 270 min. Concentrations of LH were analyzed by Proc GLIMMIX for repeated measures. In case of significance, the adjusted Tukey test was used to test for differences among treatments. GraphPad 8.0 PRISM was used to determine the area under the LH-response curve (AUC) after injection of KISS1-10. Plasma LH remained relatively constant throughout sampling after treatment with saline. The peak in LH after injection of KISS1-10 occurred at 20 min in Groups KP and EBKP and at 40 min in Group EB12KP. The peak LH response (∆LH, ng/mL) was greater ( < 0.01) in Group EB12KP (5.6 ± 0.9) than in Groups KP (2.4 ± 0.9) and EBKP (3.5 ± 0.9), which did not differ. AUC (LH ng/mL*min) was greater ( = 0.02) in Group EB12KP (439 ± 73) than in Groups KP (176 ± 73) and EBKP (241 ± 73), with the latter two groups not differing. The findings indicated that 12 h priming with EB increased both the peak and duration of the LH response to treatment with KISS1. The incorporation of EB priming and KISS1 could improve the efficiency of estrus synchronization with fixed-time AI in cows. This would have an important practical application in assisted breeding in beef and dairy cattle.
本研究检测了用苯甲酸雌二醇（EB）预处理12小时是否会增加奶牛对亲吻素（KISS1，KP）反应时促黄体生成素（LH）释放的峰值和持续时间。在拉丁方设计中，对8头去卵巢的内罗尔牛进行如下处理：对照组，肌肉注射4 mL 0.9%生理盐水；KP组，肌肉注射4 mg鼠源KISS1-10；EBKP组，同时肌肉注射4 mg KISS1-10和2 mg EB；EB12KP组，在注射KISS1-10前12小时肌肉注射4 mg KISS1-10和2 mg EB。在0（处理时）、20、40、60、90、120、150、180、210和270分钟采集血样，测定LH浓度。通过Proc GLIMMIX对LH浓度进行重复测量分析。若有显著性差异，则用校正后的Tukey检验来检测各处理组之间的差异。使用GraphPad 8.0 PRISM软件来确定注射KISS1-10后LH反应曲线下面积（AUC）。用生理盐水处理后，整个采样过程中血浆LH保持相对稳定。注射KISS1-10后，KP组和EBKP组的LH峰值出现在20分钟，EB12KP组出现在40分钟。EB12KP组的LH峰值反应（∆LH，ng/mL）（5.6±0.9）高于KP组（2.4±0.9）和EBKP组（3.5±0.9），差异有统计学意义（P<0.01），而后两组之间无差异。EB12KP组的AUC（LH ng/mL*min）（439±73）高于KP组（176±73）和EBKP组（241±73），差异有统计学意义（P = 0.02），后两组之间无差异。研究结果表明，用EB预处理12小时可增加奶牛对KISS1处理的LH反应的峰值和持续时间。结合EB预处理和KISS1可提高奶牛定时人工授精发情同步的效率。这在肉牛和奶牛的辅助繁殖中将具有重要的实际应用价值。
