牦牛围产期血清酮体消长规律及其对产后生殖激素分泌的影响

Growth and Decline Regular Pattern of Serum Ketone Body of Yak during Perinatal Period and Its Effects on Secretion of Postpartum Reproductive Hormone

本研究旨在检测围产期牦牛血清酮体的消长规律,并分析其对产后生殖激素分泌的影响。选择25头年龄[(7.00±1.23)岁]、胎次[(2.00±0.07)次]和体况相近的经产母牦牛,自产前第28天至产后第28天每7 d采集1次血清,共设9个时间点,检测血清中酮体指标[β-羟丁酸(BHBA)]、肝功能指标[游离脂肪酸(NEFA)、葡萄糖(GLU)、甘油三酯(TG)、谷草转氨酶(AST)]、蛋白质营养状况指标[总蛋白(TP)、白蛋白(ALB)和球蛋白(GLO)],研究各指标的消长规律;随后继续跟踪试验动物至产后第49天,每7 d采集1次血清,检测产前第28天至产后第49天血清中生殖激素指标[雌二醇(E 2)、孕酮(P4)、促卵泡素(FSH)和促黄体素(LH)],并监测发情情况。通过数据分析明确围产后期母牦牛生殖激素分泌情况,并结合BHBA浓度进行相关性分析,明确BHBA与生殖激素分泌的关系。结果表明:分娩当天、产后第7天和产后第14天的血清BHBA浓度显著高于其他各时间点(P<0.05)。分娩当天、产后第7天和产后第14天的血清GLU浓度显著低于产前各时间点(P<0.05)。产后第7天和产后第14天的血清NEFA浓度显著高于其他各时间点(P<0.05)。分娩当天和产后各时间点的血清TP浓度和AST活性显著高于产前各时间点(P<0.05)。分娩当天和产后各时间点的血清FSH和LH浓度显著高于产前各时间点(P<0.05)。相关性分析表明,血清BHBA浓度与E 2和LH浓度存在显著正相关(P<0.05)。由此可见,母牦牛的分娩造成其机体能量的大量流失,导致机体脂肪过度动员产生了能量负平衡,围产后期蛋白质也参与了供能过程,血清BHBA浓度的升高会影响E 2和LH的分泌模式,使经产牦牛产犊间隔较长而引起其繁殖率低下。

The aim of this study was to examine the growth and decline regular pattern of serum ketone body of yak during perinatal period,and to analyze its effects on secretion of postpartum reproductive hormone.Twenty-five multiparous female yak with similar age[(7.00±1.23)years],parity[(2.00±0.07)birth]and body condition were selected,and the serum was collected every 7 d from day 28 before delivery to day 28 after delivery,and there were 9 time points.The serum ketone body index[βhydroxybutyric acid(BHBA)],liver function indexes[nonestesterified fatty acid(NEFA),glucose(GLU),triglycerides(TG)and glutathione aminotransferase(AST)]and protein nutritional status indexes[total protein(TP),albumin(ALB)and globulin(GLO)]were detected,and to study growth and decline regular pattern of each index.The animals were then followed until day 49 after delivery,and the serum was collected every 7 d.The serum reproductive hormone indexes[estradiol(E 2),progesterone(P4),follicle stimulating hormone(FSH)and luteinizing hormone(LH)]were measured from day 28 before delivery to day 49 after delivery,and the estrus was monitored.Through the data analysis,the reproductive hormone secretion of female yak during late perinatal period was determined,and the correlation analysis was carried out with the concentration of BHBA,so as to clarify the relationship between serum BHBA and reproductive hormone secretion.The results showed that the serum BHBA concentration on day of delivery,day 7 after delivery and day 14 after delivery was significantly higher than that on other time points(P<0.05).The serum GLU concentration on day of delivery,day 7 after delivery and day 14 after delivery was significantly lower than that on time points before delivery(P<0.05).The serum NEFA concentration on day 7 after delivery and day 14 after delivery was significantly higher than that on other time points(P<0.05).The serum TP concentration and AST activity on day of delivery and time points after delivery were significantly higher than those on time points before delivery(P<0.05).The serum FSH and LH concentrations on day of delivery and time points after delivery were significantly higher than those on time points before delivery(P<0.05).Correlation analysis showed that there was a significant positive correlation between serum BHBA concentration and E 2 and LH concentrations(P<0.05).It can be seen that the delivery of yak causes a large amount of energy loss,resulting in excessive mobilization of body fat,resulting in negative energy balance,and the protein also participates in the energy supply process in the late perinatal period.The increase of BHBA concentration will affect the secretion mode of E 2 and LH,which will lead to a long calving interval and low reproduction rate of multiparous yak.