慢性冷应激对放牧蒙古母牛血清酶活力、蛋白代谢及血清激素分泌的影响

Effects of chronic cold stress on the serum enzyme activity, protein metabolism and serum hormone secretion of grazing Mongolian cows

关键词:  蒙古母牛  慢性冷应激  血清  酶活力  蛋白  激素

Key words:  Mongolian cattle  cold stress  serum  enzyme activity  protein  hormones

摘要:

为研究慢性冷应激对蒙古母牛血清酶活力、血清蛋白及下丘脑-垂体-肾上腺轴（HPA）下丘脑-垂体-甲状腺轴（HPT）轴激素分泌的影响，选取在内蒙古锡林郭勒草原体况相近，体质健康的全年放牧蒙古牛母牛各8头，并于试验期最后一天清晨进行颈静脉采血并制备血清，采用ELISA方法检测血清中碱性磷酸酶（AKP）、肌酸激酶（CK）、乳酸脱氢酶（LDH）等血清酶活性和三碘甲状腺原氨酸（T3）、甲状腺素（T4）、促肾上腺皮质激素（ACTH）、生长激素（GH）等HPA、HPT轴激素以及总蛋白（TP）、白蛋白（ALB）、尿素氮（BUN）等血清蛋白的含量。结果表明冷应激对蒙古母牛产生了一定的应激：与非应激期相比，冷应激状态下蒙古母牛血液中的T3、T4、ACTH及GH等血清激素分泌显著升高（P<0.05）；冷应激状态下蒙古母牛血液中AKP含量显著下降（P<0.05），其他酶含量无明显变化（P>0.05）；冷应激引起蒙古母牛血清中BUN含量显著增加（P<0.05），但对TP和ALB含量无显著影响（P>0.05）。综上，冬季较低环境温度对蒙古母牛造成了应激，HPA及HPT轴被激活，增加机体产热以抵抗低温环境。与非应激状态相比，蒙古母牛TP、ALB、CK以及LDH等血液生化指标无显著变化，说明蒙古牛经过多年的自然选择和人工选育，较适应蒙古高原高寒环境。

Abstract:

The aim of this study was to investigate the effects of chronic cold stress on serum enzyme activity,serum protein and hormone secretion of HPA and HPT axis in Mongolian cattle.Eight Mongolian cows with similar body condition and healthy constitution were randomly selected from Xilingol grassland of Inner Mongolia.The jugular vein blood was collected and serum was prepared on the morning of the last day of the experiment.The serum enzymes such as alkaline phosphatase (AKP),creatine kinase (CK) and lactate dehydrogenase (LDH) were detected by ELISA.The contents of HPA,HPT axis hormone,total protein (TP),albumin (ALB),urea nitrogen (BUN) and other serum proteins such as triiodothyronine (T3),thyroxine (T4),adrenocorticotropic hormone (ACTH),growth hormone (GH) and so on.The results showed that cold stress produced certain stress on Mongolian cattle.Compared with non-stress period,the secretion of serum hormones such as T3,T4,ACTH and GH in Mongolian cattle blood increased significantly under cold stress (P<0.05).The content of AKP in Mongolian cattle blood decreased significantly under cold stress (P<0.05),while the content of other enzymes did not change significantly (P>0.05).The content of BUN in Mongolian cattle serum increased significantly under cold stress (P<0.05),but there was no significant difference in the content of TP and ALB.Written influence (P>0.05).In conclusion,cold stress caused stress to Mongolian cattle.The HPA and HPT axes were activated to increase heat production in order to adapt low temperature environment.Compared with non-stress state,the blood biochemical indexes of Mongolian cattle,such as TP,ALB,CK and LDH,had no significant changes,indicating that Mongolian cattle were better adapted to the alpine environment of Mongolian plateau after many years of natural selection and artificial breeding.