热应激对拉布拉多犬生理、激素、血液生化指标的影响

Effect of Heat Stress on Physiological,Hormonal and Blood Biochemical Indexes in Labrador Dogs

为研究犬热应激时的生理生化状态,并探讨以生理生化指标作为衡量犬热应激程度的可行性,分别在14、18、28、35℃测量了拉布拉多犬的生理生化指标。结果表明,犬在14℃、18℃体内指标处于正常水平,在28℃、35℃时处于热应激状态;与正常水平比较,犬在热应激时呼吸频率显著加快、血清皮质醇(COR)水平显著升高,呼吸、COR值升高与温度、温湿指数(THI)之间存在显著相关性;直肠温度、ACTH未发生显著变化;血清中的主要酶类中ALT、ASP、CK、LDH在急性热应激时显著升高,然后恢复至正常水平,GLU、ALP未发生显著变化。证明在犬热应激研究中,气温、THI、COR、呼吸频率可作为主要的参考指标;体温及血液中ACTH、GLU、ALP含量与犬热应激程度不相关;ALT、ASP、CK、LDH在不同动物热应激中的变化规律不一致,能否作为犬热应激程度的指示指标有待进一步研究。

The purpose of this paper was to study physiological and biochemical status of dogs with heat stress and find the meanings of these indexes as the indicator of heat stress.The common physiological,hormonal and blood biochemical indexes of twenty-four Labrador dogs were surveyed at 14,18,28,35 ℃respectively.Compared with the normal state at 14 ℃ and 18 ℃,all the measured indexes indicated that dogs were under heat stress at 28 ℃ and 35 ℃.Breathing frequency and seral COR were significantly increased（P0.05）in heat stress,and this increase showed significant correlation（P0.05）with enviromental temperature（T）and temperature humidity index（THI）.The rectal temperature and seral ATCH didn＇t changed significantly.The major seral enzymes such as ALT,ASP,CK,LDH increased significantly in acute heat stress period,then dropped to normal values.GLU and ALP maintained on normal levels.These results indicated that T,THI,COR and breathing frequency are meaningful indexes to study heat stress in dogs.But the rectal temperature,seral ACTH,GLU,ALP didn＇t changed significantly in heat stress,so these indexes are meaningless.In addition,studies on heat stress proved that ALT,ASP,CK,LDH would changed no rule in different animal modelsand the significance in studies on heat stress should be further studied.