中文摘要：

选取20头处于热应激环境的泌乳奶牛,随机分成A、B、C和D组4组,分别按剂量0.0（对照）,4.0,8.0和16.0mg/头静脉注射金属硫蛋白（MT）,以探讨外源性MT对奶牛淋巴细胞凋亡、坏死和线粒体膜电位（ΔΨm）的影响。结果表明,注射MT后,在51～60d时,校正标准产奶量B、C和D组均显著性高于A组（P〈0.05）;35d时C组（8mg/头）的血淋巴细胞凋亡率显著性低于B、D组（P〈0.05）,但与A组无显著性差异（P〉0.05）,D组（16mg/头）35d时凋亡率达到最大,随后（50～60d）显著性下降（P〈0.05）;细胞的坏死率A组50d时较1d时显著下降（P〈0.05）,C组（8mg/头）35,50d时显著下降（P〈0.05）,但60d时开始呈上升趋势（P〉0.05）,而D组（16mg/头）坏死率呈现下降趋势,且在50,60d时均显著低于注射MT之前的血淋巴细胞坏死率;35d时,A组的线粒体膜电位值（ΔΨm）最高,但上升速度最快的是B组（4mg/头）,在35d时显著高于20d时的ΔΨm（P〈0.05）;50d时A组和B组的ΔΨm不但不上升,反而下降,其中A组下降的速度更快,35～50dC组（8mg/头）保持基本恒定,60d略有上升,D组（16mg/头）1～35d时逐步上升,50～60d时保持恒定。在60d时,ΔΨm与注射MT浓度呈正相关。说明外源性MT不仅能提高热应激状态动物的体质,还可让泌乳母牛从热应激状态平稳的过渡到热应激损伤修复状态,若注射8～16mg/头,能抑制南方泌乳母牛夏季热应激引起的滞后效应。

英文摘要：

Effects of exogenous metallothionein membrane voltage （AXltm） of China Holstein co were randomly allocated to groups A, B, C and （MT） on lymphocytes apoptosis, ws were studied using 20 lactating necrosis and mitochondrial D. MT was supplemented at 0.0, 4. cows in heat stre 0, 8.0 and 16.0 ta, respectively, by intravenous injection. Corrected milk yields in groups B, C, and D than those in group A after being injected MT during days 51-60 （P〈O. 05） ; at 35 d, tosis rate of group C （8 mg/capita） was significantly lower than those of groups B and not significantly different from group A （P〈0.05）. The lymphocytes apoptosis rate of were significa ss. They mg/capi- nt higher the lymphocytes apop D （P〈0.05）, but was group D （16 mg/capi- ta） was the highest at 35 d （P〈0.05） but significantly （P〈0.05） decreased during days 50-60; Compared to 1 d, the lymphocytes necrosis rate of group A significantly （P〈0.05） decreased at 50 d, group C （8 mg/capi- ta） significantly （P〈0.05） decreased at 35 d and 50 d, and began to show a rising trend at 60 d （P〈0.05）, while group D （16 mg/capita） significantly decreased at 50 d and 60 d. The mitochondrial membrane voltage （△ψm） of group A was the highest at 35 d, but the A △ψm of group B rose fastest at 35 d （P〈0.05）, and was significantly higher than at 20 d （P%0.05）. The △ψm of groups A and B decreased at 50 d with that of group A falling fastest. The △ψm of group C was constant during days 35-50 but increased slightly at 60 d. The △ψm of group D （16 mg/capita） increased gradually during days 1-35 and remained constant during days 51-60. The lymphocytes △ψm and injected MT amount were positively correlated at 60 d. In conclusion, the heath of cows under heat stress can be improved, by exogenous MT injection. The injection of 8-16 mg/capi- ta, can inhibit the lagged effects of southern summer heat stress in lactating cow.