【作者】 吴力专； 陈海燕； 张彬； 李丽立； 肖兵南； 陈宇光； 肖定福； 罗佳捷； 吴宗明；

【Author】 WU Li-zhuan1,2, CHEN Hai-yan1,ZHANG Bin1, LI Li-li3, CHEN Yu-guang1,XIAO Ding-fu1,LUO Jia-jie1, WU Zong-min1 (1. College of Animal Science and Technology, Hunan Agricultural University, Changsha 410128,China; 2. College of Animal Science , Hubei Yangtze University, Jingzhou 434025, China; 3.Instisute of Subtropical Agricultural Ecology, Chinese Academy of Sciences, Changsha 410125, China)

【机构】 湖南农业大学动物科学技术学院； 长江大学动物科学学院； 中国科学院亚热带农业生态研究所； 湖南省畜牧兽医研究所；

【摘要】 将24头泌乳奶牛,随机分成A、B、C和D组4组,分别按剂量0(对照)、6.0、12.0和16.0mg/头静脉注射经生理盐水溶解的金属硫蛋白(MT),以探讨外源性MT对轻度热应激状态下奶牛内分泌轴的调控及其作用机理。结果表明:B、C和D组的标准产奶量显著高于A组(P<0.05或P<0.01),乳脂率在后期(31～45d)有显著改善(P<0.05);INS分泌量试验组高于对照组,尤其是B组30d的分泌量极显著高于A组(P<0.01);IGF-Ⅰ和T3的分泌量,试验组显著高于A组(P<0.05或P<0.01),在45d时,C组达到最高;B和C组的FSH分泌量保持低水平且恒定,A组的变化幅度是C组4倍;B、C和D组的Prog和E2在后期(30～45d)显著高于A组(P<0.05),PRL分泌量在15d时极显著高于A组(P<0.01),但后期效果不明显。外源性MT的有效调控以注射剂量为12.0mg/头,间隔时间30～45d为宜,它一方面通过调节与能量代谢有关的内分泌轴,以降低能量的分解代谢,减少体内产热,另一方面控制性腺激素的变化,同时增加促乳素的分泌,使奶牛体内生理状态平稳过渡。更多还原

【Abstract】 To approach the effects of exogenous metallothionein (Zn-MT) on endocrine hubs of dairy cattles on the low-grade thermal stress,an experiment was conducted with 24 lactating cows,who were randomly allocated to groups A,B,C and D,and supplemented with 0,6.0,12.0 and 16.0mg Zn-MT?capita-1,respectively,by intravenous injection.The results showed that: The corrected milk yields in groups B,C and D were higher than those in groups A (P<0.05or P<0.01),the fat percentages of milk was improved significantly (P<0.05).The level of INS in control group was lower than that in experimental groups,especially in group B in 30d(P<0.01);the level of IGF-Ⅰand T3 in groups B,C and D were higher than those in groups A (P<0.05or P<0.01),and in 45d,the same level in group C was the highest among all these numbers.The level of FSH in groups B and C constantly maintained low level,but the range of variation of FSH in group A was 4 times as same as in group C;The level of P and E2 in experimental groups were higher than those of group A in anaphase (30～45d)(P<0.05);and the level of PRL in groups B,C and D were higher significantly than those in groups A (P<0.01),and the effect was faint in anaphase (P>0.05).Exogenous Zn-MT had the best effects on the thermoresistance of diary cattle 12.0mg?capita-1 by intravenous injection every 30～45 days.On one hand,the speed of catabolism and quantity of heat production in bodies were reduced by Zn-MT through adjusting secretory volume of endocrine hormone which is related to energy metabolism,on the other hand,to approach the healthful effects of thermoresistance,the gonadal hormones were controlled amplitude of variation,and on the same time,the secretory volume of PRL was improved by Zn-MT,which resulted in physiological status which was varied on balance for diary cattle.更多还原