冷暴露仔猪血清6种激素的变化规律

Effects of Cold Exposure at Different Time on Six Hormones in Serum of Piglets

目的探讨冷暴露对仔猪血清6种激素动态变化的影响。方法将50日龄普通级"军牧1号"白仔猪10头(雌雄各半)随机分为2组,分别为对照组(15～18℃)和暴露组,每组5头。暴露组于-10～-5℃冷刺激24h后,转入正常温度环境(15℃～18℃)。每天上午8:00开始进行试验,分别于冷暴露0、0.5、3、6、12、24h与恢复0.5、3、6、12、24、48h测定血清促肾上腺皮质激素、皮质醇、游离三碘甲腺原氨酸、游离甲状腺素、三碘甲腺原氨酸、甲状腺素的浓度。结果暴露组仔猪血清促肾上腺皮质激素和皮质醇的波动变化明显(P<0.05,P<0.01)。甲状腺4种激素总体上呈先升高后降低的趋势,游离三碘甲腺原氨酸在冷暴露期显著高于对照组(P<0.05),而游离甲状腺素、三碘甲腺原氨酸和甲状腺素在恢复期低于对照组(P<0.05)。结论冷暴露对仔猪血清中6种激素浓度的影响复杂但呈现有规律的变化,但个体间存在差异,提示可以把相关激素作为应激程度衡量标准的辅助指标。

Objective To explore the effects of cold exposure on six hormones in the serum of the piglets. Methods Ten ordinary ＂JunMu-1 ＂piglets aged 50 days were randomly divided into 2 groups （five in each） including control group and experiment group. The control group was kept in the temperature of 15 ℃-18 ℃, while the experiment group was kept at the temperature of-5 - -10 ℃ for 24 hours and then put in the normal temperature. The blood samples were collected at different time （0 h, 0.5 h, 3 h, 6 h, 12 h, 24 h of cold exposure at -5- -10℃ and 0.5 h, 3 h, 6 h, 12 h, 24 h after terminating cold exposure to normal temperature） to be examined for the changes of the related hormones （ACTH, cortisol, fF3, fT4, T3, T4） in serum by radio immunoassay. Results The level of ACTH and cortisol increased obviously （P〈0.05,P〈0.01）; Four thyroid-hormones showed the trend that increased in the earlier time and then decreased totally,in which IT3 changed significantly in the period of stress （P〈0.05）, but fT4, T3 and T4 decreased obviously in the period of recovery （P〈0.05）. Conclusion The effect of cold stress on the change of six hormones in blood serum is complicated and regular, so the related hormone level change can be used as the subsidiary index in evaluation of the degree of cold stress.