中草药添加剂对生长猪抗热应激机理研究

Studies on the Mechanism of Herb Additive on Alleviating Heat Stress of Growing Pigs

本文旨在观察抗热应激中草药对生长猪生产性能、免疫力和内分泌激素的影响，进而探讨高温下生长猪的生理机能变化以及抗热应激中草药的部分作用机理。选取体重约10kg的杜×（长×大）三元杂交猪36头，随机分为2组，每组3个重复，每重复6头猪，公母各1／2。采用单因子完全随机试验设计。对照组饲喂玉米-豆粕型基础日粮，试验组在基础日粮中添加1．00％的抗热应激中草药添加剂，试验分10-20kg和20～50kg两个阶段。整个试验期，猪舍平均温度（31．37±1．93）℃，平均相对湿度（65．44±2．74）％。结果表明：①抗热应激中草药添加剂有提高生长猪的增重和采食量，降低料肉比的趋势，但差异不显著（P〉0．05）。②与对照组相比，试验组猪血清中血清免疫球蛋白G（1gG）、补体C3，C4水平和淋巴细胞百分比（LYM％）在10～20kg阶段显著提高（P〈0．05），但在20～50kg阶段差异不显著（P〉0．05）；白介素2（IL-2）和红细胞数（RBC）在整个试验期间均显著提高（P〈0．05）。③试验组猪血清中促肾上腺皮质激素（ACTH）、皮质醇（Cor）水平在整个试验期间均保持稳定，且均比对照组显著下降（P〈0．05），醛固酮（ALD）在整个试验期间也保持稳定，在10～20kg阶段比对照组显著下降（P〈0．05）；游离三碘甲腺原氨酸（FT3）和游离四碘甲腺原氨酸（FT4）在10～20kg阶段与对照组差异不明显（P〉0．05），20-50kg阶段比对照组显著提高（P〈0．05）。可见，高温环境下，抗热应激中草药添加剂可以通过提高生长猪的免疫力和促进猪的血液循环，维持内分泌系统的稳定，使机体的新陈代谢正常进行，为机体抵抗高温提供物质基础，从而缓解高温对生长猪的不良影响，改善高温环境下生长猪的生产性能。

To study the effects of anti-heat stress herb additive on the performance, immunity and endocrine hormones of growing pigs, and further to find some mechanism of anti-stress herbs, an experiment was conducted using a total of 36 crossbred （Duroc × （Landrace×Yorkshire）） growing pigs of 10 kg. Pigs were randomly divided into 2 treatments （18 for each treatment, 3 replicates, 6 for each）. The basal corn-soybean diet was used as control group, basal diet plus 1.0% antiheat stress herb additive was used as experimental, and the experiment included two stages （10-20 kg and 20-50 kg）. The result showed： ①In hot environments, the herbs did not improve production performance significantly, but had the tendency to improve average daily gain （ADG） and average daily feed intake （ADFI）, and to decrease the ratio of feed and gain （F/G）.② Compared with the control, the concentrate of IgG, C4, C3 and percent of LYM of the treatment increased significantly in stage of 10-20 kg （P〈0.05）, but not significant in stage of 20~50 kg. The IL-2 and RBC of the treatment were improved significantly during the whole period （P〈0.05）. ③ During whole period, concentration of ACTH and Cor of the treatment were not changed but lower significantly than control （P〈0.05）, ALD was less than the control signifi-cantly in stage of 10-20 kg （P〈0.05）. Levels of FT3 and FT4 of treatment were not different from control in stage of 10--20 kg but significantly increased in the stage of 20-50 kg （P〈0.05）. It suggested that by improving immunity and accelerating circle of blood, the herb could strengthen capacity of resisting hard environment and diseases, and by releasing the bad influence of adrenalin and thyroxin from heat stress and maintain stability of endocrine system, anti-stress herb additive could keep normal situation of metabolism and supply nutrient for body to resist high temperature.