蚯蚓液对高温环境下番鸭生长性能、血清热应激指标、激素水平及肠道功能的影响

【目的】本试验旨在探究高温环境下蚯蚓液在番鸭健康养殖中的应用效果。【方法】选择16日龄健康番鸭360只,随机分为3组,每组6个重复,每个重复20只。对照组饲喂基础饲粮,试验组分别在基础饲粮的基础上添加1.5%和2.5%的蚯蚓液,自由采食饮水,试验期55 d,采集番鸭血清和肠组织,并测定番鸭的生长性能、血清热休克蛋白70 mRNA表达水平、激素水平(三碘甲腺原氨酸、四碘甲腺原氨酸、皮质酮、皮质醇)、肠形态学指标(绒毛高度、隐窝深度、绒毛宽度、绒腺比值和绒毛表面积)以及肠道屏障相关指标(二胺氧化酶、D-乳酸、内毒素)。【结果】高温环境下,与对照组相比,①饲粮中添加1.5%、2.5%蚯蚓液极显著提高番鸭21~42、16~70日龄的平均日增重(P<0.01),显著降低21~42日龄的料重比(P<0.05),极显著降低16~70日龄的料重比(P<0.01);2.5%蚯蚓液显著降低番鸭42~70日龄的料重比(P<0.05)。②1.5%和2.5%蚯蚓液极显著降低了42和70日龄番鸭血清热休克蛋白70 mRNA表达水平(P<0.01)。③42日龄时,1.5%蚯蚓液极显著提高番鸭血清皮质醇水平(P<0.01);2.5%蚯蚓液显著降低番鸭血清三碘甲腺原氨酸水平(P<0.05)、极显著降低四碘甲腺原氨酸水平(P<0.01)、显著升高皮质酮水平(P<0.05);70日龄时,1.5%蚯蚓液极显著降低番鸭血清皮质酮水平(P<0.01),2.5%蚯蚓液显著降低番鸭血清三碘甲腺原氨酸、皮质醇水平(P<0.05),极显著提高四碘甲腺原氨酸水平(P<0.01)。④1.5%蚯蚓液使番鸭肠道的肌层厚度和淋巴细胞阳性率极显著升高(P<0.01);2.5%蚯蚓液使番鸭肠道的绒毛高度和肌层厚度极显著升高(P<0.01)。⑤42日龄时,1.5%、2.5%蚯蚓液极显著提高番鸭血清二胺氧化酶活性(P<0.01);70日龄时,1.5%蚯蚓液极显著降低番鸭血清内毒素水平(P<0.01);2.5%蚯蚓液极显著降低番鸭血清二胺氧化酶、D-乳酸、内毒素水平(P<0.01)。【结论】在饲粮中添加蚯蚓液有助于提高番鸭生长性能,增加抗热应激能力,可用于高温环境下番鸭的健康养殖。

Effects of Traditional Chinese Herbal Medicines on Blood Ions and Enzymes of Egg-laying Hens Under Heat Stress

[Objective] This study was conducted to investigate the effects of tradi- tional Chinese herbal medicines on blood biochemical indices of egg-laying hens under heat stress and to provide theoretical basis for clinical application of the medicines. [Method] One hundred of 88-day-old ISA-Brown hens were randomly di- vided into five groups. The hens in four groups were administrated with Prescription I herbal medicines, Prescription II herbal medicines, Vc and blank control under ar- tificially simulated heat stress, respectively. The last group was raised under normal temperature condition. Blood samples of the hens were collected on 1, 4, 8 and 10 d later and detected for their biochemical indices. [Result] The blood sodium （Na）, phosphorus （P）, potassium （K） and chlorine （CI） concentrations in hens under heat stress were decreased, while the activities of alanine aminotransferase （ALT）, lactate dehydrogenase （LDH） and creatine kinase （CK） were increased. These indices grad- ually returned to normal levels after the use of traditional Chinese herbal medicines. [Conclusion] The herbal medicines can relieve the adverse effects caused by heat stress to blood biochemical indices via different metabolic pathways of ions and en- zymes.

Effects of heat stress on serum insulin, adipokines, AMP-activated protein kinase, and heat shock signal molecules in dairy cows

Heat stress affects feed intake, milk production, and endocrine status in dairy cows. The temperaturehumidity index（THI） is employed as an index to evaluate the degree of heat stress in dairy cows. However, it is difficult to ascertain whether THI is the most appropriate measurement of heat stress in dairy cows. This experiment was conducted to investigate the effects of heat stress on serum insulin, adipokines（leptin and adiponectin）, AMP-activated protein kinase（AMPK）, and heat shock signal molecules（heat shock transcription factor（HSF） and heat shock proteins（HSP）） in dairy cows and to research biomarkers to be used for better understanding the meaning of THI as a bioclimatic index. To achieve these objectives, two experiments were performed. The first experiment： eighteen lactating Holstein dairy cows were used. The treatments were： heat stress（HS, THI average=81.7, n=9） and cooling（CL, THI average=53.4, n=9）. Samples of HS were obtained on August 16, 2013, and samples of CL were collected on April 7, 2014 in natural conditions. The second experiment： HS treatment cows（n=9） from the first experiment were fed for 8 weeks from August 16, 2013 to October 12, 2013. Samples for moderate heat stress, mild heat stress, and no heat stress were obtained, respectively, according to the physical alterations of the THI. Results showed that heat stress significantly increased the serum adiponectin, AMPK, HSF, HSP27, HSP70, and HSP90（P〈0.05）. Adiponectin is strongly associated with AMPK. The increases of adiponectin and AMPK may be one of the mechanisms to maintain homeostasis in heat-stressed dairy cows. When heat stress treatment lasted 8 weeks, a higher expression of HSF and HSP70 was observed under moderate heat stress. Serum HSF and HSP70 are sensitive and accurate in heat stress and they could be potential indicators of animal response to heat stress. We recommend serum HSF and HSP70 as meaningful biomarkers to supplement the THI and evaluate moderate heat stress in dairy cows in the future.