Zeng Hanfang, Xi Yumeng, Li Yeqing, Wang Zedong, Zhang Lin, Han Zhaoyu
Institute of Dairy Science, College of Animal Science and Technology, Nanjing Agricultural University, Nanjing 210095, China.
Animal Husbandry Institute, Jiangsu Academy of Agricultural Sciences, Nanjing 210014, China.
Animals (Basel). 2020 Mar 29;10(4):574. doi: 10.3390/ani10040574.
This experiment was conducted to investigate the effects of astragalus polysaccharides (APS) on serum metabolism of dairy cows under heat stress. Thirty healthy Holstein dairy cows were randomly divided into three groups (10 cows in each group). In the experimental group, 30 mL/d (Treatment I) and 50 mL/d (Treatment II) of APS injection were injected into the neck muscle respectively. Each stage was injected with APS for 4 days (8:00 a.m. every day) and stopped for 3 days. Serum hormone and antioxidant indexes of dairy cows were investigated. Through repeated measurement analysis of variance, the results have shown that cortisol (COR) (F = 6.982, p = 0.026), triiodothyronine (T3) (F = 10.005, p = 0.012) and thyroxine (T4) (F = 22.530, p = 0.002) at different time points were significantly different. COR showed a downward trend, T3 and T4 showed an upward trend. At each time point, different concentrations of APS have significant effects on COR (F = 30.298, p = 0.000 < 0.05), T3 (F = 18.122, p = 0.001), and T4 (F = 44.067, p = 0.000 < 0.05). However, there were no significant differences in serum insulin (INS), glucagon (GC) and heat shock protein 70 (HSP70) between different time points (p > 0.05) and at each time point (p > 0.05). Additionally, the results have also shown that there were also no significant differences in serum Superoxide dismutase (SOD), malondialdehyde (MDA) and lactate dehydrogenase (LDH) between different time points (p > 0.05) and at each time point (p > 0.05). However, the injection of APS had a significant impact on glutathione peroxidase (GSH-Px) (F = 9.421, p = 0.014) at different times, and showed a trend of rising first and then falling. At each time point, APS of different concentrations had no significant effect on GSH-Px (p > 0.05). Furthermore, we used gas chromatography-mass spectrometry (GC-MS) non-targeted metabolomics to determine the potential markers of APS for heat-stressed dairy cows. Twenty metabolites were identified as potential biomarkers for the diagnosis of APS in heat-stressed dairy cows. These substances are involved in protein digestion and absorption, glutathione metabolism, prolactin signaling pathway, aminoacyl-tRNA biosynthesis, pentose and glucuronate interconversions, and so on. Our findings suggest that APS have an effect on the serum hormones of heat-stressed dairy cows, and regulate the metabolism of heat-stressed dairy cows through glucose metabolism and amino acid metabolism pathways.
本实验旨在研究黄芪多糖（APS）对热应激下奶牛血清代谢的影响。选取30头健康的荷斯坦奶牛，随机分为三组（每组10头）。实验组分别于颈部肌肉注射30 mL/d（处理I）和50 mL/d（处理II）的APS。每个阶段连续注射APS 4天（每天上午8:00），停注3天。对奶牛血清激素和抗氧化指标进行了研究。通过重复测量方差分析，结果表明，不同时间点的皮质醇（COR）（F = 6.982，p = 0.026）、三碘甲状腺原氨酸（T3）（F = 10.005，p = 0.012）和甲状腺素（T4）（F = 22.530，p = 0.002）存在显著差异。COR呈下降趋势，T3和T4呈上升趋势。在每个时间点，不同浓度的APS对COR（F = 30.298，p = 0.000 < 0.05）、T3（F = 18.122，p = 0.001）和T4（F = 44.067，p = 0.000 < 0.05）有显著影响。然而，不同时间点（p > 0.05）和每个时间点（p > 0.05）的血清胰岛素（INS）、胰高血糖素（GC）和热休克蛋白70（HSP70）无显著差异。此外，结果还表明，不同时间点（p > 0.05）和每个时间点（p > 0.05）的血清超氧化物歧化酶（SOD）、丙二醛（MDA）和乳酸脱氢酶（LDH）也无显著差异。然而，注射APS在不同时间对谷胱甘肽过氧化物酶（GSH-Px）有显著影响（F = 9.421，p = 0.014），且呈先上升后下降趋势。在每个时间点，不同浓度的APS对GSH-Px无显著影响（p > 0.05）。此外，我们采用气相色谱-质谱联用（GC-MS）非靶向代谢组学方法确定了APS对热应激奶牛的潜在标志物。鉴定出20种代谢产物作为热应激奶牛诊断APS的潜在生物标志物。这些物质参与蛋白质消化吸收、谷胱甘肽代谢、催乳素信号通路、氨酰-tRNA生物合成、戊糖与葡糖醛酸相互转化等过程。我们的研究结果表明，APS对热应激奶牛的血清激素有影响，并通过葡萄糖代谢和氨基酸代谢途径调节热应激奶牛的代谢。
