Yue Shuangming, Ding Siyan, Zhou Jia, Yang Chao, Hu Xiaofei, Zhao Xiaonan, Wang Zhisheng, Wang Lizhi, Peng Quanhui, Xue Bai
Animal Nutrition Institute, Sichuan Agricultural University, Chengdu 611130, China.
Department of Bioengineering, Sichuan Water Conservancy Vocation College, Chengdu 611845, China.
Animals (Basel). 2020 Sep 25;10(10):1741. doi: 10.3390/ani10101741.
In the present experiment, we investigated the impact of heat stress (HS) on physiological parameters, dry matter intake, milk production, the metabolome of milk, and blood plasma in lactating Holstein dairy cows. For this purpose, 20 Holstein lactating cows were distributed in two groups in such a way that each group had 10 cows. A group of 10 cows was reared in HS conditions, while the other group of 10 cows was reared in the thermoneutral zone. The results of the experiment showed that cows subjected to HS had higher respiration rates ( < 0.01) and greater rectal temperature ( < 0.01). Results of milk production and composition explored that HS lowered milk production ( < 0.01) and milk protein percentage ( < 0.05) than cows raised in a thermoneutral place. Furthermore, HS increased the concentrations of N-acetyl glycoprotein, scyllo-inositol, choline, and pyridoxamine in milk, while HS decreased the concentrations of O-acetyl glycoprotein, glycerophosphorylcholine, citrate, and methyl phosphate in milk. Moreover, HS enhanced plasma concentrations of alanine, glucose, glutamate, urea, 1-methylhistidine, histidine, and formate in cows, while the plasma concentration of low-density lipoprotein, very-low-density lipoprotein, leucine, lipid, and 3-hydroxybutyrate decreased due to HS. Based on the findings of the current research, it is concluded that HS alters the milk and blood plasma metabolites of lactating Holstein dairy cows. Overall, in the current experiment, HS altered eight metabolites in milk and twelve metabolites in the plasma of lactating Holstein dairy cows. Furthermore, the current study explored that these metabolites were mainly involved in proteolysis, gluconeogenesis, and milk fatty acid synthesis and could be potential biomarkers for dairy cows undergoing HS.
在本实验中，我们研究了热应激（HS）对泌乳期荷斯坦奶牛生理参数、干物质摄入量、产奶量、乳代谢组和血浆的影响。为此，将20头荷斯坦泌乳奶牛分成两组，每组10头。一组10头奶牛在热应激条件下饲养，而另一组10头奶牛在热中性区饲养。实验结果表明，遭受热应激的奶牛呼吸频率更高（<0.01），直肠温度更高（<0.01）。产奶量和成分的结果表明，与在热中性环境中饲养的奶牛相比，热应激降低了产奶量（<0.01）和乳蛋白百分比（<0.05）。此外，热应激增加了牛奶中N-乙酰糖蛋白、 scyllo-肌醇、胆碱和吡哆胺的浓度，而热应激降低了牛奶中O-乙酰糖蛋白、甘油磷酸胆碱、柠檬酸盐和甲基磷酸盐的浓度。此外，热应激提高了奶牛血浆中丙氨酸、葡萄糖、谷氨酸、尿素、1-甲基组氨酸、组氨酸和甲酸盐的浓度，而热应激导致血浆中低密度脂蛋白、极低密度脂蛋白、亮氨酸、脂质和3-羟基丁酸酯的浓度降低。基于当前研究的结果，得出结论：热应激会改变泌乳期荷斯坦奶牛的乳汁和血浆代谢产物。总体而言，在当前实验中，热应激改变了泌乳期荷斯坦奶牛乳汁中的8种代谢产物和血浆中的12种代谢产物。此外，当前研究发现这些代谢产物主要参与蛋白水解、糖异生和乳脂肪酸合成，可能是遭受热应激奶牛的潜在生物标志物。
