Zhao Yiguang, Xue Fuguang, Hua Dengke, Wang Yue, Pan Xiaohua, Nan Xuemei, Sun Fuyu, Jiang Linshu, Xiong Benhai
State Key Laboratory of Animal Nutrition, Institute of Animal Sciences, Chinese Academy of Agricultural Sciences, Beijing 100193, China.
College of Animal Science and Technology, Jiangxi Agricultural University, Nanchang 330045, China.
Animals (Basel). 2020 Feb 14;10(2):304. doi: 10.3390/ani10020304.
As the co-enzyme of pyruvate formate-lyase under ruminal anaerobic condition, thiamine plays a critical role in carbohydrate metabolism in dairy cows. The objective of this study was to investigate the impacts of thiamine supplementation on ruminal carbohydrate-active enzymes. Twelve Holstein dairy cows were randomly assigned into three dietary treatments: control diet (CON; 20% starch, dry matter (DM) basis), high-concentrate diet (HC; 33.2% starch, DM basis) and a high-concentrate diet supplemented with 180 mg thiamine/kg DM (HCT; 33.2% starch, DM basis). Dry matter intake and milk production were recorded for 21 days. Rumen fluid samples were collected, and ruminal pH and volatile fatty acids (VFAs) were measured. The metagenome sequencing technique was used to detect the genes in ruminal microorganisms and identify putative carbohydrate-active enzymes. The total abundances of carbohydrate-active enzymes and fiber-degrading enzymes were both reduced by HC with no effect on starch-degrading enzymes compared with CON. However, the fiber-degrading enzymes and starch-degrading enzymes were both increased after thiamine supplementation. These results indicated that 180 mg thiamine /kg DM might effectively improve rumen carbohydrate metabolism through increasing the abundance of ruminal carbohydrate-active enzymes and consequently balanced the rumen volatile fatty acids and rumen pH, providing a practical strategy in preventing subacute ruminal acidosis in cows offered HC.
作为瘤胃厌氧条件下丙酮酸甲酸裂解酶的辅酶，硫胺素在奶牛碳水化合物代谢中起关键作用。本研究的目的是调查补充硫胺素对瘤胃碳水化合物活性酶的影响。将12头荷斯坦奶牛随机分为三种日粮处理组：对照日粮（CON；淀粉含量20%，以干物质（DM）计）、高浓缩日粮（HC；淀粉含量33.2%，以DM计）和添加180毫克硫胺素/千克DM的高浓缩日粮（HCT；淀粉含量33.2%，以DM计）。记录21天的干物质摄入量和产奶量。采集瘤胃液样本，测定瘤胃pH值和挥发性脂肪酸（VFA）。采用宏基因组测序技术检测瘤胃微生物中的基因，并鉴定推定的碳水化合物活性酶。与CON相比，HC降低了碳水化合物活性酶和纤维降解酶的总丰度，对淀粉降解酶无影响。然而，补充硫胺素后，纤维降解酶和淀粉降解酶均增加。这些结果表明，180毫克硫胺素/千克DM可能通过增加瘤胃碳水化合物活性酶的丰度，有效改善瘤胃碳水化合物代谢，从而平衡瘤胃挥发性脂肪酸和瘤胃pH值，为预防采食HC日粮奶牛的亚急性瘤胃酸中毒提供了一种实用策略。
