Zhu Jinjia, Wu Yicheng, Jiang Aoyu, Li Bin, Ran Tao, Zhou Chuanshe, Xiao Dingfu, Tan Zhiliang
CAS Key Laboratory for Agro-Ecological Processes in Subtropical Region, National Engineering Laboratory for Pollution Control and Waste Utilization in Livestock and Poultry Production, Hunan Provincial Key Laboratory of Animal Nutrition Physiology and Metabolic Process, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Changsha, Hunan, China.
College of Advanced Agricultural, University of the Chinese Academy of Sciences, Beijing, China.
Front Microbiol. 2023 May 9;14:1101620. doi: 10.3389/fmicb.2023.1101620. eCollection 2023.
The Tibetan Plateau is characterized by low temperature and hypoxia. N-carbamylglutamic acid (NCG) can increase blood oxygen saturation, and have the potential to be used to prevent the high-altitude hypoxia stress state of cows. However, its beneficial effect on the rumen microbiota of Holstein dairy cows remains unclear.
Hence, the experiments 12 multiparous (parity ranged from 2 to 7) Holstein dairy cows (413.0 ± 42 kg) were randomly assigned to 2 treatments with 6 replicates in each treatment: basal diet (CON, control group) and basal diet plus 20 g/d/cow of NCG (NCG, experiment group), respectively. To study the effects of dietary NCG supplementation on rumen microbiota of Holstein dairy cows in Tibet. The experiment lasted for 45 days, with 15 days of pre-feeding and 30 days of formal trail period.
The results showed that ruminal NH-N concentration in NCG group was lower ( < 0.05) than that in the CON group, while molar proportion of acetic acid and total volatile fatty acid (VFA) concentration were increased ( < 0.05) with the addition of NCG. Microbial diversity increased ( < 0.05) in NCG group, with , and as the most abundant phyla. The KEGG pathway analysis showed that the potential function of ruminal bacteria was mainly enriched in metabolism (carbohydrates, amino acids, lipids, energy, and nucleotides) and genetic information processing (replication, repair, and translation).
In conclusion, NCG can improve rumen nitrogen utilization, total VFA and acetic acid production, and increase rumen microbial diversity, all of which could make the introduced Holstein dairy cows to better adapt to the harsh environment in Tibet and improve their production performance.
青藏高原具有低温和缺氧的特点。N-氨甲酰谷氨酸（NCG）可提高血氧饱和度，有潜力用于预防奶牛的高原缺氧应激状态。然而，其对荷斯坦奶牛瘤胃微生物群的有益作用尚不清楚。
因此，将12头经产（胎次2至7胎）的荷斯坦奶牛（413.0±42千克）随机分为2组，每组6个重复：基础日粮（CON，对照组）和基础日粮+20克/天/头的NCG（NCG，实验组）。以研究日粮添加NCG对西藏荷斯坦奶牛瘤胃微生物群的影响。试验持续45天，预饲期15天，正式试验期30天。
结果表明，NCG组瘤胃液氨态氮浓度低于CON组（<0.05），添加NCG后乙酸摩尔比例和总挥发性脂肪酸（VFA）浓度升高（<0.05）。NCG组微生物多样性增加（<0.05），其中厚壁菌门、拟杆菌门和放线菌门为最丰富的菌门。KEGG通路分析表明，瘤胃细菌的潜在功能主要富集在代谢（碳水化合物、氨基酸、脂质、能量和核苷酸）和遗传信息处理（复制、修复和翻译）。
总之，NCG可提高瘤胃氮利用率、总VFA和乙酸产量，并增加瘤胃微生物多样性，所有这些都可使引入的荷斯坦奶牛更好地适应西藏的恶劣环境并提高其生产性能。
