Jiang Yahui, Zhang Jiali, Wang Kaiwen, Feng Hengbo, You Yuting, Dai Peng, Wang Zhisheng, Hu Rui, Peng Quanhui, Zou Huawei, Xiao Jianxin, Wang Lizhi, Xue Bai
College of Animal Science and Technology, Sichuan Agricultural University, Chengdu, China.
Key Laboratory of the University in Cattle Low Carbon Breeding and Safety Production in Sichuan Province, Animal Nutrition Institute, Sichuan Agricultural University, Chengdu, China.
Front Microbiol. 2025 Aug 12;16:1621581. doi: 10.3389/fmicb.2025.1621581. eCollection 2025.
The yak (Bos grunniens) is uniquely adapted to the Qinghai-Tibet Plateau, yet nutritional guidelines for yaks remain limited and often follow cattle standards. This study aimed to clarify dietary energy requirements to improve yak feeding strategies.
Fattening yaks were assigned to three diets with different net energy for gain (NEg): low (LE, 4.06 MJ/kg), medium (ME, 4.46 MJ/kg), and high (HE, 4.87 MJ/kg), with 13% crude protein constant. Growth performance, apparent digestibility, serum biochemistry, hormones, and rumen fermentation were measured. Additional, 16S rDNA sequencing analyzed the rumen and fecal microbiota, and serum non-targeted metabolomics profiling was performed.
Results showed that ME and HE diets significantly increased average daily gain and nutrient digestibility while reducing feed conversion ratios ( < 0.05). Serum glucose, triglycerides, and growth-related hormones were higher in ME and HE groups, while non-esterified fatty acids was significantly decreased ( < 0.05). Higher energy diets increased microbial protein and reduced ruminal ammonia nitrogen. The ME diet increased ruminal , enhancing fermentation and soluble carbohydrate utilization, while promoting fiber-degrading . High energy diets elevated fecal and abundances. Metabolomics revealed differences mainly in lipidrelated metabolites correlated with specific microbial taxa.
In conclusion, increasing dietary energy improves growth, nutrient utilization, and beneficial microbiota profiles in yaks. A medium-energy diet (NEg: 4.46 MJ/kg) optimizes fermentation and microbial balance, providing a scientific basis for precise nutritional strategies in yak production on the Qinghai-Tibet Plateau.
牦牛（Bos grunniens）对青藏高原具有独特的适应性，但牦牛的营养指南仍然有限，且常常遵循牛的标准。本研究旨在明确日粮能量需求，以改进牦牛饲养策略。
将育肥牦牛分为三组，分别给予不同净能用于增重（NEg）的日粮：低能组（LE，4.06兆焦/千克）、中能组（ME，4.46兆焦/千克）和高能组（HE，4.87兆焦/千克），粗蛋白含量恒定为13%。测定生长性能、表观消化率、血清生化指标、激素水平和瘤胃发酵情况。此外，采用16S rDNA测序分析瘤胃和粪便微生物群，并进行血清非靶向代谢组学分析。
结果表明，中能组和高能组日粮显著提高了平均日增重和养分消化率，同时降低了饲料转化率（P<0.05）。中能组和高能组血清葡萄糖、甘油三酯和生长相关激素水平较高，而游离脂肪酸显著降低（P<0.05）。较高能量的日粮增加了微生物蛋白含量，降低了瘤胃氨氮含量。中能组日粮增加了瘤胃乙酸，增强了发酵和可溶性碳水化合物的利用，同时促进了纤维降解菌的生长。高能日粮提高了粪便中丁酸和戊酸的丰度。代谢组学分析显示，差异主要体现在与特定微生物类群相关的脂质代谢物上。
总之，提高日粮能量可改善牦牛的生长性能、养分利用率和有益微生物群特征。中能日粮（NEg：4.46兆焦/千克）优化了发酵和微生物平衡，为青藏高原牦牛生产的精准营养策略提供了科学依据。
