China Animal Husbandry & Veterinary Medicine ›› 2026, Vol. 53 ›› Issue (1): 165-178.doi: 10.16431/j.cnki.1671-7236.2026.01.015

• Nutrition and Feed • Previous Articles     Next Articles

Effects of Diets with Different Protein Levels on Rumen Metabolism in Yaks

CHEN Ping(), XIE Jianpeng, HE Zhenfu, WANG Fei()   

  1. Animal Husbandry,Pasture and Green Agricultural Institute,Gansu Academy of Agricultural Sciences,Lanzhou 730070,China
  • Received:2025-03-28 Online:2026-01-05 Published:2025-12-26
  • Contact: WANG Fei E-mail:gaaschenping@163.com;wangfei@gsagr.ac.cn

Abstract:

Objective This study aimed to investigate the effects of diets with different protein levels on growth performance and rumen metabolism regulation of yaks, so as to provide theoretical basis for feeding yaks with different diet protein levels. Method 20 healthy yaks with average body weight of (210.60±11.75) kg were selected for this trial. The comparable net energy level (7.73 and 7.65 MJ/kg), were divided into 2 groups according to different protein levels (18.88% and 12.77%): Low-protein diet group and high-protein diet group, each group consists of 10 heads. The trial period was 20 days and the formal period was 90 days. Then the growth performance and nutrient digestibility were measured, and the rumen fluid was collected for non-targeted metabolome analysis. Result After 90 days of fattening, the average daily gain of yaks in high protein diet group was extremely significantly higher than that in low protein diet group (P<0.01). The crude protein digestibility and crude ash digestibility of yaks in high protein diet group was significantly or extremely significantly higher than that in low protein diet group (P<0.05 or P<0.01). A total of 29 up-regulated and 28 down-regulated differential metabolites were screened by gas chromatography and mass spectrometry, and 287 up-regulated and 244 down-regulated differential metabolites were screened by liquid chromatography and mass spectrometry, respectively. Analysis of the correlation of differential metabolites showed that 21 pairs of positively correlated and 18 pairs of negatively correlated metabolites. Pathway enrichment analysis showed that phenylalanine metabolism, tyrosine metabolism, vitamin B6 metabolism, biosynthesis of ubiquinone and other terpenoid quinones, and riboflavin metabolism were more significant. Conclusion The average daily gain of yaks fed 18.88% crude protein and 7.65 MJ/kg net energy was significantly higher than that of 12.77% crude protein diet group, which could effectively shorten the fattening cycle and improve the level of rumen microbial metabolism of yaks.

Key words: yaks; protein levels; rumen metabolites; metabolomics

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