The study, published in Food Science of Animal Resources, involved thirty male yaks of similar genetic background, aged 2.5 to 3 years and weighing on average about 94.6 kilograms. The animals were randomly divided into two groups of fifteen. One group continued traditional grazing alone, while the other grazed on an adjacent meadow with identical grass composition but also received 750 grams of pelleted concentrate feed before and after each day’s grazing, from June to October. After a ten-day adaptation period, the formal experiment ran for 120 days on high-altitude meadows in Saierlong Township, Henan Mongolian Autonomous County, Qinghai Province. All procedures followed Chinese national animal welfare guidelines and provincial yak breeding and slaughter technical regulations, and samples of the longissimus lumborum muscle were snap-frozen in liquid nitrogen for laboratory analysis.

The results on meat quality were striking. Meat from the supplemented group showed a 39.6 percent reduction in Warner-Bratzler shear force, the standard laboratory measure of tenderness, with shear force falling from 6.77 kilograms to 4.09 kilograms. Cooking loss dropped by 22.4 percent and drip loss also fell significantly, meaning the meat retained more of its moisture during handling and preparation. The pH of the meat was lower both 45 minutes and 24 hours after slaughter, a shift the authors attribute to greater muscle glycogen reserves in the supplemented animals, which fuels more postmortem lactic acid production and helps prevent the formation of dark, firm and dry meat that consumers reject. Both groups still fell within the desirable red, firm and non-exudative quality class, but the supplemented meat sat comfortably closer to consumer expectations.

The nutritional upgrades were equally significant. Supplemented meat contained a higher proportion of polyunsaturated fatty acids and a 15 percent increase in the PUFA-to-SFA ratio, while saturated fatty acids, the n-6 to n-3 ratio and the atherogenic index all declined. The researchers link this shift partly to heated rapeseed included in the concentrate, which is rich in unsaturated fats. Essential amino acid content rose by about 18 percent, pushing the ratios of essential to total amino acids and essential to non-essential amino acids to 42.6 percent and 74.6 percent respectively, both exceeding the thresholds recommended by the joint FAO, WHO and UNU expert committee for ideal dietary protein. Crude fat increased from 3.56 percent to 6.17 percent, contributing to marbling, which previous sensory research has associated with enhanced flavor, juiciness and tenderness in grilled beef. Notably, cholesterol content in the meat fell significantly, an effect the authors connect to unsaturated fatty acids aiding cholesterol digestion and reducing its accumulation in muscle.

To understand how diet reshapes meat at the molecular level, the team turned to untargeted metabolomics using ultra-high-performance liquid chromatography coupled to a Q Exactive Orbitrap mass spectrometer. From the longissimus lumborum of six yaks per group, they detected 4,008 metabolites in positive ion mode and 2,925 in negative ion mode. Principal component analysis confirmed tight clustering of quality-control samples and reliable data, while supervised orthogonal partial least squares discriminant analysis revealed clear separation between the metabolic fingerprints of grazing-only and supplemented meat. The model, validated with 200 permutation tests, showed robust statistics with R2Y of 0.797 and Q2Y of 0.817, confirming that supplementation genuinely rewired the muscle metabolome rather than producing statistical noise.

Screening for metabolites with variable importance in projection values of at least one and p-values below 0.05, the researchers identified 177 significantly altered metabolites in positive mode and 198 in negative mode. After annotation against the Kyoto Encyclopedia of Genes and Genomes and removal of duplicates, 38 annotated differential metabolites remained, spanning amino acids, organic acids, cofactors, lipids, sugars, purines and other compound classes. Thirty-one were upregulated in the supplemented group, including pyruvic acid, L-tyrosine, L-isoleucine, L-tryptophan, L-glutamine and eicosapentaenoic acid, while harmful compounds such as toxic sulfites were markedly downregulated. Among the standouts was guanosine, a nucleoside central to RNA, DNA, coenzyme A and ATP metabolism, whose concentration in supplemented meat was 17.4 times higher than in grazing-only meat, signaling a surge in cellular energy metabolism and protein synthesis.

Correlation analysis linked these molecular shifts directly to eating quality. Eight meat quality parameters, including shear force, cooking loss and drip loss, correlated significantly with the 38 differential metabolites. Sulfite and methyl selenocysteine Se-oxide, both antioxidants, were associated with improved water-holding capacity, while L-carnosine, with its well-established antioxidant and pH-buffering properties, showed a strong negative correlation with shear force, pointing to a pivotal role in tenderness. Creatine, a key molecule in energy metabolism, helps delay ATP depletion, stabilize postmortem pH and promote protein synthesis, and L-glutamyl 5-phosphate participates in regulating the balance between protein synthesis and degradation, helping preserve muscle structure and moisture. The researchers then built a linear discriminant model using the five most influential metabolites—L-glutamine, D-phenylalanine, arachidonic acid, pyridoxal phosphate and taurine—and it classified meat from the two feeding systems with 100 percent accuracy in both original and cross-validated cases, raising the prospect of metabolite-based authentication of feeding origin.

Pathway enrichment analysis of 93 implicated metabolic routes revealed that amino acid metabolism and fatty acid metabolism were the primary engines of the quality improvement. Enhanced amino acid biosynthesis and aminoacyl-tRNA biosynthesis reflected an increased capacity for protein turnover, supporting muscle integrity and reducing cooking loss, while the 2-oxocarboxylic acid metabolism pathway, a hub linking amino acid and carbohydrate metabolism, maintained glycolytic flux and postmortem pH stability. On the lipid side, upregulated eicosapentaenoic acid, arachidonic acid and cis-8,11,14-eicosatrienoic acid fed into unsaturated fatty acid biosynthesis, linoleic acid metabolism and adipocyte lipolysis pathways, raising n-3 polyunsaturated fatty acid levels. Supplementation also significantly increased deoxycholic acid, a bile acid involved in fat digestion, which the authors say explains the reduced cholesterol synthesis and lower cholesterol content in the supplemented meat. Meanwhile, elevated D-glucose-6-phosphate accelerated glycolysis, promoting lactate accumulation that stabilizes postmortem pH and slows meat hardening, while the higher unsaturated fat content softened muscle fiber structure—together accounting for the exceptional tenderness.

Beyond the plate, the findings carry real ecological weight. Supplemented yaks consumed 0.38 kilograms less grass per day than their grazing-only counterparts, easing pressure on degraded alpine grasslands, and they gained weight more than twice as fast, with a daily gain 2.01-fold higher than the control group and a significantly better feed-to-gain ratio. For a region where more than 14 million yaks—roughly 92 percent of the global population—produce some 300,000 tons of meat annually, a feeding strategy that simultaneously boosts tenderness, nutrition and growth while reducing overgrazing could reshape sustainable production on the plateau. The authors caution that future work should examine the long-term sustainability of supplementation and its adaptability across diverse grazing systems, but the study demonstrates that targeted nutrition can deliberately steer muscle metabolism toward a healthier, more tender and more valuable product, offering herders on the roof of the world a scientifically grounded path to better meat and healthier grasslands.

Subject of Research: Effects of supplemental feeding on yak meat quality and muscle metabolism analyzed by untargeted metabolomics

Article Title: Effect of supplemental feeding on metabolic profiles and meat quality in yaks: a non-targeted metabolomics approach

Article References: Wang, M., Huang, Y., Hocquette, J.-F., Degen, A., Liu, Z., Zhong, R., Liu, S., Xiang, Y., & Hao, L. (2026). Effect of supplemental feeding on metabolic profiles and meat quality in yaks: a non-targeted metabolomics approach. Food Science of Animal Resources, 46(1), Article 57. https://doi.org/10.1007/s44463-025-00027-8

Image Credits: AI Generated

DOI: 10.1007/s44463-025-00027-8

Keywords: yak, supplemental feeding, metabolomics, meat quality, tenderness, fatty acids, amino acids, Qinghai-Tibet Plateau, UHPLC-MS, KEGG pathways, grassland sustainability, cholesterol