Researchers led by Shanshan Han and Xiaoyu Wang set out to test whether Astragalus polysaccharides, bioactive macromolecules extracted from the medicinal herb Astragalus membranaceus, could reshape the quality profile of late lactation goat milk in ways that differ from conventional probiotic supplementation. Astragalus polysaccharides, commonly abbreviated APS, have attracted scientific attention for their stability, immunomodulatory properties, and potential metabolic effects. Previous work in heat-stressed dairy cows linked APS intervention to shifts in serum metabolites connected with glucose metabolism, amino acid metabolism, glutathione metabolism, and prolactin signaling, while separate studies reported improved oxidative stability in Cashmere goats receiving Astragalus supplementation. What remained unclear was whether APS could produce coordinated changes in the actual composition of goat milk, spanning everything from bulk nutritional traits to volatile fingerprints and molecular signatures, and whether those changes would look different from what probiotics achieve.

To find out, the team recruited thirty clinically healthy Saanen dairy goats from a commercial farm in Xi’an, China, all in late lactation at roughly 260 days in milk, with balanced parity and baseline milk yields of about 1.2 kilograms per day. Animals with a history of mastitis or recent antibiotic treatment were excluded. After a seven-day acclimatization period, the goats were randomly assigned to two groups of fifteen. One group received a basal total mixed ration top-dressed with five grams per head per day of a composite microbial agent containing Lactobacillus plantarum, Bacillus subtilis, and Saccharomyces cerevisiae. The other received the same ration supplemented with five grams per head per day of feed-grade Astragalus polysaccharide powder with 55 percent polysaccharide purity. The trial ran for thirty days, with milk samples collected at the start and end of the intervention under strict hygienic protocols, snap-frozen in liquid nitrogen, and coded so that analytical personnel remained blind to treatment assignments. All animal procedures followed ARRIVE guidelines and were approved by the Animal Ethics Committee of the Bio-Agriculture Institute of Shaanxi.

The analytical arsenal deployed on these samples was formidable. Conventional composition, including fat, protein, lactose, dry matter, milk urea nitrogen, and somatic cell count, was measured with a CombiFoss FT+ analyzer. Volatile-related sensory profiles were digitized using a PEN3-Plus electronic nose equipped with ten metal oxide semiconductor sensors covering sensitivities to aromatic compounds, nitrogen oxides, sulfur-containing compounds, alkanes, alcohols, and more. The proteome was quantified using data-independent acquisition mass spectrometry on an Orbitrap Astral instrument, with identification controlled at a one percent false discovery rate against the goat protein database. Untargeted metabolomics was performed on an Orbitrap Exploris 480 in both positive and negative ionization modes, while lipidomics employed a Q Exactive mass spectrometer with methyl tert-butyl ether extraction to capture the full lipid repertoire. Supervised multivariate models were rigorously validated with seven-fold cross-validation and two hundred permutation tests to guard against overfitting.

The conventional composition results immediately revealed two divergent response profiles. In the probiotic group, milk fat percentage increased significantly, accompanied by a parallel rise in total solids, suggesting the probiotic effect was largely driven by the fat fraction. Milk urea nitrogen, a widely used indicator of nitrogen utilization efficiency, rose markedly in the probiotic group, a pattern generally associated with less efficient nitrogen use. The APS group told a different story. Milk fat percentage fell significantly relative to baseline, total solids did not increase, and milk urea nitrogen dropped by 6.20 milligrams per deciliter, a reduction the authors interpret as a more favorable nitrogen-use profile. Lactose remained stable in both groups, indicating that the aqueous secretory characteristics of milk were preserved, and protein percentage showed a non-significant upward tendency of 0.42 percent under APS. Somatic cell counts, an indicator of udder health, did not change in either group, providing a stable background against which to interpret the other shifts.

The electronic nose data added a sensory dimension to this divergence. Radar plots of the ten sensor channels showed that the probiotic group’s volatile fingerprint remained broadly similar to its baseline, with only modest expansion. The APS group, by contrast, displayed a pronounced expansion of its sensor response polygon, particularly in the W5S, W2W, and W1S channels, which respond broadly to nitrogen oxide-related compounds, sulfur-containing and aromatic compounds, and methane-related or broad-range volatile classes. Principal component analysis confirmed that APS endpoint samples shifted clearly away from their baseline distribution and formed a distinct cluster, while probiotic endpoint samples stayed closer to the center. Loading analysis identified W5S as the dominant contributor to the separation, and the authors note the intriguing coincidence that lower milk urea nitrogen and a strong W5S response, both nitrogen-related indicators, changed in parallel under APS supplementation.

Proteomic profiling deepened the picture. APS endpoint samples separated clearly from their baselines in principal component space, whereas probiotic samples did not, indicating a stronger proteomic shift under APS. Functional enrichment analysis showed that proteins increased after APS supplementation were annotated mainly to starch and sucrose metabolism, aminoacyl-tRNA biosynthesis, glycolysis and gluconeogenesis, nucleotide metabolism, and sphingolipid signaling pathways, while decreased proteins mapped to cholesterol metabolism and various glycan biosynthesis and degradation pathways. A heatmap of the top fifty differentially abundant proteins revealed two opposing protein modules: a probiotic-associated module containing fibrinogen gamma chain, complement component 9, lipoprotein lipase, and other extracellular matrix and immune-related proteins, and an APS-associated module enriched in heat shock protein 90 beta, calreticulin, protein disulfide isomerases, calnexin, asparagine synthetase, and glycolytic enzymes such as lactate dehydrogenase A and glyceraldehyde-3-phosphate dehydrogenase.

Targeted inspection of lipid metabolism proteins sharpened the APS signature further. Compared with baseline, the APS group showed elevated abundance of acetyl-CoA carboxylase alpha, fatty acid synthase, and ATP citrate lyase, with fold changes of 1.49, 1.70, and 2.52 respectively, enzymes central to acetyl-CoA supply, malonyl-CoA formation, and fatty acid biosynthesis. NADPH-generating enzymes, including isocitrate dehydrogenase 1, glucose-6-phosphate dehydrogenase, and 6-phosphogluconate dehydrogenase, also rose, with the latter two increasing more than two-fold, providing the reducing equivalents that lipid biosynthesis demands. Meanwhile lipoprotein lipase abundance fell dramatically to 0.26 of baseline, suggesting a redistribution of lipid-processing capacity rather than a blanket increase. The probiotic group showed only mild changes in the same protein set, reinforcing the distinctness of the APS response.

The metabolomic and lipidomic layers completed the molecular portrait. Untargeted metabolomics identified 904 differential metabolites in the APS group versus 587 in the probiotic group, with lipid-related metabolites and organic acids, including tricarboxylic acid cycle intermediates such as citrate and malate, among the prominent responsive categories. Lipidomic profiling detected 2,553 lipid molecules spanning 42 subclasses, with triacylglycerols dominating at more than 88 percent of total lipid signal as expected for mammalian milk. Within that architecture, APS supplementation was associated with a 1.12-fold increase in total triacylglycerol signal, enrichment of medium-chain triacylglycerol species containing C6:0, C8:0, and C10:0 acyl groups, which are characteristic contributors to goat milk flavor after lipolysis, and a coordinated remodeling of polar lipids. Phosphatidylethanolamine and phosphatidylcholine, major components of the milk fat globule membrane, increased approximately 1.4-fold and 1.5-fold respectively, while ceramide rose nearly five-fold and sphingomyelin declined, an inverse pattern the authors interpret as sphingolipid compositional remodeling within the milk matrix.

Finally, an integrated correlation network linking proteins, lipids, metabolites, and electronic nose responses tied the layers together. Glucose-6-phosphate dehydrogenase and fatty acid synthase correlated strongly and positively with phosphatidylethanolamine- and ceramide-related lipid features, with correlation coefficients exceeding 0.85, while lipoprotein lipase was strongly negatively correlated with a specific ceramide species at r equal to minus 0.96. Strikingly, the ether-linked phosphatidylcholine species PC(18:0e/22:4) and an oxidized ceramide were positively correlated with W5S- and W2W-related sensor responses at r equal to 0.83, connecting milk polar lipid chemistry directly to volatile-related sensor signals. The authors are careful to frame these findings as association-based and hypothesis-generating rather than causal proof, noting the absence of an untreated control group, the use of milk rather than mammary tissue, and the sensor-level rather than compound-level nature of electronic nose data. Even so, the coherent multi-omics signature, spanning reduced milk urea nitrogen, a distinct volatile fingerprint, enriched lipid-synthesis proteins, and selective remodeling of medium-chain triacylglycerols, membrane phospholipids, and sphingolipids, positions Astragalus polysaccharide as a promising plant-derived, non-microbial nutritional strategy for stabilizing goat milk quality precisely when the industry needs it most.

Subject of Research: Multi-omics analysis of milk quality responses to Astragalus polysaccharide supplementation in late lactation dairy goats

Article Title: Milk-based multi-omics reveals distinct quality signatures associated with Astragalus polysaccharide supplementation in late lactation goats

Article References: Han, S., Wang, P., Hu, Y., Zhang, Q., Wan, K., & Wang, X. (2026). Milk-based multi-omics reveals distinct quality signatures associated with Astragalus polysaccharide supplementation in late lactation goats. Food Chemistry: X, 39, Article 104395. https://doi.org/10.1016/j.fochx.2026.104395

Image Credits: AI Generated

DOI: Not provided

Keywords: goat milk, Astragalus polysaccharide, late lactation, multi-omics, proteomics, metabolomics, lipidomics, electronic nose, milk urea nitrogen, milk fat globule membrane, probiotics, dairy quality