CONCLUSION

This study demonstrated that HP and LP Sapera goats exhibit distinct serum metabolomic signatures, indicating that variation in milk production is associated with coordinated metabolic remodeling rather than isolated biochemical changes. Multivariate analyses clearly discriminated between the two production groups and identified 15 candidate metabolites associated with differences in milk production performance. Metabolites related to central carbon metabolism, lipid metabolism, amino acid metabolism, and sphingolipid signaling, including pyruvate, fumarate, β-hydroxybutyric acid, glycerol 3-phosphate, N-acetylneuraminic acid, and sphinganine, contributed substantially to the metabolic differentiation between HP and LP animals. Enrichment and KEGG pathway analyses further revealed that fatty acid degradation, fatty acid elongation, the TCA cycle, carbohydrate metabolism, and amino acid metabolism are key metabolic pathways associated with differences in milk production.

These findings provide important practical implications for precision livestock management and precision nutrition in dairy goats. The identified metabolites may serve as candidate biomarkers for evaluating metabolic efficiency and lactation performance, and may facilitate the development of targeted nutritional strategies to optimize energy utilization, lipid metabolism, and amino acid availability, thereby improving milk production while maintaining metabolic health.

A major strength of this study lies in the integration of LC-HRMS-based metabolomic profiling with multivariate analysis, metabolite set enrichment analysis, and KEGG pathway topology analysis, providing a comprehensive systems-level understanding of metabolic adaptations associated with milk production in Sapera goats. In addition, this study provides one of the first detailed characterizations of serum metabolic signatures that distinguish HP and LP Sapera goats under tropical production conditions, thereby expanding current knowledge of dairy goat metabolomics.

Overall, the present findings demonstrate that lipid, central carbon, and amino acid metabolism are closely associated with lactation efficiency in Sapera goats. The identified metabolites represent promising candidate biomarkers of milk production performance and provide a foundation for future validation studies and the development of metabolomics-assisted nutritional and management strategies to enhance productivity and sustainability in dairy goat production systems.