ABSTRACT

Background and Aim: Milk production efficiency in dairy goats is strongly influenced by metabolic adaptation during lactation. However, information regarding metabolomic signatures associated with milk production performance in Sapera goats remains limited. This study aimed to characterize serum metabolomic differences between high-production (HP) and low-production (LP) Sapera goats and to identify candidate biomarkers and metabolic pathways associated with milk production performance using a liquid chromatography-high resolution mass spectrometry (LC-HRMS)-based metabolomics approach. 

Materials and Methods: Twenty lactating Sapera goats were classified into HP (n = 10) and LP (n = 10) groups according to previously established milk yield records. Blood samples were collected from the jugular vein, and serum metabolites were profiled using LC-HRMS. Principal component analysis (PCA) and partial least squares-discriminant analysis (PLS-DA) were used to evaluate metabolic differences between groups. Differential metabolites were identified based on statistical significance and variable importance in projection scores. Metabolite set enrichment and Kyoto Encyclopedia of Genes and Genomes pathway analyses were subsequently performed to identify biological pathways associated with differences in production. 

Results: Both PCA and PLS-DA demonstrated clear separation between HP and LP goats, indicating distinct metabolic signatures. Fifteen discriminant metabolites were identified as candidate biomarkers associated with milk production performance. Metabolites related to energy and lipid metabolism, including pyruvate, fumarate, glycerol 3-phosphate, β-hydroxybutyric acid, and 3-hydroxy-3-methylglutaric acid, were more abundant in HP goats. In contrast, sphinganine, phytosphingosine, sphingosine, cystathionine, and ceramide-related intermediates were enriched in LP goats. Enrichment and pathway topology analyses revealed that fatty acid degradation, fatty acid elongation, the citrate cycle, carbohydrate metabolism, and amino acid metabolism were the principal pathways associated with differences in milk production. 

Conclusion: Distinct systemic metabolic signatures were associated with milk production performance in Sapera goats. The identified metabolites indicate coordinated alterations in lipid, central carbon, and amino acid metabolism and may serve as candidate biomarkers of lactation efficiency. These findings provide valuable insights for precision nutrition and metabolic management strategies in dairy goat production systems. Further validation using larger populations and longitudinal studies is required to confirm their predictive utility. 

Keywords: amino acid metabolism, biomarkers, dairy goats, lactation efficiency, lipid metabolism, metabolomics, milk production, Sapera goats.