Metabolomics characteristics associated with milk yield and milk quality in sheep

Abstract

Standard milk tests include monitoring traits such as milk yield and quality. In addition to performing standard milk tests, it is now possible to evaluate metabolites that could act as potential biomarkers to determine milk properties. This study was conducted to identify the metabolomic parameters related to milk yield and quality in Awassi sheep. In our study, a total of 26 Awassi ewes, 13 with high milk yield and 13 with low milk yield, were examined. Liquid chromatography tandem mass spectrometry was used for metabolomic analysis. There was a statistically significant difference at different levels between the two groups in terms of aspartic acid, ornithine, anserine, and cystathionine levels (P<0.05 and P<0.01). A moderate negative correlation was determined between milk yield and aspartic acid (r=−0.63) and anserine (r=−0.52) levels (P<0.01). A significant negative correlation was found between lactose levels and lysine (r=−0.50), alpha-aminoadipic acid (r=−0.52), and hydroxylysine (r=−0.51) levels (P<0.01). The somatic cell count and alanine (r=0.49), aspartic acid (r=0.42), proline (r=0.42), alpha-aminoadipic acid (r=0.41), beta-alanine (r=0.43), and thiaproline (r=0.43) levels (P<0.05) showed positive correlation. Our results provide important insights into the metabolic events involved in sheep milk yield and milk quality which may guide further research to improve milk production and enhance the constituents of sheep milk.