Milk proteomic analysis reveals differentially expressed proteins in high-yielding and low-yielding Guanzhong dairy goats at peak lactation.

The aim of this experiment was to investigate the differential proteomic characteristics of milk from high- and low-yielding Guanzhong dairy goats during the peak lactation period under the same feeding conditions. Nine Guanzhong dairy goats with high yield (H: 3.5 ± 0.17 kg/d) and nine with low yield (L:1.2 ± 0.25 kg/d) were selected for milk proteomic analysis using tandem mass tag technology. A total of 78 differentially expressed proteins were identified. Compared with L, 50 proteins including HK3, HSPB1 and ANXA2 were significantly upregulated in H milk, while 28 proteins including LALBA and XDH were significantly downregulated. Bioinformatics analysis of the differentially expressed proteins showed that galactose metabolism, purine metabolism, glycolysis/gluconeogenesis, MAPK signaling pathway, regulation of actin cytoskeleton and other pathways were closely related to milk yield. HK3, HSPB1, ANXA2, LALBA and XDH were important candidate proteins associated with the milk production characteristics of Guanzhong dairy goats. Our data provide relevant biomarkers and a theoretical basis for improving milk production in Guanzhong dairy goats.

Comparative analysis of different metabolites in semen of Guanzhong dairy goats with different motility rates.

In order to explore the different metabolites of buck semen with different motility stored at 4 °C, the semen of bucks was collected by artificial vagina. The collected semen was divided into high motility group and low motility group after treatment, with 6 replicates set for each group. The semen metabolites of high motility group and low motility group were detected by Liquid Chromatography-Mass Spectrometry (LC-MS). The results showed that 101 different metabolites were detected in the high and low motility groups of bucks, of which 48 metabolites were significantly up-regulated (P < 0.05) and 53 metabolites were significantly down regulated (P < 0.05). Most of these metabolites belonged to lipids and lipid-like molecules, organic acids and their derivatives, and organic oxygen compounds, which were mainly related to energy metabolism. According to the functional enrichment analysis of the former differential metabolites in KEGG database, the top 20 most representative metabolic pathways were detected, among which the glycerophospholipid metabolic pathways changed significantly. From the perspective of metabolomics, this study revealed the differences of metabolites and characteristic compounds of semen with different motility of bucks under low temperature preservation, which provided a scientific basis for the preservation and utilization of semen of Guanzhong dairy goats in the future.