Metabolomic changes following PMSG-induced estrus synchronization in Qianbei Ma goats

The Qianbei Ma goat breed is unique to the mountainous areas of the Guizhou Plateau in China. Herein, synchronized estrus and artificial insemination techniques were used to investigate the changes in follicular development, hormone levels, and pregnancy rates in Qianbei Ma goats after pregnant mare serum gonadotropin (PMSG) synchronized estrus. We selected a control group treated with controlled internal drug release (CIDR) + prostaglandin (PG) and an experimental group treated with CIDR + PG + 250 IU of PMSG (n = 6 per group). Twenty-four hours after PMSG injection, serum samples were collected from goats in each group and analyzed using non-targeted metabolomics technology to evaluate PMSG-induced metabolic changes. Multivariate statistical methods, including principal component analysis (PCA), partial least squares discriminant analysis (PLSDA), and orthogonal partial least squares discriminant analysis (OPLSDA), were used for data analysis. A total of 58 differentially abundant metabolites were screened, including 49 in the positive ion mode and nine in the negative ion mode. The levels of phytic acid (PA), urolithin B (UB) and KDdiA-PC increased after PMSG treatment, whereas those of bilirubin, cyclic adenosine monophosphate (cAMP), and carnosine decreased. In addition, there were significant differences in inositol phosphate metabolism between the control and PMSG-treated groups. Further in vitro experiments showed that UB upregulated steroid hormone synthesis-related genes and proteins in goat ovarian granulosa cells and promoted estradiol (E2) levels in culture supernatant, though the regulatory mechanism requires further study. This study provides insights into the metabolic characteristics of Qianbei Ma goats following PMSG treatment.