Short-Term Exposure of Bisphenol A Deteriorates the Quality of Rabbit Milk by Impairing Milk Fat Synthesis.

This study aimed to investigate the effects of short-term exposure of Bisphenol A (BPA) on the growth and lactation performance, blood parameters, and milk composition of lactating rabbits and explore its potential molecular mechanisms. Eight lactating rabbits with similar body weight were selected and randomly divided into the experimental group (BPA) and the control group (Ctrl). The group BPA was orally administered 80 mg/kg/day BPA on the 15th day postpartum, while the group Ctrl received a corresponding volume of vehicle. Blood and milk samples were collected after 7 days treatment. The results showed that short-term ingestion of BPA did not obviously alter the body weight, feed intake, or milk yield of the lactating rabbits. ELISA assays indicated that BPA did not significantly affect the plasma levels of glutathione peroxidase (GSH-Px), superoxide dismutase (SOD), creatinine (CRE), alanine aminotransferase (ALT), aspartate aminotransferase (AST), uric acid (UA), and urea. Utilizing untargeted metabolomics, we first depicted the metabolomic profile of rabbit milk, and identified 277 differential metabolites (DMs), with 141 DMs upregulated (e.g., BPA, and its metabolites including Cetirizine N-oxide) and 136 DMs downregulated (e.g., Oleamide, Tiglic acid, PC O-38:4) in the group BPA. KEGG analysis revealed that the DMs were mainly enriched in pathways comprising fatty acid metabolism, fatty acid degradation, and phosphatidylinositol signaling system, emphasizing the effect of BPA on milk fat metabolism. Hence, we established the BPA-induced MAC-T model, and the results showed that BPA significantly reduced cell viability and impacted lipid synthesis, as evidenced by reduced lipid droplets (BODIPY and Oil Red O staining) and decreased expression of genes related to lipid synthesis (e.g., , , ). In summary, we first drew the metabolomic profile of rabbit milk and confirmed that short-term BPA exposure impacted mammary lipid synthesis, thereby reducing the milk quality of lactating rabbits and providing fundamental data for resolving the toxicological mechanisms of BPA on mammal lactation.