104 Investigation Into the Serum Metabolome and Identification of Biomarkers for Early Detection of Postpartum Dysgalactia Syndrome in Sows

Abstract

Abstract The swine industry is comprised of highly productive and healthy sows capable of weaning large litters for multiple parities. This prolificacy has resulted in greater metabolic demands during lactation due to increased capacity and demand for milk production. Modern sows also have increased genetic merit for leanness which has altered the amount of energy reserves available for mobilization to support the growing demands of lactation. Together, these factors may render modern sows more vulnerable to metabolic disorders such as postpartum dysgalactia syndrome (PDS) or mastitis-metritis-agalactia (MMA). Described as a metabolic and hormonal disturbance, a hallmark of PDS is a reduction (dysgalactia) or cessation (agalactia) in milk production after farrowing. Insufficient milk production by the sow leads to increased piglet mortality, causing substantial economic losses, reducing sow welfare, and resulting in premature removal of sows from the herd. Our prior reports have shown differences in circulating analytes and inflammatory markers between healthy sows and sows affected with PDS following parturition. However, very few differences were observed before clinical signs were evident, rendering these analytes ineffective in early detection of PDS. Therefore, the objective of the current study was to utilize gas-chromatography mass-spectrometry (GC-MS) to further characterize the biological conditions and metabolic pathways contributing to PDS in sows. Through this, we aimed to identify small molecules in circulation with the potential for use as a biomarker to aid in early detection of PDS. To accomplish this, a study was conducted on a commercial sow farm with a history of poor lactation performance. Sows (n = 36) with clinical signs of PDS were matched by parity and day of lactation with healthy control (CON) sows (n = 36) that remained unaffected. Blood samples collected at farrowing (timepoint 1) and at onset of clinical PDS (timepoint 2) were subjected to GC-MS. As expected, piglets from PDS sows had decreased (P < 0.01) average daily gain and greater mortality than piglets from control sows. Following GC-MS analysis, 16 and 41 molecules were identified as significantly different between CON and PDS sows at timepoint 1 and timepoint 2, respectively (P < 0.10). A difference in 2-hydroxybutyric acid, an early marker for insulin resistance and impaired glucose regulation, was observed at timepoint 1. Additional molecules identified as significantly different at timepoint 1 include D-pinitol, D-glucose, inositol (3,6)-bisphosphate, and others. These differentially abundant molecules at timepoint 1 represent potential biomarkers for early detection of PDS.