Metabolomic differences in early and late lactation first-parity gilts

Abstract Text: Investigating the metabolome provides the evaluation of all cellular processes occuring while accounting for environmental influence and may provide additional information for selection criteria to fully evolve. Blood samples and body condition measurements were acquired from 68, first-parity gilts at post-farrowing and weaning. Twenty gilts were retrospectively selected for similar (P ≥ 0.4475) number of piglets born and nursed, and similar (P ≥ 0.3141) body condition traits post-farrowing, yet exhibited minimal or extreme change (P ≤ 0.0094) in body weight (-8.6 ± 1.48 kg and -26.1 ± 1.90 kg, respectively) and backfat thickness (-1.3 ± 0.67 mm and -4.7 ± 0.86 mm, respectively) from post-farrowing to weaning.  The plasma metabolome at post-farrowing and weaning was investigated using non-targeted UPLC-MS and GC-MS. Retention time alignment and feature detection and matching were performed in XCMS using raw spectral data.  Grouping of features yielded approximately 700 compounds from each of the two techniques. An ANOVA was performed on each detected compound in R for time of collection, body condition change, and the interaction, followed by a false discovery correction. No differences were detected for the interaction and only two compounds were different for extreme versus minimal body condition change. However, several compound differences (P ≤ 0.10) were identified between post-farrowing and weaning. Thirty-two of the 84 significant compounds detected by UPLC-MS had at least a fold change of ±1.0 while only 18 compounds had a fold change of ±0.6 for the significant GC-MS compounds.  Annotation of several compounds implicated various metabolic pathways.  Unsurprisingly, creatinine was greater at weaning (P = 0.0224) and others have reported increased serum concentrations of creatinine in response to body weight loss.  A liver metabolite associated with protein catabolism was also greater (P = 0.0007) at weaning.  Phospholipid compounds were greater (P ≤ 0.0347) at weaning.  Two putative inositol-related compounds were greater (P ≤ 0.0236) at weaning. Inositol compounds have been implicated in second messenger signalling in the brain while others may exert insulin-like effects. A fructose epimer was greater (P =0.0731) at weaning and has several physiologically relevant traits including glucose suppression, ROS scavenging, and neuroprotective activity. Lactation is a metabolically demanding event that may have unfavorable impacts on sow lifetime potential. Plasma biomarkers may prove useful as nutraceuticals or aide in metabolome-GWAS studies to ascertain genetic points of interest relevant to body condition loss during lactation. USDA is an equal opportunity provider and employer.

Keywords: GC-MS, Gilts, Lactation, LC-MS, Metabolomics