Blood plasma metabolomic changes in pigs from pre-weaning to post-weaning

Weaning piglets involves a dietary shift from sows' milk to solid, cereal-based feed, requiring a physiological change in digestion and metabolism. This study aimed to identify key metabolites and metabolic pathways in the same pigs that differed between suckling and weaned phases. In addition to suckling the sow, piglets had access to supplementary milk from birth, and creep feed from 14 days pre-weaning, and were weaned at d27 of age. Post-weaning feed was supplied ad libitum. Pigs were blood-sampled at d26 and d54, and were selected to be within 1SD of the batch mean weight at d26. Non-targeted Gas Chromatography-Mass Spectrometry (GCMS) techniques were used to identify metabolites from blood plasma samples, and differences between the pre- and post-weaning metabolome were analyzed using MetaboAnalyst (v6.0). The pig plasma metabolome 28 days post-weaning compared to pre-weaning showed an increase in carbohydrate metabolism at the expense of fat metabolism, and greater relative abundance of most amino acids. The exceptions were lysine and valine, which were identified in lower relative abundance in plasma post-weaning, indicating further research into lysine and branched-chain amino acid requirements may be warranted.