Atlantic Grey Seal Milk Shows Continuous Changes in Key Metabolites and Indicators of Metabolic Transition in Pups From Birth to Weaning

Mothers of the Atlantic grey seal, Halichoerus grypus , lactate for about 20 days, during which they do not feed and may have no access to water. Following weaning, depart sea leaving their pups unattended unfed up another 40 days. We are interested in how this lactation strategy supports pups’ rapid growth development while also preparing them long fast before independently going sea. report a broad spectrum metabolomic analysis whole milks these seals that reveals continuous changes key metabolites from birth weaning. Certain components exhibit abbreviated appearances at onset lactation, followed by rises or falls others until Riboflavin/Vitamin B2, hormone-related sterol sulfates, lactose, complex oligosaccharides all appear milk briefly after then disappear. Lipids associated with cellular signaling brain occur highest levels shortly birth, diminish. In contrast, other lipids Vitamin B6/pyridoxine steadily increase as weaning approaches. Overall, findings indicate an early transition carbohydrate fat-based energy metabolism establishment gut microbiomes pups, provisioning post-weaning fasting.