Metabolic response of dolphins to short-term fasting reveals physiological changes that differ from the traditional fasting model

Dorian S Houser* (Corresponding Author), Davina Derous, Alex Douglas, David Lusseau

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

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Abstract

Bottlenose dolphins (Tursiops truncatus) typically feed on prey that are high in lipid and protein content and nearly devoid of carbohydrate, a dietary feature shared with other marine mammals. However, unlike fasted-adapted marine mammals that predictably incorporate fasting into their life history, dolphins feed intermittently throughout the day and are not believed to be fasting-adapted. To assess whether the physiological response to fasting in the dolphin shares features with or distinguishes them from those of fasting-adapted marine mammals, the plasma metabolomes of eight bottlenose dolphins were compared between post-absorptive and 24-hour fasted states. Increases in most identified free fatty acids and lipid metabolites and reductions in most amino acids and their metabolites were consistent with the upregulation of lipolysis and lipid oxidation and the downregulation of protein catabolism and synthesis. Consistent with a previously hypothesized diabetic-like fasting state, fasting was associated with elevated glucose and patterns of certain metabolites (e.g. citrate, cis-aconitate, myristoleic acid) indicative of lipid synthesis and glucose cycling to protect endogenous glucose from oxidative disposal. Pathway analysis predicted an upregulation of cytokines, decreased cell growth, and increased apoptosis including apoptosis of insulin-secreting β-cells. Metabolomic conditional mutual information networks were estimated for the post-absorptive and fasted states and 'topological modules' were estimated for each using the eigenvector approach to modularity network division. A Dynamic Network Marker indicative of a physiological shift toward a negative energy state was subsequently identified that has the potential conservation application of assessing energy state balance in at-risk wild dolphins.

Original languageEnglish
Article numberjeb238915
Number of pages16
JournalJournal of Experimental Biology
Volume224
Issue number9
Early online date25 Mar 2021
DOIs
Publication statusPublished - 4 May 2021

Keywords

  • Tursiops truncatus,
  • Dynamic network marker
  • Metabolome
  • Fasting
  • Dolphin

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