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Functional loss of ketogenesis in odontocete cetaceans

Michael J Wolfgang1,2, Joseph Choi1, Susanna Scafidi3

  • 1Department of Biological Chemistry, The Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.

The Journal of Experimental Biology
|October 4, 2021
PubMed

Insights

Odontocete cetaceans cannot produce ketone bodies due to genetic mutations. Biochemical analysis confirms a lack of ketogenesis, suggesting a different metabolic role in these marine mammals.

Area of Science:

  • Biochemistry
  • Genomics
  • Marine Mammal Metabolism

Background:

  • Odontocete cetaceans possess genomic mutations in critical ketogenesis genes.
  • Previous genome sequencing suggested a lack of ketogenesis in these animals.

Purpose of the Study:

  • To biochemically validate the absence of ketogenesis in odontocetes.
  • To investigate the metabolic adaptations related to fatty acid oxidation and ketone body utilization in cetaceans.

Main Methods:

  • Biochemical analysis of liver tissues from multiple odontocete species.
  • Measurement of hepatic β-hydroxybutyrate (βHB) and acylcarnitines.
  • Single molecule, real-time next-generation sequencing of liver and brain RNA from Tursiops truncatus.

Main Results:

  • Odontocete liver tissues showed no significant β-hydroxybutyrate (βHB) or its carnitine ester.
  • Liver tissue displayed reduced long-chain acylcarnitines and increased odd-chain acylcarnitines.
  • Succinyl-CoA transferase, essential for acetoacetate metabolism, is expressed in the nervous system of Tursiops truncatus.

Conclusions:

  • Odontocete cetaceans have lost the capacity for ketogenesis.
  • Ketogenesis in these species may serve a hepatocentric coenzyme A recycling function rather than a systemic bioenergetic role.
  • This contrasts with the established role of ketogenesis in humans and other mammals.
Keywords:
DolphinFastingKetogenic diet

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