Differences in mitochondrial DNA inheritance and function align with body conformation in genetically lean and fat...

Area of Science:

• Animal Science
• Metabolic Physiology
• Genetics

Background:

• Body weight and adiposity result from energy intake, expenditure, and deposition.
• Differences in appetite-regulating peptides exist between genetically lean and fat sheep lines.
• The mechanisms driving these body composition differences remain unclear.

Purpose of the Study:

• To investigate if differences in postprandial thermogenesis are associated with body composition variations in lean and fat sheep.
• To explore the role of adipose tissue and skeletal muscle thermogenesis.
• To examine potential links with mitochondrial DNA haplotypes.

Main Methods:

• Measurement of postprandial temperature in retroperitoneal adipose tissue and vastus lateralis muscle.
• Intracerebroventricular (ICV) cannulation and meal feeding protocols.
• Mitochondrial genome sequencing and UCP1/UCP3 mRNA expression analysis.

Main Results:

• Lean sheep had higher body weight but lower fat mass compared to fat sheep.
• Postprandial thermogenesis was significantly greater in the retroperitoneal adipose tissue of lean sheep.
• Lean sheep showed increased UCP1 mRNA expression in retroperitoneal fat; mitochondrial DNA sequencing revealed distinct haplotypes.

Conclusions:

• Differences in body composition between lean and fat sheep are associated with enhanced thermogenesis in adipose tissue.
• Thermogenic variations may be linked to specific mitochondrial DNA haplotypes, indicating a maternal genetic influence.