Correlated responses in body composition based on selection for different indicator traits in mice

Area of Science:

• Animal genetics
• Body composition research
• Metabolic studies

Background:

• Understanding genetic control of body composition is crucial for metabolic health.
• Previous studies suggest genetic correlations between different fat depots.

Purpose of the Study:

• To investigate correlated responses in whole-body composition in mice selected for epididymal fat pad weight.
• To examine the genetic basis of fat deposition and lean mass regulation.

Main Methods:

• Selection of mice lines for high (HF) or low (LF) epididymal fat pad weight and high (HL) or low (LL) hind carcass weight over 12 generations.
• Analysis of body composition traits including fat percentage, protein, water, lean body mass, and body weight.

Main Results:

• HF and LF lines showed significant divergence in body fat percentage and subcutaneous fat.
• Epididymal fat pad weight changes were disproportionate to overall fat changes in HF and LF lines.
• Protein, fat, and water percentages showed negative correlated responses to epididymal fat selection, while lean body mass, body weight, and length showed positive responses.

Conclusions:

• Despite high genetic correlations between fat depots, localized control of lipogenesis and lipolysis exists in mice.
• Additive genetic variances for fat-free protein and ash percentages are likely low, or their genetic correlations with selection criteria are low.