Cold acclimation in food-restricted rats

Area of Science:

• Physiology
• Metabolism
• Thermogenesis

Background:

• Cold acclimation influences energy balance and body weight regulation.
• Brown adipose tissue (BAT) plays a crucial role in non-shivering thermogenesis.
• The relationship between food intake, body weight, and BAT adaptation during cold exposure requires further elucidation.

Purpose of the Study:

• To investigate the effects of cold acclimation on food intake, body weight, and interscapular brown adipose tissue (IBAT) mass and composition in rats.
• To determine whether increased food intake accompanying cold exposure is necessary for BAT-mediated non-shivering thermogenesis.

Main Methods:

• Rats were exposed to 6°C with either ad libitum feeding or food restriction, and compared to controls at thermoneutrality.
• Measurements included food intake, body weight, and IBAT mass and composition.
• Analysis focused on changes after 3 weeks of cold exposure.

Main Results:

• Cold acclimation with ad libitum food intake increased food intake and prevented body weight gain, alongside increased IBAT mass and altered composition.
• Cold acclimation with food restriction led to progressive body weight decrease, with IBAT mass increasing after 3 weeks and compositional changes occurring earlier.
• IBAT mass increased in both cold-exposed groups, irrespective of feeding regimen.

Conclusions:

• Cold acclimation significantly impacts food intake, body weight, and BAT adaptation.
• Increased food intake during cold acclimation is not a prerequisite for the development of non-shivering thermogenesis in BAT.
• BAT can adapt to cold temperatures even under conditions of restricted food availability.