Ambient temperature and food costs: effects on behavior patterns in rats

Area of Science:

• Animal behavior
• Environmental physiology
• Nutritional science

Background:

• Understanding how environmental factors and food accessibility influence animal behavior is crucial.
• Rodent models are frequently used to study energy balance and behavioral responses to environmental stressors.

Purpose of the Study:

• To investigate the effects of ambient temperature and food cost on feeding, drinking, nesting, and wheel running behaviors in rats.
• To determine how the cost of initiating meals versus the cost of food pellets affects these behaviors at different temperatures.

Main Methods:

• Continuous recording of eating, drinking, wheel running, and nesting in rats under controlled conditions.
• Manipulation of two distinct food costs (initiation and per-pellet) at two ambient temperatures (24°C and 0°C).

Main Results:

• Cold exposure (0°C) doubled food and water intake and increased nesting time over twofold compared to room temperature (24°C).
• Wheel running behavior remained unaffected by temperature or food cost.
• Increasing the cost of initiating meals affected meal frequency and size but not total intake or feeding time.
• Increasing the cost of food pellets increased feeding time but decreased total daily food intake, with a more pronounced effect at 0°C.

Conclusions:

• Ambient temperature significantly impacts energy intake and expenditure behaviors, with cold promoting greater consumption and nesting.
• Food cost, particularly the price per pellet, is a critical factor in regulating daily food intake, especially under cold stress.
• Rats in the cold did not sufficiently increase feeding duration to compensate for higher pellet costs, leading to reduced intake.