Drinking spout orifice size affects licking behavior in inbred mice

Area of Science:

• Animal Behavior
• Neuroscience
• Physiology

Background:

• Licking behavior is a fundamental aspect of ingestive behavior in rodents.
• Standardized experimental conditions are essential for reliable results in animal studies.

Purpose of the Study:

• To investigate the influence of drinking spout orifice size on mouse licking behavior.
• To determine how orifice size affects fluid intake and licking patterns.
• To assess the implications for experimental design in ingestive behavior research.

Main Methods:

• Utilized a lickometer to record licking behavior in four inbred mouse strains (C57BL/6J, SWR/J, 129P3/J, DBA/2J).
• Compared licking patterns and fluid intake using drinking spouts with large (2.7 mm) and small (1.5 mm) orifices.
• Analyzed licking bursts, frequency, and lick volume across different experimental conditions.

Main Results:

• Mice exhibited twice as many licks from small orifices but maintained similar total intake volume.
• Fluid intake was regulated by adjusting lick volume (0.55 µL/lick for small, 1.15 µL/lick for large orifices).
• Smaller orifices increased licking responsiveness and trial counts in brief access tests, suggesting differences in reinforcement efficacy.

Conclusions:

• Drinking spout orifice size is a critical variable that significantly influences licking behavior and fluid intake in mice.
• Experimental control over orifice size is necessary to avoid confounding results in studies of ingestive behavior.
• Findings highlight the importance of standardizing lickometer spout dimensions for reproducible research.