Consistency of meal patterns in laboratory rats

Area of Science:

• Animal behavior research
• Rodent models in scientific studies
• Nutritional and ingestive behavior analysis

Background:

• Meal pattern measures (bout length, bout number) offer detailed ingestive behavior insights.
• These measures are sensitive to experimental manipulation, inferring responses to stimuli or treatments.
• Research relies on the assumption of consistent rat meal patterns across light-dark cycles.

Purpose of the Study:

• To critically evaluate the consistency of meal patterns in Sprague-Dawley and Fisher-344 rats.
• To determine if individual rat meal patterns are stable across consecutive light-dark cycles.
• To inform the design and sample size considerations for studies using meal pattern analysis.

Main Methods:

• Monitored meal patterns in Sprague-Dawley and Fisher-344 rats over 10 consecutive light-dark cycles.
• Measured total daily intake, night bout duration, night bout number, and licks per night bout.
• Analyzed the distribution of feeding and drinking activity throughout each night.

Main Results:

• Ingestive measures were highly consistent over time in all Sprague-Dawley rats.
• Ingestive measures were consistent in only a minority of Fisher-344 rats.
• Sprague-Dawleys exhibited consistent lights-off and lights-on activity peaks, unlike most Fisher-344s.

Conclusions:

• Rat strains exhibit significant differences in meal pattern consistency.
• Fisher-344 rats demonstrate less consistent ingestive behavior compared to Sprague-Dawley rats.
• Strain-specific consistency should be considered in comparative meal pattern studies.