Influence of food availability on water and alcohol consumption in murine models

Alcohol use disorder remains a global issue. Thus, understanding the factors that contribute to alcohol abuse, including how food availability can influence drinking behavior, is critical.

Female and male C57Bl/6 and Swiss mice underwent a two-bottle choice Intermittent Overnight Drinking (IOD) protocol consisting of 12 sessions on alternate nights, three times per week, using lickometer devices. Mice had access to two bottles, containing either water or 10% ethanol, for 16 hours, starting 2 hours before the dark cycle. Animals were initially assigned to two groups: one with access to water, ethanol, and standard rodent chow (FOOD group), and another with access only to water and ethanol (NFOOD group). After six sessions, half of the mice in the second group were reassigned to a new group with delayed access to chow (NFOOD-FOOD group).

Food availability led to increased drinking, but the modulation was liquid dependent for each strain. The presence of food primarily increased ethanol intake in C57Bl/6 mice, while it enhanced water intake in Swiss mice. Microstructure analysis revealed that food heightened ethanol licks in C57Bl/6 mice, whereas it elevated water licks in Swiss mice, without altering numbers of bouts. Additionally, overnight analysis showed that C57Bl/6 mice with access to food had a peak in ethanol licks between 20:00 and 22:00, while Swiss mice exhibited an increase in water licks starting at 20:00 to 2:00, highlighting a strain-specific response to the dark cycle.

This study provides normative data on the temporal patterns of water and ethanol consumption in C57Bl/6 and Swiss female and male mice, contributing valuable insights to the field of voluntary drinking behaviors in murine models.