Rat strain-specific differences in alcohol intake following patterned feeding of a palatable diet

29.5 million people aged 12 and older met the diagnostic criteria for alcohol use disorder (AUD) in the United States in 2021, which presents a significant social and economic burden to the modern society. Impaired nutritional status has been frequently documented in patients with AUDs and could contribute to escalated alcohol consumption and behavioral impairments commonly observed in AUD. Interestingly, increased highly palatable food intake during recovery has been reported in patients with AUD, suggesting the importance of understanding the relationship between palatable food and problematic alcohol drinking. We have previously shown that patterned feeding of a palatable diet attenuated alcohol drinking in Long Evans rats. Present study evaluated the impact of patterned feeding on high and low alcohol drinking. Individually housed male high drinking (P), moderate drinking (Long Evans), and low drinking (Wistar) rats received intermittent access (24 hours, Tuesdays, and Thursdays) to a nutritionally complete high fat diet (Int-HFD) or standard chow (controls). Normal chow and water were available ad libitum to all groups of rats. Intermittent HFD access induced a feeding pattern in which Int-HFD group of rats escalated their caloric intake on Tuesdays and Thursdays. Two weeks of Int-HFD pre-exposure preceded any alcohol access, after which all rats were given unsweetened alcohol (20% v/v) in their home cages via a two-bottle choice paradigm of voluntary alcohol drinking. Alcohol was available for 24 hours on chow only days (Mondays, Wednesdays, Fridays) while Int-HFD feeding continued. Long Evans rats receiving Int-HFD displayed a significant (p<0.05) ~50% reduction in alcohol drinking when compared to controls. The Int-HFD group of P rats also reduced their alcohol intake significantly (p<0.05), ~20%, when to the respective chow controls. Interestingly, alcohol drinking in Wistar rats was not significantly affected (p>0.05) by intermittent HFD exposure. These data highlight rat strain specific differences in alcohol intake following patterned feeding of a palatable diet and identify Long Evans as an ideal model to evaluate impact of palatable diet on alcohol drinking.