Impact of Patterned Feeding of a Palatable Diet on Chronic Alcohol Drinking and Anxiety‐Like Behavior in Alcohol‐Preferring Rats

Abstract

Previous studies from our lab have shown that patterned feeding of a palatable diet (PD; moderately high in fat) significantly reduced alcohol drinking in rats. In these studies, PD and alcohol were never presented concurrently, and alcohol testing occurred on non‐palatable diet access days (Mon, Wed, and Fri). Therefore, it is unclear if the patterned feeding of a PD would produce similar effects when alcohol is presented simultaneously in a chronic access paradigm. The present study examined the impact of patterned feeding of a PD on chronic alcohol drinking and anxiety‐like behavior in male and female alcohol‐preferring P‐rats. P‐rats (n=6/group) were allowed to drink alcohol 10% v/v in their home cages for six weeks, along with intermittent (24 hrs twice a week) PD access on Tuesdays and Thursdays. Control rats received chow on Tuesdays and Thursdays along with chronic alcohol access. Anxiety‐like behavior (Light/Dark box and Open Field testing) was assessed during acute alcohol withdrawal (24hr following alcohol access) on non‐PD access days. Water and chow were available ad libitum to all groups. Male and female data were analyzed together and separately. There were no significant between‐group differences in baseline alcohol drinking in chow and PD groups of rats. Overall, in cage alcohol drinking significantly (p<0.0001) increased with time, an effect evident in both male (p<0.001) and female (p<0.01) group of rats. Following initiation of patterned feeding, overall, a strong trend (p=0.07; main effect of treatment) towards reduced alcohol drinking was observed in rats receiving intermittent PD exposure compared to the chow controls. Further analysis revealed that alcohol drinking was only significantly reduced in males (p=0.0096), whereas alcohol drinking was identical in the female group of rats receiving PD compared to their chow controls. Similar effects were observed when alcohol drinking data on PD access days (Tuesdays and Thursdays) were analyzed, documenting reduced alcohol drinking when PD was concurrently available. Anxiety‐like behavior under acute alcohol deprivation conditions was not affected by patterned feeding of PD. Collectively, these data provide the effectiveness of patterned feeding in reducing chronic alcohol drinking and highlight striking sex differences in the ability of patterned feeding of PD in regulating these effects.