Assessment of the Effects of 6 Standard Rodent Diets on Binge-Like and Voluntary Ethanol Consumption in Male C57BL/6J Mice

Abstract

Background In recent years much attention has been given to the lack of reproducibility in biomedical research, particularly in pre-clinical animal studies. This is a problem that also plagues the alcohol research field, particularly in consistent consumption in animal models of alcohol use disorders. One often overlooked factor that could affect reproducibility is the maintenance diet used in pre-clinical studies. Methods Herein, two well-established models of alcohol consumption, the “drinking in the dark” (DID) procedure and the continuous two-bottle choice paradigm (C2BC), were employed to determine the effects of diet on ethanol consumption. Male C57BL/6J were given one of six standard rodent-chow diets obtained from Purina LabDiet®, Inc. [St. Louis, MO; Prolab® RMH 3000] or Harlan Laboratories Inc. [Indianapolis, IN; Teklad Diets T.2916, T.2918, T.2920X, T.7912, or T.8940]. A separate group of animals were used to test dietary effects on ethanol pharmacokinetics and behavioral measures following intraperitoneal (IP) injections of various doses of ethanol. Results Mice eating Harlan diets T.2916 (H2916) and T.2920X (H2920) consumed significantly less ethanol and exhibited lower blood ethanol concentrations (BECs) during DID; however, during C2BC animals maintained on Harlan T.7912 (H7912) consumed more ethanol and had a higher ethanol preference than the other diet groups. Ethanol consumption levels did not stem from changes in alcohol pharmacokinetics, as a separate group of animals administered ethanol IP showed no difference in BECs. However, animals on Harlan diet T.2920X (H2920) were more sensitive to alcohol-induced locomotor activity in an open-field task. No diet dependent differences were seen in alcohol-induced sedation as measured with loss of righting reflex. Conclusions Although these data do not identify a specific mechanism, together they clearly show that the maintenance diet impacts ethanol consumption. It is incumbent upon the research community to consider the importance of describing nutritional information in methods, which may help decrease inter-laboratory reproducibility issues.

Modulation of Binge-like Ethanol Consumption by IL-10 Signaling in the Basolateral Amygdala

“…Mice were housed individually in an AALAC accredited vivarium maintained at 22° C with a reversed 12:12 hour light:dark cycle. Mice had ad libitum access to either Prolab® RMH 3000 (Purina LabDiet®; St. Louis, MO) or Teklad Diet® 2920X (Harlan Laboratories Inc.; Indianapolis, IN) and water, unless otherwise stated (Marshall et al 2015). Prior to any experimental procedures, animals were allotted at least a week to fully acclimate to the environment.…”

“…Binge drinking was modeled using a 4 day DID paradigm exactly as previously described (Marshall et al 2015; Rhodes et al 2005). Three hours into the dark cycle, home cage water bottles were removed and replaced with a single sipper tube container.…”

Behavioral and Neurobiological Consequences of Hedonic Feeding on Alcohol Drinking

“…Furthermore, the relationship between HFD consumption and alcohol intake could be dependent on the presence or absence of dietary manipulations while alcohol testing occurred [62], raising the necessity of testing alcohol drinking at multiple times following palatable diets exposure. A relatively recent study showed that alcohol drinking behavior in rodents could be differentially impacted in mice maintained on various standard rodents chows [63]. This study not only helps to address some of the discrepancies in the HFD-induced alterations in alcohol drinking mentioned above but also raises an important point on experimental design while assessing the impact of various dietary manipulations.…”

Alcohol intake in two different mouse drinking models after recovery from the lipopolysaccharide-induced sickness reaction

“…In addition, alcohol intake and preference of control mice were at a similar level to what was reported by Blednov et al (2011) for male C57BL/6J mice. Although these parameters were closely similar, many factors, including microbiological status of animals, rodent diet used (Marshall et al, 2015), and our use of individually ventilated cages can modulate consequences of LPS challenge, producing the lack of expected enhancing effect on alcohol intake. For example, a recent study indicates a strong impact of microbiological status of animal husbandry on the mouse immune system (Beura et al, 2016).…”