Impact of Two Different Rodent Diets on Rat Dam Voluntary Ethanol Consumption, Serum Ethanol Concentrations and Pregnancy Outcome Measures
23 Pages Posted: 13 Jul 2022
Recent studies report varying levels of voluntary ethanol consumption by rodents maintained on different commercially available diets. Here, we compared the impact of the Envigo 2920X extruded diet used in our lab with an isocalorically equivalent PicoLab 5LOD pelleted diet used in recent alcohol consumption studies. Long-Evans rat dams maintained on 5LOD diet consumed 35% more ethanol during the daily four-hour drinking sessions compared to dams on 2920X diet. This difference did not affect litter size. However, rat dams consuming 5LOD diet gained significantly less weight during pregnancy, but pup birth weight was significantly higher. Cumulative ethanol consumption was not different between diets during the first two hours of a daily four-hour drinking session, but was significantly increased for 5LOD rats at the end of the third and fourth hours. The mean serum ethanol concentration in 5LOD dams after the first two hours of drinking was 42.0 + 3.0 mg/dL, significantly greater than the 21.8 + 3.0 mg/dL in 2920X dams. Further, ethanol consumption at the two-hour blood sampling time point was more variable in 2920X dams compared to 5LOD dams. An in vitro analysis mixing each powdered diet with 5% ethanol in acidified saline revealed that a 2920X diet suspension adsorbed more aqueous medium than 5LOD diet suspension. Total ethanol recovery from the aqueous phase of the 5LOD mixture was nearly twice the amount recovered from the 2920X mixture. We conclude that the extrusion process used to manufacture 2920X diet expands more in aqueous medium than 5LOD diet, increasing the adsorption of water and ethanol. This, in turn, reduces or delays the amount of ethanol available for gastric absorption, thus decreasing serum ethanol concentration to a greater extent than would be predicted from ethanol consumption data.
Funding Information: This research was supported by NIH NIAAA 1 P50 AA0022534.
Declaration of Interests: The authors have no conflict of interests to declare.
Ethical Approval Statement: The University of New Mexico Health Sciences Center (UNM HSC) Institutional Animal Care and Use Committee approved all of the procedures involving the use of live rats. All experiments were in compliance with the ARRIVE guidelines.
Keywords: Ethanol Consumption, Prenatal Alcohol Exposure, Rodent Diet
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