Evaluation of Effects of Food Addiction in Rat Model: An Experimental Study

Abstract

Introduction: Palatable foods have potent reinforcing effects that are mediated, partly, by an abrupt augmentation of dopaminergic neurotransmitters in the brain’s reward pathways. Food addiction to highly palatable foods contributes to the increasing prevalence of obesity. Aim: To evaluate the effect of food addiction on neurobehavioural parameters and the Behavioral Satiety Sequence (BSS) during restriction to a highly palatable diet in a food addiction rat model. Materials and Methods: The experimental study was conducted in the Pharmacology Department at PSG Institute of Medical Sciences and Research, Coimbatore, Tamil Nadu, India from April 2018 to January 2019. The study included six animals out of 28 female Sprague Dawley rats aged approximately 10 weeks and weighing 180-220 g were allocated to the control group and were fed a Standard Chow diet (SC) throughout the study. Twenty-two animals (induction group) were exposed to free choice between SC and a highly palatable Cafeteria Diet (CD), a mix of equal amounts of Bounty®, Snickers®, Mars®, and Milka® chocolate made into homogenous food pellets. After six weeks, 12 animals were randomly selected to have restricted access to the CD diet with free access to SC, while the rest continued to receive a free choice between the two diets for two weeks. Central Nervous System (CNS) parameters, BSS, 24-hour food intake, and body weight were recorded. Results: A significant decrease of 25.4 seconds (18.27%) in the mean time the CD restricted group stayed on the rotarod (113.6±8.31) seconds. and a reduced locomotor activity score of 46.92 (20.94%) in the CD access group in the actophotometer (177.08±5.29) compared to SC was noted. In the open field test, the CD restricted group demonstrated a 47.33% increase in grooming (12.0±1.11) and a 30% lower number of central squares crossed (2.80±0.57). In the Elevated Plus Maze (EPM), the time spent in the open arm (15.00±8.10) was statistically lower (p=0.045). No statistically significant difference between groups was recorded in the forced swim or tail suspension tests. Disruption of the BSS in varying dimensions was apparent in both CD groups. Conclusion: The study has shown that anxiety and altered feeding behaviour were evident in the CD restricted rats in the food addiction model.

Keywords

• behavioural satiety sequence
• body weight
• cafeteria diet
• food intake
• highly palatable diet
• neurobehavioural