DIFFERENTIAL ALCOHOL CONSUMPTION IN FOOD-DEPRIVED COMPETING RATS

Many studies have been conducted to further the understanding of factors influencing alcohol consumption. The purpose of the current study was to investigate: (1)The competitive behavior of food-deprived rats housed as fixed pairs and competing for food. (2)The correlation between the animal's specific competition score, within its specific dyad, and its individual chronic alcohol consumption, when given a free access to 10% (w/v) alcohol or water. (3)Differential chronic alcohol consumption of winners and losers of rat dyads. (4)The effect of alcohol withdrawal on the competitive behavior of animals.
Forty male rats were used in this study; thirty animals composed 15 fixed dyads, and 10 animals served as a control. Each pair of food-deprived animals was tested in the hone cage for food competition. Eleven out of 15 dyads established a stable dominance hierarchy, winners and losers. These animals were then housed individually and had free access to 10% (w/v) alcohol and water for 4 hours a day over a period of 14 days. Daily alcohol consumption was recorded for each subject. It was found that the total amount of alcohol consumed by winners was significantly higher than that of losers (Winners, 39.2+2.3 ml vs Losers, 31.8±2.27ml, psO.05). Further, there was a strong positive correlation between the individual animal's alcohol consumption and its average competition score, that was evident for both winners (r-0.91) and losers (r-0.85). Alcohol withdrawal failed to significantly change the social status of the animals, only two animals switched rank position. However, chronic alcohol consumption proved deleterious effects on the liver. Animals were sacrificed on the first day of alcohol withdrawal had livers with elevated weight (% of body weight), (Liver weight %, Day-1 Withdrawal, 3.6±0.1 vs Control, 3.2+0.07, p50.01).
It is concluded that animals housed in a social environment could establish a stable dominance hierarchy. Highly competitive animals consumed a significantly higher amount of alcohol than low competitors. Further, the amount of alcohol consumed by the animal, winner or loser, positively correlated with the animal's specific competition score.