Effects of Environmental Conditions on Activity, Feeding, and Body Weight in Male and Female Adolescent Rats

摘要

Excessive body weight, particularly in children, is a growing concern in the United States and around the world. Body weight is affected by feeding behavior and physical activity. Environmental factors affect feeding behaviors and physical activity; therefore, environment is an important influence on body weight. Three separate experiments examined the behavioral effects of environmental enrichments on feeding, activity, and body weight. For the first two experiments, subjects were 36 adolescent, male (Experiment I) and 36 adolescent female (Experiment II) Sprague-Dawley rats. Experiment III examined the behavioral effects of enrichment on 24 male and 24 female adolescent Sprague-Dawley rats. Responses to environmental enrichment included: body weight (BW), Body Mass Index score (BMI), Lee Index score (LI), consumption of standard rat chow, Oreo cookies, and Lays potato chips, and physical activity (PA) in the animal's home cage (HCA) and in an open field (OF). The major findings from these experiments were that: (1) environmental enrichment results in lower body weight, (2) environmental enrichment decreased food consumption, especially the bland foods, (3) animals housed in environmental enrichment were less active in novel surroundings and were more active in their home cages compared to animals in non-enriched housing, and (4) males and females responded similarly to environmental enrichment with regard to body weight, feeding, and physical activity. These findings highlight the importance of the effects of housing conditions in animal research and suggest ways to help control body weight in animals and humans.