Alterations in total carcass fat of female rats maintained on fat option diets

We recently reported that limited access fat option diets increased body adiposity without concomitant increases in total calorie consumption or in body weight in non-food-deprived male rats (1). The present study was designed to investigate the effect of these diets on body weight and body fat in female rats. Forty female Sprague-Dawley rats, were individually housed, matched for body weight, and divided into 4 groups. All groups had 24-hour access to chow (Laboratory Rodent Diet 5001, PMI Feeds, Inc., Richmond, IN) and tap water. In addition to the chow, Group A. was given no fat. Group B was given 2-hour access to fat (Crisco brand all vegetable shortening, Procter and Gamble, Cincinnati, OH) on M, W, and F, Group C was given 2-hour access to fat every day, and Group D was given 24-hour access to fat every day. At 8 weeks, all rats were sacrificed, and carcasses were later homogenized for body composition analysis. Total fat intake increased significantly with increasing availability of fat in a dose response manner (p<0.001). Neither body weights nor total calories consumed differed between groups. Total carcass fat was higher in Groups C and D, compared to Group A (p<0.001). Furthermore, total carcass fat in Groups C and D did not differ from each other even though total fat intakes did significantly differ between these two groups (p<0.001). These results show that fat option diets can induce increases in body adiposity that are independent of body weight or total calorie consumption in non-food-deprived female rats. 1) Rice, et al. (1995) Obesity Research 3: 372s.