Metabolic responses to short- and long-term guar gum consumption were studied in adolescent and adult rats. For the Song-term study, male adolescent rats were divided into four groups (n = 60/group) and fed guar gum, cellulose, or bran diet for 67 weeks. Metabolic studies (food–water intake, feces–urine output, body weight, carbohydrate tolerance) were performed eight times during the 67 weeks. The guar gum group consumed less diet throughout the entire study and gained less weight over the first 20 weeks compared with the cellulose and bran groups. A second bran-fed group was food restricted over the first 20 weeks to match the reduced weight gain of the guar gum group and then fed ad libitum. Reduced plasma glucose excursions were measured for only the guar gum group after both fibre-free glucose and sucrose challenges at weeks 6, 12, and 18; from 24 to 64 weeks all four groups had similar glucose tolerance responses. Twenty-four hour urinary glucose excretion was similar during all eight metabolic studies up to 64 weeks for guar gum and cellulose groups. In the short-term study, male adolescent (200 g; n = 10/group) and adult (630 g; n = 15/group) rats were divided into five and four groups, respectively, and fed guar gum, guar by-product (GBP), cellulose, or bran diet for 6 weeks. A metabolic study was performed during the 6th week. Adolescent rats fed guar gum or GBP diets gained less weight than the cellulose group; only the guar gum group displayed improved carbohydrate tolerance. Adult rats had similar weight gain and carbohydrate tolerance responses to the four diets. Both adolescent and adult rats fed GBP had significantly reduced 24-h urinary glucose excretion. These studies suggest that adolescent rats respond to guar gum consumption with reduced body weight gain and improved carbohydrate tolerance and demonstrate that these responses are lost or absent in adult rats.
Adolescent Rats Find Repeated Δ9-THC Less Aversive Than Adult Rats but Display Greater Residual Cognitive Deficits and Changes in Hippocampal Protein Expression Following Exposure
