DOSAGE EFFECTS OF CHROMIUM PICOLINATE ON GROWTH AND BODY-COMPOSITION IN THE RAT

This 12-week study examined the effects of six different levels of die tary chromium (Cr) (0, 75, 150, 300, 600, 500 ppb Cr) in the form of C r picolinate (CrPic) upon growth and body composition in the rat. Nine ty male Harlan Sprague-Dawley weanling rats arrived in three groups of 30 animals (referred to as Blocks 1, 2, and 3). Five animals from eac h block were assigned to each treatment resulting in a 6 x 3 (treatmen t x block) Randomized Block Design. Body composition was assessed via dual energy X-ray absorptiometry (DEXA). At Week 5, significant treatm ent x block interactions were found for fat weight and percent body fa t (P less than or equal to 0.05), but there were only trends at Week 1 0 (P less than or equal to 0.10). These interactions reflected decreas es in body fat for Block 1 that corresponded with increasing CrPic lev els in the diet. No interactions nor treatment effects were seen for g rowth rate, lean body mass, or tissue weights, but most block effects were highly significant (P less than or equal to 0.01). A significant treatment x block interaction for feed intake (P = 0.01) revealed a de crease for Blocks 1 and 2, but an increase for Block 3, at the highest CrPic level. Except for the highest dietary level, body fat reduction s for Block 1 occurred without decreases in feed intake, implicating a possible dietary-induced thermogenic effect of CrPic. It was conclude d that genetic differences between the blocks of animals could have ac counted for some of the differential effects of CrPic supplementation. (C) 1997 Elsevier Science Inc.