Influence of chromium tripicolinate on glucose metabolism and nutrient partitioning in growing lambs

Twenty-four Suffolk lambs (average BW 38 +/- 2.7 kg; 16 ewes and 8 wethers) were fed either a corn-cottonseed hull-based control diet (CON) or CON plus 250 ppb of Cr as chromium tripicolinate (CrPic). Lambs were penned in groups of three and ADG and DMI were measured through d 85 of the experiment. Jugular blood samples were obtained during wk 2, 7, and 11. An i.v. glucose tolerance test (IVGTT; 500 mg of glucose/kg BW) and an i.v. insulin challenge test (IVICT; 0.1 IU of ovine insulin/kg BW) were performed during wk 2 and 10 of the trial. This was followed by a N balance trial during wk 3 and 11. Wethers were slaughtered at the end of the experiment and carcass characteristics determined. No differences (P 0.10) were observed between dietary treatments in DMI, ADG, or N balance; however, the CrPic-fed wethers had 18% less fat over the 10th rib (P = 0.082) and a lower yield grade ( P = 0.014). Plasma NEFA was lower throughout the trial (P 0.03) and cholesterol was 17% lower during wk 2 (P 0.02) in lambs fed CrPic. There were no differences due to diet (P 0.10) in plasma concentrations of urea N, glucose, albumin, total protein, insulin, glucagon, triiodothyronine, or thyroxine. Glucose clearance rate and half-life during the IVGTT and IVICT did not differ (P 0.10) between CON and CrPic groups; however, during the IVGTT on wk 2, plasma insulin was elevated (P 0.05) and glucose reduced (P