Supplementation of chromium propionate alters growth performance and GLUT4 activity in feedlot steers

The impacts of administration of chromium propionate (CrP) on live performance, blood metabolites, carcass characteristics, gene expression, protein expression, and various cellular parameters were evaluated. Supplementation of chromium propionate (CrP) resulted in a positive linear relationship (P < 0.05) between amount of supplemental CrP and BW from d 56 until harvest, with animals receiving 0.45 mg Cr/kg diet DM having the heaviest BW. Additionally, ADG, feed efficiency, and HCW had positive linear responses (P = 0.01) to supplementation of CrP. No difference (P > 0.10) was detected in blood parameters due to CrP administration. The relative mRNA and protein expression of GLUT4 was not different (P > 0.10) between control or CrP treatments, but the density of GLUT4 internalized in skeletal muscle fibers was increased (P = 0.07) due to supplementation of CrP. No differences (P > 0.10) in skeletal muscle fiber type distribution, cross-sectional area, satellite cell populations, or nuclei density due to CrP supplementation were observed. Administration of CrP resulted in improved live performance, no change in blood glucose concentrations, and fewer GLUT4 on the cell surface. This indicates CrP is able to allow GLUT4 to be more efficient at transporting extracellular glucose into the cell, resulting in improved growth.