EFFECTS OF DIETARY CHROMIUM PICOLINATE SUPPLEMENTATION ON GROWTH, CARCASS CHARACTERISTICS, AND ACCRETION RATES OF CARCASS TISSUES IN GROWING-FINISHING SWINE

An experiment was conducted to evaluate the effects of chromium picolinate (CrP) on growth performance, carcass composition, and tissue accretion rates in pigs from 27 to 109 kg BW. Seven littermate sets of Yorkshire-Hampshire barrows, individually penned, were fed a fortified, corn-soybean meal basal diet (.95% lysine from 27 to 55 kg; .80% lysine from 55 to 109 kg) supplemented with 0 or 200 mu g/kg of Cr from CrP. Addition of CrP increased (P < .09) ADG but did not affect ADFI or feed:gain ratio. Average and 1Oth rib backfat arid longissimus muscle area were not affected by Cr supplementation. The right side of the carcass was physically dissected into muscle, fat, bone, and skin. Additionally, five pigs were killed for determination of initial body composition. Dietary CrP addition increased (P <.02) the percentage of muscle and decreased (P <.06) the percentage of fat. Total gain of dissected bone and skin were not different between treatments, but CrP increased (P <.06) the total gain of dissected muscle and decreased (P <.02) the total gain of dissected fat. Also, CrP increased the daily accretion rates of muscle (P <.05) and bone (P .03) and decreased the daily accretion rate of fat (P <.05). The left side of the carcass was ground for determination of water, protein, lipid, and ash. The addition of CrP to the diet increased the percentage (P <.09) and accretion rate (P <.09) of water and increased the percentage (P < .004), total gain (P <.02), and accretion rate (P < .02) of protein while decreasing (P <.04) the percentage of lipid. Pigs fed CrP also had a decreased (P <.004) percentage of lipid in the dissected carcass muscle. Water, protein, and ash from the dissected muscle were not different between treatments. These results suggest that CrP supplementation throughout the entire growing-finishing phase increases the total gain and accretion rate of muscle while decreasing the total gain and accretion rate of fat. This results in carcasses with an increased percentage of muscle and decreased percentage of fat.