Efficacy of chromium picolinate and chromium chloride as potential carcass modifiers in swine

We conducted two experiments to evaluate the effects of chromium picolinate and chromium chloride (CrCl3) on growth performance, carcass composition, percentages and accretion rates of carcass tissues and chemical components, and blood metabolites in pigs. In Exp. 1, 35 individually penned pigs were fed a fortified, corn-soybean meal basal diet (.95% lysine) supplemented with 0, 200, or 400 micrograms/kg of Cr from chromium picolinate or 5,000 or 25,000 micrograms/ kg of Cr from CrCl3. Each diet was fed to seven pigs for 35 d (19.6 to 43.2 kg BW). Addition of 200 micrograms/kg of Cr from chromium picolinate increased ADG (P < .07) and ADFI (P < .03) but did not affect feed:gain ratio. Backfat measurements and longissimus muscle area were not affected by either source of Cr. The percentages of muscle, fat, bone, and skin from the right ham and the percentages of water, protein, lipid, and ash from the left carcass were not significantly altered by Cr. The addition of 200 micrograms/kg Cr from chromium picolinate increased (P < .07) the accretion rate of lipid in the carcass. In Exp. 2, 42 individually penned pigs (three from each of 14 litters) were fed a fortified, corn-soybean meal basal diet (.95% lysine from 19 to 55 kg; .80% lysine from 55 to 109 kg) without or with 200 micrograms/kg of Cr from chromium picolinate or 5,000 micrograms/kg of Cr from CrCl3. Dietary Cr addition had no effect on the performance or backfat measurements of the pigs; however, both sources of Cr increased (P < .07) longissimus muscle area. The percentages and accretion rates of muscle tissue were increased (P < .001) and the percentages of fat tissue were decreased (P < .001) in pigs fed Cr, with chromium picolinate being more effective than CrCl3 (P < .05). The percentages (P < .01) and accretion rates (P < .07) of carcass protein were increased and the percentages and accretion rates of carcass lipid were decreased (P < .04) in pigs fed Cr. No changes in blood metabolites occurred as a result of supplemental Cr in either experiment. These results suggest that chromium picolinate is more effective than CrCl3 and that Cr must be supplemented throughout the growing-finishing period to improve the carcass composition.