Effect of supplemental vitamins and trace minerals on performance and carcass quality in finishing pigs

Two trials with finishing pigs (PIC line 355 x Camborough 22) were conducted to evaluate the effects of vitamin and trace mineral (VTM) supplement deletions on performance, carcass quality, and tissue nutrient levels. Trial 1, a 3 x 2 factorial arrangement of treatments involving three VTM supplement regimens and two stress regimens, was conducted for 12 wk with 252 pigs (mixed sex). Average initial weight of pigs was 54 kg. The VTM regimens consisted of control (adequate level of VTM throughout trial), VTM deleted for the final 6 wk, and VTM deleted for entire 12 wk of the trial. The stress regimens consisted of leaving half the treatments in their original location or moving the other half of the treatments to a new pen location every 3 wk. There were three replications (pens) per treatment with 14 pigs per pen (0.80 m2). Diets were medicated with bacitracin methylene disalicylate. Overall, there were no treatment differences (P > 0.05) for ADG, ADFI, gain:feed ratio, longissimus muscle area, or last-rib backfat. However, there was a greater than 75% decrease (P < 0.001) in vitamin E content of longissimus muscle from deleting VTM for 6 or 12 wk. Trial 2, a 3 x 2 factorial arrangement of treatments involving three VTM regimens and two genders, was conducted for 12 wk with 306 pigs. Average initial weight of pigs was 58 kg. The VTM regimens were identical to those used in Trial 1. Each treatment consisted of three gender replications of 17 pigs per pen (0.66 m2), and all diets were unmedicated. Overall, pigs fed diets without VTM for 12 wk had lower (P < 0.06) ADG than those fed the control diets. Vitamin E content of the ham muscle was reduced by greater than 50% (P < 0.001) when pigs were fed diets without VTM for 6 or 12 wk compared with those fed the control diet. Concentrations of copper in ham muscle were reduced (P < 0.05) in pigs fed diets without VTM. These data suggest that deleting VTM during the finishing stage markedly lowers the vitamin E content of pork muscle.