Effects of modified tall oil and vitamin E on growth performance, carcass characteristics, and meat quality of growing-finishing pigs

Crossbred barrows (n = 72) were used to evaluate effects of diet supplementation with modified tall oil (MTO; 0.0 or 0.50%) and vitamin E (0, 22, or 110 IU/kg) on growth performance, carcass traits, and longissimus muscle (LM) quality traits of finishing pigs. Pigs were blocked by ancestry and initial BW and allotted randomly to treatments in a 2 x 3 factorial. Corn-soybean meal-based diets were fed in two phases: 45.5 to 81.6 (1.00% lysine) and 81.6 to 114.6 (0.75% lysine) kg BW with no added fat. From 45.5 to 81.6 kg, pigs fed MTO had greater ADG (P = 0.03) regardless of added vitamin E; otherwise, treatment did not affect growth performance. Carcasses from pigs fed MTO had reduced (P < 0.05) average backfat (2.76 vs 2.92 cm) and firmer bellies compared to those fed no MTO. Boneless loins were cut into 2.54-cm chops at 7 d postmortem and evaluated for display color, thiobarbituric acid-reactive substance (TBARS), Warner-Bratzler shear force (WBSF), and sensory panel ratings. Visual color was similar (P > 0.05) among treatments at 0 and 1 d of display. At 4 and 6 d of display chops from pigs fed MTO with 110 IU vitamin E/kg had less deterioration (P < 0.05) than chops from pigs fed MTO with 0 IU vitamin E/kg and 0.0% MTO with 22 or 110 IU vitamin E/kg. The CIE L*, a*, b* and spectral values also suggested a delay in color deterioration for chops from pigs fed MTO with 110 IU vitamin E/kg. At 6 and 8 d of display, chops from pigs fed 110 IU vitamin E/kg had lower (P < 0.05) L* values than those from pigs fed 0 or 22 IU vitamin E/kg, and higher (P < 0.05) a* values than those from pigs fed 0 IU vitamin E/kg feed. A higher (P < 0.05) %R630/%R580 (indicator of more oxymyoglobin) was observed for chops from pigs fed MTO with 110 IU vitamin E/kg than those from pigs fed 0.0% MTO with 22 or 110 IU vitamin E/kg and MTO with 0 IU vitamin E/kg. Chops from pigs fed MTO with 110 IU vitamin E/kg had lower (P < 0.05) TBARS values than those from pigs fed MTO with 0 IU vitamin E/kg. No differences (P > 0.05) were detected among treatments for WBSF or sensory evaluations. The addition of MTO in swine diets improved belly firmness and reduced backfat, and feeding MTO with high levels of vitamin E extended display life without affecting palatability of LM chops.