Impact of Feeding Different Fat Sources and Levels of Vitamin E Isoforms to Heavy Slaughter Weight (150 kg) Pigs: I. Carcass Characteristics and Fresh Pork Quality

The objective of this study was to evaluate the effect of supplementing α-tocopheryl-acetate (ATA) and γ-tocopherol (GT) vitamin E isoforms with corn oil (CO) and tallow (TW) on carcass characteristics and meat quality characteristics of pigs grown to heavy weights (150 kg). Individually fed pigs (n = 72; 36 barrows, 36 gilts) were randomly assigned to 12 dietary treatments in a 2 × 6 factorial arrangement. Fat treatments were 5% TW and 5% CO. The vitamin E treatments included 4 levels of ATA (11, 40, 100, and 200 ppm) and 2 levels of mixed tocopherols (primarily GT; 40 and 100 ppm). Pigs were humanely slaughtered at approximately 150 kg. Carcass characteristics, pH, primal cuts, and meat quality attributes were evaluated. Slaughter weight (P = .04) increased with increasing dietary ATA. Dressing percentage was lower (P = .04) for pigs fed CO. Increasing dietary ATA had a quadratic effect on 45-min pH (P = .02) and 24-h pH (P = .02). Fresh bellies from pigs fed fat sources with higher saturated fat acids displayed a greater belly depth (P = .04), a larger belly angle (P < .01), and a greater lateral (P < .05) and a lower vertical (P < .05) belly flex. In general, loins from pigs fed 40 ppm GT supplementation exhibited greater L* (P < .05) and lower a* (P < .05) values during shelf life than their counterparts fed 40 ppm ATA. In contrast, feeding GT at 100 ppm resulted in loins with lower (P < .05) L* and greater (P < .05) a* values than 100 ppm ATA. Lipid oxidation in loins from pigs fed CO diets increased at a greater (P < .05) rate than in loins from pigs fed TW diets. Lipid stability in loin improved (P < .01) when dietary ATA increased over 40 ppm. The results indicated that TW can be used as a dietary strategy for firmer and desirable pork bellies from heavy-weight pigs. Additionally, inclusion of GT at 100 ppm or more could be exploited as a preharvest strategy to improve color of loins from heavy-weight pigs during retail display.