Effects of supplemental manganese on performance of growing-finishing pigs and pork quality during retail display

¹ Department of Animal Sciences, University of Arkansas, Fayetteville 72701
² Department of Animal Science, Oklahoma State University, Stillwater 74074
³ Zinpro Corporation, Eden Prairie, MN 55344

^* To whom correspondence should be addressed. E-mail: japple{at}uark.edu.

	Abstract

Crossbred barrows and gilts (n = 168) were used to test the effects of supplemental manganese (Mn) during the growing-finishing period on performance, pork carcass characteristics, and pork quality during 7 d of retail display. Pigs were blocked by weight, and allotted within blocks to pens (5 pigs/pen in blocks 1, 2, 5, and 6, and 4 pigs/pen in blocks 3 and 4). A total of 36 pens were randomly assigned to 1 of 6 dietary treatments where basal diets were formulated with (PC) or without Mn (NC) in the mineral premix, and supplemented with 0 or 350 ppm (as-fed basis) Mn from either MnSO₄ or a Mn-AA complex (AvMn). Pigs were slaughtered at a commercial pork packing plant when the lightest block of pigs averaged 113.6 kg. During fabrication, boneless pork loins were collected and transported to Oklahoma State University, where 2.5-cm-thick LM chops were packaged in a modified atmosphere (80% O₂ and 20% CO₂) and subsequently placed in display cases (2 to 4°C) under continuous fluorescent lighting (1,600 lux) for 7 d. Pig performance was not (P 0.44) affected by supplemental Mn; however, during the grower-II phase, pigs fed basal diets including Mn consumed less (P < 0.02) feed and tended to be more efficient (P < 0.09) than pigs fed basal diets devoid of Mn. Throughout the entire feeding trial, neither dietary nor supplemental Mn altered (P 0.22) ADG, ADFI, or G:F. Chops from pigs fed diets supplemented with MnSO₄ received higher (P 0.05) lean color scores, and had a redder (greater a* and hue angle values), more vivid color than chops from pigs fed diets supplemented with AvMn. Additionally, LM chops from pigs fed the PC-diets supplemented with MnSO₄ were darker (lower L* values; P < 0.05) than chops from pigs fed the NC-diets or PC-diets supplemented with 0 or 350 ppm AvMn. Even though discoloration scores were similar during the first 4 d of display, chops from pigs fed PC-diets supplemented with MnSO₄ were less (P < 0.05) discolored on d 6 and 7 of retail display than chops from pigs fed PC- or NC-diets and diets supplemented with AvMn (dietary treatment x display time, P = 0.04). Results of this study indicate that feeding an additional 350 ppm of Mn from MnSO₄ above maintenance requirements of growing-finishing swine does not beneficially impact live pig performance but may improve pork color and delay discoloration of pork during retail display.

Key Words: Color, Manganese, Performance, Pork, Quality, Retail display