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- Title
Effect of dietary zinc and ractopamine hydrochloride on pork chop muscle fiber type distribution, tenderness, and color characteristics.
- Authors
Paulk, C. B.; Tokach, M. D.; Nelssen, J. L.; Burnett, D. D.; Vaughn, M. A.; Phelps, K. J.; Dritz, S. S.; DeRouchey, J. M.; Goodband, R. D.; Woodworth, J. C.; Houser, T. A.; Haydon, K. D.; Gonzalez, J. M.
- Abstract
A total of 320 finishing pigs (PlC 327 x1050; initially 98 kg) were used to determine the effects of adding Zn to diets containing ractopamine HC1 (RAC) on muscle fiber type distribution, fresh chop color, and cooked meat characteristics. Dietary treatments were fed for approximately 35 d and consisted of a corn-soybean meal-based negative control (CON), a positive control diet with 10 mg/kg of RAC (RAC+), and the RAC+ diet plus 75, 150, or 225 mg/kg added Zn from either ZnO or Availa-Zn. Loins randomly selected from each treatment (n = 20) were evaluated using contrasts: CON vs. RAC+, interaction of Zn level xsource, Zn level linear and quadratic polynomials, and Zn source. There were no Zn source effects or Zn source xlevel interactions through out the study (P> 0.10). Pigs fed RAC+ had increased (P <0.02) percentage type lixand a tendency for increased (P = 0.10) percent type JIB muscle fibers. Increasing added Zn decreased (linear, P = 0.01) percentage type hA and tended to increase (P = 0.09) IIIX muscle fibers. On d 1, 2, 3,4, and 5 of display, pork chops from pigs fed the RAC+ treatment had greater (P < 0.03) L* values compared to the CON. On d 0 and 3 of display, increasing added Zn tended to decrease (quadratic, P = 0.10) L* values and decreased (quadratic, P < 0.03) L* values on d 1, 2,4, and 5. Pigs fed RAC+ had decreased (P < 0.05) a* values on d 1 and 4 of display and tended to have decreased (P <0.10) a* values on d 0 and 2 compared to CON pork chops. Pork chops from the RAC+ treatment had a tendency for increased (P < 0.08) oxymyoglobin percentage compared to CON pork chops on d 1, 2,4, and 5. On d 0, as dietary Zn increased in RAC+ diets, there was a decrease (linear, P < 0.01) in the formation of pork chop surface oxymyoglobin percentage. Metmyoglobin reducing ability (MRA) of pork chops on d 5 was decreased in the RAC+ group. Chops from pigs fed added Zn had increased (quadratic, P < 0.03) MRA on d 3 and 5 of the display period. There was a trend for increased (linear, P = 0.07) cooking loss with increasing Zn in RAC diets and treatments did not affect tenderness as measured by Wamer-Bratzler shear force (P> 0.07). In conclusion, RAC+ diets produced chops that were lighter and less red but maintained a greater percentage of surface oxymyoglobin throughout a 5-d simulated retail display. Ractopamine reduced MRA at the end of the display period, but supplementing Zn to RAC diets restored MRA to near CON treatment levels at the end of the display period.
- Subjects
ZINC; MEAT; RACTOPAMINE; PLANT products; CATTLE industry
- Publication
Journal of Animal Science, 2014, Vol 92, Issue 5, p2325
- ISSN
0021-8812
- Publication type
Article
- DOI
10.2527/jas.2013-7318