Date of this Version
Journal of Animal Science, August 2, 2012; doi: 10.2527/jas.2010-3239
Ninety-four, calf-fed crossbred steers were randomly allocated to three different dietary treatments (0%, 15% or 30% wet distillers grains plus solubles - WDGS – DM basis) and fed for 167 d to test the influence of different levels of WDGS on quality attributes of beef. At 48 h postmortem, marbling score, marbling texture, and marbling distribution were assessed by a USDA grader. After grading, one ribeye slice (Longissimus thoracis) about 7 mm thick was excised from each carcass, trimmed of subcutaneous fat, and analyzed for fatty acid profile and lipid content. At 7 d postmortem, 48 top blades (Infraspinatus), strip loins (Longissimus lumborum) and tenderloins (Poas major) (16 per treatment) were removed from shoulder clods and short loins and two steaks were obtained for measurement of mineral content, fatty acid profile (except strip loins), trained sensory analysis, objective color and lipid oxidation. Finishing diet did not influence the content of total lipid (P = 0.19) or marbling, marbling texture, or marbling distribution (P = 0.46, P = 0.84 and P = 0.40, respectively). Feeding WDGS created a linear increase (P < 0.01) of PUFA in all three muscles (Longissimus thoracis showed: 4.90, 5.91, and 6.23 % for 0, 15 and 30%, respectively). Similar responses were observed for 18:2(n-6) and total omega 6 fatty acids. Conversely, lower proportions of 18:1(n-7) fatty acid were observed in beef from animals fed 30% WDGS (P < 0.01). Total trans fatty acids increased linearly in strip loin and top blade steaks (P < 0.01) whereas proportions of 16:0 and 14:1(n-5) fatty acids decreased in all muscles (P < 0.01) as levels of WDGS increased. Diet did not affect mineral content of top blades or strip loins. For tenderloin steaks, sulfur concentration was lower when 30% of WDGS was fed (P = 0.05). No effects on sensory attributes and Warner Bratzler shear force were observed (P ≥ 0.50), except a minimal effect on strip loin juiciness (5.32, 4.86, and 5.52 for 0, 15, and 30%, respectively; P = 0.02). Top blade and tenderloin steaks from cattle fed 30% WDGS were significantly less red (lower a* values) on day 3 of simulated retail display (P < 0.04). Inclusion of 30% WDGS in the diet resulted in higher levels of oxidation after 7 d of retail display for top blade and strip loin steaks (P < 0.01). Feeding WDGS to calf-fed steers altered fatty acid profile, increased oxidation and decreased color stability during retail display.