The chemical composition, fatty acid (FA) profile and antioxidant potential of beef from steers fed corn (CDG) or wheat (WDG) dried distillers’ grains were determined. Thirty-six Charolais and Limousin-sired steers (421.9 ± 38.9 kg) were blocked by breed and body weight and randomly assigned to one of three dietary treatments (n = 12 steers/treatment). Treatments consisted of ad libitum grass silage supplemented with concentrate ration (4.0 kg dry matter basis daily) containing either barley/soybean meal (control), 80% CDG or 80% WDG (as-fed basis) fed for 124 days pre-slaughter. Following slaughter, the longissimus thoracis muscle (LT) was excised at 48 h post-mortem, vacuum packaged and aged for 14 days pr... More
The chemical composition, fatty acid (FA) profile and antioxidant potential of beef from steers fed corn (CDG) or wheat (WDG) dried distillers’ grains were determined. Thirty-six Charolais and Limousin-sired steers (421.9 ± 38.9 kg) were blocked by breed and body weight and randomly assigned to one of three dietary treatments (n = 12 steers/treatment). Treatments consisted of ad libitum grass silage supplemented with concentrate ration (4.0 kg dry matter basis daily) containing either barley/soybean meal (control), 80% CDG or 80% WDG (as-fed basis) fed for 124 days pre-slaughter. Following slaughter, the longissimus thoracis muscle (LT) was excised at 48 h post-mortem, vacuum packaged and aged for 14 days prior to subsequent analysis. Feeding CDG increased (P < 0.05) the pH and decreased the ash content of LT relative to the control. Dietary CDG (P < 0.05) increased the protein content of LT compared to WDG. The proportion of C14:0 (P < 0.05) was lower in LT from steers fed WDG relative to the control whereas the percentage of C15:0 and C20:0 (P < 0.01) were greater in LT from WDG compared to the control. Both CDG and WDG increased (P < 0.05) the percentage of conjugated linoleic acids (c-9 t-11+t-9 c-11 18:2) and tended to increase the percentage of α-linolenic acid (P= 0.08), C22:2 n-6 (P = 0.05) and polyunsaturated FA (PUFA, P = 0.06) compared to the control. There was no treatment effect (P > 0.05) on antioxidant status (total phenol and α-tocopherol contents) or activity (radical scavenging and iron-chelating activities, and iron-reducing antioxidant power) of LT. In addition, dietary CDG or WDG did not influence lipid or oxymyoglobin oxidation in muscle homogenates incubated with iron/ascorbate pro-oxidants. Overall, the inclusion of distillers’ grains in supplementary concentrates may improve the FA composition of beef irrespective of distillers’ grains type.