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* Appalachian Farming Systems Research Center, USDA-ARS, Beaver, WV 25813;
and
Department of Animal Sciences, Ohio Agricultural Research and Development Center, The Ohio State University, Wooster 44691; and
and
Agricultural Technical Institute, The Ohio State University, Wooster 44691
2 Correspondence:
phone: 304-256-2843; fax: 304-256-2921; E-mail:
kturner{at}afsrc.ars.usda.gov.
Two experiments were conducted to evaluate 
-tocopherol accumulation in muscle of lambs finished on pasture or concentrates. The objective for Exp. 1 was to compare accumulation of -tocopherol in the longissimus muscle of pasture-fed lambs to that of lambs fed three concentrations (15, 150, and 300 IU/kg of DM) of supplemental vitamin E (all rac -tocopheryl acetate) in all-concentrate diets. The objective in Exp. 2 was to investigate the effect of duration of supplemental vitamin E feeding on -tocopherol content and color change during display case storage of lamb muscle. Treatments evaluated in Exp. 2 were: 15 IU of supplemental vitamin E/kg DM fed to finish; 15 IU/kg followed by 300 IU/kg of DM during the last 21 d; and 15 IU/kg DM until 7 d prior to finish, then 300 IU/kg DM. In Exp. 1, -tocopherol concentration of rotational grazed alfalfa and perennial ryegrass averaged 137 and 169 mg/kg of DM. Vitamin E treatments for lambs fed concentrate diets did not affect ADG (P > 0.15), but ADG was greater (P < 0.01) for concentrate-fed lambs than for grazing lambs. For the concentrate-fed lambs, -tocopherol in longissimus muscle increased quadratically (P < 0.05) as dietary concentrations of vitamin E increased. Predicted maximum -tocopherol concentration in muscle occurred at about 400 IU/kg of diet DM. Longissimus muscle from lambs grazing alfalfa or ryegrass had similar (P > 0.50) -tocopherol concentrations, and those concentrations were similar to values obtained when the concentrate diet supplemented with 150 IU of vitamin E/kg was fed. In Exp. 2, no differences (P > 0.10) in ADG were observed. Concentrations of longissimus -tocopherol were highest when 300 IU supplemental vitamin E was fed for 21 d prior to slaughter. During a 6-d display period, semimembranosus steaks from lambs fed 300 IU of supplemental vitamin E/kg for either 7 or 21 d had higher a* and b* color readings than steaks from lambs fed 15 IU/kg of supplemental vitamin E. Increased consumption of vitamin E either via pasture or supplementation results in higher -tocopherol concentrations in meat.
Key Words: Color • Lambs • Pastures • Tocopherols • Vitamin E
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