Animal Science Abstract
Dose-response effect of dietary vitamin E concentration on meat quality characteristics in light-weight lambs
C. J. López-Bote1,A, A. Daza2, M. Soares1 and E. Berges3
AE-mail: clemente@eucmax.sim.ucm.es
1Departamento de Producción Animal, Facultad de Veterinaria, Universidad Complutense, 28040 Madrid, Spain2ETSIA, UPM 28040 Madrid, Spain
3Productos Roche SA, San Fernando de Henares, Madrid, Spain
Abstract
The research was carried out to evaluate the effect of different dietary a-tocopheryl acetate (DTA) concentrations in light-weight lambs on muscle a-tocopherol accumulation and on quality characteristics of stored meats. Thirty-two Manchego lambs were randomly distributed to four groups and given diets containing four levels of DTA (20, 270, 520 and 1020 mg/kg diet) for 6 weeks. Lambs were slaughtered at live weights ranging from 23•5 to 26•4 kg. A linear (P < 0•001) and quadratic (P < 0•001) effect of dietary supplementation level was observed on muscular a-tocopherol concentration, which fitted the following equation: mg muscle a-tocopherol per kg muscle = 1•78(s.e. 0•18) + 7•08 (s.e. 0•89)(1 - e0•0012DTA)) (P < 0•001, R2 = 0•99). There was a linear effect (P < 0•001) of muscle vitamin E concentration on thiobarbituric acid reactive substance on day 0 of storage, but a linear plus quadratic effect (P < 0•001) on days 3, 6 and 9. Broken line analysis of data at day 9 of storage indicated a target muscle a-tocopherol concentration of 5•4 mg/kg. Evolution of surface redness of lamb chops also showed a linear and quadratic effect of dietary treatment on days 3 and 6 of storage, but only a linear effect on day 9. Broken line analysis of data at 3 and 6 days indicated a target a-tocopherol concentration in the range 5•3 to 5•6 mg/kg muscle for optimum red colour stability. Surface luminosity showed no effect of dietary treatment at days 0, 3 and 6 of storage but a linear (P < 0•01) plus quadratic (P < 0•05) effect on day 9 of storage. Broken line analysis at this point indicated a target muscle a-tocopherol concentration of 3•2 mg/kg. It is concluded that the effectiveness of dietary a-tocopheryl acetate supplementation depends on the meat quality attribute assessed. A significant positive effect for lipid oxidation can be reached even at the lower supplementation level utilized in this experiment (270 mg/ kg diet). However, considering the protecting effect at different storage times and particularly the effect on meat surface redness, the optimum level would be in the range 5•3 to 5•6 mg/kg muscle, which correspond to a dietary inclusion of 550 to 625 mg a-tocopheryl acetate/kg diet.
Keywords: lamb (meat), lipid peroxidation, meat quality, a-tocopherol
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