Supplementation of lamb diets with vitamin E and rosemary extracts on meat quality parameters

BACKGROUND: Supranutritional supplementation of lamb diets with α-tocopherol is an effective method to reduce lipid oxidation and colour deterioration in meat products. However, alternative antioxidant sources have been proposed to replace the supranutritional vitamin E applications. RESULTS: Indoor concentrate-fed Rasa Aragonesa male lambs (n = 480) were supplemented with increasing levels of all-rac-α-tocopheryl acetate (0.25, 0.5, 1.0 g kg⁻¹ compound feed), rosemary extract (0.20, 0.40, or 0.80 g kg⁻¹ compound feed), or rosemary extract embedded in a fat matrix (0.20, 0.40, or 0.80 g kg⁻¹ compound feed) for 14 days before slaughter. The longissimus thoracis et lumborum muscle from three lambs per pen (18 lambs per treatment) were modified-atmosphere packaged (70% O₂ + 30% CO₂) and maintained under retail conditions for 14 days. Supranutritional supplementation with antioxidants had no effect (P > 0.05) on average daily weight gain, feed intake, and feed efficiency. Rosemary extract supplementation (with or without fat embedment) had no effect on lipid oxidation, myoglobin forms, or colour stability parameters, regardless of the dose. All vitamin E supplementation levels significantly affected lipid oxidation, colour stability (L*, C*, and h), myoglobin forms, and meat discoloration parameters compared with non-supplemented lambs. CONCLUSIONS: This study demonstrates that, unlike vitamin E, neither dose nor protection of the rosemary extract had an effect on lipid oxidation or meat colour stability of lambs during the 14 days of storage under retail conditions.