Effects of Dietary Rhodotorula Yeast Culture Supplementation on Physicochemical Properties, Antioxidant Capacity, Shelf Life, and Flavor Substance of the Longissimus dorsi Muscle in Fattening Lambs

This study evaluated the effects of dietary Rhodotorula yeast culture (RYC) supplementation on carcass traits, meat quality, antioxidant capacity, shelf life, and flavor substance in fattening lambs. Twenty-four three-month-old male Dorper × Han crossbred sheep (body weight: 36 ± 4 kg) were randomly assigned to four groups: R0 (basal diet), R10 (basal diet + 10 g RYC/day), R20 (basal diet + 20 g RYC/day), and R40 (basal diet + 40 g RYC/day). The experiment lasted 75 days. Compared to the control group, the R10, R20, and R40 groups exhibited significant reductions in shear force (p < 0.01), malondialdehyde levels (p < 0.01), and day-15 total volatile basic nitrogen values (p < 0.05), along with significant increases in glutathione peroxidase activity (p < 0.05) and total umami-taste amino acid content (p < 0.01). The R20 group also demonstrated significant increases in backfat thickness, muscle crude protein content, and total antioxidant capacity (p < 0.05). These results indicate that dietary supplementation with 20 g RYC improves physicochemical properties, antioxidant capacity, shelf life, and flavor compounds in fattening lambs.