Residual Black Wolfberry Fruit Improves Meat Quality of Sheep by Enhancing Immune and Antioxidant Capacity

The residual black wolfberry fruit (RBWF), rich in nutrients and active substances, has the potential to serve as an antibiotic alternative. This study evaluated the concentration-dependent effects of RBWF on serum biochemistry, immunity, antioxidant capacity, and meat quality of fattening sheep. Forty 3-month-old sheep were randomly assigned into four groups with 10 replicates in each group and fed experimental RBWF-supplemented diets (0%, 2%, 5%, and 8%). The results showed that RBWF supplementation significantly increased the serum levels of TP, BUN, ALT, AST, IgA, IgM, T-AOC, SOD, and GSH-Px in sheep (p < 0.05), while significantly decreasing the levels of LDH, TG, LDL-c, IgG, and MDA (p < 0.05). Furthermore, dietary RBWF significantly increased the VB1 and IMP levels in the longissimus dorsi muscle of sheep (p < 0.05) and significantly decreased the contents of fat and cholesterol (p < 0.05). Finally, RBWF increased the contents of C20:4 and Glu (p < 0.05). In conclusion, dietary supplementation with RBWF can improve the immune and antioxidant capacity of sheep and has a certain effect on improving the flavor of meat, of which 5% is the best.