Effects of dietary Inonotus obliquus fermentation products supplementation on meat quality and antioxidant capacity of finishing pigs.

This study aimed to investigate the supplementation of finishing pigs with Inonotus obliquus fermentation products (IOFP) on the meat quality, amino acid and fatty acid composition, muscle fiber characteristics, and antioxidant capacity. Eighteen healthy castrated piglets were randomly divided into three groups and fed a basal diet or supplemented with IOFP (obliquus (Chaga fungus) products fermented for 3 or 7 days (IOFP-3 and IOFP-7) at 8 g per kg feed). The results demonstrated that, compared to the control group, IOFP significantly increased the pH from 5.44 to 5.52, a* value from 3.8 to 4.5, crude protein content from 21.9 % to 24.0 %, and intramuscular fat content from 3.03 % to 3.56 %. Additionally, IOFP led to significant increases in the content of total amino acids (TAA), essential amino acids (EAA), flavor amino acids, total polyunsaturated fatty acids (PUFA), and the percentage of unsaturated fatty acids (P < 0.05). Furthermore, it resulted in a significant decrease 45.3 N to 40.3 N in shear force (P < 0.05) in the Longissimus thoracis et lumborum (LTL) muscle of pigs. IOFP-7 supplementation also increased (P < 0.05) the MyHC I mRNA expression and decreased (P < 0.05) MyHC IIb mRNA levels. IOFP not only increased superoxide dismutase (SOD) (P < 0.05) in the serum and muscle tissue, but also decreased the content of MDA (P < 0.05) in serum. IOFP-7 supplementation significantly increased enzyme activity and enhanced the expression of Nuclear factor E2-related factor 2 (Nrf2) and downstream genes (P < 0.05), and reduced MDA and carbonyl contents of pork during storage in high‑oxygen modified atmosphere packaging. In summary, this study demonstrated that dietary IOFP supplementation can effectively improve pork's color and nutritional value, increase slow-twitch fiber percentage, enhance the antioxidant capacity of pigs, prevent lipid and protein oxidation, and improve pork quality.