Effect of long-term dietary supplementation with Bacillus subtilis in pigs on meat color and oxidative stability under high‑oxygen packaging.

This study aimed to investigate the effects of dietary Bacillus subtilis (B. subtilis) supplementation in pigs on the meat color and oxidative stability of the meat under high‑oxygen packaging. The results showed B. subtilis increased redness (a*) (P < 0.05), accompanied by inhibiting the formation of metmyoglobin (MetMb) of pork, and maintained better meat color during storage. Compared to the control group, dietary B. subtilis supplementation increased the R630/580 value, metmyoglobin-reducing activity (MRA) and the oxygen consumption rate (OCR) of pork (P < 0.05), and the pork had better meat color stability. B. subtilis supplementation also upregulated the expression of Nrf2 and downstream antioxidant enzyme genes (SOD, CAT, and GSH-Px) in the Nrf2-Keap1 signaling pathway and downregulated the expression of the Keap1 (P < 0.05). The activities of superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) and catalase (CAT) in longissimus thoracis et lumborum (LTL) muscle were increased by B. subtilis while the levels of lipid and protein oxidation were decreased (P < 0.05). All results confirmed that dietary B. subtilis supplementation could effectively maintain the meat color and delay the oxidation of chilled pork compared to the control.