Effects of nitric oxide synthase inhibitor on mitochondria apoptosis and meat quality in postmortem Gannan yak (Bos grunniens) meat.

This research aimed to explore the effects of the nitric oxide synthase (NOS) inhibitor (L-NAME) on mitochondria apoptosis in postmortem Gannan yak (Bos grunniens) longissimus dorsi (LD) muscle and to explore its effect on meat quality further. The Gannan yak meat samples were treated with the control group (0.9% NaCl) and L-NAME (20, 60, and 100 mM) for 24 h and then stored for 0, 1, 3, 5, and 7 days at 4°C. NOS activity and NO content were investigated, and the parameters of mitochondrial apoptosis of the postmortem Gannan yak meat were determined. Meanwhile, the meat quality such as the centrifugation loss, meat color, and myofibril fragmentation index (MFI) was evaluated. The results indicated that after treatment with L-NAME, NOS activity and NO content decreased, causing mitochondrial membrane damage, Bax protein, and Cyt-c levels increased, and resulted in increased activities of caspase-9 and -3, promoting the occurrence of mitochondrial apoptosis. Furthermore, it increased the tenderness and water retention of Gannan yak meat. The results indicated that NOS inhibitor played a regulatory role in postmortem Gannan yak meat quality by regulating mitochondria apoptosis during postmortem aging. PRACTICAL APPLICATIONS: The meat's tenderness is often considered the most important factor affecting consumers' willingness to repurchase. The relationship of caspases and MFI suggested that L-NAME played a regulatory role in postmortem Gannan yak meat quality by regulating mitochondria apoptosis during postmortem aging. This study provides valuable information for the development of the Gannan yak economy in Tibetan areas.