Caffeic Acid Improves Pork Quality in Finishing Pigs via Modulating Oxidative Muscle Remodeling Associated with Nrf2 Activation and HIF-1α Inhibition

Abstract This study integrated in vivo finishing pig trials and in vitro primary porcine myotube assays to assess the effects of caffeic acid (CA) in relation to pork quality and its molecular mechanisms. Our results showed that CA increased muscle pH at 24 h and redness, and reduced drip loss and cooking loss. CA enhanced muscle antioxidant capacity and oxidative fibers proportion, while suppressing muscle glycolysis. CA upregulated nuclear factor erythroid 2-related factor 2 (Nrf2) expression and decreased hypoxia-inducible factor-1α (HIF-1α) expression. Myotube tests verified that ML385 abolished the promoting effects of CA on muscle antioxidant capacity and oxidative muscle fiber expression, whereas DMOG attenuated the regulatory effects of CA on glycolytic metabolism and muscle fiber composition. In conclusion, CA improves pork quality, and its mechanisms are closely linked to Nrf2 pathway activation to enhance the antioxidant capacity of skeletal muscle and suppression of HIF-1α-mediated glycolysis, thereby driving a glycolytic-to-oxidative fiber-type switch.