Abstract：To explore the regulatory effect of oxidative stress on meat quality post-slaughter, six hybrid male lambs of Mongolian sheep and Duper sheep were selected and randomly divided into two groups: one as HC (fed on a basal diet composed of roughage mixed with forage and concentrated supplement) and the other as TG (fed on a basal diet supplemented with 0.3‰ thymol (based on the mass of the diet)). At the end of the feeding trial, the animals were slaughtered and longissimus dorsi samples were collected for analysis of antioxidant indices and RNA sequencing (RNA-Seq). It was found that dietary thymol was effectively deposited in lamb meat, inhibiting the oxidation of myofibrillar protein and fat, reducing reactive oxygen species levels, mitigating Ca2+ overload and mitochondrial lipid peroxidation, inhibiting the opening of mitochondrial permeability transition pores, enhancing the reduction level of cytochrome c, and reducing the activities of caspase-3 and caspase-9, the key enzymes in the mitochondrial apoptotic pathway. Through RNA-Seq analysis, seven candidate genes regulating the oxidative stress level of lamb muscle fibers were selected, namely IFI6, PDL4, PDGFB, IL6, MCL1, HMOX1, and FOXO1. Overall, the mechanism by which dietary thymol enhances the antioxidant capacity of lamb muscle fibers begins with the regulation of gene expression.
2026, Vol. 40 
