This study investigates the effects of astaxanthin on oxidative stress, mitochondrial function, and follicular development in mouse preantral follicles, with a focus on the involvement of the adenosine monophosphate-activated protein kinase (AMPK) signaling pathway. Astaxanthin (2.5 nM) significantly enhanced both the antrum formation (from 85.96% in the control group to 94.38% in the astaxanthin group) and maturation rates (from 79.15% to 85.12%) of oocytes (