Anthocyanins Alleviate Persistent Corpus Luteum and Ovarian Quiescence in Beef Cows by Modulating Gut Microbiota and Reducing Granulosa Cell Apoptosis

Persistent corpus luteum (PCL) and ovarian quiescence (OQ) are key manifestations of ovarian dysfunction (OD) that lead to reduced reproductive capacity in beef cattle, posing a serious challenge to the industry. Anthocyanins (ACNs) are known for their antioxidant properties. This study aimed to investigate the regulatory effects of ACNs on PCL and OQ and to explore the underlying mechanisms. Forty-eight beef cows diagnosed with both OQ and PCL were selected and continuously fed ACNs for 60 days. The results showed that the regulatory effects of ACNs were dose-dependent. A high dose of ACNs (ACNH) significantly increased the number of large follicles and reduced the occurrence of PCL. ACNH treatment significantly decreased serum progesterone (P4) levels and increased estradiol (E2) levels. Furthermore, ACNH reduced microbial diversity in OD cows but significantly increased the abundance of Patescibacteria, Actinobacteriota, Proteobacteria, and Chloroflexi, while decreasing the abundance of Desulfobactera, indicating that ACNs may affect ovarian function by regulating the gut microbial environment. In an ovarian granulosa cell model of oxidative damage, ACN intervention could reduce oxidative stress levels and mitigate oxidative damage. ACNs downregulated various pro-apoptotic genes, such as P53, Fas, and Bax, while upregulating anti-apoptotic genes Bcl-2 and Bcl-xL, suggesting that ACNs significantly inhibit cell apoptosis. To conclude, these results demonstrate that ACNs improve the ovarian function of beef cows by regulating gut microbiota and reducing oxidative stress-induced apoptosis in ovarian granulosa cells, thereby enhancing the reproductive capacity of beef cattle that show reproductive disorders. These findings provide a theoretical basis for the application of ACNs in the cattle industry and showcase their potential value as natural antioxidants.