Supplementing Coenzyme Q10 During the Vitrification and In Vitro Maturation of Dromedary Camel Oocytes Significantly Enhances Their Developmental Competence

This study aimed to evaluate the impact of coenzyme Q10 (CoQ10) supplementation during in vitro maturation (IVM) and/or vitrification of immature dromedary camel oocytes on their subsequent in vitro developmental competence. Additionally, total antioxidant capacity (TAC) and malondialdehyde (MDA) concentrations were assessed in the IVM spent medium. In experiment 1, cumulus–oocyte complexes (COCs, n = 808) collected from slaughtered dromedary camel ovaries were cultured in IVM media supplemented with either 0, 25, 50, or 100 μM CoQ10 for 36 h. Matured oocytes were then fertilized in vitro with epididymal camel spermatozoa. Eighteen hours post-insemination (pi), presumptive zygotes were cultured in vitro for 7 days. In experiment 2, a total of 875 COCs were randomly allocated to one of four experimental groups, namely (a) Vit−/IVM− (control) group, where COCs were vitrified in vitrification solution (VS; 25% DMSO + 25% EG) and matured in IVM media without CoQ10 supplementation; (b) Vit+/IVM− group, in which COCs were vitrified in a VS supplemented with 50 µM CoQ10 and matured in IVM media without CoQ10 supplementation; (c) Vit−/IVM+ group, where COCs were vitrified in VS without CoQ10 supplementation and matured in IVM media supplemented with 50 µM CoQ10; and (d) Vit+/IVM+ group, where COCs were vitrified in VS and matured in IVM media, both supplemented with 50 µM CoQ10. Following vitrification and warming, oocyte viability was evaluated morphologically and by trypan blue staining. Viable oocytes were then matured, fertilized, and cultured in vitro. In experiment 3, TAC and MDA concentrations in the IVM spent media were analyzed. Results showed that 50 µM CoQ10 supplementation to IVM media enhanced cumulus expansion, nuclear maturation, cleavage, and blastocyst rates (experiment 1). Adding 50 µM CoQ10 to the VS enhanced (p ≤ 0.05) oocyte viability compared to those vitrified in CoQ10-free media. Cumulus cell expansion and nuclear maturation rates were higher (p ≤ 0.05) in Vit−/IVM+ than in Vit+/IVM+ and Vit−/IVM− groups. Furthermore, cleavage and blastocyst rates were the highest (p ≤ 0.05) in Vit−/IVM+ group (experiment 2). The concentrations of TCA were higher, and the concentrations of MDA were lower (p ≤ 0.05) in Vit−/IVM+ than in other groups (experiment 3). In conclusion, supplementation of CoQ10 in the maturation medium of vitrified–warmed immature dromedary camel oocytes may enhance their in vitro developmental competence.