Immature oocytes collected from ovaries are important animal genetic resources. Owing to the widespread use of assisted reproductive technologies, including in vitro maturation (IVM) and cryopreservation, ovarian oocytes can be used for in vitro embryo production and female gamete storage. However, compared to porcine or bovine oocytes, the methodological approaches for IVM in the oocytes from goats are relatively scarce. Therefore, developing an efficient and stable IVM approach to preserve goat oocytes is crucial. During IVM, oocytes disengage from the stable maternal low-oxygen environment, leading to reactive oxygen species (ROS) accumulation [1]. Excessive ROS levels causes organelle dysfunction, spindle abnormalities and apoptosis in oocytes [2], [3], [4]. Oxidative stress is one of the main causes of low-quality oocytes during in vitro culture [5], [6]. Thus, maintaining the intracellular redox balance is critical for improving the quality of IVM oocytes [7].

IVM technology and oocyte cryopreservation are commonly used for the long-term storage of domestic animal genetic resources. Despite recent progress in goat oocyte vitrification [8], [9], [10], the developmental competence of vitrified-warmed oocytes requires improvement. Previous studies have shown that the developmental competence of vitrified-warmed oocytes is associated with aberrant organelle distribution and function due to cryoinjury [11], [12]. Vitrification damages oocyte structure, increases oxidative stress [13], and affects the organelle distribution and function [14], [15], [16]. Accordingly, improving the developmental potential of goat oocytes by reducing ROS and cryoinjury could provide a strategy for optimizing IVM and vitrification technologies.

C-Phycocyanin (PC) is a soluble pigment protein existing in the bile body complex of light-harvesting algae, including cyanobacteria and red algae. PC is crucial role in various cellular functions, such as antioxidant, antiinflammatory, antitumor, kidney protection, and neuroprotective properties [17], [18], [19], [20]. Supplementation with PC during IVM enhances the pre-implantation developmental competence of parthenogenetic and cloned embryos in pigs [21]. Recently, we reported that PC administration by oral gavage improved reproductive function in obese female mice by reducing oxidative stress and early cell apoptosis in the ovaries and oocytes [22]. Furthermore, PC improves sperm quality, fertilitates spermatogenesis and fertility in male mice, and enhances antioxidation ability in a cyclophosphamide-injury model [23].

Although several studies have highlighted the ability of PC to improve oocyte quality through its antiinflammatory and antioxidant properties, its effects on goat oocyte quality during IVM and cryopreservation remains unclear. We hypothesized that PC plays a role in minimizing ROS production and enhancing the efficiency of oocyte maturation during oocyte in vitro maturation and vitrification in goats. Therefore, the objective of this study was to investigate the protective effects and mechanisms of action PC on IVM and cryopreservation of goat oocytes.