Effects of Embryo Production Method and Culture Medium on Embryonic Development in Red-Rumped Agouti

Advances in Assisted Reproductive Technologies (ARTs) help overcome reproductive barriers. However, a comprehensive understanding of embryonic development is crucial for their success. In vitro fertilization (IVF) and artificial oocyte activation (AOA) are embryo production methods commonly used. Previous studies have reported low developmental success with these methods, possibly due to the culture medium used. Therefore, we aimed to optimize ARTs in red-rumped agouti by evaluating the influence of production method and culture medium on embryonic development. Oocytes were matured in vitro and divided into two groups: IVF with capacited spermatozoa or AOA with strontium chloride and cytochalasin B. Presumed zygotes were cultured in either KSOM or SOF medium after a 6-h incubation. Morphology, oocyte-sperm interaction, developmental kinetics, and oxidative stress levels were assessed. IVF-derived structures exhibited a higher rate of normal morphology compared to AOA-derived structures (p < 0.05). Embryo kinetics analysis showed that AOA-KSOM and IVF-KSOM groups had a higher number of cleaved structures than the SOF groups (p < 0.05) on Day 2. On Day 5, the IVF-KSOM group presented the highest percentage of cleavage/total zygotes and the highest percentage of structures with eight or more cells (p < 0.05). Morula formation was significantly higher in IVF-KSOM and AOA-KSOM (p < 0.05), highlighting KSOM's effectiveness. Notably, only the IVF-KSOM group produced blastocyst (p < 0.05). Oxidative stress assessment showed no differences between groups (p > 0.05). These findings confirm that IVF-KSOM is the most effective methodology for developing red-rumped agouti embryos, offering valuable insights into the reproductive biology of this species and aiding in the refinement of protocols for closely related rodents.