Abstract
BACKGROUND AND AIM: Indonesia's indigenous Kacang goat population is in decline, posing a threat to food security and genetic diversity. In vitro maturation and cryopreservation techniques are key strategies for genetic conservation. However, heat shock stress during cryopreservation can compromise oocyte viability. This study evaluates the post-warming quality of Kacang goat oocytes exposed to different cryoprotectants. This study aimed to compare the efficacy of a modified cryoprotectant (30% ethylene glycol + 1M sucrose) with a commercial cryoprotectant in preserving post-warming oocyte quality, based on maturation rates and biomarker levels (heat shock protein 70 [HSP70], adenosine triphosphate [ATP], and glutathione [GSH]). MATERIALS AND METHODS: Oocytes were collected from goat ovaries and matured in vitro for 22 h. They were divided into three groups: Control (no vitrification), commercial cryoprotectant (T1), and modified cryoprotectant (T2). Post-warming quality was assessed using an enzyme-linked immunosorbent assay to quantify HSP70, ATP, and GSH levels. Statistical analysis included one-way analysis of variance and Pearson's correlation (p < 0.05). RESULTS: Maturation rates were comparable across groups (control group [CG]: 84.3%, T1: 79.8%, T2: 77.2%; p > 0.05). HSP70 levels were significantly elevated in T2 compared to CG (p < 0.05). T2 also showed significantly higher ATP (52.13 ± 7.7 ng/mL) and GSH (1.27 ± 0.66 ng/mL) levels compared to T1 (ATP: 25.65 ± 1.63; GSH: 0.06 ± 0.01 ng/mL; p < 0.05). A positive correlation was found between ATP and GSH (p = 0.014). CONCLUSION: The modified cryoprotectant formulation offered superior protection against cryo-induced stress, maintaining higher ATP, GSH, and HSP70 levels post-warming. This formulation holds promise for improving oocyte cryopreservation protocols and conserving the genetic resources of the Kacang goat. Further studies should assess long-term developmental outcomes.