Comparative analysis of sperm selection methods and their impact on in vitro fertility in the red-rumped agouti (Dasyprocta leporina).

Despite advances in sperm manipulation techniques for the red-rumped agouti, methodologies for selecting these cells before in vitro fertilization (IVF) remain insufficiently explored. This study evaluated the effects of various sperm selection methods on red-rumped agouti sperm, focusing on morphological and functional parameters, oxidative stress status, and fertilization potential using heterologous oocytes (he-IVF). Epididymal spermatozoa were recovered from six animals by retrograde flushing and equally distributed into four distinct protocols (100 × 106 sperm/mL for protocol): without selection (WS group), centrifugation (CT group), density gradient (DG group), and swim-up (SP group). Sperm recovery was significantly lower following selection compared to the WS group (p < 0.05). The CT method yielded the highest progressive motility (64.6 %), surpassing WS (32.2 %), DG (47.0 %), and SP (48.4 %) (p < 0.05). Regarding membrane functionality maintenance, CT (85.9 %) was comparable to WS (90.7 %) and superior to the other groups (p < 0.05). The CT protocol maintained a greater proportion of cells with intact membranes and normal mitochondrial activity (p < 0.05). A strong ROS/GSH correlation was observed in the CT group (r = -0.92), with significantly reduced ROS levels and increased GSH, outperforming the moderate correlations seen in DG (r = -0.83) and SP (r = -0.79) (p < 0.05). Lastly, he-IVF resulted in cleaved embryos and morulae, though fertilization rates did not differ between groups (p > 0.05). In conclusion, centrifugation was the most effective method for maintaining sperm functionality and oxidative balance, while all selection protocols-maintained sperm fertilization capacity. This study enhances our understanding of oocyte-sperm interactions in the red-rumped agouti, contributing to advancing assisted reproduction techniques.