Fertility testing of preserved epididymal sperm by microinjection: A model for the rescue and utilization of genetically superior animals

Abstract

Background: Epididymal sperm preservation is a simple conservation approach that can help prevent the loss of high genetic quality of farm animals. The chance of loss increases, especially during disease outbreaks or other interruptions to normal reproduction function. Aim: This study looked into the ability of preserved ram epididymal sperm to fertilize oocytes. Due to motility becoming an issue following sperm storage for fertilization, the sperm micro injection of known as intracytoplasmic sperm injection (ICSI) approach was employed. Methods: The study was divided into two parts. First, involved preservation of epididymal sperm at 5°C for 12 days. During preservation, sperm quality parameters namely motility, viability, intact membrane, acrosome, and DNA are evaluated every three days. For fertility test in the second experiment, matured oocytes were injected with immotile sperm discovered in the last days of preservation. The presence of pronucleus development following in vitro culture is used as an indicator of sperm ability to activate and fertilize oocytes. Results: All sperm quality parameters significantly (p<0.05) declined during preservation time. On day 12, motility was discovered to be 0%, but viable sperm, sperm with intact membrane, acrosome and DNA remained at 41.86±9.30, 31,18±5.15, 21,88±1.93 and 33.35±8.74%, respectively. On the fertility test, we inject immotile sperm from day 12 of preservation, which has lowest motility found, into matured oocytes. Those sperms are able to activated (52.05±7.15%) and fertilize (31.37±1.75%) the injected oocytes, but their fertilizing ability is significantly lower (p<0.05) when compared to the sperm derived from ejaculate. Conclusion: In this study, simple preservation of epididymal sperm reduces all sperm quality criteria, particularly motility. Using the microinjection approach preserved sperm which no motility, still demonstrated its ability to activate and fertilize the oocytes. According to that, this study provides potential approaches and tools for using genetically superior animals that have lost their ability to execute regular fertilization, and also prolonging reproduction function.