Glycerol, ethyleneglycol and cryopreservation influences on semen and sperm DNA-Protein complex in stallion

Abstract

The cryopreservation process cause stress physical and chemical to the spermatozoa, causing biochemistry alteration, irreversible reduction of the spermatic motility, increase of the DNA degeneration and intrcellular enzyme and lipids release. The aim of this study was to evaluate the influence of non-breeding and breeding seasons, glycerol and ethylene glycol, cryopreservation and thawing processes on stallion spermatozoa DNA-protein complex. It was compared fresh semen, diluted semen frozen without cryoprotectants, diluted semen exposured to cryoprotectants but not frozen and d) diluted semen frozen with cryoprotectants. Six stallions had 12 semen collections each. DNA-protein complex pathology was assessed by optical microscopy (1000x) using spermatozoa treated with ethanol-acetic acid 3:1 (v/v), HCl 4N at room temperature and toluidin blue 0,025% in McIlavaine buffer. Results showed that DNA-protein complex were different between frozen and not frozen spermatozoa groups (P<0,05). Frozen semen without cryoprotectants had no increasing of DNA-protein complex pathology compared to semen cryopreserved with cryoprotectant, but both showed increasing in relation to fresh and diluted semen exposured to cryoprotectants. The influence of non breeding and breeding season showed significant difference (P<0,05) in the fresh semen and fresh semen frozen without cryoprotectants. Cryopreservation process had negative influence on spermatozoa DNA-protein complex.