Abstract
The objective of the present study was to test dimethylacetamide (DMA) at different concentrations, associated or not to glycerol (GL), on the sperm viability of frozen sheep semen. Ten ejaculates of two adult sheep of Santa Ines breed were used. The ejaculates were divided into seven experimental groups, respecting the maximum limit of 5% of DMA: GL6%, DMA3%, GL5%+DMA1%, GL4%+DMA2%, GL3%+DMA3%, GL2%+DMA4%, and GL1%+DMA5%. The sperm cryopreserved in the different treatments was analyzed based on the subjective kinetic, structural integrity of the plasma membrane (EOS), functional integrity of the plasma membrane (OS) and sperm morphology, observing total defects (TD) and major defects (MD). The post-thawed total mortality (TM) and progressive mortality (PM) in the GL5%+DMA1% groups; GL4%+DMA2% and GL3%+DMA3% were similar (P> 0.05) to the control treatment (GL6%). Of these, the diluent GL4%+DMA2% was the only one that promoted the maintenance of post-thawed TM and PM when compared to in natura semen (P> 0.05). No significant differences (P> 0.05) were observed for the EOS, OS, TD and MD parameters, in the different groups evaluated. Dimethylacetamide associated to glycerol were effective in maintaining sperm viability in post-thawed sheep semen. However, a deleterious effect of DMA was observed at the highest concentrations or when it was not associated with glycerol.
Keywords:
cryopreservation; dimethylacetamide; semen; sheep