CARACTERÍSTICAS MORFOFUNCIONAIS DO SÊMEN CANINO REFRIGERADO E CONGELADO, USANDO DOIS DIFERENTES MEIOS DILUENTES

Abstract

The objective of this study was to verify the efficiency of two different extenders: TRIS/Fructose/Citric Acid/Glycerol (8 %) - (TRIS 8 %) (Morton, 1988 modified) and commercial extender - MP50) (PAPA et al., 2002) – for freezing dog semen. Ten ejaculates from different adult dogs were collected by digital manipulation. The samples semen were evaluated for sperm motility and vigor, hypo-osmotic swelling test, sperm membrane integrity, sperm morphology, ultra structural analysis in three different moments, fresh (T1), cooled (T2) and thawed (T3). The samples were packaged in 0.5 mL French straws with 40 x 106 spermatozoa/ straw, and kept at 5 0C for 60 minutes (T2); then frozen in static vapor of nitrogen for the following 20 minutes and immersed in liquid nitrogen until being thawed in 70 0C water for 8 seconds (T3). By analysis of variance, it would be possible to verify the animal effect on almost all variables observed in this study, except for sperm motility and membrane integrity. For cooled semen (T2), MP50 were significantly better for hypo-osmotic swelling test, sperm membrane integrity (p<0.05) and for thawed semen (T3), there was no significant difference between extenders. By ultra structural analysis, it was possible to verify swelling plasma and acrosomal sperm membranes in the different stages of freezing process. In conclusion, the extenders showed the same results as to morphofunctional characteristics the semen canine thawed. KEY WORDS: Semen, dog, freezing and extender.