Dimethylacetamide alone or in combination with glycerol can be used for cryopreservation of ovine semen.

Dimethylacetamide has been included in different extenders for the cryopreservation of semen from species with promising results. The objective of this study was to evaluate the use of dimethylacetamide (DMA) in different concentrations, associated or not with glycerol (GLY), for the cryopreservation of ovine semen, and its effects on in vitro sperm parameters and post-thaw in vivo fertility. Five semen samples of five adult Santa Ines sheep (n=25) were used. The collected ejaculates were divided among the seven treatments for subsequent cryopreservation. The treatments presented different concentrations of DMA and GLY, being divided as G1: GLY 6%; G2: DMA 3%; G3: GLY 5% + DMA 1%; G4: GLY 4% + DMA 2%; G5: GLY 3% + DMA 3%; G6: GLY 2% + DMA 4%; G7: GLY 1% + DMA 5%. %. Post-thawing of the straws, aliquots were evaluated for computerized sperm kinetics (CASA) and plasma membrane integrity, using fluorescent probes and flow cytometry. After the in vitro evaluation of the sperm parameters, in vivo testing was performed by laparoscopic artificial insemination of 72 females. The post-thaw total motility (%) evaluated by CASA were 51.4, 51.4, 50.1, 53.6, 52.3, 52.8 and 46.9, respectively, for the seven groups. And the plasma membrane integrity (%) were 19.7, 28.4, 22.3, 29.4, 24.3, 17.9 and 16.9, respectively. There were no differences (P> 0.05) between the treatments for the parameters of spermatic kinetics and membrane integrity. For females inseminated with semen from the control group (G1, GLY6%), the percentage of pregnant females was 36.1%, a result similar to that obtained with G3 treatment (GLY5% + DMA1%). In conclusion, dimethylacetamide, either alone or in combination with glycerol, can be used for cryopreservation of ovine semen.

Dimethylacetamide and trehalose for ram semen cryopreservation.

Eighteen semen samples from nine Santa Ines rams were cryopreserved in order to study the cryoprotective capacity of dimethylacetamide (DMA) at two concentrations (3% and 6%), and its interaction with trehalose (TRE, 100 mOsmol). A further objective of this study was to evaluate in vivo fertility of ram semen cryopreserved with dimethylacetamide. The control treatment was an extender medium with 6% glycerol (GLY). Five treatments were examined: 6% GLY, 3% DMA, 6% DMA, 3% DMA + TRE, and 6% DMA + TRE. After thawing, the kinetic sperm parameters were analyzed using a computerized system. Sperm viability was observed using a multiple parameter sperm staining with propidium iodide (for plasmatic membrane integrity), JC-1 (for mitochondrial membrane potential), and FITC-PSA (for acrosomal integrity). The isosmotic extender with GLY was the most effective medium for the maintenance of sperm characteristics, compared to extenders containing DMA as cryoprotectant. Regarding fertility, the extender medium with 3% DMA may be a safe alternative for sperm cryopreservation, and does not compromise the fertility rates. The addition of TRE decreased the kinetic sperm parameters; however, a positive effect on the integrity of the plasmatic and acrosomal membranes was observed.