Avaliação in vitro do sêmen congelado de carneiros com diluidor suplementado com miricetina

Effect of antifreeze protein type III on frozen/thawed of spermatozoa recover from goat epididymis

The objective of this study was to evaluate the effect of antifreeze protein type III (AFP III) on the freezing of epididymal spermatozoa of goats. A total of 16 pairs of testicles were collected in a slaughterhouse and transported at approximately 5 °C in a thermal box. Epididymal spermatozoa were recovered by retrograde lavage and evaluated using a phase contrast microscope. Then, they were cryopreserved in extender based on Tris-egg yolk, supplemented with AFP III (0, 1, 10, 100 μg/mL), using an automated system. After thawing (37 °C/30 s), the spermatozoa kinetics were evaluated using the CASA automated system; and plasma and acrosome membrane integrity, mitochondrial membrane potential, and intracellular ROS production, by flow cytometry. There was no difference (P ≥ 0.05) between the experimental groups for the parameters of spermatozoa kinetics, mitochondrial membrane potential, and ROS production. However, the integrity of plasma and acrosome membranes of frozen spermatozoa with 100 μg/mL of AFP III was lower (P < 0.05) than the control group. It was concluded that the addition of AFP III to the Tris-egg yolk extender, used in the freezing of sperm obtained from the epididymis of goats, did not improve the preservation of these cells.

Diluent Containing Dimethylformamide Added With Sucrose Improves In Vitro Quality After Freezing/Thawing Stallion Sperm

The aim of this study was to investigate the effects of sucrose on post-thawed equine semen quality. Semen samples (n = 24) were collected from six stallions. They were diluted (200 × 10⁶ sperm/mL) in a freezing medium based on skimmed milk, egg yolk, dimethylformamide, and supplemented with sucrose at concentrations of 0 (Control), 25, 50, and 100 mM and in a commercial extender (BotuCrio). Subsequently, they were filled in straws (0.5 mL) and subjected to freezing and storage (-196°C). Immediately after thawing (37°C, 30 seconds), semen samples were evaluated for kinetics (CASA), plasma and acrosomal membrane integrity, and mitochondrial membrane potential (flow cytometry). The addition of 50 and 100mM sucrose to the freezing extender increased (P < .05) the parameters of TM, PM, VCL, VSL, and VAP, compared to the control group. The WOB parameter of the group supplemented with 100 mM sucrose was higher (P < .05) than the control group. Higher values ​​(P < .05) of ALH and BCF were observed in groups treated with sucrose (25, 50, and 100 mM), compared to BotuCrio. The semen frozen in the presence of 100 mM sucrose presented higher percentages (P < .05) of sperm with intact plasma and acrosomal membranes, and high mitochondrial membrane potential in relation to the other groups. It is concluded that the addition of sucrose to equine semen freezing extender increase motility (50 and 100 mM), plasma and acrosomal membrane integrity preserve, and high sperm mitochondrial membrane potential (100 mM) after thawing.