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The addition of antioxidants to semen cryopreservation extenders has been employed for combating oxidative damage. This work aimed to evaluate the addition of carotenoid canthaxanthin to a cryopreservation extender of ram semen. Three breeder rams were used and, after semen collection, with 48-hour intervals between collection, the samples were included in the pool formation (n = 6). The experimental groups comprised 0 (control), 0.1, 1, 10, and 25 μM of canthaxanthin. After thawing (37°C/30 s) and incubation at 37°C for 2 hours, semen aliquots from each group were evaluated for sperm kinetics (CASA), the integrity of the plasma and acrosomal membranes (iPAM), intracellular reactive oxygen species (ROS) production, and lipid peroxidation (LPO) by flow cytometry associated with the image. The control group and canthaxanthin 1 μM after incubation at 37°C for 2 hours showed increases of curvilinear velocity and amplitude of lateral head displacement with decreases of linearity, straightness, and wobble (p < 0.05), which were not observed for the canthaxanthin 10 and 25 μM. The supplementation of a Tris-egg yolk extender with canthaxanthin had no effect on the iPAM, intracellular ROS production in viable spermatozoa, or LPO. In conclusion, supplementation with 10 and 25 μM of canthaxanthin in a Tris-egg yolk extender used for ram semen cryopreservation is able to protect ovine sperm from kinetic changes after incubation at 37°C for 2 hours post-thawing.

The aim was to verify the efficiency of different glycerol concentrations (1%, 3%, and 5%) for cryopreservation of stallion semen. After semen collection, sperm cells were evaluated for motility and acrosin activity. The semen was divided into three equal parts and resuspended in freezing diluent without glycerol in a 1:1 proportion and were incubated for 20 minutes at room temperature. Immediately after centrifugation for 10 minutes at 600g and discarding the supernatant, each pellet was diluted with the same diluent and further centrifuged for 10 minutes. After the second centrifugation, each pellet received freezing glycerol-containing diluent under concentrations of 1%, 3%, and 5% and was loaded in 4mL macro-tubes. These macro-tubes were placed in liquid nitrogen vapor for 15 minutes for immediate immersion in liquid nitrogen and storage at -196°C. After thawing at 50°C for 40 seconds, semen samples were initially evaluated for sperm motility and acrosin activity. Moreover, semen was also incubated at 37ºC and evaluated for sperm motility after 60 and 120 minutes in a thermoresistance test (TRT). Immediately after thawing and during the TRT, both progressive and total sperm motility was lower in 1% glycerol (P0.05) between these two later concentrations. The acrosin activity in fresh semen was only greater (P0.05) between these later glycerol concentrations. In conclusion, based on sperm motility and acrosin activity, that 3% and 5% glycerol concentrations are suitable for stallion semen cryopreservation. [ABSTRACT FROM AUTHOR]

An abstract of the article "Resveratrol as a protective agent of goat sperm submitted to sex sorting in discontinuous Percoll gradient - preliminary results" by Ellen C. B. Silva and colleagues is presented.