Influence of Ascorbic Acid and Glutathione Antioxidants on Frozen‐Thawed Canine Semen

Abstract

Poor sperm viability post-thaw has resulted in constant research into methods of cryopreservation of canine semen. One factor that may be involved in poor viability is sperm oxidative stress caused by excessive formation of reactive oxygen species. The present study was performed in order to evaluate the effect of different concentrations of ascorbic acid (AA) and glutathione (Glu) added to an extender for the freeze-thawing of dog sperm. Semen from five mature dogs was collected and frozen in two studies. Prior to and after freezing, sperm motility, morphology and membrane status were examined. In addition, sperm motility was examined up to 120 min after thawing to evaluate thermo-resistance. In study I, semen was collected twice from each dog. On both occasions, semen was divided into three aliquots: control, Glu 1 mM and Glu 5 mM. In study II, semen was collected twice and divided into three aliquots; control, AA 50 microM and AA 250 microM. Initial sperm motility was significantly higher in sperm diluted with AA 50 microM; sperm longevity, however, measured by a thermal-resistance test (TRT), was higher for Glu treatments. Higher concentration of Glu produced significant improvement in TRT and membrane status, whereas higher concentration of AA had a negative impact in sperm longevity. Antioxidant supplementation to semen freezing extenders improved semen quality post-thaw. Moreover, Glu had the most beneficial effect when supplemented at 5 mM.

The Efficacy of In Vitro Sperm Tests in Predicting Pregnancy Success after Artificial Insemination in the Bitch

“…Sperm must function adequately in order to achieve satisfactory interaction with the oocyte. Sperm membranes are known to be rich in polyunsaturated fatty acids and thus, very susceptible to lipid peroxidation, which causes partial or total functionality loss [33,34].…”

Vitamin E and reduced glutathione in Prochilodus lineatus (curimba) semen cryopreservation (Characiformes: Prochilodontidae)

“…There are many studies that show the positive effects of antioxidants in semen motility of cryopreserved semen (Askari et al, 1994;Bilodeau et al, 2001;Monteiro et al, 2009). In our study the effect of antioxidant concentration on the rate of semen motility was not significant when compared with the control treatment.…”

“…The authors obtained an increase in the motility of human and dog semen cryopreserved with these antioxidants compared to semen that was cryopreserved without these substances (Askari et al, 1994;Monteiro et al, 2009).…”

The use of reduced glutathione (GSH) as antioxidant for cryopreserved sperm in dogs

“…To reduce the effects of ROS during sperm cryopreservation, researches involve an addition of antioxidants agents to extenders (Monteiro et al, 2009;Lucio et al, 2016b). Antioxidants are produced physiologically by organisms, to minimize or prevent the oxidation by ROS effect in a determined substrate (Shi et al, 2013).…”

“…Therefore, antioxidant supplementation (i.e. SOD or GSH) in extender to cryopreservation improves the spermatic quality after thawing (Monteiro et al, 2009). Actually, in humans the supplementation or addition of antioxidant substances presents more promising results when in domestic animals (Kobori et al, 2014;Kedechi et al, 2017).…”