39 The effect of supplementation of different concentrations of dithiothreitol and glutathione on post-thawed semen from Large White boars
M. R. Ledwaba A B , M. L. Mphaphathi A , M. A. Thema A B , C. M. Pilane A and T. L. Nedambale A BA Agricultural Research Council, Animal Production, Germplasm Conservation and Reproductive Biotechnologies, Pretoria, RSA
B Tshwane University of Technology, Faculty of Science, Department of Animal Sciences, Pretoria, RSA
Reproduction, Fertility and Development 35(2) 145-146 https://doi.org/10.1071/RDv35n2Ab39
Published: 5 December 2022
© 2023 The Author(s) (or their employer(s)). Published by CSIRO Publishing on behalf of the IETS
The study aimed to compare different concentrations (0, 2.5, 5, 7.5, and 10 mM) of antioxidants, dithiothreitol (DTT), and glutathione (GSH), on sperm parameters following the freeze-thawing of semen from Large White boars. Semen was collected from three Large White boars, then transported to the laboratory for evaluation. Semen was diluted with Beltsville Thawing Solution, equilibrated at 17°C for 120 min, and later centrifuged at 800 × g for 10 min at 15°C. Semen was supplemented with DTT or GSH at various concentrations (0, 2.5, 5, 7.5, and 10 mM) and then loaded into 0.25-mL freezing straws. The straws were then placed in liquid nitrogen (LN2) vapour for 20 min, and later plunged into the LN2 tank (−196°C). Semen was thawed at 37°C and then evaluated for sperm motility and velocity parameters using a computer-aided sperm analyser system. Eosin-nigrosin staining was used to evaluate sperm viability; hypo-osmotic swelling test was used to evaluate the sperm plasma membrane under the microscope (×100 magnification). Treatment means were separated using Fisher’s protected t-test least significant difference at a 0.05 level of significance (mean ± s.d.). The average sperm total motility (TM) for frozen-thawed semen ranged from 12.4% to 51.1% for all treatments. A higher percentage of sperm TM and progressive motility was recorded on control (51.1 ± 12.7; 27.1 ± 10.8), 5 mM GSH (45.2 ± 16.1; 24.7 ± 11.3), and 5 mM DTT (43.8 ± 10.3; 23.9 ± 10.7) as compared to all the treatments (P < 0.05). Control (21.3%) and 5 mM DTT (21.5%) treatments recorded a high percentage of sperm rapid motility as compared to all the treatments (P < 0.05). The 10 mM DTT recorded a high percentage of sperm velocity curvilinear (125.6 ± 34.3), velocity straight line (29.5 ± 4.7), and beat cross frequency (27.6 ± 8.4; P < 0.05). The average for normal live sperm for frozen-thawed semen ranged from 23.1% to 46.8% for all the treatments. The control (46.8 ± 6.5), 5 mM GSH (44.8 ± 8.2), and 5 mM DTT (40.3 ± 2.20) had a high percentage of normal live sperm following thawing (P < 0.05). For the hypo-osmotic swelling test, the control treatment (38.8 ± 6.1) had a higher percentage of swollen tail as compared to all other treatments (P < 0.05). In conclusion, supplementation of 5 mM GSH and 5 mM DTT in freezing extenders was found to be suitable concentrations for cryopreservation of Large White boar semen.
The authors express their sincere gratitude to the Agricultural Research Council for the financial assistance.
