1- Department of Biology, Faculty of Basic Sciences, Azarbaijan Shahid Madani University, Tabriz, Iran,
2- Department of Animal Science, Faculty of Agriculture, University of Kurdistan, Sanandaj, Iran
3- Department of Biology, Faculty of Basic Sciences, Azarbaijan Shahid Madani University, Tabriz, Iran
4- Department of Animal Science and Poultry, Faculty of Agricultural Technology, University of Tehran, Tehran, Iran
2- Department of Animal Science, Faculty of Agriculture, University of Kurdistan, Sanandaj, Iran
3- Department of Biology, Faculty of Basic Sciences, Azarbaijan Shahid Madani University, Tabriz, Iran
4- Department of Animal Science and Poultry, Faculty of Agricultural Technology, University of Tehran, Tehran, Iran
Abstract: (315 Views)
Extended Abstract
Background: The progress of breeding programs and improvement of the reproductive status of livestock in the last few decades is the result of using the artificial insemination technique. This technique is widely used in heavy livestock, but in light livestock, the complex anatomical system of the female animal and the very high sensitivity of ram sperm to cold shock and oxidative stress are among the limitations that have often made the use of artificial insemination difficult. Given the importance of the quality of the produced sperm in sheep artificial insemination, the sperm used is mostly fresh and chilled semen. However, it is not always possible to use fresh semen, and sperm preservation is inevitably necessary. Therefore, sperm cooling can be used in sheep artificial insemination in the short term with minimal damage to sperm and also has the necessary fertility. However, due to the decrease in temperature and the occurrence of cold shock, the production of free radicals increases during the cooling process and causes numerous structural and biochemical damages to sperm, reducing their fertility chances. To combat this problem, it is crucial to use the right antioxidant compound in the diluent. Gamma oryzanol is a natural antioxidant compound derived from barley, whose antioxidant properties have been proven in many studies. The antioxidant properties of gamma oryzanol are primarily related to the scavenging of free radicals, especially superoxide, hydroxyl, and hydrogen peroxide radicals, with the hydroxyl group on the phenolic ring of the ferulic acid moiety being the main inhibitor of free radicals. Gamma oryzanol acts as an activator of intracellular antioxidant enzymes, such as superoxide dismutase, catalase, glutathione peroxidase, and glutathione reductase, increasing their activity. It has also been shown that gamma oryzanol can interfere with the Nrf-2 biochemical pathway and increase the expression of proteins related to some antioxidant enzymes, such as superoxide dismutase, glutathione peroxidase, and catalase, and increase their production. Therefore, this study aimed to investigate the effects of adding different concentrations of gamma oryzanol to the ram epididymal sperm diluent at different incubation times at 4 °C.
Methods: In this experiment, testicular tissue was transported to the laboratory within one hour after collection from the slaughterhouse. Sperm was prepared by cutting the epididymal tail. After initial evaluation, sperm samples, with viability above 85%, progressive motility above 75%, and abnormalities below 10%, were selected and diluted in the Tris-egg yolk-based diluent. At 37 °C, different concentrations of gamma oryzanol (0, 50, 100, and 200 μM) were added to the diluent containing sperm. Subsequently, the samples were transferred to 4 °C in isothermal water for cooling. The samples were gradually cooled to 4 °C and equilibrated after about 2 hours. At 6, 12, 24, and 48 hours after fixation, the samples were evaluated at this temperature for the following parameters: total motility, progressive motility, viability, plasma membrane integrity, percentage of abnormalities, malondialdehyde (MDA) concentration, and antioxidant enzyme activities of superoxide dismutase (SOD), glutathione peroxidase (GPX), and catalase (CAT). The data obtained from the evaluations were analyzed by the SAS software and the GLM procedure at a significance level of 0.05.
Results: The results of this experiment showed that the diluent containing 100 μM of gamma oryzanol significantly improved the overall motility characteristic compared to the control group at 12, 24, and 48 hours (P < 0.05). However, no significant difference was observed between the diluents in the progressive motility characteristic at all evaluated times (P > 0.05). In examining the percentage of sperm viability, only the diluent containing 100 μM of gamma oryzanol significantly increased sperm viability at 12 hours, but there was no significant difference between the groups at the other times. Regarding the sperm plasma membrane integrity parameter, adding 100 μM of gamma oryzanol had a significant effect compared to the control group. Regarding sperm abnormalities, no significant difference was found between the groups at any time. The results of the present experiment showed that adding 50 and 100 μM of gamma oryzanol significantly reduced MDA concentrations at 12 and 24 hours. Moreover, the 100 μM concentration of this compound significantly increased SOD enzyme activity at 12 and 24 hours, and the 100 and 200 μM concentrations significantly increased GPX enzyme activity only at 24 hours (P < 0.05). However, the addition of gamma oryzanol concentrations did not significantly increase CAT enzyme activity compared to the control group at all the evaluated times (P > 0.05).
Conclusion: The results of this experiment show that the use of the antioxidant compound gamma oryzanol in the diluent medium can improve the quality of ram epididymal sperm to some extent in short periods after refrigeration. Therefore, using gamma oryzanol at a concentration of 100 μM in ram sperm diluent is recommended for short-term refrigeration.
Background: The progress of breeding programs and improvement of the reproductive status of livestock in the last few decades is the result of using the artificial insemination technique. This technique is widely used in heavy livestock, but in light livestock, the complex anatomical system of the female animal and the very high sensitivity of ram sperm to cold shock and oxidative stress are among the limitations that have often made the use of artificial insemination difficult. Given the importance of the quality of the produced sperm in sheep artificial insemination, the sperm used is mostly fresh and chilled semen. However, it is not always possible to use fresh semen, and sperm preservation is inevitably necessary. Therefore, sperm cooling can be used in sheep artificial insemination in the short term with minimal damage to sperm and also has the necessary fertility. However, due to the decrease in temperature and the occurrence of cold shock, the production of free radicals increases during the cooling process and causes numerous structural and biochemical damages to sperm, reducing their fertility chances. To combat this problem, it is crucial to use the right antioxidant compound in the diluent. Gamma oryzanol is a natural antioxidant compound derived from barley, whose antioxidant properties have been proven in many studies. The antioxidant properties of gamma oryzanol are primarily related to the scavenging of free radicals, especially superoxide, hydroxyl, and hydrogen peroxide radicals, with the hydroxyl group on the phenolic ring of the ferulic acid moiety being the main inhibitor of free radicals. Gamma oryzanol acts as an activator of intracellular antioxidant enzymes, such as superoxide dismutase, catalase, glutathione peroxidase, and glutathione reductase, increasing their activity. It has also been shown that gamma oryzanol can interfere with the Nrf-2 biochemical pathway and increase the expression of proteins related to some antioxidant enzymes, such as superoxide dismutase, glutathione peroxidase, and catalase, and increase their production. Therefore, this study aimed to investigate the effects of adding different concentrations of gamma oryzanol to the ram epididymal sperm diluent at different incubation times at 4 °C.
Methods: In this experiment, testicular tissue was transported to the laboratory within one hour after collection from the slaughterhouse. Sperm was prepared by cutting the epididymal tail. After initial evaluation, sperm samples, with viability above 85%, progressive motility above 75%, and abnormalities below 10%, were selected and diluted in the Tris-egg yolk-based diluent. At 37 °C, different concentrations of gamma oryzanol (0, 50, 100, and 200 μM) were added to the diluent containing sperm. Subsequently, the samples were transferred to 4 °C in isothermal water for cooling. The samples were gradually cooled to 4 °C and equilibrated after about 2 hours. At 6, 12, 24, and 48 hours after fixation, the samples were evaluated at this temperature for the following parameters: total motility, progressive motility, viability, plasma membrane integrity, percentage of abnormalities, malondialdehyde (MDA) concentration, and antioxidant enzyme activities of superoxide dismutase (SOD), glutathione peroxidase (GPX), and catalase (CAT). The data obtained from the evaluations were analyzed by the SAS software and the GLM procedure at a significance level of 0.05.
Results: The results of this experiment showed that the diluent containing 100 μM of gamma oryzanol significantly improved the overall motility characteristic compared to the control group at 12, 24, and 48 hours (P < 0.05). However, no significant difference was observed between the diluents in the progressive motility characteristic at all evaluated times (P > 0.05). In examining the percentage of sperm viability, only the diluent containing 100 μM of gamma oryzanol significantly increased sperm viability at 12 hours, but there was no significant difference between the groups at the other times. Regarding the sperm plasma membrane integrity parameter, adding 100 μM of gamma oryzanol had a significant effect compared to the control group. Regarding sperm abnormalities, no significant difference was found between the groups at any time. The results of the present experiment showed that adding 50 and 100 μM of gamma oryzanol significantly reduced MDA concentrations at 12 and 24 hours. Moreover, the 100 μM concentration of this compound significantly increased SOD enzyme activity at 12 and 24 hours, and the 100 and 200 μM concentrations significantly increased GPX enzyme activity only at 24 hours (P < 0.05). However, the addition of gamma oryzanol concentrations did not significantly increase CAT enzyme activity compared to the control group at all the evaluated times (P > 0.05).
Conclusion: The results of this experiment show that the use of the antioxidant compound gamma oryzanol in the diluent medium can improve the quality of ram epididymal sperm to some extent in short periods after refrigeration. Therefore, using gamma oryzanol at a concentration of 100 μM in ram sperm diluent is recommended for short-term refrigeration.
Send email to the article author
| Rights and permissions | |
 |
This work is licensed under a Creative Commons Attribution-NonCommercial 4.0 International License. |
