The effects of glutathione supplementation on post-thawed Turkey semen quality and oxidative stress parameters and fertilization, and hatching potential.

This study was conducted to investigate the effect of semen extenders enriched with glutathione (GSH) on in vitro quality parameters and fertility of post-thawed turkey. In experiment 1, pools of semen diluted in glucose-based extender containing 0.5, 1, and 2 mM of GSH were cryopreserved. During the next step, a different variable such as motility and motion parameters, plasma membrane integrity (PMI) and functionality (PMF), DNA integrity, lipid peroxidation (MDA), total antioxidant capacity (TAC), catalase (CAT), glutathione peroxidase (GPx) and superoxide dismutase (SOD) activity were determined in the post-thawed samples. In the second experiment, artificial insemination was used to evaluate the fertility and hatchability performances of the post-thawed semen. The results of the first experiment showed that the extenders supplemented with 2, 1 and 0.5 mM of GSH had higher levels (p ≤ 0.05) of motility and motion parameters, PMI, PMF, TAC, CAT and SOD activity and lower abnormal morphology, DNA damage, and lipid peroxidation respectively in comparison to the control group (only extender with semen). Notably, the second experiment showed a higher rate of fertility (p ≤ 0.05) in 2 mM of GSH compared to the control group. It can be concluded that adding 2, 1 and 0.5 mM of glutathione leads to an improvement in the survival of the post-thawed turkey, while 2 mM of GSH can increase the fertility strength of the turkey sperm; hence it can be used to improve fertility and hatchability performance.

Effect of Different Cryoprotectants (Glycerol, Methanol and Dimethyl Sulfoxide) on Post-thaw Quality, Viability, Fertilization Ability and DNA Damage of Cryopreserved Nile Tilapia (Oreochromis niloticus) Spermatozoa.

BACKGROUND: Cryopreservation of sperm from different fish species requires different protocols. Therefore, it is necessary to perform studies to establish reliable procedures for each species. OBJECTIVE: Experiments were designed to analyse the effect of different types of cryoprotectants on post-thaw motility, viability and fertility as well as cryoresistance of cryopreserved Nile tilapia (Oreochromis niloticus) sperm. MATERIALS AND METHODS: Sperm samples were diluted with an ionic extender containing glycerol (Gly), methanol (MeOH) and dimethyl sulfoxide (DMSO) at ratios of 5, 10 and 15 % respectively. Diluted samples were aspirated into 0.25 ml French straws and frozen 3 cm above the surface of liquid nitrogen (LN) in a styrofoam box and stored in a LN tank. DNA damage was evaluated with the comet assay technique following cryopreservation. RESULTS: Supplementation of extender with 10% glycerol gave the highest motility rate compared with the other cryoprotectant groups (P<0.05). Differences in terms of post-thaw motility duration, cell viability and fertilization rates were not significant among treatments (P>0.05). Although Gly gave the best score (5.0 ± 0.1%, P>0.05) at the concentration of 10%, 5% Me2SO caused significant DNA damage (15.0 ± 1.0%, P<0.05) with the comet test. CONCLUSION: Gly or MeOH are more suitable cryoprotectants than DMSO for the cryopreservation of Nile tilapia sperm.

Antioxidative effects of cysteamine, hyaluronan and fetuin on post-thaw semen quality, DNA integrity and oxidative stress parameters in the Brown Swiss bull.

The aim of this study was to compare the effectiveness of antioxidants including cysteamine (2.5, 7.5 mm), hyaluronan (0.25, 1 mg ml(-1) ) and fetuin (5, 10 mg ml(-1) ) in the freezing of Brown Swiss bull semen. The best percentages of CASA motilities were achieved with 10 mg ml(-1) of fetuin and 2.5 mm of cysteamine. For sperm morphology, 10 mg ml(-1) of fetuin and 2.5 mm of cysteamine had better protective effects (P < 0.001). The results of hypo-osmotic swelling test showed that the percentage values of membrane integrity in all the groups, excluding that supplemented with 5 mg ml(-1) of fetuin, were higher than those of the control group (P < 0.001). Results obtained for the DNA damage of sperm cells demonstrated that 0.25 mg ml(-1) of hyaluronan, and 2.5 and 7.5 mm of cysteamine led to lower rates of spermatozoa with damaged DNA, compared with the control group (P < 0.001). The maintenance of superoxide dismutase and glutathione peroxidase antioxidant activities following freeze-thawing with 2.5 and 7.5 mm of cysteamine and 10 mg ml(-1) of fetuin was demonstrated to be at a higher level in comparison with the control group (P < 0.001). Malondialdehyde formation was found to be lower in the groups supplemented with 0.25 mg ml(-1) of hyaluronan and 7.5 mm of cysteamine after the freeze-thawing process (P < 0.001).

Lycopene and resveratrol improve post-thaw bull sperm parameters: sperm motility, mitochondrial activity and DNA integrity.

We focussed on evaluating the protective effect of lycopene and resveratrol on post-thaw bull sperm and oxidative stress parameters. Nine ejaculates for each bull were used in the study. Each ejaculate, splitted into three equal aliquots and diluted at 37 °C with base extenders containing lycopene (1 × 10(-3)  g ml(-1) ) and resveratrol (1 mm), and no antioxidant (control), was cooled to 5 °C and then frozen. Frozen straws were thawed in a water bath for evaluation. The supplementation of the semen extender with lycopene and resveratrol increased the percentages of post-thawed computer-assisted sperm analysis (CASA) motility (55.8 ± 3.8 and 61.9 ± 4.0%) and progressive motility (38 ± 2.4 and 37 ± 8.8), compared with the controls (50.7 ± 2.65 and 33.3 ± 3.74%, respectively, P < 0.05). Resveratrol provided a higher ALH (4.3 ± 0.1), in comparison with the control (3.9 ± 0.3, P < 0.05). The supplementation of the semen extender with lycopene and resveratrol produced a higher mitochondrial activity (24.6 ± 2.9 and 30.1 ± 6.5% respectively), compared with that of the control (11.8 ± 9.5%, P < 0.05). It was determined that both antioxidants resulted in a lower percentage of sperm with damaged DNA than that of the control (P < 0.05). Sperm motion characteristics except for ALH, acrosome integrity, sperm viability and oxidative stress parameters were not affected by the adding of lycopene and resveratrol.

Effects of curcumin and dithioerythritol on frozen-thawed bovine semen.

The aim of this study was to determine the effects of curcumin and dithioerythritol added into bull semen extender on sperm parameters, lipid peroxidation, total glutathione and antioxidant potential levels of bull spermatozoa following the freeze/thawing process. Twenty-seven ejaculates obtained from three bulls were included in the study. Each ejaculate that was splitted into five equal groups and diluted in a Tris-based extender containing curcumin (0.5 and 2 mM), dithioerythritol (0.5 and 2 mM) and no additive (control) was cooled to 5 °C and frozen in 0.25-ml French straws. The extender supplemented with 0.5 mMdose of curcumin led to lower percentage of total abnormality (20.40 ± 2.36%) when compared to the control (30.60 ± 1.47%, P < 0.05). Curcumin and dithioerythritol at 0.5 mM provided a greater protective effect in the membrane functional integrity (54.40 ± 2.09% and 50.00 ± 2.68%), in comparison with control (37.20 ± 1.77%, P < 0.001). Supplementation with antioxidants did not significantly affect the lipid peroxidation and antioxidant potential levels, while the maintenance of total glutathione levels in curcumin 0.5 mM was demonstrated to be higher than that of control, following the freeze/thawing (P < 0.05). Supplementation with these antioxidants prior to the cryopreservation process may be recommended to facilitate the enhancement of sperm cryopreservation techniques.

Effects of different extenders and centrifugation/washing on postthaw microscopic-oxidative stress parameters and fertilizing ability of Angora buck sperm.

The main objective of the current study was to evaluate the effects of extender type and centrifugation/washing prior to cryopreservation on the postthaw sperm parameters, lipid peroxidation, and superoxide dismutase activity of Angora buck (Capra hircus ancryrensis) sperm. Ejaculates collected from three Angora bucks were used in this study. Two consecutive ejaculates from each buck were pooled and split into equal parts in four Falcon tubes. Two tubes were diluted at 37 degrees C and then centrifuged to remove semen plasma. After centrifugation, two sediment parts were diluted with a Tris-based extender and commercial Bioxcell extender, respectively. The remaining two parts, which were not centrifuged/washed, were diluted with the above-mentioned extenders, respectively. Diluted samples were cooled to 5 degrees C and frozen in 0.25-mL French straws to be stored in liquid nitrogen. Frozen straws were thawed individually at 37 degrees C for 20 sec in a water bath for evaluation. The semen part with centrifugation/washing in the Bioxcell extender (BC) demonstrated a higher rate of subjective motility (58.1+/-3.0%) compared with that of groups with (TC) or without (T) centrifugation/washing in the Tris-based extender (P<0.01). Angora buck sperm frozen with (BC) or without (B) centrifugation/washing in the Bioxcell extender demonstrated higher percentages of motility (60.6+/-2.7% and 54.3+/-4.8%, respectively) compared with that of groups T and TC. The postthaw progressive motility rate (22.3+/-2.7%) was significantly greater for semen parts diluted in B compared with that of other groups. BC gave rise to a lower value of average path velocity (90.0+/-5.2 microm/sec) compared with that of other groups (P<0.01). For straight linear velocity and linearity index, the highest values (103.2+/-4.7 microm/sec, 47.5+/-1.6% and 94.8+/-3.0 microm/sec, 44.8+/-1.1%, respectively) were obtained from B and TC (P<0.001). For sperm acrosome and total abnormalities, TC gave the highest values (11.2+/-0.6% and 26.6+/-1.5%, respectively, P<0.01). In the group frozen in BC, the percentage of membrane integrity assessed by hypo-osmotic swelling test was higher (61.2+/-2.2%) than that of the other groups (P<0.001). With respect to fertility results based on 35-d pregnancy rates, BC gave a higher rate (76.5%) than that of TC (27.8%, P<0.05). Malondialdehyde formation was found to be lower (1.64+/-0.26 nmol/L) in BC than in the other groups after the freeze-thawing process (P<0.001). In the semen part frozen in BC, superoxide dismutase activity was higher (0.18+/-0.02 U/mg protein) compared with that of the other groups (P<0.05). Further studies are required to obtain more precise results for the characterization of oxidative stress parameters and fertilizing ability in cryopreserved buck spermatozoa.