جستجوی مقالات مرتبط با کلیدواژه "انجماد-یخ گشایی" در نشریات گروه "علوم دام"

The decrease in the sperm number in each dose of artificial insemination (AI) has led to the deterioration of sperm quality in different species. Decreasing sperm quality could be a major obstacle to the commercial application of flow-sorted sperm for gender selection. The reduction in the viability of cryopreserved spermatozoa at high dilution rates (low number of sperm/dose) has been attributed to the lack of useful components of the seminal plasma in the final freezing medium. Although the effect of adding or removing seminal plasma or its proteins on sperm activity has been widely investigated, the results of these studies are contradictory. Factors such as the final dilution rate and the extenders used in each work may influence the results. On the other hand, a milk-based extender was reported to be better than a Tris-citrate-fructose extender for a percentage of uncapacitated and linear motile spermatozoa after freezing-thawing of ovine semen. However, milk-based diluents interfere with the evaluation of sperm kinematics by the computer-assisted sperm analysis (CASA) systems. It is speculated that by adding milk to the composition of Tris diluents while taking advantage of the positive effects of milk, problems related to sperm evaluation disorders by CASA will not occur. Therefore, this study aimed to investigate the impacts of adding bovine skim milk and seminal plasma into the formulation of a Tris-citrate-egg yolk LDL extender on the kinematics and viability of frozen-thawed bull sperm when sub-optimal sperm numbers were packed in straws.

Semen samples were collected from four bulls once a week for four consecutive weeks. The ejaculates collected on the same day were pooled provided that the semen concentration and progressive motility in each ejaculate were ≥2×109 cells/mL and ˃70%, respectively. The semen pool was divided into four equal aliquots and diluted with experimental extenders to obtain a final sperm concentration of 15×106 spermatozoa per mL. The base extender [made by Tris buffer (80% v/v), liquid ammonium sulfate-insoluble yolk fraction (20%), and glycerol (7% v/v)] was supplemented with 0, 5, and 10% (v/v) milk, and 0, 2 and 5% bovine seminal plasma. Therefore, the experiment was conducted in a completely randomized design with a factorial arrangement of 3×3. Diluted semen samples were frozen and stored in liquid nitrogen after being cooled and packed in 0.5 mL straws. The percentage of live cells in thawed samples was determined after Eosin-nigrosin staining and motility and kinematic parameters were analyzed by CASA. Data were subjected to analysis of variance using the general linear model of SAS software (version 9.2). Significant differences among treatment means were evaluated using the Tukey test. The statistical significance level was set at 0.05.

The results indicated that the addition of milk at both 5 and 10% led to an increase in progressive motility, straightness, and sperm velocity parameters (Average path velocity, curvilinear velocity, and straight-line velocity). Adding 5% seminal plasma to the basal extender formulation increased the motility indexes (total and progressive motility), velocity indexes, and directional indices of cryopreserved spermatozoa. Among the parameters reflecting sperm wobble characteristics, wobble and amplitude of literal head increased; however, beat cross frequency and mean angular displacement decreased in the freeze-thawed spermatozoa diluted in the extenders containing 5% seminal plasma compared to those in the control straws. The average concentrations of both factors (5% milk and 2% seminal plasma), when present together in the base composition of the diluent, have shown a better result in terms of percentage sperm viability than when present alone.

According to the results, adding 5% seminal plasma to the extender formulation increased the kinematic parameters of frozen-thawed sperms. However, it should be noted that these increases do not seem to be desirable in sperm doses for artificial insemination but could be acceptable for in vitro fertilization (IVF). However, the 2% level of seminal plasma reduced the mean angular displacement parameter without affecting the velocity indices, which may indicate an improvement in sperm fertility. The addition of 2% semen plus 5% milk in bull semen diluent has resulted in better sperm viability. In addition, the 5% proportion of milk improved many parameters of sperm motility and kinematics, as did the 10% proportion. Therefore, the addition of 2% bovine seminal plasma plus 5% skimmed cow's milk to a Tris-LDL-citrate extender may positively affect the viability of frozen-thawed bull sperm and kinematic values ​​associated with fertility when semen is diluted in small amounts/doses.

Studies had shown that excessive production of free radicals during sperm processing decreases its quality parameters including motility, viability, and fertilizing ability. Therefore, it seems necessary to use a compound with antioxidant properties during this process. Evening primrose oil has antioxidant properties due to its phenolic compounds. the purpose of this research is to investigate the effect of adding evening primrose seed oil to freezing diluent on the quality of ram sperm after freezing and thawing process.

In this research, the semen of 5 adult Romanov rams with an average age of 3 to 4 years and average weight of 60 to 65 kg were used. Semen collected using artificial vagina from trained rams twice a week. The treatments included control (without evening primrose seed oil), treatment 1 with 25 microliters EPSO, treatment 2 with 50 microliters EPSO, treatment 3 with 100 microliters EPSO. The collected semen sample to laboratory and examined in terms of volume, concentration and motility. Semen samples were diluted with a diluent based on Tris- lecithin soy and frozen. After thawing, parameters of general mobility and progressive mobility and other parameters related to mobility were evaluated. The survival percentage, membrane integrity, mitochondrial activity and peroxidation were determined.

The results showed that the level of 25 microliters of evening primrose seed oil improve the motility of the whole sperm compared to the control group, and no significant difference was observed in other experimental treatments compared to the control group. There was no significant difference between the 25 and 50 microliters treatments with the control group in the progressive parameter, but there was a significant difference with the 100 microliters treatment compared to the other treatments and the control treatment(P<0.01).The results of lipid peroxidation showed that the lowest amount of Malon-di-aldehyde production was related to the 25 microliters treatment but no significant difference was observed with the control treatment. The results of the apoptosis test showed that the addition of levels of 25 and 50 microliters of evening primrose seed oil decreased the amount of apoptosis compared to the control group and the level of 100 microliters of evening primrose seed oil(P<0.01). Also, survival in the treatment of 25 and 50 microliters compared to others The treatments had a significant difference and increased survival(P<0.01). And finally, dead sperms in the 25 microliters treatment were less compared to other experimental groups, and this caused a significant difference in this trait compared to other levels(P<0.01).

In general, the addition of evening primrose seed oil in the freezing diluent leads to an increase in the viability and health of the plasma membrane of sperms after thawing. Adding 25 microliters of evening primrose seed oil to the diluent caused a significant difference in the parameters of lipid peroxidation and apoptosis compared to the control treatment.

The aim of this study was to evaluate the effect of adding different levels of Rosemary extract with two different dose of glycerol on the motility, viability and membrane integrity of Moghani rams semen after freeze-thawing process. Semen was collected from four healthy and mature Moghani rams (3-4 years), twice a week for 3 weeks. Afterward the samples were evaluated and pooled for altering individual effects. After that the pooled semen was divided in to aliquots and extended with the treatments including 3 levels (0, 2 and 6 percent of rosemary extract with 5 or 7 percent of glycerol. then semen equilibrated at 5 ºC for 2 h, and aspirated into 0.25 mL straws. After equilibration, straws were frozen in liquid nitrogen vapor and plunged into liquid nitrogen for storage. Sperm parameters, including motility, viability, membrane integrity, and progressive motility by CASA (Computer Assisted Sperm Analysis) software were assessed. The results showed that the treatment supplemented with 2 percent of rosemary extract including 5 percent of glycerol could improve total and progressive motility, viability and membrane integrity (P>0.05). There were no any significant differences for VCL, VSL, ALH and VAP parameters among the experimental treatments (P> 0.05). In conclusion it is proposed that addition of 2 percent of rosemary extract with 5 percent of glycerol could improve the quality of Moghani ram sperms parameters after freeze-thawing process.

This study was designed to add the reduced glutathione to a lecithin nanoparticle-based extender and evaluate the quality of bull sperm after freezingand thawing. In the present study, the effect of four different levels of glutathione (0, 1, 2.5 and 5 mM) in extender-based on lecithin nanoparticles wasevaluated. The lecithin nanoparticles were prepared and the particle size was reduced by using a sonicator device. During three weeks, 48 ejaculatesfrom six Holstein bulls were collected and frozen. Properties evaluated after freezing and thawing were kinetic parameters (CASA), membraneactivity (HOST), membrane integrity (eosin-nigrosine) and morphology (Hancock solution). The results showed that using 2.5 mM glutathione in theextender significantly increased total and progressive motility (63.38±1.5 and 43.1±1.1 respectively, P <0.05). The results of eosin-nigrosine stainingand Host test showed that the highest viability and cell membrane functionality were related to 2.5 mM treatment (64.8±1.5 and 58.1±1.1 respectively)(P<0.05). In general, 2.5 mM glutathione could improve the quality of bull sperm compared with other concentrations after freezing and thawingprocess. It seems that the 2.5 mM glutathione is optimum concentration for bull extender based on the lecithin nanoparticles.

The use of cryopreserved semen in artificial insemination (AI) has numerous advantages for the animal husbandry, especially when used in breeding programs. Long-term storage of sperm in liquid nitrogen is a valuable technique for genetic resources preservation (Mazur et al., 2008). Animals are transported frequently and widely around the world, and it is necessary to create and maintain suitable conditions during animal transportation (Salamon and Maxwell, 2000). However, the costs, the risks of escape, and the potential for accidental death of animals are unavoidable. On the other hand, cryopreserved sperm can be transported in liquid nitrogen at a markedly lower cost and without the risk of escape or death of animals (Aires et al., 2003). Numerous investigations have been performed to improve the protocols for cryopreservation of sperm. The extenders used for semen cryopreservation protect the sperm against thermal shock, preserving both motility and fertility by promoting the stabilization of the plasma membrane, and providing energy substrates (Amirat et al., 2004). These attributes reduce the deleterious effects of changes in the pH and osmolarity, prevent the growth of bacteria, and protect the sperm cells from the damage caused by refrigeration, freezing, and thawing. For sperm cryopreservation, protocols using egg yolk have been successfully established and applied in various animal species (Aisen et al., 2002). However, the use of egg yolk in cryopreservation has been questioned, because of certain potential negative aspects. Egg yolk contains a wide variety of compounds that are both beneficial and also potentially harmful to sperm. Additionally, egg yolk introduces a risk of contamination by microbes that can subsequently produce endotoxins; and so, the egg yolk and sperm are subjected to quarantine inspection in the case of import or export. Therefore, a replacement for egg yolk with a well-defined chemical composition would be very advantageous. Lecithin, also known as phosphatidylcholine, is a component of egg yolk and is known to prevent cold shock during the freezing and thawing process in sperm cryopreservation. Soybean lecithin in particular has already been used as a replacement for egg yolk in sperm cryopreservation in various animals. Its non-animal origin and minimal sanitary risks make it preferable for this application. Soybean Lecithin can be used as an extender in the cryopreservation process (Akhter et al., 2012). The aim of this study was to evaluate the effects of Soybean Lecithin as extender on the ram semen quality after freeze-thawing. Semen was collected from the indigenous Ghezel rams. Twenty five ejaculates were collected throughout the entire study, with semen being collected twice a week (every Sunday and Tuesday) from each ram, using the artificial vagina. Ejaculates were collected in graduated test tubes, placed in a thermo flask at 34°C, and transported to the laboratory for evaluation within 1h interval. The raw or fresh undiluted semen was then microscopically evaluated for volume, concentration, and sperm motility. The sperm concentration was determined with the aid of a neubauer lam. A Computer Assisted Sperm Analysis (CASA) system was used to evaluate the different sperm motility characteristics. All data were analyzed using the statistical procedure of SAS (version 9.2). The analysis of variance (ANOVA) was used to test for significant differences between treatments. Characterization of the Ghezel ram sperm viability (percentage live/dead) of the semen samples was determined using an eosin/nigrosin stain (50μl eosin/nigrosin and 5μl semen). The volume of the ram ejaculates ranged between 0.75 and 1.5mL. The sperm concentration recorded in this study ranged between 0.9 and 1.3 × 109 sperm/mL. The effect of different soybean lecithin levels on the Ghezel ram semen characteristics following cryopreservation was evaluated. After initial evaluation of the ejaculates, all ram ejaculates were pooled and semen sample was then divided into three portions; then, semen samples were diluted with soybean lecithin (1, 1.5 and 2 %) citrate extender and cooled over a period of 2h to 5°C. The semen samples were equilibrated for 2h and then loaded into 0.25mL semen straws. The straws were frozen in liquid nitrogen (LN2) vapor, then semen straws were plunged into the LN2 (-196°C). The semen straws were thawed 30 days later, in a water bath (37°C) for 30 seconds. The sperm characteristics included motility and motion parameters, viability, plasma membrane and acrosome integrity, sperm abnormality, and lipid peroxidation were evaluated. Motility and velocity were microscopically evaluated using the Sperm Class Analyzer® (CASA) system. This study demonstrated that soybean lecithin (1.5%) containing 7% glycerol can be used to cryopreserve Ghezel ram semen effectively, based on the sperm motility characteristics. The low sperm motility results recorded when semen was cryopreserved in soybean lecithin (2%). The results showed that total motility and some sperm motion parameters (VSL, VCL, VAP and ALH) were significantly higher in 1.5% lecithin soybean treatment group (P <0.05). In terms of survival, the percentage of abnormal sperm, plasma membrane integrity, and lipid peroxidation were not significant between treatments. Acrosome membrane integrity of 1.5% soybean lecithin treatment group was higher than other treatments (P< 0.05). Briefly, 1.5% soybean lecithin treatment had better performance than other levels on the quality of the sperm after freeze-thawing.

The purpose of this study was to compare the effect of different levels of zinc sulfate on improving the quality of ram semen during freeze-thawing process outside of the reproductive season. Semen samples were collected from five Ghezel ram twice a week using the artificial vagina. Sperm samples were assigned to four treatment groups including: control, 17.5, 35 and 52.5 μm zinc sulfate, and then the freezing process was performed. After thawing motility, morphology and malondialdehyde levels of sperm were studied. Total and progressive motility of sperm containing the 17.5 µmol/ml zinc sulfate were significantly higher than control group (P <0.05). There was a significant difference in sperm morphology in the group receiving 52.5 μmol of zinc sulfate compared to the control group, which caused 52.5% increase in abnormal sperm (P <0.05). Adding 17.5 μmol of zinc sulfate increased unsignificantly the viability of sperms compared to the control group, but adding 35 and 52.5 μmol decreased significantly (P <0.05). The level of malondialdehyde production in the 35 µmol was lower than the other treatment groups and the control group and there was a significant difference between the groups 17.5 and 35 in comparison with the control group (P <0.05). Therefore, it can be concluded that the use of 17.5 and 35 µmol Zinc sulfate in Ghezel ram diluent semen improves some of the parameters of the sperm after the freeze-thawing process.

Introduction Semen cryopreservation has detrimental effects on sperm cell organelles, including cell membranes, mitochondria, and DNA due to the increased level of reactive oxygen species (ROS). Oxidation of polyunsaturated fatty acids in the sperm cell membranes is caused by high levels of ROS produced during the freezing-thawing process. This problematic condition causes decreased sperm motility, membrane integrity, increased metabolic changes and, ultimately, decreased fertility of the sperm. The addition of antioxidant compounds to the semen extender before semen cryopreservation can decrease ROS levels and their deleterious effects on spermatozoa. This study was conducted to assess the antioxidant effect of different levels of Rosa canina extract on microscopic and biochemical parameters and antioxidant enzyme activities of Ghezel ram semen after freezing-thawing process.
Materials and Methods Semen samples were collected from five Ghezel rams. Ejaculates were collected twice a week. To eliminate individual effects, ejaculates containing sperm with >80% progressive motility, volume of 0.75-2 mL, sperm concentrations greater than 3×109 sperm/mL and sperm abnormalities of less than 10% were pooled. Different concentrations of Rosa canina extract (0, 100, 150, 200 μL/mL) were added into the tris-egg yolk based diluent. After processing and freezing, the samples were stored in liquid nitrogen until the time of evaluation. Sperm motility characteristics were analyzed using computer-assisted sperm analysis (CASA). Sperm motility parameters including total motility, progressive motility, average path velocity, straight-line velocity, curvilinear velocity, linearity, straightness, amplitude of lateral head displacements and beat/cross frequency of sperm, viability, membrane integrity, sperm abnormalities, lipid peroxidation, antioxidant enzymes of glutathione peroxidase, superoxide dismutase and total antioxidant capacity were evaluated after thawing. Statistical analyses were performed using SAS software. The data were analyzed using the GLM procedure. Tukey–Kramer test were used to determine the significance differences between the experimental treatments. Significant differences were reported at the level of 5 percent.
Results and Discussion The results of lipid peroxidation (LPO) measurements show that adding 100 μl / ml Rosa canina extract to the diluent medium reduced the amount of malondialdehyde, which was not significant in comparison to the control group. This could be indicative of the beneficial effect of Rosa canina extract to reduce the process of lipid peroxidation of the sperm membrane. The results showed no significant difference in malondialdehyde and morphology of sperm in treatments containing Rosa canina extract compared to the control group. The addition of Rosa canina extract was not significantly effect in morphology and structure of sperms compared to the control group. However, the percentage of abnormal sperms decreased at levels of 100 and 150 μL/mL compared to the control group. The addition of 150 μL/mL of Rosa canina extract significantly improved the viability and plasma membrane integrity of sperms after freezing-thawing compared to the control and other treatment groups (P

The aim of the present research was to study the effect of different concentrations of rosemary (Rosmarinus officinalis L.) extract, (0, 10, 12.5, 16.6, 25 and 50) mg/L added to semen extender, on sperm qualitative and quantitative parameters after freezing-thawing process of rooster sperm. 10 Ross strain rooster were used. Semen samples were collected, 2 times a week. After adding the samples of semen based on the lecithin extender, they were placed and preserved at 5 ° C. The treatments of 10 and 12.5 mg/L of Rosemary significantly improved the mobility, in addition, treatments of 10, 12.5 and 16.6 mg/L improved progressive motility and viability before freezing (p≤ 0.05). The lowest and highest motility rates were respectively found in treatments of 0 and 10 mg/L of essential oil of rosemary (p≤ 0.05). Functional integrity of the sperm plasma membrane increased with treatment of 10 mg/L of essential oil of rosemary in comparison to other groups, except 12.5 mg/L. Also treatments of 10, 12.5 and 16.6 mg/L significantly decreased the apoptosis. According to these results, it seems that adding the levels of 10 and 12.5 mg/L rosemary extract’ in semen, based on lecithin extender can improve rooster’s sperm quality after thawing.