Academic literature on the topic 'Sperm freezability. eng'

Ejaculates were collected twice a week from the bulls, via an artificial vagina, during two weeks. The suitable ejaculates obtained for sperm density (≥ 1.4 × 10 9 spermatoz oa / ml) and for motility (≥ 75%) were used for dilution and freezing of semen. A Tris - based extender (Tris 297.58mM, citric acid 96.32mM, fructose 82.66mM, egg yolk 15% (v/v), glycerol 5% (v/v), gentamicin 0.1 ml / 100ml, pH 6.8 - 7.0) was used as the base extender (cryopreservation diluent). Pooled ejaculate was split into 2 equal aliquots and diluted at 32 °C with base extender containing ferulic acid (100 μM) and no antioxidant (control), respectively. Each aliquot was diluted to a final semen concentrati on of approximately 1.2 × 10 8 sperm/ml (single step dilution), in 15 - ml polypropylene centrifuge tubes. After dilution, semen samples were kept at room temperature for 10 minutes then, the diluted semen samples were aspirated into 0.25 ml French straws, seal ed with polyvinyl alcohol powder and equilibrated at 5 °C for 3 h. After equilibration, the straws were frozen in liquid nitrogen vapour (4 cm above the liquid nitrogen, ~ - 100 o C ) for 10 min and then plunged into liquid nitrogen for storage, - 196 o C . In the study, sperm samples containing antioxidant and non - antioxidant were evaluated for spermatozoa motility and membrane integrity after freezing / thawing. In the present study, no statistically significant difference was found between the control and experim ental groups for motility and membrane integrity after freeze - thawing. The application consisted of 4 replications.

Sperm cryopreservation is the best technology for long-term storage of the semen. However, the damage of boar spermatozoa by cryopreservation is more severe than in other animal species and a standardized freezing protocol for efficient cryopreservation has not been established yet. Semen quality and freezability vary greatly between breeds as well as between individual boars and even the season. Boar spermatozoa are sensitive to low temperatures; they sustain damage and a high rate of mortality and freezing/thawing the boar semen may strongly impair the sperm function and decrease the semen quality. The freezability of boar semen can be influenced by a cryopreservation procedure, and also by using various additives to freezing and thawing extenders such as antioxidants. In order to obtain acceptable results after thawing the boar semen, it is necessary to combine an optimal amount of additives (glycerol, egg yolk, sugars, antioxidants), cooling and warming velocities.

The aim of this study was to investigate the effect of two kinds of commercial egg yolk-free extenders: Bioxcell and AndroMed on in vitro sperm function of sheep. A total of 10 ejaculates were collected from 5 adult Iranian Zandi rams using artificial vagina. Semen samples were mixed and diluted with Bioxcell or AndroMed. Freezing was conducted using imv semi-automatic equipment. The percentage of motility and progressive motility of sperm were evaluated before freezing (at 37°C), after refrigeration (at 5°C) and thawing, and recovery rate was calculated. Data was analyzed using proc GLM of SAS. The effect of extender on sperm qualitative characteristics after thawing was significant. Mean percentage of motility, progressive motility and recovery rate were higher (P≤0.01) in AndroMed than Bioxcell. Results suggested that AndroMed in comparison with Bioxcell had more ability to preserve sperm quality during freezing process.

The aim of this study was to compare the effect of two semen extenders and four permeating cryoprotectants on post-thaw sperm quality of Andalusian donkeys. First, 32 ejaculates were pooled, split and frozen in either Gent B or INRA 96 with egg yolk and glycerol. Second, 12 pooled semen samples were simultaneously frozen in Gent B (glycerol) or Gent A containing ethylene glycol (EG; 1 or 1.5%) or dimethyl sulfoxide (DMSO; 1.5 or 2%). Finally, nine pooled samples were simultaneously cryopreserved in Gent A containing 1% EG (as control), dimethylformamide (DMFA; 1 or 2.5%) or a combination of 1% EG and 1.5% DMFA. Gent B yielded a higher (P < 0.01) post-thaw sperm motility than modified INRA96. EG 1% increased the sperm membrane integrity (P < 0.001), whereas DMSO affected sperm motility and membrane integrity (P < 0.001). DMFA 2.5% yielded higher (P < 0.001) values for sperm motility and membrane integrity. We concluded that Gent B improves in vitro post-thaw sperm quality of donkey spermatozoa, but the replacement of glycerol with 1% EG or 2.5% DMFA increased sperm protection against cryodamage. The use of DMSO for freezing donkey semen was unsuccessful and a toxic effect is suspected. These extenders should be included in the pre-freeze test for each donkey.

Here, we compared the effects of ram, buck and dromedary camel seminal plasma mixed with TRIS-egg yolk glycerol extender on the freezing preservation of ram semen. Awassi ram semen samples underwent primary evaluation and were then pooled and diluted with the following diluents: TRIS-egg yolk glycerol mixed with (1) whole ram semen as a control (T); (2) ram sperm after seminal plasma removal (W); or (3) ram, (4) buck or (5) camel seminal plasma (R, B and C, respectively). The diluted semen was frozen using liquid nitrogen vapor. Various sperm parameters were evaluated in the frozen semen. Total motility before and after freezing was significantly higher in R, B and C diluents than in T and W diluents. Progressive motility after freezing was significantly higher in R, B, C and T diluents than in W diluent. Vitality after freezing was significantly higher in B than in W diluent. DNA fragmentation before and after freezing was significantly lower in R, B, C and T diluents than in W diluent. Plasma membrane integrity before and after freezing was significantly higher in R, B and C diluents than in W diluent. Sperm abnormalities before freezing were significantly lower in R, B and C diluents than in W diluent. Malondialdehyde concentration was significantly higher in T and W diluents than other diluents. Reduced glutathione concentration was significantly higher in B diluent than other diluents. Moreover, reduced glutathione concentration was significantly higher in C, R and W diluents than in T diluent. Thus, the addition of ram, buck or camel seminal plasma to TRIS-egg yolk glycerol extender improved the quality of frozen ram semen, while seminal plasma removal adversely affected it. Ram, buck and camel seminal plasma had similar effects, with no significant differences between them on the evaluated parameters of frozen ram semen.

The aim of this study was to investigate the effect of 2 different commercial egg yolk-free extenders, Bioxcell and AndroMed, on post-thaw ram sperm motility and recovery rate. A total of 10 ejaculates were collected from 5 adult Iranian Zandi rams using artificial vagina during 3 weeks, once per week. Preexamination was conducted on semen, and semen motility >70% were selected. Semen samples were pooled and diluted with Bioxcell or AndroMed. Pooled semen was split into 2 treatments and extended to a final concentration of 200 × 108 spermatozoa per mL with extenders. The extended semen was manually packed into 0.25-mL mini-straws and sealed with PVC powder. After 4 h of equilibration in a waterbath at 5°C, the straws were dried with paper tissue, placed horizontally on a rack, and transferred to an isothermal box to be frozen in vapor 5 cm above liquid nitrogen. After 10 min, the straws were plunged into liquid nitrogen. Freezing was conducted using IMV semi-automatic equipment. The percentage of motility and progressive motility of sperm were evaluated before freezing (at 37°C), after refrigeration (at 5°C) and thawing, and recovery rate was calculated. To evaluate indices of sperm motility including the percentage of motile sperm and the progressive forward motility, semen was diluted with 0.9% NaCl w/v (1:100). Ten μL of diluted semen was placed on the prewarmed (37°C) microscope slide (76.2 mm × 24.5 mm; Pearl, China) covered with a cover slip (24 × 24 mm; Menzel-Glaser, Germany) and examined 10 different fields under a phase contrast microscope (Nikon, Tokyo, Japan), at ×200. Dilution factor 1:5 was used. The microscope was equipped with warm plate set at 37°C. Data were analyzed using Proc GLM of SAS. The effect of extender on sperm qualitative characteristics after thawing was significant. Least squares mean percent motility and progressive motility of AndroMed (36.05% ± 0.75; 29.0% ± 0.84) was significantly higher (P < 0.01) than Bioxcell (8.02% ± 0.35; 4.0% ± 0.60); least squares mean recovery rate in AndroMed (34.23% ± 1.05) also was higher (P < 0.01) than Bioxcell (10.0% ± 0.92). Results suggested that AndroMed in comparison with Bioxcell had more ability to preserve sperm quality during the freezing and thawing process.

Inter- and intra-boar differences in sperm freezability are observed independent of the sperm quality before freezing, the breed, or the genetic line. This study aimed to determine whether boars with different post-thaw sperm quality also show differences in sperm DNA integrity. Sperm-rich fractions (3 to 10 ejaculates per boar) from 19 fertile mature boars were extended in Beltsville thawing solution (BTS) and cooled to 17�C for 16 h. Then, samples were centrifuged at 2400g for 3 min, extended in freezing extender (lactose/egg yolk/glycerol/Equex STM; Nova Chemical Sales, Inc., Scituate, MA, USA) to a final concentration of 1 � 109 spermatozoa/mL, dispensed into 0.5 mL straws, and frozen in a programmable cell freezer at a rate of -20�C min. Thawing was carried out in a water bath at 37�C for 20 s. Frozen-thawed spermatozoa were evaluated for progressive sperm motility (PSM) using a computer-assisted sperm analysis (CASA) system, and sperm viability (PMI) using flow cytometry. All data generated were used for a multivariate pattern analysis (PATN; CSIRO, Canberra, Australia) which objectively classified all boars into two groups, categorized as good (n = 10; >60% PSM and PMI) or bad (n = 9; <40% PSM and PMI) based on their sperm freezability. Post-thaw sperm quality was consistent for different ejaculates within boars (P < 0.05). The DNA-integrity of frozen-thawed spermatozoa was evaluated according to the sperm chromatin structure assay (SCSA; Evenson et al. 1980 Science 210, 1131-1133). All SCSA variables (X mean, DNA fragmentation index (DFI), and the standard deviation of the DFI), were significantly higher for bad freezers (P < 0.001). The percentage of spermatozoa with abnormal chromatin structure ranged from 1.06 to 3.42% for good and 3.06 to 6.04% for bad freezers. Although these differences exist between good and bad sperm freezers, and can only to some extent be the product of cryopreservation, the levels of affected spermatozoa can not explain the differences on post-thaw sperm survival seen in the two categories of sires. This work was supported by CICYT, AGL05-0471 (Spain), SLF and Formas (Sweden).

The aim of this study was to examine ovine sperm cryoresistance during the rutting season (RS) and its association with sperm head area and seminiferous epithelium proliferation. Small ruminants show fluctuating testosterone levels throughout the year, which could interfere with spermatogenesis and sperm cryopreservation. Ejaculates, testicular biopsies and blood were collected during the middle and at the end of the RS (Middle-RS vs End-RS) during periods of high and low testosterone levels in Merino and Mouflon rams. Fresh and frozen–thawed sperm quality, sperm morphometry, seminiferous tubule morphometry and testicular proliferation markers (proliferating cell nuclear antigen, proliferation marker protein Ki-67 and transcription factor GATA-4) were evaluated. Post-thaw sperm viability was higher in the End-RS group in both Merino (69.9±8.2 vs 41.6±7.3%; P=0.020) and Mouflon rams (40.9±3.3 vs 24.2±5.0%; P=0.008). Mouflons had larger sperm head area at the End-RS (38.3±0.2 vs 34.3±0.1µm2; P=0.029), whereas there was no difference between Merino groups (35.7±0.5 vs 34.8±1.0µm2). Seminiferous tubule morphometry and proliferation markers showed higher levels of germinal epithelium proliferation in the Middle-RS of both species. In conclusion, sperm freezability is affected during the RS in domestic and wild rams, which could be correlated with changes that occur during spermatogenesis, since there is an effect of season on cell proliferation in the testis.

Having recently observed that survival of red deer spermatozoa after cryopreservation seemed to reflect the size of sperm heads, we hypothesized that cryoresistance of brown bear spermatozoa might also be dependent on head size, since in a preliminary study we had also observed significant differences in sperm head sizes among male brown bears (median values for area 22.2 �m2, perimeter 18.2, length 6.1 and width 4.4 �m). In the present report, we analyzed the post-thaw survival of spermatozoa of 6 brown bears that were assigned to 2 groups (3 bears/group) based on sperm size: Group A with large-size sperm heads; Group B with small-size heads. Ejaculates were obtained by electroejaculation of adult brown bears (semi-free ranging in Cabarceno Park, Cantabria, Spain) under general anesthesia (7 mg kg-1 tiletamine + zolazepan and 2 mg kg-1 ketamine). Semen was diluted (Tes-Tris-fructose, 8% glycerol, 20% egg yolk, EDTA, and Equex paste), loaded in 0.25-mL straws, and frozen in a biofreezer at 20�C min-1 to -100�C. After storage in liquid nitrogen, samples were thawed in water at 65�C for 6 s and survival was measured. Sperm motility (TM: total, and PM: progressive; %) was assessed microscopically, and sperm viability, acrosome integrity (PI/PNA-FITC), and mitochondrial status (JC-1) were assayed for fresh and thawed sperm by flow cytometry. Recovery rates (RR: thawed/fresh � 100) were calculated for all parameters. For measurement of head size, fresh sperm samples were fixed in glutaraldehyde and slides were air-dried for 2 h. The samples were then stained with Diff-Quik� staining at 37�C. The area (Ar), perimeter (P), length (L), and width (W) of the heads of &gt;100 spermatozoa per slide were measured (Sperm Class Analyzer�; Microptic S.L., Barcelona, Spain). Data were analyzed with the SAS ver8 system, and the Wilcoxon test was applied. The respective morphometric dimensions of the 2 groups were practically identical (Ar = 22; P = 18; L = 6; W = 4). The post-thaw recovery rates of spermatozoa from Group A were: TM: 60.1 � 29.3; PM: 54.8 � 36.0; viability: 99.4 � 8.0; acrosomes: 96.2 � 3.1; mitochondria: 70.9 � 15.5. The recovery rates for Group B were: TM: 78.7 � 13.8; PM: 69.0 � 18.8; viability: 93.8 � 5.2; acrosomes: 98.2 � 9.8; mitochondria: 72.5 � 22.5. Because of the high variability of recovery rates between males within each group, there were no statistical differences between the 2 groups. The absence of differences can be explained by the small number of males examined and the high variability between them. More studies are necessary to determine whether large sperm cells of brown bears are more susceptible to damage during cryopreservation. This work was supported in part by CANTUR S.A. and CICYT (CGL 2004-0278/BOS).

Contradictory results have been reported about the effect of seminal plasma (SP) on the freezability of mammalian spermatozoa. In pigs, current methods for sperm cryopreservation involve removing seminal plasma. Therefore, no conclusive evidence of the potential effect of SP on the freezability of boar spermatozoa has been reported. In this study, we evaluate the effect of the addition of low concentrations of SP from individual boars to the freezing extender on post-thaw sperm survival. Sperm cryopreservation procedure included: dilution of sperm-rich fraction in Beltsville Thaw Solution extender (BTS), cooling to 17°C for 16h, centrifugation at 2400g for 3min, dilution in lactose/egg-yolk/glycerol/Equex Stem (freezing extender) to a final concentration of 1×109 spermmL−1, dispensing into 0.5-mL straws, and freezing in a programmable cell freezer at 20°Cmin−1. Thawing was carried out in a waterbath at 37°C for 20s. Post-thaw sperm survival was assessed by progressive sperm motility (PSM) using a CASA system (SCA); plasma membrane integrity (PMI) and acrosome membrane integrity (AMI) were assessed by flow cytometric procedures (SYBR-14/PI and FITC-PNA/PI, respectively) at 30 and 150min post-thawing in BTS-diluted thaw spermatozoa held in a waterbath at 37°C. Four individual seminal plasma donors (SP1 to SP4) were selected in a preliminary study in which 48 ejaculates from 12 boars (4 ejaculates/boar) were cryopreserved. Then the boars were classified into 3 groups (good, moderate and bad freezers) based on their post-thaw sperm survival. SP1 and SP2 were good freezers (&gt;60% PSM and PMI), SP3 was a moderate freezer (40–60% PSM and PMI) and SP4 was a bad freezer (&lt;40% PSM and PMI). In the main experiment, pooled sperm-rich fractions collected from 9 mature hybrid boars were divided into five aliquots and each was diluted with freezing extender supplemented with 0% (control) or 10% of SP (1–4). Data from eight replicates were analyzed as a split plot design using a PROMIXED model. The addition of SP to freezing extender had a significant effect (P&lt;0.05) on post-thaw sperm survival compared to control. Moreover, there were significant differences (P&lt;0.05) between SP donors. PSM, PMI and AMI were significantly (P&lt;0.05) higher in SP1 (56.71±4.30; 57.16±4.01 and 57.22±4.01, respectively) and SP2 (59.48±4.30; 60.17±4.01 and 60.05±4.01, respectively) compared to control (50.39±4.30; 49.98±4.01 and 49.54±4.01, respectively). There were no differences (P&gt;0.05) between SP3, SP4 and control. These results indicate that the addition of SP from particular boars (good freezers) to freezing extender may improve post-thaw sperm survival. Individual differences in the SP composition should explain the above results. Supported by INIA (RZ01-019) and MCYT (AGL2001-0471).

Orientador: Frederico Ozanam Papa
Banca: João Carlos Pinheiro Ferreira
Banca: Alício Martins Junior
Resumo: A despeito das inúmeras variáveis que influenciam direta e indiretamente a fertilidade das fêmeas bovinas, a qualidade das amostras seminais exerce um papel importante na determinação das taxas de concepção dos programas de inseminação artificial. Os objetivos dessa pesquisa foram comparar a efetividade de dois diluidores de criopreservação de sêmen bovino no processamento de amostras seminais apresentando diferentes concentrações espermáticas em relação aos índices de congelabilidade determinados laboratorialmente (Experimento I) e as taxas de concepção proporcionadas por cada metodologia quando utilizada em programas de inseminação artificial em tempo fixo (IATF) em bovinos (Experimento II). No Experimento I foram utilizados 14 ejaculados de diferentes touros da raça Nelore. Cada ejaculado foi fracionado em oito alíquotas iguais, submetidas a criopreservação com os diluidores Tris-gema de ovo-frutose (meio TRIS) e MKA nas concentrações de 12, 25, 50 e 100 milhões de espermatozóides totais por mililitro de meio, formando oito grupos experimentais em função das variáveis diluidor e concentração. As amostras foram descongeladas a 46 ºC por 20 segundos, avaliando-se os padrões de motilidade através do método computadorizado (CASA), integridade de membrana plasmática (IMP), resistência ao teste de termorresistência rápido (TTR) e taxa de recuperação e IMP após seleção espermática pela técnica de swim-up. Para o Experimento II foram selecionados sete touros utilizados no Experimento I, obtendo-se um ejaculado de cada animal por eletroejaculação...(Resumo completo, clicar acesso eletrõnico abaixo)
Abstract: Although there are many variables which directly or indirectly influence female bovine fertility, the quality of sperm samples plays a important role in the determination of conception rates in artificial insemination programs. The aim of the present study was to compare the efficiency of two bovine semen extenders for sperm freezing with different spermatic concentrations in the freezability determined by lab tests (Experiment I), and conception rates after fixed time artificial insemination (FTAI; Experiment II). In Experiment I 14 ejaculates of different Nelore bulls were used. Each ejaculate was splitsampled in to eight equal parts and then submitted to cryopreservation with Tris-egg yolk fructose (TRIS) and MKA extenders, at concentrations of 12, 25, 50 and 100 millions spermatozoa per milliliter forming eight experimental groups. The samples were thawed at 46 ºC for 20 seconds, and the following parameters were evaluated: sperm motility and movement (by computer-assisted semen analysis - CASA), sperm membrane integrity (SMI), resistance to the fast thermoresistance test (TT), recovery rate and sperm membrane integrity after sperm selection through swim-up technique. Seven of 14 bulls used in Experiment I were selected for Experiment II, and semen was collected from each of the animals by electroejaculation. The seven ejaculates obtained were mixed (semen pool) and cryopreserved, thus forming eight experimental groups according to the freezing extenders and sperm concentrations/straws: TRIS 12, 25, 50 and 100, and MKA 12, 25, 50 and 100...(Complete abstract, click electronic address below)
Mestre