Idiopathic subfertility in stallions. Clinical approaches to a complex problem

At least 30-40% of stallions in commercial breeding programs are moderately fertile and 8-12% are subfertile (0.5-3% with severe subfertility). From the total reported cases of the subfertility, in 2-20% of the stallions the cause is unknown or was not established. The objective of this work is to present the concept of subfertile stallion based on the current state of knowledge and advanced molecular diagnostic technologies. Low pregnancy rates have been reported in stallions with normal semen quality after conventional evaluation. Acrosome reaction (AR) is necessary for natural fertilization and impaired acrosome reaction (IAR) leads to subfertility or infertility in horses, however, AR test is not included in routine semen analysis. Genome-wide association study identified FKBP6 as a strong candidate gene responsible for this failure. The gene encodes for FK506 binding protein 6 (FKBP6) which is involved in sperm development and functions. We could conclude that the evaluation of the acrosomal status is essential in cases of stallions with good motility, concentration, morphology and viability but unexplained (idiopathic) subfertility or infertility. It is important to highlight the recent increase in reports of fertility problems in stallions related to disorders of genetic origin.(AU)

Influence of thawing temperature on sperm motility, structure, and metabolism of frozen bovine semen / Influência da temperatura de descongelamento na motilidade, estrutura e metabolismo do sêmen bovino congelado

ABSTRACT: The heating rate used during semen thawing plays an important role in reducing structural and functional damage to spermatozoa. In this study, we evaluated the influence of thawing temperature on semen quality, reactive oxygen species (ROS) production, and mitochondrial activity of cryopreserved bovine semen. A total of 195 straws of 0.5 mL from five Holstein Friesian bulls were used (39 straws per bull). Samples underwent 8 to 22 years of storage; they were processed under a standard protocol with tris-egg yolk and stored in liquid nitrogen. Samples were thawed for 30 seconds in a water bath at T1: 36 °C, T2: 38 °C or T3: 40 °C. Sperm motility and kinematics, morphology, structural membrane integrity (SMI), functional membrane integrity (FMI), acrosome integrity (AI), ROS, and mitochondrial membrane potential (ΔΨM) of post-thawing bovine sperm were evaluated. Generalized linear models were fitted to the data. Each model included the effects of bull, storage time, and treatment. The Shapiro-Wilk test was used to assess data normality, and means were compared using the Tukey test. T2 and T3 showed better results for sperm motility and kinematic parameters, SMI (%) (T1 41.9 ± 2.3; T2 45.7 ± 1.9; T3 47.4 ± 2.8), ROS (RFU/min) (T1 0.026 ± 0.007; T2 0.032 ± 0.001; T3 0.031 ± 0.001) and high-ΔΨM (RFU x 103) (67.1± 0,4; 71.3 ± 0.4; 74.2 ± 0.4) (P < 0.05). However, T1 had higher FMI (39.3 ± 2.3) than T2 (34.0 ± 1.9) (P < 0.05), though not significantly (P > 0.05) different from T3 (38.4 ± 2.2). Thawing temperatures of 38 °C and 40 °C increases motility, kinetics, membrane integrity, mitochondrial activity and ROS of cryopreserved bovine semen, compared with more conventional thawing at 36 °C.

RESUMO: A taxa de aquecimento usada durante o descongelamento do sêmen desempenha um papel importante na redução dos danos estruturais e funcionais nos espermatozóides. O objetivo desta pesquisa foi avaliar a influência da temperatura de descongelamento na qualidade do sêmen, produção de espécies reativas de oxigênio (ROS) e atividade mitocondrial do sêmen bovino criopreservado. Foram utilizados 195 palhetas de 0,5 mL de cinco touros Holstein Friesian (39 palhetas por touro). As amostras passaram por oito a 22 anos de armazenamento e foram processadas sob protocolo padrão com Tris-gema de ovo e armazenadas em nitrogênio líquido. As temperaturas de descongelamento foram T1: 36 °C, T2: 38 °C, T3: 40 °C, cada uma por 30 segundos em banho-maria. Pós-descongelamento, a motilidade e cinética dos espermatozoides, morfologia, integridade estrutural da membrana (SMI), integridade funcional da membrana (FMI), integridade acrossomal (AI), ROS e potencial de membrana mitocondrial (ΔΨM) foram avaliados. Modelos lineares generalizados foram ajustados. Cada modelo incluiu os efeitos de touro, tempo de armazenamento e tratamento. A normalidade dos dados foi avaliada pelo teste de Shapiro-Wilk e as médias comparadas pelo teste de Tukey. T2 e T3 apresentaram resultados mais elevados para a maioria dos parâmetros de motilidade e cinemática espermática, SMI (%) (T1 41,9 ± 2,3; T2 45,7 ± 1,9; T3 47,4 ± 2,8), ROS (RFU/min) (T1 0,026 ± 0,007; T2 0,032 ± 0,001; T3 0,031 ± 0,001) e alto ΔΨM (RFU x 103) (67,1 ± 0,4; 71,3 ± 0,4; 74,2 ± 0,4) (P < 0,05). No entanto, T1 apresentou maior FMI (%) (39,3 ± 2,3) em comparação a T2 (34,0 ± 1,9) (P < 0,05), mas não foi diferente do T3 (38,4 ± 2,2) (P > 0,05). Conclui-se que as temperaturas de descongelamento de 38 °C e 40 °C produzem um aumento na motilidade, cinética, integridade de membrana, atividade mitocondrial e ROS do sêmen bovino criopreservado, em comparação com o uso mais convencional de uma temperatura de descongelamento de 36 °C.

Espermiogênese alterada em um touro doador de sêmen: relato de caso / Altered spermiogenesis in a semen donor bull: case report

A espermiogênese é o processo final da espermatogênese no qual a espermátide se transforma em espermatozoide. Durante esse processo podem ocorrer alterações espermáticas, especialmente no acrossoma, na morfologia da cabeça, na condensação da cromatina e na formação dos vacúolos nucleares. A diferenciação entre os quadros clínicos é feita com repetições dos exames andrológicos. A avaliação morfológica indica a situação da espermiogênese nas 4 semanas anteriores a coleta do sêmen. Com os resultados do exame andrológico é possível identificar a qualidade seminal naquele período. O presente artigo é o relato de caso de um touro jovem doador de sêmen com 26 meses de idade, no início do regime de coletas de sêmen em um Centro de Coleta e Processamento de Sêmen no Sul do Brasil. A produção espermática deste animal foi avaliada durante 12 meses de coleta, apresentando sempre morfologia espermática muito alterada e motilidade média de 54% no exame imediato. Em 13 coletas seminais, o ejaculado deste animal apresentou em média 86% de defeitos maiores, 10% de defeitos menores e 96% de defeitos totais. Os defeitos maiores, que são os que possuem maior efeito na fertilidade, estão diretamente ligados a espermiogênese e os defeitos menores, que possuem menor efeito na fertilidade, são ocasionados principalmente durante o trânsito pelo epidídimo. O quadro clínico desse animal demonstrou a importância do exame morfológico para avaliar a espermatogênese e principalmente o processo de diferenciação final da espermátide em espermatozoide. Casos como este devem ser descritos como espermiogênese alterada e o reprodutor deve ser afastado da reprodução, após descartar alterações morfológicas devido a degeneração testicular grave.(AU)

Spermiogenesis is the final process of spermatogenesis in which the spermatid transforms into sperm. During this process, sperm alterations may occur, especially in the acrosome, head morphology, chromatin condensation and formation of nuclear vacuoles. Differentiation between clinical conditions is made with repetitions of andrological exams. The morphological evaluation indicates the status of spermiogenesis in the 4 weeks prior to semen collection. With the results of the breeding soundness examination, it is possible to identify the seminal quality in that period. The present article is a case report of a young 26-month-old semen donor bull, that started semen collection routines at a Semen Collection and Processing Center in southern Brazil. The sperm production of this animal was evaluated during 12 months of collection, always showing very altered sperm morphology and average motility of 54% in the immediate examination. In 13 seminal collections, the ejaculate of this animal presented an average of 86% of major defects, 10% of minor defects and 96% of total defects. Major defects, which have the greatest impact on fertility, are directly linked to spermiogenesis and minor defects, which have less effect on fertility, are mainly caused during transit through the epididymis. The clinical conditions of this animal demonstrated the importance of the morphological examination to evaluate spermatogenesis and especially the process of final differentiation of the spermatid into spermatozoa. Cases like this should be described as altered spermiogenesis and the bull should be withdrawn from breeding, after ruling out morphological changes due to severe testicular degeneration.(AU)

Influence of thawing temperature on sperm motility, structure, and metabolism of frozen bovine semen / Influência da temperatura de descongelamento na motilidade, estrutura e metabolismo do sêmen bovino congelado

The heating rate used during semen thawing plays an important role in reducing structural and functional damage to spermatozoa. In this study, we evaluated the influence of thawing temperature on semen quality, reactive oxygen species (ROS) production, and mitochondrial activity of cryopreserved bovine semen. A total of 195 straws of 0.5 mL from five Holstein Friesian bulls were used (39 straws per bull). Samples underwent 8 to 22 years of storage; they were processed under a standard protocol with tris-egg yolk and stored in liquid nitrogen. Samples were thawed for 30 seconds in a water bath at T1: 36 °C, T2: 38 °C or T3: 40 °C. Sperm motility and kinematics, morphology, structural membrane integrity (SMI), functional membrane integrity (FMI), acrosome integrity (AI), ROS, and mitochondrial membrane potential (ΔΨM) of post-thawing bovine sperm were evaluated. Generalized linear models were fitted to the data. Each model included the effects of bull, storage time, and treatment. The Shapiro-Wilk test was used to assess data normality, and means were compared using the Tukey test. T2 and T3 showed better results for sperm motility and kinematic parameters, SMI (%) (T1 41.9 ± 2.3; T2 45.7 ± 1.9; T3 47.4 ± 2.8), ROS (RFU/min) (T1 0.026 ± 0.007; T2 0.032 ± 0.001; T3 0.031 ± 0.001) and high-ΔΨM (RFU x 103) (67.1± 0,4; 71.3 ± 0.4; 74.2 ± 0.4) (P < 0.05). However, T1 had higher FMI (39.3 ± 2.3) than T2 (34.0 ± 1.9) (P < 0.05), though not significantly (P > 0.05) different from T3 (38.4 ± 2.2). Thawing temperatures of 38 °C and 40 °C increases motility, kinetics, membrane integrity, mitochondrial activity and ROS of cryopreserved bovine semen, compared with more conventional thawing at 36 °C.

A taxa de aquecimento usada durante o descongelamento do sêmen desempenha um papel importante na redução dos danos estruturais e funcionais nos espermatozóides. O objetivo desta pesquisa foi avaliar a influência da temperatura de descongelamento na qualidade do sêmen, produção de espécies reativas de oxigênio (ROS) e atividade mitocondrial do sêmen bovino criopreservado. Foram utilizados 195 palhetas de 0,5 mL de cinco touros Holstein Friesian (39 palhetas por touro). As amostras passaram por oito a 22 anos de armazenamento e foram processadas sob protocolo padrão com Tris-gema de ovo e armazenadas em nitrogênio líquido. As temperaturas de descongelamento foram T1: 36 °C, T2: 38 °C, T3: 40 °C, cada uma por 30 segundos em banho-maria. Pós-descongelamento, a motilidade e cinética dos espermatozoides, morfologia, integridade estrutural da membrana (SMI), integridade funcional da membrana (FMI), integridade acrossomal (AI), ROS e potencial de membrana mitocondrial (ΔΨM) foram avaliados. Modelos lineares generalizados foram ajustados. Cada modelo incluiu os efeitos de touro, tempo de armazenamento e tratamento. A normalidade dos dados foi avaliada pelo teste de Shapiro-Wilk e as médias comparadas pelo teste de Tukey. T2 e T3 apresentaram resultados mais elevados para a maioria dos parâmetros de motilidade e cinemática espermática, SMI (%) (T1 41,9 ± 2,3; T2 45,7 ± 1,9; T3 47,4 ± 2,8), ROS (RFU/min) (T1 0,026 ± 0,007; T2 0,032 ± 0,001; T3 0,031 ± 0,001) e alto ΔΨM (RFU x 103) (67,1 ± 0,4; 71,3 ± 0,4; 74,2 ± 0,4) (P < 0,05). No entanto, T1 apresentou maior FMI (%) (39,3 ± 2,3) em comparação a T2 (34,0 ± 1,9) (P < 0,05), mas não foi diferente do T3 (38,4 ± 2,2) (P > 0,05). Conclui-se que as temperaturas de descongelamento de 38 °C e 40 °C produzem um aumento na motilidade, cinética, integridade de membrana, atividade mitocondrial e ROS do sêmen bovino criopreservado, em comparação com o uso mais convencional de uma temperatura de descongelamento de 36 °C.

Sperm cell capacitation status of ram semen after cooling

Background: The use of conventional artificial insemination (AI) in sheep production is usually associated with lower fertility rates when frozen semen is used. Cooled ram semen has been an alternative over frozen semen due to the higher viability, seminal quality and fertility rates following AI. The semen preservation process promotes sperm cell modifications similar to capacitation (capacitation-like) that causes cell damage affecting viability and seminal quality, but such effects are unclear for cooled semen. The aim of this study was to determine the status of sperm cell capacitation (CA) and acrosome reaction (AR) during ram semen processing and cooling under different extenders, dilution factors, and aerobiosis conditions as a function of storage time at 5o C. Materials, Methods & Results: Two consecutive ejaculates per day per male were collected from 2 adult rams by artificial vagina at 48-72 h intervals, in three replications. After macro- and microscopic evaluations, semen was segregated into groups under 3 extenders (Tris-egg yolk or TY, citrate-egg yolk or CY, skimmed milk or SM), 2 dilution factors (1 x 109 or Bi, 100 x 106 or Mi cells/mL), and 2 aerobiosis conditions (aerobic or A, semi-anaerobic or SA). Diluted semen was cooled to 5ºC and stored for up to 72 h, with evaluations every 24 h. Aliquots of fresh ejaculates and of each cooled diluted subgroup, according to extender, dilution, and aerobiosis, were collected at times T0 and T72 for determination of acrosome status and membrane integrity by the chlortetracycline (CTC) and trypan blue-Giemsa stainings, respectively. No differences were detected in sperm cell motility (M) and motility vigor (V) between fresh and diluted semen. After cooling, a significant decrease in M was observed after 48 h in CY and SM compared with fresh semen and 0 h of cooling, while V started to decrease after 24 h in CY compared with TY. Likewise, M/V from different dilutions and aerobic conditions decreased more significantly after 48 and 24 h of cooling, respectively. The sperm capacitation status did not show differences in the proportion of non-capacitated (NCA), CA and AR sperm cells between TY, CY, and SM extenders (NCA: 75.0%, 71.3%, 74.0%; CA: 15.7%, 17.2%, 15.9%; AR: 9.3%, 11.5%, 10.2%) or between Bi and Mi dilutions (NCA: 74.0%, 72.9%; CA: 15.9%, 16.6%; AR: 10.1%, 10.5%), respectively. However, differences (P < 0.05) were observed between A and SA aerobic conditions, with CA (17.0% vs. 15.5%) and AR (11.9% vs. 8.7%) rates being higher in A than SA, respectively, with no differences in NCA (71.1% vs. 75.8%), irrespective of the storage time. Sperm cell viability decreased after 48 h, especially in CY (P < 0.05). Discussion: Ram sperm cells can suffer irreversible damage due to thermal shock during cooling. Egg yolk-based extenders provide phospholipids and cholesterol to protect the sperm cell membrane during the thermal shock caused by the change in temperature. In this study, sperm cells had irreversible decreases in M/V, with increase in acrosome and plasma membrane damage after cooling to 5ºC. The largest and smallest decreases in M and V over time were observed in the CY and TY extenders, respectively. In addition to the extender type, the semen preservation method and storage time promoted changes in the capacitation status, AR and in sperm cell viability, which per se were associated with a decrease in semen fertility. In fact, the proportions of CA and/or AR sperm cells gradually increased over time after dilution and storage at 5ºC, with a negative correlation between sperm cell viability and M/V over time. In summary, extender and cooling time affected mostly M/V, while aerobiosis condition and dilution factor were more associated with acrosome status and sperm survival, with the extender having less impact on the acrosome status as a function of time.

Assessment of coconut water added to Numida meleagris egg yolk as cryoprotectant for goat semen

Effects were assessed of the dilutants TRIS and ACP - 101c® with the addition of different guinea fowl (Numida meleagris) egg yolk concentrations. Fifteen ejaculates were collected from five goats of the Anglo Nubian breed. The ejaculates were pooled and then divided into 12 groups, two control groups (GC1 TRIS, with 2.5% Gallus gallus domesticus hen egg yolk GOGD), (GC2 Control Group ACP - 101c®, with the addition of 2.5% Gallus gallus domesticus hen egg yolk GOGD) and ten experimental groups (EG), containing TRIS and ACP added with different concentrations of egg yolk from guinea hen (Numida meleagris) (TRIS 2,5% GONM; TRIS 5% GONM; TRIS 10% GONM; TRIS 15% GONM; TRIS 20% GONM; ACP® 2,5% GONM; ACP® 5% GONM; ACP® 10% GONM; ACP® 15% GONM; ACP® 20% GONM). Then cryopreservation was carried out and the samples stored in liquid nitrogen (-196 °C). After seven days, the samples were thawed and assessed for spermatic kinetics, immunofluorescence and sperm morphology. Analysis of GOMN by the CASA system showed that the various parameters were similar to those of GOGD (P>0.05). The membrane integrity, mitochondrial potential and the acrosome were not influenced by the treatment (P>0.05) nor by the dilutant used for cryopreservation (P>0.05). The spermatic morphology was also preserved by the different GOGD and GONM concentrations in the ACP® and TRIS dilutants, with no statistically significant differences (P<0.05). It was concluded that Numida meleagris egg yolk, as external membrane cryoproctant added to the dilutants ACP-101c® and TRIS, improved goat semen quality.(AU)

The interference of ozone gas in kinects and mitochondrial potential of equine sperm submitted on cryopreservation

The objective of this study was to evaluate the effects of the addition of different concentrations of ozone to quarter horse semen submitted to cryopreservation. Six ejaculates from four stallions were collected and were divided in four experimental groups: a control group (BotuCRIO® extender) and three other groups with BotuCRIO® ozonized at concentrations of 6, 8 and 12 μg of O3/mL. The semen samples were diluted (200 x 106 spermatozoa/mL), filled in straws and frozen. After thawing (37 ºC, 30s), the samples were evaluated at 0, 30 and 60 minutes of incubation regarding sperm kinetics by a computer-assisted sperm analysis (CASA), and plasma membrane integrity (PMI), acrosome integrity (ACi) and mitochondrial membrane potential (MMP) by fluorescent probes. There was a reduction in the kinetic parameters total motility (TM), progressive motility (PM), curvilinear velocity (VCL), straight line velocity (VSL) and average path velocity (VAP) in all groups during the thermoresistance test (TT), a pattern also found in PMI and MMP analyses (p<0.05). There was no difference (p>0.05) between the control and treatment (6, 8, and 12 μg of O3/mL) groups, in any of the evaluated times for the kinetic parameters TM, linearity (LIN), straightness (STR), wobble index (WOB), amplitude of lateral head displacement (ALH) and beat cross frequency (BCF). Regarding the VCL, VSL and VAP parameters, the group treated with 6 μg did not differ from the control or from 8 μg, but was higher than 12 μg at 30 and 60 minutes. ACi and PMI did not differ between groups (p>0.05), but PMI was lower in groups 8 μg and 12 μg compared to the control and 6 μg (p<0.05). It was concluded that the addition of ozone does not present beneficial effects for cryopreservation of equine semen at the concentrations used and decreases important parameters of fertility.(AU)

The interference of ozone gas in kinects and mitochondrial potential of equine sperm submitted on cryopreservation

The objective of this study was to evaluate the effects of the addition of different concentrations of ozone to quarter horse semen submitted to cryopreservation. Six ejaculates from four stallions were collected and were divided in four experimental groups: a control group (BotuCRIO® extender) and three other groups with BotuCRIO® ozonized at concentrations of 6, 8 and 12 μg of O3/mL. The semen samples were diluted (200 x 106 spermatozoa/mL), filled in straws and frozen. After thawing (37 ºC, 30s), the samples were evaluated at 0, 30 and 60 minutes of incubation regarding sperm kinetics by a computer-assisted sperm analysis (CASA), and plasma membrane integrity (PMI), acrosome integrity (ACi) and mitochondrial membrane potential (MMP) by fluorescent probes. There was a reduction in the kinetic parameters total motility (TM), progressive motility (PM), curvilinear velocity (VCL), straight line velocity (VSL) and average path velocity (VAP) in all groups during the thermoresistance test (TT), a pattern also found in PMI and MMP analyses (p0.05) between the control and treatment (6, 8, and 12 μg of O3/mL) groups, in any of the evaluated times for the kinetic parameters TM, linearity (LIN), straightness (STR), wobble index (WOB), amplitude of lateral head displacement (ALH) and beat cross frequency (BCF). Regarding the VCL, VSL and VAP parameters, the group treated with 6 μg did not differ from the control or from 8 μg, but was higher than 12 μg at 30 and 60 minutes. ACi and PMI did not differ between groups (p>0.05), but PMI was lower in groups 8 μg and 12 μg compared to the control and 6 μg (p<0.05). It was concluded that the addition of ozone does not present beneficial effects for cryopreservation of equine semen at the concentrations used and decreases important parameters of fertility.

Uso de placa aquecedora visando a incubação do espermatozoide ovino após criopreservação / Use of heating plate aiming at the ovine sperm incubation after cryopreservation

Objetivou-se avaliar a utilização da placa aquecedora, em substituição ao banho-maria, no teste de termorresistência (TTR) de espermatozoides de carneiros após a criopreservação. Foram coletados 10 ejaculados de três carneiros adultos (n=30), por meio de vagina artificial para ovinos. Em seguida, foram diluídos em TrisGema de ovo, a uma concentração final de 200 x106 sptz/mL, e submetidos á curva de resfriamento, para posterior criopreservação em palhetas em nitrogênio líquido. Após descongelação, as amostras foram analisadas quanto à integridade de membrana, de acrossoma e atividade mitocondrial. O sêmen então foi dividido em dois tubos e submetido ao TTR, um em banho-maria e outro em placa aquecedora, e, ainda, avaliado a cada 30 minutos, do tempo zero (pós-descongelação) até 90 minutos de incubação, a 37 °C, quanto à motilidade espermática e à motilidade progressiva. As variáveis foram submetidas à análise de variância e as médias comparadas pelo teste de Tukey a 5% de probabilidade. Após o processo de congelação/descongelação, os espermatozoides apresentaram baixo percentual de integridade de membrana e elevado percentual de atividade mitocondrial e integridade do acrossoma. Não foi observada diferença na motilidade espermática nem na motilidade progressiva ao longo do TTR, quando comparados os espermatozoides que foram incubados em banho-maria aos incubados em placa aquecedora durante o período de 90 minutos. A placa aquecedora pode ser utilizada como meio de incubação dos espermatozoides de carneiros em substituição ao banho-maria.

The objective was to evaluate the use of the hot plate to replace the water bath in the thermo resistance test of ovine sperm after cryopreservation. Ten ejaculates were also collected from three adult sheep (n=30), by means of artificial sheep vagina. The collected samples were diluted in Tris-Egg Yolk, at a final concentration of 200 x106 sptz/mL and subjected to a cooling curve for subsequent cryopreservation in liquid nitrogen straws. Immediately after thawing, the samples were analyzed for membrane and acrosome integrity, and mitochondrial activity. The semen was then divided into two tubes and submitted to TTR, one in a water bath and the other in a hot plate, and evaluated every 30 minutes, from time zero (post-thaw) until 90 minutes of incubation at 37 °C, for sperm motility and progressive motility. The variables were subjected to analysis of variance and the means were compared using the Tukey test at 5% probability. After the freeze/thawing process, sperm showed a low percentage of membrane integrity, high percentage of mitochondrial activity, in addition to maintaining the integrity of acrossome. No difference was observed in sperm motility nor progressive motility, along the TTR, when comparing the sperm that were incubated in a water bath in relation to those incubated in a hot plate during the period of 90 minutes. The heating plate can be used as a means of incubating sheep sperm in replacement of the water bath.

Effect of adding anethole to the cryopreservation medium (powdered coconut water) on morphology, kinetics, and oxidative stress of buck sperm / Efeito da adição de anethole ao meio de criopreserção (água de coco em pó) na morfologia, cinética e estresse oxidativo do sêmen de bode

The quality of post-thawing goat sperm is critical to the success of artificial insemination protocols and may be influenced by extenders, cryoprotectants, and antioxidant substances. Therefore, the objective of this study was to evaluate the effects of the antioxidant anethole on goat sperm diluted in preservation medium based on powdered coconut water (ACP-101c) and frozen. For that, each ejaculate was submitted to the following treatments: ACP-101c (control); control plus supplementation with 30, 300, or 2000 µg/ mL anethole. The samples were thawed and evaluated for morphology, kinetics, membrane integrity, and reactive oxygen species (ROS). The addition of anethole increased morphological abnormalities (P < 0.05), however, it did not affect sperm kinetics. Flow cytometry analysis showed that sperm cells cryopreserved with 300 µg/mL anethole had lower acrosome integrity than those cryopreserved in other treatments. Evaluation of oxidative stress revealed that cells stored in the presence of 2000 µg/mL anethole had small amounts of ROS when compared to those preserved in the control medium alone or supplemented with 300 µg/mL anethole (P < 0.05). After cryopreservation of sperm with 2000 µg/mL anethole, the highest percentage of viable sperm without ROS was observed (P < 0.05). In conclusion, despite reducing ROS levels, the supplementation of anethole in ACP-101c did not affect sperm kinetics or membrane integrity post-thawing, however, it did cause morphological damage to sperm.(AU)

A qualidade do espermatozoide caprino pós-descongelação é crítica para o sucesso dos protocolos de inseminação artificial e pode ser influenciada por extensores, crioprotetores e substâncias antioxidantes. Portanto, o objetivo deste estudo foi avaliar os efeitos do antioxidante anetole sobre espermatozoides caprinos diluídos em meio de conservação à base de água de coco em pó (ACP-101c) e congelados. Para tanto, cada ejaculado foi submetido aos seguintes tratamentos: ACP-101c (controle); controle mais suplementação com 30, 300 ou 2000 µg / mL de anetole. As amostras foram descongeladas e avaliadas quanto à morfologia, cinética, integridade de membranas e espécies reativas de oxigênio. A adição de anetole aumentou as anormalidades morfológicas (P < 0,05), no entanto, não afetou a cinética dos espermatozoides. A análise da citometria de fluxo mostrou que as células de esperma criopreservadas com 300 µg / mL anethole tinham integridade acrosma menor do que aquelas criopreservadas em outros tratamentos. A avaliação do estresse oxidativo revelou que as células armazenadas na presença de 2000 µg / mL anethole apresentaram pequenas quantidades de ROS quando comparadas às preservadas em meio de controle isoladamente ou suplementadas com 300 µg / mL anethole (P < 0,05). Após a criopreservação de espermatozoides com 2000 µg / mL anethole, observou-se a maior porcentagem de espermatozoides viáveis sem ROS (P < 0,05). A população com espermatozoides viáveis sem ROS foi maior quando utilizado 2.000 µg / mL (P < 0,05). Em conclusão, apesar de reduzir os níveis de ROS, a suplementação de anetole em ACP-101c não afetou a cinética espermática e a integridade da membrana pós-descongelação, entretanto, causou danos morfológicos nos espermatozoides.(AU)

Diferentes tipos de embalagens e qualidade do sêmen suíno criopreservado / Different types of packaging and quality of cryopreserved swine semen

Devido à alta sensibilidade do espermatozoide suíno à criopreservação, torna-se importante o estudo acerca dos danos provocados à célula, pela agressão térmica ocasionada durante este processo. Sendo assim, avaliou-se neste trabalho, a influência de diferentes embalagens, utilizadas para o armazenamento de sêmen suíno, sobre a qualidade do espermatozoide criopreservado. Foram utilizados animais híbridos, a coleta do sêmen foi feita pela técnica da mão enluvada. Foram analisados o vigor (0 a 5), a motilidade (0 a 100%), a taxa de degradação da motilidade e a integridade acrossomal. O sêmen foi congelado em palhetas de 0,5mL, criotubos de 2,0mL e macrotubos de 4 e 5mL. As amostras de sêmen suíno congelado em palhetas apresentaram os melhores resultados de vigor espermático (2,3), de motilidade (45,4%), de taxa de degradação da motilidade (56,5%) e de integridade acrossomal (60,6%), quando comparadas às amostras criopreservadas nos demais tipos de embalagens avaliadas (p<0,05). Somente para o parâmetro taxa de degradação da motilidade, o sêmen conservado em palhetas apresentou resultados similares ao conservado em macrotubo de 4mL (54,1%). Os resultados pós-descongelação indicaram que o sêmen envasado nas palhetas foi o que apresentou características condizentes com a possibilidade de serem utilizados nos protocolos de inseminação artificial, com possibilidades de bons resultados de fertilidade. Concluiu-se que embalagens que permitam uma maior velocidade de trocas de temperatura entre as células encontradas no bordo e no centro, favorecem a uma melhor qualidade do sêmen descongelado.

Due to high sensitivity of the swine spermatozoa to cryopreservation, it is important to study the damage caused to the cell by thermal aggression during this process. Thus, this study evaluated the influence of different packages used for the storage of swine semen on the quality of cryopreserved spermatozoa. Hybrid animals were used, and semen collection was made by the gloved hand technique. The vigor (0 the 5), motility (0 the 100%), rate of motility degradation and acrosome integrity were analyzed. The semen was frozen in straws of 0.5mL, cryotubes of 2.0mL and macrotubes of 4 and 5mL. The swine semen samples frozen in straws showed the best results in sperm vigor (2.3), motility (45.4%), motility degradation rate (56.5%) and acrosomal integrity (60.6%), when compared to the cryopreserved samples in the other types of packaging evaluated (p<0.05). Only for the motility degradation rate parameter, the semen preserved in straws showed results similar to the one conserved in a 4 mL macrotube (54.1%). The results after thawing indicated that the semen packed in straws was the one that presented consistent characteristics with the possibility of being used in artificial insemination protocols with possibilities of good fertility results. It was concluded that packages that allow a higher speed of temperature changes between the cells found on the edge and in the center of them, favor a better quality of the thawed semen.

The effects of cryopreservation on the acrosome structure, enzyme activity, motility, and fertility of bovine, ovine, and goat sperm

The study was designed to investigate the effects of cryopreservation on bovine, ovine, and goat sperm motility, acrosome structure, enzyme activity, and fertilization ability. Percentage of sperm with hyaluronidase enzyme (HYD) activity was detected by a modified sodium hyaluronate-gelatin membrane. The N-α-benzoyl-DL-arginine-p-nitroanilide (BNPNA) method was used to assess the sperm acrosome enzyme (ACE). The mean percentage of sperm acrosome integrity dropped significantly (P < 0.01) after cryopreservation. The ACE activity of bovine sperm (100.48) was higher (P < 0.01) than that of ovine (57.88) or goat sperm (50.30), while the percentage of sperm with HYD activity of bovine (71.10%) and ovine (67.60%) sperm was higher than that of goat sperm (58.52%) after cryopreservation (P < 0.01). Sperm motility was positively correlated with the activity of the two acrosome enzymes before and after cryopreservation (P < 0.01). Cryopreservation had a negative effect on acrosomal morphology, motility, and acrosomal enzyme activity in their sperm. The fertilization ability of ovine and goat sperm decreased significantly after cryopreservation, but that of frozen bovine sperm did not differ significantly when compared with fresh sperm. There was no significant difference between ovine and goat sperm indices, except for percentage of sperm with HYD activity.

The effects of cryopreservation on the acrosome structure, enzyme activity, motility, and fertility of bovine, ovine, and goat sperm

The study was designed to investigate the effects of cryopreservation on bovine, ovine, and goat sperm motility, acrosome structure, enzyme activity, and fertilization ability. Percentage of sperm with hyaluronidase enzyme (HYD) activity was detected by a modified sodium hyaluronate-gelatin membrane. The N-α-benzoyl-DL-arginine-p-nitroanilide (BNPNA) method was used to assess the sperm acrosome enzyme (ACE). The mean percentage of sperm acrosome integrity dropped significantly (P < 0.01) after cryopreservation. The ACE activity of bovine sperm (100.48) was higher (P < 0.01) than that of ovine (57.88) or goat sperm (50.30), while the percentage of sperm with HYD activity of bovine (71.10%) and ovine (67.60%) sperm was higher than that of goat sperm (58.52%) after cryopreservation (P < 0.01). Sperm motility was positively correlated with the activity of the two acrosome enzymes before and after cryopreservation (P < 0.01). Cryopreservation had a negative effect on acrosomal morphology, motility, and acrosomal enzyme activity in their sperm. The fertilization ability of ovine and goat sperm decreased significantly after cryopreservation, but that of frozen bovine sperm did not differ significantly when compared with fresh sperm. There was no significant difference between ovine and goat sperm indices, except for percentage of sperm with HYD activity.(AU)

Effects of chelating calcium in cryopreservation extender on frozen-thawed dog semen / [Efeitos da quelação de cálcio no meio de criopreservação no sêmen descongelado de cão]

We evaluated the effect of reducing free calcium in the cryopreservation medium, using the calcium chelator ethylene diamine tetracetic acid (EDTA) at 0.3% and 0.5% concentrations. Three male mixed breed dogs were subjected to semen collection by digital manipulation (n=16). Each ejaculate was divided in three aliquots, and each one was diluted in TRIS-glucose-egg yolk extender with 6% glycerol and 0.5% Equex STM Paste® (TGE, control); and added with 0.3% EDTA (EDTA 0.3) or 0.5% EDTA (EDTA 0.5). Calcium concentration reduced in EDTA 0.3 and all the calcium ions were chelated in EDTA 0.5. The EDTA addition did not affect sperm morphology or plasma membrane integrity; however, by removing all free calcium (EDTA 0.5), the sperm motility reduced (64.7% in TGE and 45% in EDTA 0.5; p<0.05). Acrosome integrity and sperm binding ability were not improved by calcium chelation. The failure to prevent the premature AR may explain why sperm longevity was not affected by calcium removal. Thus, the partial or complete calcium removal, through EDTA addition, is not able to prevent acrosomal damage or premature acrosomal reaction, and therefore does not improve the dog sperm binding ability.(AU)

Avaliou-se o efeito da redução do cálcio livre no meio de congelamento, usando-se o quelante de cálcio etilenodiaminotetracético (EDTA) a 0,3% e 0,5%. Três cães machos sem raça definida foram submetidos à coleta de sêmen por manipulação digital (n=16). Cada ejaculado foi diluído em diluidor controle com TRIS-glicose - gema de ovo (TGE, controle), ou em diluidor TGE enriquecido com 0,3% (EDTA 0,3) ou 0,5% de EDTA (EDTA 0,5). A concentração de cálcio reduziu no meio EDTA 0,3, e todos os íons de cálcio foram quelados no meio EDTA 0,5. A adição do EDTA e a consequente quelação do cálcio não afetaram a morfologia espermática ou a integridade da membrana plasmática, no entanto, ao remover todo o cálcio do meio (EDTA 0,5), a motilidade espermática se reduziu (64,7% no TGE e 45% no EDTA 0,5; P<0,05). A integridade do acrossoma e a capacidade de ligação do espermatozoide não melhoraram com a quelação do cálcio. Apesar da influência da concentração de cálcio sobre a motilidade espermática após o descongelamento, a falha em prever a reação acrossomal prematura pode explicar por que a longevidade espermática não foi afetada pela remoção do cálcio no meio. Dessa forma, a remoção parcial ou total do cálcio, por meio da adição de EDTA, não é capaz de prevenir o dano no acrossoma ou a reação acrossomal prematura e, portanto, não aumenta a capacidade do espermatozoide de se ligar ao oócito.(AU)

Análises da membrana plasmática, acrossoma e mitocôndrica de espermatozoide ovino após criopreservação com adição de Ácido Fólico no meio tris-gema / Plasma membrane, acrosome and mitochondria analysis of sheep sperm after cryopreservation with addition of folic acid in the tris-yolk medium

Folic acid is closely linked to cobalamin, which is a carrier of hydroxymethyl and ant groups. The objective of this work was to evaluate the effect of adding folic acid to the TRIS-yolk diluter and possible effect on the membrane, mitochondria and acrosome of sheep sperm after thawing the semen. There were six sheep and seven collections of each animal in sessions between 48 and 72 hours. After collection and analysis, the semen samples were mixed and submitted to the formation of a pool. Diluted in TRIS-yolk medium, and divided into 3 groups; Group control; Group 2: 10,000 µM of folic acid and in Group 3: 5000 µM of folic acid. Subsequently, the semen samples were packaged in 0.25 mL straws and processed in a semen freezing machine. After a few days, the semen was thawed and evaluated: plasma membrane integrity, acrosome function and integrity. They were analyzed using an analysis of variance (ANOVA) followed by the Newman-Keuls test, using SAS. The additionof a micronutrient with potential antioxidant action in the semen indicates that it can reduce the action of free radicals that alter the plasma membrane and sperm DNA. The evaluation of the plasma membrane integrity, mitochondrial activity and the acrosome integrity of post-thawed sperm were not significantly different between the groups evaluated. Thus, it is concluded that the addition of folic acid in concentrations of 5000 µM and 10000 µM to the TRIS-yolk seminal diluter does not significantly influence the variables evaluated in this experiment.

Análises da membrana plasmática, acrossoma e mitocôndrica de espermatozoide ovino após criopreservação com adição de Ácido Fólico no meio tris-gema / Plasma membrane, acrosome and mitochondria analysis of sheep sperm after cryopreservation with addition of folic acid in the tris-yolk medium

Folic acid is closely linked to cobalamin, which is a carrier of hydroxymethyl and ant groups. The objective of this work was to evaluate the effect of adding folic acid to the TRIS-yolk diluter and possible effect on the membrane, mitochondria and acrosome of sheep sperm after thawing the semen. There were six sheep and seven collections of each animal in sessions between 48 and 72 hours. After collection and analysis, the semen samples were mixed and submitted to the formation of a pool. Diluted in TRIS-yolk medium, and divided into 3 groups; Group control; Group 2: 10,000 µM of folic acid and in Group 3: 5000 µM of folic acid. Subsequently, the semen samples were packaged in 0.25 mL straws and processed in a semen freezing machine. After a few days, the semen was thawed and evaluated: plasma membrane integrity, acrosome function and integrity. They were analyzed using an analysis of variance (ANOVA) followed by the Newman-Keuls test, using SAS. The additionof a micronutrient with potential antioxidant action in the semen indicates that it can reduce the action of free radicals that alter the plasma membrane and sperm DNA. The evaluation of the plasma membrane integrity, mitochondrial activity and the acrosome integrity of post-thawed sperm were not significantly different between the groups evaluated. Thus, it is concluded that the addition of folic acid in concentrations of 5000 µM and 10000 µM to the TRIS-yolk seminal diluter does not significantly influence the variables evaluated in this experiment.(AU)

Improvement of in vitro fertilization by a tannin rich vegetal extract addition to frozen thawed boar sperm

Boar spermatozoa are very susceptible to cryopreservation injuries and, for this reason, pig remains one of the few species in which fresh semen is still preferred to thawed one for routine artificial insemination (AI). The present work evaluated the effect of supplementing boar sperm thawing medium with Silvafeed SP (SSP), a mixture of Chestnut and Quebracho wood extracts (60/40 w/w) rich in polyphenols (92.4% tannin content) on in vitro fertilization (IVF) and on the following sperm parameters: sperm motility (assessed by CASA), viability, acrosome integrity, mitochondrial function and lipid peroxidation (assessed by flow cytometry) and capacitation status (immunolocalization of tyrosine phosphorylated proteins). Thawed spermatozoa were incubated 1 h at 37°C in BTS without (CTR) or with (5, 10, 20 µg/mL) SSP. After incubation sperm suspension was divided in three aliquots: one was used for IVF trials, one for sperm analysis, and the last one was capacitated for 1 h at 39°C 5% CO2 in IVF medium. Sperm motility parameters, viability, acrosome integrity, mitochondrial functionality, lipid peroxidation and tyrosine phosphorylated protein immunolocalization, used as capacitation parameter, were not influenced by SSP. However, oocytes inseminated with thawed spermatozoa pretreated with all the different SSP concentrations presented a significant (P < 0.01) increase in penetration rate compared to CTR. In addition, 5 µg/mL SSP exerted a positive effect (P<0.05) on the total efficiency of fertilization. These results encourage the use of SSP in the thawing medium since post-thawing fertility is a limit for the large-scale use of boar frozen semen.

Improvement of in vitro fertilization by a tannin rich vegetal extract addition to frozen thawed boar sperm

Boar spermatozoa are very susceptible to cryopreservation injuries and, for this reason, pig remains one of the few species in which fresh semen is still preferred to thawed one for routine artificial insemination (AI). The present work evaluated the effect of supplementing boar sperm thawing medium with Silvafeed SP (SSP), a mixture of Chestnut and Quebracho wood extracts (60/40 w/w) rich in polyphenols (92.4% tannin content) on in vitro fertilization (IVF) and on the following sperm parameters: sperm motility (assessed by CASA), viability, acrosome integrity, mitochondrial function and lipid peroxidation (assessed by flow cytometry) and capacitation status (immunolocalization of tyrosine phosphorylated proteins). Thawed spermatozoa were incubated 1 h at 37°C in BTS without (CTR) or with (5, 10, 20 µg/mL) SSP. After incubation sperm suspension was divided in three aliquots: one was used for IVF trials, one for sperm analysis, and the last one was capacitated for 1 h at 39°C 5% CO2 in IVF medium. Sperm motility parameters, viability, acrosome integrity, mitochondrial functionality, lipid peroxidation and tyrosine phosphorylated protein immunolocalization, used as capacitation parameter, were not influenced by SSP. However, oocytes inseminated with thawed spermatozoa pretreated with all the different SSP concentrations presented a significant (P < 0.01) increase in penetration rate compared to CTR. In addition, 5 µg/mL SSP exerted a positive effect (P<0.05) on the total efficiency of fertilization. These results encourage the use of SSP in the thawing medium since post-thawing fertility is a limit for the large-scale use of boar frozen semen.(AU)

Trehalose addition to a Tris-fructose egg yolk extender on quality of ram sperm preserved at 0 °C

The present study investigated the effects of various concentrations of trehalose in Tris-fructose egg yolk diluent on ram semen preservation at 0 ℃. Semen was collected by artificial vagina ejaculation from six rams of proven fertility. High-quality ejaculates were diluted with 0 (control), 5, 10, 15, and 20 mM trehalose of Tris-fructose egg yolk extender and control (tris-fructose egg yolk extender without trehalose), respectively. Then, the ejaculates were diluted to a concentration of 5×108 sperm/mL, cooled to 0 ℃ for 90 min, and maintained at that temperature for twelve days. The diluted semen samples were examined, and their sperm progressive motility, membrane functionality, and acrosome integrity recorded at 0, 24, 72, 144, 216, and 288 h. Two hundred ninety-six ewes were transcervically inseminated with the 216-h control (without trehalose) or the optimal trehalose concentration group semen, and the pregnancy and lambing rates were measured. No significant differences were established in the sperm progressive motility and membrane functionality among the control and 5, 10, 15, and 20 mM groups. The sperm samples of trehalose addition groups had no significant difference in the acrosome integrity of sperm, but they were, nonetheless, significantly higher than those in the control. No significant difference was detected in the lambing and pregnancy rates between the 5 mM and control groups. These results suggest that ram sperm is capable of fertilization after cooling and preservation at 0 ℃ by the use of 5 mM trehalose for Tris-fructose egg yolk diluent. Under these conditions, ram sperm can be more effectively preserved than under other four concentrations of diluents.(AU)

Análises de membrana plasmática, acrossoma e mitocôndria de espermatozoides ovino após criopreservação com adição do ácido fólico no meio Tris-gema / Plasma membrane, acrosome and mitochondria analysis of sheep sperm after cryopreservation with addition of folic acid in the tris-yolk medium

Folic acid is closely linked to cobalamin, which is a carrier of hydroxymethyl and ant groups. The objective of this work was to evaluate the effect of adding folic acid to the TRIS-yolk diluter and possible effect on the membrane, mitochondria and acrosome of sheep sperm after thawing the semen. There were six sheep and seven collections of each animal in sessions between 48 and 72 hours. After collection and analysis, the semen samples were mixed and submitted to the formation of a pool. Diluted in TRIS-yolk medium and divided into 3 groups; Group control; Group 2: 10,000µM of folic acid and in Group 3: 5000µM of folic acid. Subsequently, the semen samples were packaged in 0.25mL straws and processed in a semen freezing machine. After a few days, the semen was thawed and evaluated: plasma membrane integrity, acrosome function and integrity. They were analyzed using an analysis of variance (ANOVA) followed by the Newman-Keuls test, using SAS. The additionof a micronutrient with potential antioxidant action in the semen indicates that it can reduce the action of free radicals that alter the plasma membrane and sperm DNA. The evaluation of the plasma membrane integrity, mitochondrial activity and the acrosome integrity of post-thawed sperm were not significantly different between the groups evaluated. Thus, it is concluded that the addition of folic acid in concentrations of 5000µM and 10000µM to the TRIS-yolk seminal diluter does not significantly influence the variables evaluated in this experiment.