The characterisation and cryopreservation of Venda chicken semen

Protective Effect of N-Acetylcysteine on Rooster Semen Cryopreservation

Cryopreservation of avian semen is a useful reproductive technique in the poultry industry. However, during cooling, elevated reactive oxygen species (ROS) levels have destructive effects on both quality and function of thawed sperm. The aim of the current study is to investigate the antioxidant effects of N-acetylcysteine (NAC) during rooster semen cryopreservation. Semen samples were collected from ten Ross 308 broiler breeder roosters (32 weeks) and mixed. The mixed samples were divided into five equal parts and cryopreserved in Lake Buffer extender that contained different concentrations (0, 0.01, 0.1, 1, and 10 mM) of NAC. The optimum concentration of NAC was determined based on quality parameters of mobility, viability, membrane integrity, acrosome integrity, lipid peroxidation, and mitochondrial membrane potential after the freeze-thaw process. There was a higher percentage (p < 0.05) of total motility (TM) (60.9 ± 2.4%) and progressive motility (PM) (35.6 ± 1.9%) observed with the NAC-0.1 group compared to the other groups. Significantly higher percentages of viability (74.4 ± 2.3% and 71 ± 2.3%), membrane integrity (76.4 ± 1.5% and 74.7 ± 1.5%) and mitochondrial membrane potential (67.1 ± 1.6% and 66.3 ± 1.6%) were observed in the NAC-0.1 and NAC-1 groups compared to the other frozen groups (p < 0.05). The lowest percentage of lipid peroxidation and nonviable sperm was found in the NAC-0.1 and NAC-1 groups compared to the other groups (p < 0.05). The average path velocity (VAP), straight line velocity (VSL), curvilinear velocity (VCL), and acrosome integrity, were not affected by different concentrations of NAC in the thawed sperm (p > 0.05). Both NAC-0.1 and NAC-1 appear to be beneficial for maintaining the quality of rooster sperm after thawing.

Effect of freeze-dried quail egg white and yolk addition to semen extender on viability of rooster sperm stored for 6 h at 4°C

The effect of freeze-dried quail egg white and yolk addition to basic EK extender on morphology and motility of chicken broiler breeder semen was investigated. Fresh pooled semen was divided into eight parts: fresh, undiluted (control), diluted in 1:2 ratio (v/v) with basic EK extender, EK + 200 mg/ml of egg white, EK + 100 mg/ml of egg white, EK + 50 mg/ml of egg white, EK + 100 mg/ml of egg yolk, EK + 50 mg/ml of egg yolk, EK + 25 mg/ml of egg yolk. Semen samples were evaluated 15 min after dilution and after 6 h of storage at 4°C. In the fresh semen, the number of live normal sperm was the highest in semen diluted with EK + 200 mg of egg white and EK + 100 mg of egg yolk, while the highest sperm motility was in the neat semen. Semen storage reduced the number of normal sperm in all analysed semen samples. In the neat semen, the number of normal sperm decreased, in relation to the fresh not-stored samples, by 36.8% (from 72.3% to 35.5%), with EK extender by 9.2%, in samples enriched with egg white, from 8.4% (EK + 200 mg) to 10.0% (EK + 100 mg), and in EK with egg yolk addition, from 1.2% (EK + 50 mg) to 10.6% (EK + 100 mg). The highest percentage of motile sperm was observed in EK extender enriched with 50 mg of egg white (77.1%) and EK + 25 mg of egg yolk (65.3%).

Effect of glycerol concentration, glycerol removal method, and straw type on the quality and fertility of frozen chicken semen

The long-term semen cryopreservation is increasingly crucial for conservation of endangered livestock and poultry species. Glycerol is the most widely used cryoprotectant for freezing chicken semen. Continuous improvement in details with glycerol may help increase the fertility of post-thawed semen. Two experiments were performed in the present study to investigate the effects of glycerol concentration, removal method, and straw type on the quality of post-thawed sperm. In experiment 1, glycerol concentration (3%, 5%, 7%, 9%, 11%, and 13%) and glycerol removal method (final dilution ratio 1:1, 1:2, 1:4, 1:8, 1:16, and 1:20) combination groups were investigated for post-thawed sperm quality, residual glycerol concentration, and fertility to find the best combinations. Experiment 2 was performed to evaluate the effects of straw type (0.25 and 0.5 mL) and glycerol concentration (3%, 5%, 7%, 9%, 11%, and 13%) on the post-thawed sperm quality. Results showed that post-thawed sperm motility of 6 glycerol concentration groups were different (P < 0.01). Sperm motility of 5%, 7%, 9%, 11% and 13% was higher than that of 3% (P < 0.01). There was no difference among different concentrations of glycerol in VSL, VCL, VAP, ALH, WOB, BCF, LIN, or STR (P > 0.05). As for the glycerol removal method, sperm motility of 1:8 dilution was the highest, followed by 1:1 and 1:2, while the difference among groups was not statistically significant (P = 0.11). Glycerol concentration and removal method had no interaction effect on sperm motion parameters (P > 0.05). The highest fertility (48.70%) was found for the 5% and 1:2 combination. There was no difference for sperm motility between 0.25 and 0.5 mL straws (P > 0.05). Glycerol concentration and straw type had no interaction effect on the sperm motion parameters (P > 0.05). It can be concluded from these observations that the combination of 5% glycerol and 1:2 dilution rendered higher fertility should be suggested in practice, and that both 0.25 and 0.50 mL straws fit the present procedure.

New semen freezing method for chicken and drake using dimethylacetamide as the cryoprotectant

The aim is to optimize the dimethylacetamide (DMA) straw freezing technology of Black silkies rooster semen through the handy patent equipment, screening the formula of freezing basic extender and optimizing the DMA addition method, and then by comparing the fertility of DMA straw frozen semen with the pellet frozen semen. After the DMA straw freezing technology is optimized, it is extended to the Youxian Partridge drake semen. The result showed that the frozen sperm motility of Lake and Ravie (LR) group is 64%, the fertility 49.57% and the hatchability 91.52%, all of which are superior to those of FEB, Beltsville Poultry Semen Extender (BPSE) and Lake (P < 0.05). The sperm motility of adding DMA stock solution is 59%, which is superior to adding DMA directly into diluted semen (P > 0.05). The fertility and hatchability of DMA straw group are 77.61% and 92.30%, respectively, and it is significantly higher than those in the pellet group (P < 0.01; P < 0.05). The fresh drake sperm motility of induction collection method is 71%, the massage collection method 61% and the frozen drake sperm motility of induction 33% while the massage 19%. The fertility of frozen drake semen group is 85.93%, while that of the fresh semen group is 88.17%. The frozen drake semen fertility of the highest batch is 93.8%. In conclusion, the world's advanced fertility of frozen semen can be obtained both in the chicken and drake through the optimized DMA straw freezing technology and the method of screening freeze-resistant individuals.

Cryopreservation of Ghagus chicken semen: Effect of cryoprotectants, diluents and thawing temperature

The present study evaluated the effects of cryoprotectants, semen diluents and thawing temperature during Ghagus chicken semen cryopreservation. Four different experiments were conducted; Experiment 1-semen was cryopreserved using 6% dimethylacetamide (DMA) and 2% dimethylsulphoxide (DMSO) in Sasaki diluent (SD) and Lake and Ravie diluent (LR), Experiment 2 and 3-semen was cryopreserved using 8% ethylene glycol (EG) in SD, LRD and Red Fowl Extender (RFE), Experiment 4-semen was cryopreserved using 6% dimethylformamide (DMF) in SD, LR and Beltsville poultry semen extender (BPSE). Semen was cryopreserved in 0.5 ml French straws. Thawing was done at 5°C for 100 s in ice water in Experiments 1, 2 and 4, whereas in Experiment 3 thawing was done at 37°C for 30 s. The post-thaw sperm motility, viable sperm and acrosome-intact sperm were significantly (p < .05) lower in cryopreserved samples in all the experiments. No fertile eggs were obtained from cryopreserved samples in Experiments 1 and 2, except for 8% EG RFE treatment where the fertility was 0.83%. In Experiments 3 and 4, highest fertility was obtained in LR treatment 48.12 and 30.89%, respectively. In conclusion, using cryoprotectant EG (8%) and thawing at 37°C for 30 s, and DMF(6%) resulted in acceptable level of fertility in Ghagus chicken. Though the diluents influenced post-thaw in vitro semen parameters, the fertility was not affected. In addition, results indicated that thawing temperature may be a critical stage in the cryopreservation protocol.

Effect of N-Methylacetamide Concentration and Thawing Rate on Chicken Sperm Quality after Cryopreservation

Simple Summary

The semen cryopreservation technology is still the only efficient method for the ex situ conservation of genetic diversity in birds. This study investigates the effect of different concentrations (6% and 9%) of the cryoprotectant N-Methylacetamide and of different thawing temperatures (at 5 °C for 100 s; 38 °C for 30 s) on chicken semen quality after cryopreservation. The cryoprotectant concentration significantly affected sperm membrane integrity, total and progressive motility after cryopreservation and this effect was dependent by the thawing temperature. The treatment that provided the best cryoprotective action and decreased the cellular cryodamage was the concomitant use of 6% N-Methylacetamide and thawing at 5 °C for 100 s. These results can contribute to improve the efficacy of the current chicken semen cryopreservation technology.

Abstract

In seeking alternative cryoprotectants to glycerol for a reference chicken semen freezing procedure, the aim of the present study was to compare the effect of two concentrations of N-Methylacetamide (MA) and two thawing rates on the quality of frozen-thawed semen. Semen samples were diluted in Lake pre-freezing extender, including 0.1 M trehalose in presence of 6% or 9% MA, loaded into straws, frozen in nitrogen vapors, and stored in liquid nitrogen. The following thawing treatments were used: 5 °C for 100 s and 38 °C for 30 s. Sperm quality (cell membrane integrity, motility and kinetic parameters) was assessed before and after cryopreservation. The decrease of MA concentration from 9 to 6% improved sperm quality after freezing/thawing and this effect was dependent on thawing temperature. Decreasing the MA concentration from 9 to 6% improved the proportion of undamaged membrane, motile, and progressive motile sperm recovered after thawing at 5 °C for 100 s; in contrast, no effect of the MA concentration was observed thawing at 38 °C for 30 s. Therefore, the treatment with 6% MA and thawing at 5 °C for 100 s has given the best cryoprotective action. These results contribute to improve the efficacy of the current chicken semen cryopreservation procedures.

Effect of dimethylacetamide and N-methylacetamide on the quality and fertility of frozen/thawed chicken semen

The aim was to compare the effect of dimethylacetamide (DMA) and N-methylacetamide (NMA) concentrations on the quality and fertility of post-thaw chicken semen. Ejaculates were obtained from 30 Hi-Line White roosters and processed according to the following treatments: lake pre-freezing extender + 0.1 M trehalose (LPF-T) + 6% DMA (control treatment), LPF-T + 9% DMA, LPF-T + 6% NMA, and LPF-T + 9% NMA. Sperm quality (viability, motility, and kinetic traits) was assessed before and after cryopreservation. A total of 15 laying hens per treatment were inseminated to assess fertility and embryo viability. Sperm cryopreserved in presence of DMA had significantly better in vitro quality compared to NMA, showing the highest proportion of viable and progressive motile sperm recovered after thawing. Furthermore, proportion of progressive motile sperm and the VCL, LIN, ALH, and WOB mean values were significantly improved in semen samples frozen/thawed with 6% compared to 9% cryoprotectant concentration. However, the best cryoprotective action on sperm quality played by DMA and the lowest cryoprotectant concentration did not translate into a concomitant advantage in in vivo semen fertility that showed no differences between cryoprotectant and cryoprotectant concentration treatments. Finally, the cryoprotectant DMA and NMA showed an opposite effect on embryo viability in comparison with the effect played on in vitro semen quality, being NMA more efficient than DMA on preserving viable embryos. The present results suggest the urgency to further decrease the cryoprotectant concentration in poultry semen freezing procedures and to assess the specific toxic effect of cryoprotectant on sperm integrity, fertility, and embryo development.

A diluent containing coconut water, fructose, and chicken egg yolk increases rooster sperm quality at 5°C

Aim:

The present study was conducted to evaluate the quality of rooster sperm at 5°C after treatment with a diluent containing coconut water, fructose, and chicken egg yolk and stored the semen sample at 5°C.

Materials and Methods:

Ten semen samples from 10 healthy roosters were subjected to four different treatments. For the treatments, 0.2 ml fresh semen with a sperm concentration of 5.2×10⁹ cell/ml was mixed with T0 (no diluent), T1 (0.34 ml coconut water and 6 µl fructose), T2 (0.274 ml coconut water, 0.12 ml egg yolk, and 6 µl fructose), and T3 (0.34 ml egg yolk and 6 µl fructose) solutions. Each treated solution was stored at 5°C and evaluated both macroscopically and microscopically. Macroscopically, semen volume, pH, and sperm concentration were evaluated. The microscopic sperm characteristics examined included total motility (i.e., rapid, medium, or slow), progressive and non-progressive motility, viability, and spermatozoa abnormalities noted at different storage times. The results showed that spermatozoa motility was under 40%.

Results:

The results indicated that sperm viability significantly affected (p<0.05). The highest mean value of sperm viability on day 7 of storage was found after treatment with the T2 solution (46.100±0.5677%). Similarly, spermatozoa abnormalities were significantly lower after treatment with the T2 solution (6.680±1.702%).

Conclusion:

The addition of a diluent containing coconut water, egg yolk, and fructose helped in the better preservation spermatozoa motility, as well as viability for up to 7 days when the semen samples were stored at 5°C.

Sperm quality characteristics and fertilization capacity after cryopreservation of rooster semen in extender exposed to a magnetic field

There has not been as much success in the effectiveness of avian semen cryopreservation as that of mammalian semen cryopreservation. This has been attributed to the unique characteristics of poultry sperm. In the area of mammalian semen, the use of magnetized extenders has enhanced the cryo-resistance of sperm in some species. The applicability of this strategy to avian semen has not yet been evaluated. The purpose of this study was to evaluate the effects on sperm quality and fertility after magnetization of extenders and use of these extenders for cryopreservation of rooster semen. Extenders were passed between two neodymium magnets that produced different magnetic induction values (0, 2000, 4000 and 6000 G). Physicochemical properties of the extenders were assessed and then semen samples were cryopreserved in the magnetized extenders. The smallest cluster sizes and zeta potentials in the extenders were observed in the extender magnetized at 2000 gauss (G). There were greater percentages of sperm total motility, viability and mitochondrial membrane potential in semen treated with the extender magnetized at 2000 G A greater percentage of sperm with enhanced membrane functionality was observed when sperm were stored in extenders magnetized with 2000 G and 4000 G. In a field trial, there were greater percentages of fertility and hatching rates of eggs using semen treated with extenders magnetized at 2000 G and 4000 G. Cryopreservation of rooster semen with magnetized extenders at 2000-4000 G resulted in enhanced quality indices of thawed sperm as well as the fertility capacity of the cryopreserved semen.

Cryoprotectant effects of egg yolk on Indian red jungle fowl (Gallus gallus murghi) sperm

Egg yolk is a good external cryoprotectant of mammalian sperm and some wild bird's sperm, but, at least in domestic breeds of chicken (Gallus gallus domesticus), it may inhibit eventual fertilization of ova when high concentrations are used. We hypothesized that egg yolk can protect the sperm from cryo-induced damages providing adequate fertilization in one phylogenetic wild ancestor of current chicken breeds: the Indian red jungle fowl (Gallus gallus murghi). To test the hypothesis, the present study was designed to evaluate different concentrations of egg yolk in extender in comparison with glycerol. Semen collected from Indian red jungle fowl cocks (n = 8) was cryopreserved using different egg yolk concentrations (10%, 15%, 20% and 25%) or 20% glycerol (control group) following routine protocol of cryopreservation. During cryopreservation, sperm motility (67.5 ± 2.5%), plasma membrane integrity (66.3 ± 2.4%), viability (58.8 ± 1.3%) and acrosomal integrity (60.0.8 ± 2.0%) were recorded highest in an extender with 15% egg yolk compared to other experimental extenders and control at post-dilution, cooling, equilibration and thawing. The no. of fertilized eggs (26.6 ± 0.7, 21.6 ± 1.2), percent fertility (55.9 ± 4.4, 46.5 ± 2.2), no. of hatched chicks (23.6 ± 1.0, 17.2 ± 1.0), percent hatch (49.5 ± 3.2, 37.1 ± 2.5%) and hatchability of the fertile eggs (89.4 ± 2.2, 79.7 ± 3.7) were recorded higher (P < 0.05) with semen cryopreserved with 15% egg yolk compared to control (20% glycerol). It is concluded that 15% egg yolk can be used in cryopreservation protocol of Indian red jungle fowl sperm.

In vitro effect of various cryoprotectants on the semen quality of endangered Oravka chicken

We aimed to compare the effect of three different permeating cryoprotectants on the post-thaw spermatozoa quality. Pooled semen from Oravka cock line (n = 6) was diluted in Kobidil+ extender and frozen in cryoprotectant solutions containing 8% dimethylsulfoxide (DMSO), 8% ethylene glycol (EG) or 8% glycerol (GL) in liquid nitrogen vapours before being plunged into the liquid nitrogen. Spermatozoa motility parameters were assessed in vitro after freezing-thawing by a computer-assisted semen analysis (CASA) system and viability status was examined using fluorescent probes. The lower percentage (P < 0.05) of motile and progressively moving spermatozoa immediately after thawing were obtained in all experimental groups (DMSO, EG, GL) compared with the control. Significant (P < 0.05) differences in total motility and progressive movement between GL and DMSO, EG groups were observed. However, the higher number (P < 0.05) of acrosome damaged spermatozoa was found in the DMSO and EG groups and no significant differences were observed in the GL group compared with the control. Differences (P < 0.05) between experimental groups and the control in the results of spermatozoa necrosis were observed. No significant differences in the percentage of apoptotic spermatozoa were found between control and experimental groups. However, significant differences (P < 0.05) in number of live and necrotic spermatozoa between GL and DMSO, EG groups were examined. The findings of the present study indicate that glycerol seems to be suitable for semen cryopreservation in the gene banks. In addition, fertility evaluation in vivo is needed in order to evaluate the possible contribution for the bank of animal genetic resources.

Effect of cryoprotectants and thawing temperatures on chicken sperm quality

There is need for standardization of freezing-thawing protocol for rooster semen to minimize variability among results. Therefore, we aimed to compare effect of four different permeating cryoprotectants and two thawing temperatures (37 vs. 5°C) on sperm post-thaw motility and to analyse combined effect of the best permeating cryoprotectant (P-CPA) with one of four non-permeating cryoprotectants (N-CPA) on post-thaw quality of rooster semen evaluated in vitro. Pooled semen from Ross PM3 rooster heavy line was diluted in Kobidil extender and frozen in cryoprotectant solution containing 6% dimethylacetamide, 7.5% dimethylformamide, 9% N-methylacetamide or 8% ethylene glycol (EG) in liquid nitrogen vapours. To determine the best thawing rate, straws were thawed either at 37 or 5°C. Furthermore, samples were frozen in the presence of the best N-CPA either with 0.75 mol/L ficoll, 0.2 mol/L sucrose, 0.2 mol/L trehalose or 0.05 mol/L glycine. Sperm motility, membrane destabilization and viability were analysed to compare different freezing-thawing conditions. In addition, morphology and ultrastructure analysis were performed to compare fresh and frozen-thawed sperm quality. Our results indicate that the combination of EG and the thawing at 5°C improves (p ≤ .05) sperm post-thaw motility. Moreover, ficoll addition to EG-based freezing extender provided additional beneficial effect (p ≤ .05) on progressive movement and apoptosis incidence. Further work should evaluate different N-CPA concentrations to improve freezing protocol. In addition, fertility evaluation and testing on different chicken lines are needed in order to contribute to animal genetic resources bank.