Validation of simple and cost-effective stains to assess acrosomal status, DNA damage and mitochondrial activity in rooster spermatozoa

Dietary supplementation with ginseng extract enhances testicular function, semen preservation, and fertility rate of mature and aging Thai native roosters

The decrease in fertility in aging roosters is related to the reduced quality of ejaculated sperm. This study aimed to investigate the effect of dietary supplementation with ginseng extract at various concentrations (0-150 mg/kg) on testicular function, semen preservation, and fertility at different stages of sexual maturity (mature and aging roosters) in Thai native roosters. Pradu Hang Dum roosters at 32 (mature; n = 24) and 75 (aging; n = 24) weeks of age were fed diets with non-supplemented or supplemented ginseng extracts (50, 100, and 150 mg/kg) until the end of the experiment. In experiment 1, fresh semen samples were examined for the quality parameters of semen volume, sperm concentration, sperm motility, sperm viability, lipid peroxidation, and enzymatic activities. In experiment 2, semen was preserved at 5 °C for up to 48 h, and the semen quality and fertility potential were determined. In experiment 3, testicular function and testosterone concentrations were evaluated. The results showed that ginseng extract supplementation in the diets of both mature and aging roosters at 50 and 100 mg/kg improved fresh semen quality (P < 0.05). A decrease in malondialdehyde levels in fresh semen was observed with increasing enzyme activities. In mature roosters, the progressive motility of cold-stored semen and fertility rates were higher in the G50 and G100 groups compared to the control and G150 groups after 24 h of storage (P < 0.05). In aging roosters, the highest significant differences in progressive motility, viability, and fertility rates were observed in the G50 and G100 groups at all storage times (P < 0.01). These improvements might be attributed to good testicular function in spermatogenesis, as revealed by the results of histological examination and testosterone concentrations. However, higher doses of ginseng extract supplementation negatively affected sperm quality. In summary, the recommended dose of ginseng extract supplementation in diets is 50 mg/kg. Fertility results indicated that insemination with semen preserved for 24 h was satisfactory in both mature and aging roosters.

Collection, Handling, and Preservation of Wild Bird Semen: Current Status, Challenges, and Perspectives

Semen preservation is a significant biotechnology used to safeguard the genetic material of birds, especially those with declining populations, through biobanking. However, there are limited reports on the successful chilling or cryopreservation of wild bird semen. In general, these techniques are not yet well-established for several species of wild birds and pose several challenges such as the need for bird handling and training, contamination of semen samples, low volume of semen collected, and inefficient preservation protocols. To address these challenges and improve post-thawing outcomes, new possibilities are being investigated, including alternative collection methods to traditional digital massage, the use of antioxidants and enzymes in the medium for chilling or freezing, storage methods using different straws from the usual pellet, and slower freezing rates. This review aims to discuss the various aspects of applying semen preservation in wild birds to create germplasm banks, highlighting the primary results obtained and the challenges that need to be addressed.

Effect of the addition of antifreeze protein type I on the quality of post-thawed domestic cat epididymal sperm

Cryopreservation of domestic cat semen is mainly performed as a model for the establishment of endangered wild feline protocols. The supplementation of antifreeze protein type I (AFP I) to cryopreservation medium has shown improvement in frozen-thawed sperm quality in other species, but its effect on cat semen has not yet been tested. This study aimed to assess the addition of AFP I to cryopreservation medium in domestic cats. Sperm was obtained from the cauda epididymis of orchiectomized cats; sperm was then pooled in Tris buffer and allocated into three treatments, according to AFP I final concentration: 0 (control), 0.1, and 0.5 µg/ml. Nine replicates were cryopreserved in a two-step protocol and subsequently thawed at 37°C for 30 s. There was no difference (P > 0.05) among the control, 0.1 and 0.5 µg/ml groups for parameters such as motility, vitality, functional membrane integrity, mature chromatin, normal morphology, and sperm binding to egg perivitelline membrane. In the 0.5 μg/ml group only, percentages of live sperm with intact acrosome and of sperm with most inactive mitochondria (DAB III) showed a significant reduction, along with a tendency (P = 0.053) to an increase in the percentage of sperm with most active mitochondria (DAB II). In conclusion, the supplementation of 0.1 and 0.5 µg/ml of AFP I did not promote consistent beneficial effects on the overall sperm cryotolerance in domestic cats.

Solid storage supplemented with serine of rooster semen enhances higher sperm quality and fertility potential during storage at 5 degrees Celsius for up to 120 hours

Information on prolonging the storage duration of cold semen with acceptable fertility in roosters is limited. This study aimed to determine the efficiency of solid storage with the addition of various concentrations of serine to the Thai native rooster (Pradu Hang Dum) semen extender on semen quality and fertility potential during storage at 5°C for up to 120 h. Pooled semen was diluted with a base extender and a gelatin extender containing 0, 2, 4, and 6 mM serine, then stored at 5°C for 120 h. In Experiment 1, the semen quality and malondialdehyde (MDA) concentrations were assessed at 0, 24, 72, and 120 h after storage. In Experiment 2, fertility potential in terms of fertility and hatchability rates was determined using the most effective solid-storage semen from Experiment 1. Sperm quality decreased with increasing storage time (P < 0.05). The lowest semen quality was observed in the control group since T24 of storage compared with the other groups (P < 0.05). Progressive motility, viability, and mitochondrial function were higher (P < 0.05) in the extender supplemented with gelatin and serine groups than those in the gelatin alone group at T72 and T120. In the extender supplemented with gelatin and serine groups, the highest semen quality was observed in the gelatin with 4 mM serine groups. The differences among extenders supplemented with serine were insignificant (P > 0.05), and the lowest MDA was observed in the gelatin with 4 mM serine groups. The fertility and hatchability rates in gelatin with 4 mM serine at T24 were comparable to those in fresh semen (83.87 and 86.12% vs. 86.66 and 88.3%; P > 0.05). Those of T72 were significantly better than those of the control at the same hour of storage (64.08 and 71.61% vs. 52.38 and 64.48%), while those of T120 were not different among groups. In summary, a semen extender as a solid medium supplemented with 4 mM serine successfully preserved the rooster semen for a long duration up to 72 h of storage time.

Methylene blue-mediated antimicrobial photodynamic therapy on chicken semen

BACKGROUND

Artificial insemination is widely employed in poultry, but high degrees of bacterial contamination are often observed in semen because of its passage through the cloaca. Consequently, most semen extenders for birds have antibiotics that could aggravate bacterial resistance.

METHODS

We evaluated the potential of antimicrobial photodynamic therapy (PDT) as an alternative to the use of antibiotics, and assessed whether changes in concentration and incubation time with methylene blue (MB), radiant exposure, and irradiance of light affect spermatozoa activity and bacteria in chicken semen.

RESULTS

Incubation with MB (< 25 µM) did not alter sperm motility, regardless of the pre-irradiation time (PIT, 1 or 5 min). Following 1 min of PIT with MB at 10 µM, samples were irradiated for 30, 60, 120, and 180 s at irradiances of 44, 29, and 17 mW/ cm² (660 nm LedBox). MB and light alone did not interfere with the analyzed parameters. However, when both factors were associated, increases in light dose led to greater reductions in sperm parameters, regardless of the irradiance used. Besides, PDT conditions that were less harmful to spermatozoa were not able to significantly reduce bacterial colonies in chicken semen.

CONCLUSIONS

A failure in MB selectivity could explain unsuccessful bacterial reduction following PDT. Further research involving other photosensitizers or conjugating molecules to MB to target microbial cells is needed for PDT application in poultry breeders.

Effect of prooxidants and chelator Desferal on the oxidative status and sperm motility of Muscovy semen

This study aimed to establish the sensitivity of Muscovy duck semen to oxidative stress (OS) and the effect of Desferal, applied as an antioxidant. The effect of three prooxidant systems in presence and absence of Desferal were tested on the motility and kinetic parameters (determined using CASA system), as well as the level of lipid peroxidation (LPO) and glutathione (tGSH) of Muscovy semen. The semen was diluted (1:3 v/v) with four extenders (saline solution, IMV Canadyl, HIA-1, and AU) and stored at 4 °C for 6 h. The cooled semen was divided into aliquots (50 × 106 sperm cells/mL), which were incubated at 37 °C for 30 min with one of the following prooxidative agents: ferrous sulfate (FeSO4, 0.1 mM), hydrogen peroxide (H2O2, 1 mM), and Fenton system (FeSO4(Fe2+), 0.1 mM + H2O2, 1 mM), in the presence or absence of Desferal (0.1 mM). The addition of FeSO4 + H2O2 or FeSO4 regardless of the used extender, as well as the addition of H2O2 to the diluted semen with saline solution significantly increased the levels of LPO (P < 0.05). With the lowest prooxidant effect was H2O2. The application of Desferal reduced significantly (P < 0.05) the LPO levels induced by FeSO4 + H2O2 or FeSO4 and in a weaker degree by H2O2. Among all prooxidants, FeSO4 + H2O2 decreased in the greatest extent the tGSH concentration in semen diluted with each used extenders in comparison to the relevant control. The addition of Desferal in semen diluted with HIA-1 extender and incubated with FeSO4, and H2O2, showed the best restoration of tGSH level, close to that of respectively controls. The studied prooxidants significantly reduced total, progressive, and kinetic sperm motility (P < 0.05). Although the inclusion of Desferal reduced the sperm OS, it did not improve the impaired by OS sperm motility.

Assessing different liquid-storage temperatures for rooster spermatozoa

Although liquid-storage is extensively used in poultry, there are still questions on how sperm physiology is affected and to what extent sperm functions are disrupted by storage temperature and time. There, therefore, was investigation of storage temperature and durations on multiple semen variables. The storage at 37 °C was the most damaging, affecting values for several variables within 4 h of storage, whereas most differences occurred between 5 and 25 °C after 8 h. Progressive motility and mitochondrial function started to decrease within 2 h at 25 and 37 °C, and within 4 h at 5 °C. Acrosomal damage only occurred in samples at 37 °C. Eosin-negrosin staining indicated there was damage to the plasma membrane at 37 °C, however, with use of propidium iodide there were differences between 5 and 25 °C following 24 h. Temperatures of 5 and 25 °C resulted in similar curves for chromatin dispersion although chromatin integrities differed with storage for periods longer than 4 h. At 37 °C, results using both chromatin evaluations indicated there was damage after 2 h of incubation. Oxidative stress at 5 and 25 °C was similar when there was 24 h of storage. Intriguingly, there were no interaction between temperature and storage duration for peroxidized sperm membrane and total peroxidation status. These findings indicated that with a prolonged storage at 5 °C there were not marked changes in chicken spermatozoa, whereas at 25 °C there did not appear to be sperm damage occurring as a result of short-term storage.

Identification of Bacterial Profiles and Their Interactions with Selected Quality, Oxidative, and Immunological Parameters of Turkey Semen

Simple Summary

Overbreeding—and its associated increase in the chest areas of turkeys—has led to the loss of their natural ability to reproduce. Therefore, commercial production of turkey meat relies on artificial insemination. However, along with the physiology of the genital tract of turkeys, there is high potential for bacterial contamination of ejaculates. These bacteria may affect crucial semen quality parameters required for successful fertilization. As such, it is important to pay close attention to the bacteria present in turkey ejaculates and possible solutions to eliminate their adverse effects on avian spermatozoa.

Abstract

This study focused on the identification of naturally occurring bacteria in the reproductive fluid and impact on the quality of ejaculates obtained from the turkey breed British United Turkeys (BUT) Big 6 (n = 60). We determined possible relationships between the bacterial load and advanced sperm quality parameters that are important for effective artificial insemination and high fertility, as well as the concentration of selected antimicrobial proteins and pro-inflammatory markers of turkey semen. Sperm motility was assessed with computer-assisted sperm analysis (CASA), while the membrane and acrosome integrity were examined with smearing and staining methods. Reactive oxygen species (ROS) generation was quantified via luminometry, sperm DNA fragmentation was evaluated using the TUNEL assay, and the JC-1 assay was applied to evaluate the mitochondrial membrane potential. Cell lysates were prepared to investigate the extent of lipid and protein oxidation. Furthermore, levels of interleukins 1 and 6 (IL-1, IL-6), C-reactive protein, cathelicidin, and β-defensin were quantified in the seminal plasma using the ELISA method. The most dominant species identified by the matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometry was Escherichia coli, Proteus mirabilis, Staphylococcus lentus, and Citrobacter braakii. The bacterial load had a negative effect on the sperm motility (p < 0.001), as well as membrane (p < 0.05) and acrosome integrity (p < 0.01). A strong positive relationship between the bacterial load and DNA fragmentation (p < 0.001) was detected as well. Positive associations were recorded between the increasing presence of bacteria, ROS overgeneration (p < 0.001), and a subsequent oxidative damage to the proteins (p < 0.001) and lipids (p < 0.01). It was revealed that the antimicrobial peptides β-defensin (p < 0.001) and cathelicidin (p < 0.001) had a positive relationship with the motility. In contrast, pro-inflammatory markers, such as IL-1 (p < 0.001) and IL-6 (p < 0.001), had a negative impact on the motion behavior of turkey spermatozoa. Our results suggest that the semen quality may be notably affected by the bacterial quantity as well as quality. It seems that bacteriospermia is associated with inflammatory processes, oxidative stress, sperm structural deterioration, and a subsequent risk for a failed artificial insemination in turkey breeding.

Addition of antifreeze protein type I or III to extenders for ram sperm cryopreservation

Antifreeze proteins (AFP) play an important role in cellular survival at sub-zero temperatures. This study assessed the effect of AFP type I or III in semen extender (TRIS-egg yolk) for ram sperm cryopreservation. Pooled semen of four rams were allocated into five treatments: Control (CONT, without AFP); AFP Type I [0.1 (AFPI-0.1) or 0.5 (AFPI-0.5) μg/mL]; or III [0.1 (AFPIII-0.1) or 0.5 (AFPIII-0.5) μg/mL], and then frozen in six replicates. Treatments affected kinetic parameters, plasma membrane integrity and morphology (P < 0.05). The AFPIII-0.1 presented lesser total motility. Linearity was greater in AFPI-0.1, AFPI-0.5 and AFPIII-0.5 and straightness was greater in all AFP-supplemented extenders. Plasma membrane integrity was greater in AFPI-0.1 and AFPI-0.5. All AFP groups had greater percentage of normal sperm than CONT. No differences (P > 0.05) were observed in hypoosmotic test, sperm acrosome status, mitochondrial activity, chromatin condensation, perivitelline membrane binding rate and lipoperoxidation. In conclusion, the use of AFP, predominantly type I, may increase sperm cell protection during cryopreservation, with no adverse effect on potential fertilization capacity or increase in reactive oxygen species, being a potential cryoprotectant to ram sperm.

Practical methods to assess the effects of heat stress on the quality of frozen-thawed Belgian Blue semen in field conditions

The increased exportation of semen and embryos of double-muscled beef breeds to tropical and developing countries makes it important to investigate the reproductive capacity of these breeds in adapting to tropical conditions. The aim of this study was to evaluate the quality of Belgian Blue semen collected after there is heat-stress (HS; as a mimic of tropical condition) compared with non-heat stressed (NHS; as their comfort zone), using practical spermatozoa staining methods such that prevail in developing countries. There was screening of semen kinetics using CASA and evaluation of their DNA-, acrosome, plasma membrane-integrity, and mitochondrial activity. For each staining technique, there was evaluation of 12 frozen-thawed semen samples from six Belgian Blue bulls collected after there were HS and NHS conditions in Belgium. Mixed linear regression models were used to assess the effects of HS for each CASA variable and staining method outcome using the replicate nested with bull as a random effect. There were differences (P < 0.05) in values when there were semen collections following HS and NHS conditions for several post-thawing kinetic variables. Furthermore, the mean percentages of DNA-, acrosome-, and plasma membrane-integrity, as well as mitochondrial activity were greater (P < 0.05) when semen was collected following NHS compared with HS conditions. Conclusively, results indicated that when there was collection of semen following HS conditions, there were detrimental effects on the viability and quality of Belgian Blue semen which is an important consideration for the semen collection, processing, and evaluation in tropical countries.

Beneficial influence of fetal bovine serum on in vitro cryosurvival of chicken spermatozoa

Chicken spermatozoa are highly susceptible to cryopreservation often requiring extenders containing additives to enhance their post-thaw quality. Although protective properties of fetal bovine serum (FBS) during freezing of tissue cultured cells are widely known, its potential as a cryoprotectant for sperm cells has not been largely explored. Thus, the aims of our study were to (i) investigate the protective effect of FBS at different concentrations (0, 5, 10, 15 and 20%) against cryodamages in chicken spermatozoa, and (ii) test the FBS concentration that yielded the best preservation versus 1 mg/mL of cholesterol-loaded cyclodextrins (CLCs). Samples were assessed before and after freezing for sperm motility parameters, plasma membrane and acrosomal integrities, mitochondrial membrane potential, oxidative stress and plasma membrane peroxidation. Our findings showed that, despite their beneficial effects on fresh spermatozoa, higher FBS concentrations (15 and 20%) obtained the worst results for most motility and functional parameters after thawing. In contrast, lower FBS concentrations (5 and 10%) improved all post-thaw variables when compared to control. Afterwards, based on regression analysis, the concentration of 7% FBS was chosen to be assessed against CLCs in an experiment composed by four groups: control, FBS, CLCs, and FBS + CLCs. FBS and FBS + CLCs groups exhibited higher progressive motility in fresh samples, whereas only FBS maintained higher post-thaw progressive motility. Additionally, the incorporation FBS into extenders increased the percentage of rapid cells and reduced free radicals production and plasma membrane peroxidation. Together, these outcomes indicated that FBS minimize some harmful effects of cryopreservation, providing an alternative for chicken semen extenders that in many aspects appears to be superior to CLCs at 1 mg/mL.

Semen cryopreservation in golden-headed lion tamarin, Leontopithecus chrysomelas

Wild animal genetic resource banking (GRB) represents a valuable tool in conservation breeding programs, particularly in cases involving endangered species such as the golden-headed lion tamarin (Leontopithecus chrysomelas). Thus, we aimed to assess a sperm freezing protocol for golden-headed lion tamarins using two different exenders: BotuBOV® (BB) and Test Yolk Buffer® (TYB). Ejaculates were collected by penile vibrostimulation from animals housed at São Paulo Zoological Park Foundation, São Paulo, Brazil, and after immediate analysis, two aliquots were diluted in BB and TYB. Postthawing samples were evaluated for total and progressive motility, plasma membrane and acrosome integrities, mitochondrial activity, susceptibility to oxidative stress, and sperm-egg-binding. No differences between BB and TYB were found for most seminal parameters, except for acrosome integrity and susceptibility to oxidative stress (in both cases BB showed higher values). However, in spite of these differences and regardless of the extender used, postthaw sperm motility and viability with the described protocol were encouraging (on average >50% and >80%, respectively), indicating that sperm cryopreservation may be a short-term measure for the conservation of golden-headed lion tamarins.

Assessment of different sperm functional tests in golden-headed lion tamarins (Leontopithecus chrysomelas)

The golden-headed lion tamarin (Leontopithecus chrysomelas) is an endangered species endemic to Brazil's Atlantic Forest, a shrinking biodiversity hotspot. As in other Neotropical primates, its semen characteristics and freezability are poorly studied. Hence, reproductive technologies for callitrichids would greatly benefit from reliable methods of semen analysis. In a bid to promote reproductive research in tamarins, we validated simple and inexpensive sperm function tests that can be used to monitor sperm-egg binding, plasma membrane and acrosome integrity, mitochondrial activity, and DNA fragmentation. Ejaculates from adult males were individually diluted and divided into control and damage-induced aliquots, and then samples comprising assorted amounts of damaged spermatozoa were examined by organelle-specific tests. Our findings showed that sperm-binding in chicken egg perivitelline membrane (EPM) positively correlated with the number of spermatozoa injured by snap-freezing. Eosin-nigrosin (EN) and propidium iodide readings were correlated with each other, and both provided robust measurements of plasma membrane integrity. A high correlation between expected and measured amounts of acrosome-intact spermatozoa was found using Fast Green-Rose Bengal (FG-RB), Coomassie Blue (CB), and FITC-PSA stains, and all three methods exhibited comparable results. Likewise, different percentages of UV-irradiated spermatozoa were accurately assessed for DNA integrity by Toluidine Blue (TB) and sperm chromatin dispersion (SCD) tests. Comparisons between 3,3'-diaminobenzidine (DAB) and JC-1 stains also indicated the reliability of the former assay to ascertain gradual increases in spermatozoa with greater mitochondrial function. These data confirmed that different parts of the tamarin spermatozoa can be simply and consistently evaluated by EPM, EN, FG-RB, CB, TB, and DAB protocols.