Search Results (61)

Waterfowl semen cryopreservation technology is a key link in genetic resource conservation and artificial breeding, but poultry spermatozoa, due to their unique morphology and biochemical properties, are prone to oxidative stress during freezing, resulting in a significant decrease in vitality. In this study, we first used four different freezing procedures (P1–P4) to freeze duck semen and compared their effects on duck sperm quality. Then, the changes in antioxidant indexes in semen were monitored. The results showed that program P4 (initial 7 °C/min slow descent to −35 °C, followed by 60 °C/min rapid descent to −140 °C) was significantly better than the other programs (p < 0.05), and its post-freezing sperm vitality reached 71.41%, and the sperm motility was 51.73%. In the P1 and P3 groups, the sperm vitality was 65.56% and 53.41%, and the sperm motility was 46.99% and 31.76%, respectively. In terms of antioxidant indexes, compared with the fresh semen group (CK), the activities of superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GSH-px) in the P2 group were significantly decreased (p < 0.05), while the activities of SOD and CAT in the P4 group showed no significant changes (p > 0.05) except that the activity of GSH-px was significantly decreased (p < 0.05). And the CAT and GSH-px activities in the P4 group were significantly higher than those in the P2 group (p < 0.05). The content of malondialdehyde (MDA) in the P2 group was significantly higher than that in the fresh semen group (p < 0.05), and there was no significant difference between the P2 group and the P4 group (p > 0.05). The total antioxidant capacity (T-AOC) content of the P2 and P4 groups was significantly lower than that of the fresh semen group (p < 0.05). The staged cooling strategy of P4 was effective in reducing the exposure time to the hypertonic environment by balancing intracellular dehydration and ice crystal inhibition, shortening the reactive oxygen species accumulation and alleviating oxidative stress injury. On the contrary, the multi-stage slow-down strategy of P2 exacerbated mitochondrial dysfunction and the oxidative stress cascade response due to prolonged cryogenic exposure time. The present study confirmed that the freezing procedure directly affects duck sperm quality by modulating the oxidative stress pathway and provides a theoretical basis for the standardization of duck semen cryopreservation technology. Full article

Liquid storage is an important tool used to prolong fresh semen shelf-life while protecting spermatozoa from damage, conserving their overall functionality, and ensuring better fertility than frozen semen from sheep. The increased production of reactive oxygen species (ROS) during sperm storage leads to a decline in sperm quality, particularly with regard to sperm nuclear DNA damage and mitochondrial membrane potential (MMP). This study evaluated the effect of storing Sarda ram semen at 15 °C for 7 h on its redox status, motility, morphology, acrosome integrity, ATP content, mitochondrial potential membrane, and in vivo fertility after artificial insemination. Two different extenders were compared: a lab-made skimmed milk (SM)-based extender and a commercial extender (OviXcell^®, IMV-Technologies, France). Lower ROS levels in the SM (p < 0.001) indicated that its oxidative status was better maintained compared to the commercial extender (CE). Antioxidant defenses (total antioxidant capacity, TEAC; superoxide dismutase, SOD; total thiols) were higher in the SM (p < 0.01) than in the CE. SM also had higher MMP (p < 0.05), acrosome integrity (p < 0.05), ATP content (p < 0.01), and in vivo fertilizing capacity (p < 0.05) compared to the CE, which indicated higher semen quality. In conclusion, the SM extender, while maintaining a better oxidative/antioxidant balance, ensured higher semen quality after 7 h of storage at 15 °C in vitro compared to the CE. Full article

Semen collection is an important component of conservation and animal husbandry. Semen quality is generally improved using voluntary collection methods, particularly artificial vaginas (AVs). Most commercially available AVs are tube-shaped with few species-specific design augmentations. As genitalia are highly variable across taxa, incorporating species-specific genital morphologies into AV designs may enhance collected semen quality. We compared dolphin semen quality using: (1) silicone bioinspired artificial vaginas (BAVs) that reflect the internal shape of dolphin vaginas, and (2) manual stimulation. Sperm motility and kinematic parameters of five bottlenose dolphins (Tursiops sp.) were assessed using computer-aided sperm analysis (CASA). Sperm collected using BAVs showed non-significant increases in median progressive and rapid motility, and increases in median and mean linear motility, supporting a sexual selection functional hypothesis for the biodiverse vaginal folds unique to whales, dolphins, and porpoises. Sperm concentration decreased with BAV collection, while no consistent trends were detected in volume, pH, velocity, or plasma membrane integrity. Modifications to AVs for other species that incorporate genital morphologies may also optimize collected semen quality for application to artificial insemination. Full article

The significant decline in amphibians worldwide is demanding the development of reliable techniques to save species and their genetic diversity. Considerable efforts are currently in progress to develop assisted reproductive technologies (ARTs), focusing mainly on sperm cryopreservation and in vitro fertilization (IVF). In Xenopus, a simple and efficient transgenesis method based on the intracytoplasmic injection (ICSI) of cryoconserved sperm was developed several decades ago, allowing for quick generation of large numbers of transgenic animals, for biological research. Such a methodology could be critical for the recovery of species and their genetic diversity, contributing to amphibian conservation. However, this approach raised the question of whether the sperm preservation method used with ICSI is compatible with long-term storage. To address this question, animals were generated by ICSI using a twenty-year-old cryopreserved sperm preparation. Their development, behavior, and reproduction ability were compared with those of animals obtained using a recently frozen sperm preparation and those of animals obtained via IVF using fresh semen. Although lower than with IVF, we showed that fertilization rates using ICSI after 20 years of cryopreservation are similar to those of a recent preparation, with viable offspring leading to normal F2 generation. This pioneering achievement is proof of concept for long-term sperm cryopreservation using simple and readily available technologies for the conservation of endangered amphibians. Full article

The study investigated the sperm motility and morphometry of pre-freeze and post-thaw boar epididymal semen cooled at increasing holding times at 18 °C. A total of 50 testes of heterogeneous boars were collected (5 testes/day) from the local abattoir and transported to the laboratory at 5 °C within 30 min after slaughter. Semen was retrieved from the caudal part of the epididymis using the slicing float-up method, diluted with Beltsville Thawing Solution extender, pooled in a 50 mL centrifuge tube/5 testes/day, and cooled at 18 °C. Following each holding time (0, 3, 6, 9, 12, 24, and 48 h), the cooled semen sample was re-suspended with Fraction A extender and stored at 5 °C for an additional 45 min. A cooled resuspended semen sample was then diluted with Fraction B extender, loaded into 0.25 mL straws, and frozen using liquid nitrogen vapour. Thawing was accomplished by immersing the semen straws in warm (37 °C) water for 1 min and the samples were evaluated for sperm motility and morphometry traits using the computer-assisted sperm analyzer system. The data were analyzed using variance analysis. Descriptive statistics were used to assess sperm morphometry, establishing the minimum and maximum values. Boar epididymal sperm survived for up to 48 h when held at 18 °C. Furthermore, the highest post-thawed sperm motility rates were observed in semen frozen after 3 h of holding time, with a sperm total motility of 85.9%, a progressive motility of 60.3%, and a rapid motility of 33.2%, as compared to other holding times (p < 0.05). The acceptable ranges for pre-freeze and post-thawed sperm morphology were head length (8.4–9.1 µm), width (4.4–4.8 µm), area (29.9–38.2 µm²), perimeter (20.1–23.7 µm), midpiece width (1.1–2.8 µm), and sperm shape, were consistent regardless of the holding time. A holding time of 3 h enhances the cryoresistance of sperm cooled at 18 °C. Therefore, these findings suggest that boar epididymal sperm can be effectively conserved and can maintain fertilization capability when cooled for 3 h at 18 °C before freezing. Full article

Semen cryopreservation is a crucial technology in the artificial insemination of livestock and poultry. It not only contributes to the conservation of germplasm resources but also facilitates the cross-regional exchange of high-quality breeding stock. In this study, 165 Duroc boars were selected for genome-wide genotyping, and the sperm freezing/thawing motility ratio (sperm recovery rate) was used as phenotypic data for genome-wide association analysis (GWAS). Considerable individual variations in sperm recovery rates (SRRs) were detected, and the sperm structure after cyropreservation was significantly better in highly freeze-tolerant individuals compared to non-freeze-tolerant ones. The heritability of the SRR was calculated and found to be 0.199 ± 0.158, representing low heritability. Through GWAS, eight single-nucleotide polymorphism (SNP) loci and four candidate genes (SLC10A6, MYRF, GGA1, and UTRN) were identified as being significantly associated with sperm freezing tolerance. Moreover, the dominant genotypes of four SNPs were finally determined to be valuable for identifying individuals with high sperm freezing tolerance. This study reveals the heritability of the sperm recovery rate and identifies molecular markers associated with sperm freezing tolerance in Duroc boars, which is of great significance for accelerating boar genetic improvement and enhancing the economic efficiency of pig breeding industry. Full article

While most lizard species are polygamous, dominant males typically have greater access to females and copulate more frequently than submissive ones. Several studies suggest that applying assisted reproduction techniques to this taxon could be an effective tool to enhance conservation programs. Therefore, the proper selection of males for assisted breeding programs is crucial for their overall success. In this study, we report for the first time data on semen and sperm quality from dominant males of the Mexican lizard Sceloporus torquatus using techniques commonly employed in assessing mammalian fertility. The semen and sperm characteristics were as follows: volume, 14.0 µL; sperm concentration, 125.7 × 10⁶ cells/mL; wave motion, 2.7; total motility, 87.8%; sperm viability, 89.0%; normal morphology, 88.8%; plasma membrane integrity, 87.7%; low plasma membrane fluidity, 94.9%; capacitation status: uncapacitated (F), 90.5%; capacitated (B), 7.2%; sperm with acrosome reaction (AR), 2.3%; and, acrosome integrity, 88.8%. These results suggest that, according to mammalian fertility parameters, dominant males of S. torquatus are fertile. This series of tests provides a valuable tool for conducting a comprehensive analysis of the functional changes that may occur in sperm handling during assisted processes, and that may contribute—along with the proper selection of individuals—to reproductive success. Full article

Sperm cryopreservation is a powerful tool for the conservation of endangered species, but its application requires adapting protocols to particular species, due to differences in sperm structure, function, and cryosensitivity. Research on the biology of endangered felids primarily relies on the domestic cat as an experimental model. Semen from live animals can be collected using several methods. However, in animals that die due to roadkill or in the field, spermatozoa must be retrieved from the epididymis. Differences may exist in the cryosensitivity of epididymal and ejaculated sperm due to the influence of secretions from accessory genital glands. We analyzed the effects of several factors on the motility and acrosomal integrity of cryopreserved cat epididymal spermatozoa, including cooling rate, storage system, time and temperature of straw loading, and the freezing method in nitrogen vapors. There were no significant differences in motility or acrosomal integrity at thawing between fast (−0.5 °C/min) or slow (−0.125 °C/min) cooling rates or between loading straws at room temperature versus 5 °C. Post-thaw motility was significantly higher when using straws compared to pellets and when freezing in nitrogen vapors at two levels rather than at a single level. Additionally, interactions between the loading temperature of straws and both motility and acrosomal integrity were not significant. These results are important for standardizing protocols to cryopreserve feline epididymal sperm, facilitating the rescue of genetic material from endangered species in the field. Full article

Understanding the genetic, physiological, and nutritional characteristics of native chickens in South Africa has been significantly hindered by studies over the last ten years. These chickens hold significant economic, social, and cultural importance for South African communities, particularly those marginalized. Despite their reputation for lower egg productivity, they are highly valued for their flavorful meat by consumers. Many local chicken ecotypes and breeds remain undocumented and in danger of going extinct, even though some have been classified. To tackle this issue, the Food and Agriculture Organization has launched an indigenous poultry conservation program. One crucial method employed is assisted reproductive biotechnologies such as cryopreservation, which serves as an ex situ conservation strategy for preserving the germplasm of endangered animals. In avian species, cryopreservation is particularly beneficial for the long-term storage of sperm cells, although it necessitates the use of cryoprotectants to shield sperm cells from cold shock during freezing. However, the use of cryoprotectants can lead to thermal shocks that may damage the sperm cell plasma membrane, potentially reducing viability and fertility. Furthermore, the membranes of avian sperm cells are highly polyunsaturated fatty acids, which can undergo lipid peroxidation (LPO) when reactive oxygen species (ROS) are present. This review focuses on current knowledge and the latest effective strategies for utilizing cryopreservation to conserve semen from indigenous poultry breeds. Full article

Poultry semen preservation is crucial for sustaining genetic diversity, improving production efficiency, and facilitating various breeding initiatives. This review underscores the importance and challenges associated with different preservation techniques. We investigate effective techniques for semen collection and evaluation, focusing on vital parameters such as volume, concentration, motility, and morphology. Preservation strategies are categorized into short-term approaches, such as dilution with extenders, and mid-to-long-term strategies, like freezing and the use of cryoprotectants. Additionally, we explore several factors affecting semen quality, including male age and genetics, seasonal impacts, and stress during handling. Assessing the quality of preserved semen is critical, particularly regarding post-thaw motility. The applications of these preservation techniques in artificial insemination, genetic enhancement, the conservation of endangered breeds, and biobanking are highlighted. This review identifies critical research opportunities, including the development of improved cryoprotectants, refining freezing protocols, comprehending the mechanisms of semen damage, and innovating novel preservation technologies. Addressing these challenges will enhance poultry semen preservation and contribute to sustainable poultry farming. Full article

South Africa recognizes the value of indigenous breeds such as Potchefstroom Koekoek, Boschveld, Ovambo, Venda, Naked Neck, and nondescript village chickens. Indigenous chickens support sustainable food systems, improve nutrition, and enhance livelihoods in rural communities, thereby contributing to the United Nations’ Sustainable Development Goal (SDG) 2 on Zero Hunger. These breeds are not only vital to rural farmers for food production, income generation, and subsistence but also provide rural farmers with cheap nutritious protein such as eggs and meat for household consumption. Moreover, they are preferred by rural farmers because they are relatively affordable to produce, can withstand harsh environmental conditions amid accelerated climate change compared to exotic breeds, and require less/no feed supplementation. However, despite the numerous advantages of keeping these chickens, it has been found that they are mostly in danger of extinction due to evolving production methods that favor exotic breeds. Therefore, understanding their extinction status, different implications for conserving their genetic material, challenges encountered, and future approaches to rescue these breeds remain vital. Hence, the aim of this systematic review was to assess the extinction status, challenges, and conservation approaches for these breeds. The Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines were utilized to search for suitable articles addressing the objective of the current review. Research articles were grouped and evaluated for eligibility, and the data from the Domestic Animal Diversity Information System database were used. Records such as duplicates of studies addressing origins, phenotypic and genetic diversity, the conservation of indigenous chickens, semen cryopreservation of indigenous chickens, climate change effects on indigenous chickens, and the use of extenders with exotic chickens and other chicken types, reports in other languages, and reports that were inaccessible were excluded. Articles addressing origins, phenotypic and genetic diversity, the conservation of indigenous chickens, semen cryopreservation of indigenous chickens, climate change effects on indigenous chickens, and the use of extenders with indigenous chickens were included in this review. The keywords used to search articles online were as follows: South African indigenous chicken; extension status; conservation; genetic resources; genetic markers; effective population size; inbreeding; and characterization. This systematic review found that there is less information in the Domestic Animal Diversity Information System regarding South African indigenous and village chickens, suggesting a lack of reporting in this system. Moreover, our review confirmed that most South African indigenous chickens are threatened and, hence, require interventions such as assisted reproductive technologies and other strategies in order to improve efficiency. Full article

The increasing reliance of modern agriculture on honey bee (Apis mellifera) pollination has driven efforts to preserve and enhance bee populations. The cryopreservation of drone semen presents a promising solution for preserving genetic diversity and supporting breeding programs without live animal transport risks. This study aimed to evaluate a one-step dilution antibiotic-free drone semen slow-freezing protocol under field conditions with in vitro and in vivo parameters. Semen viability was tested by two different mixes of dyes, and both techniques gave similar results, showing a post-thaw viability drop of 37%. Virgin queens were inseminated either with fresh or frozen–thawed semen. Survival rates until egg-laying onset and female brood production were similar for both groups; however, colonies with queens inseminated with fresh semen were more likely to go into wintering. Results suggest that frozen–thawed semen can support viable queen insemination, with potential for female brood production even without antibiotics in the diluent. This study highlights the need for further refinement of cryopreservation protocols, particularly regarding semen quality and queen longevity, to improve the feasibility of cryobanking for Apis mellifera conservation and breeding. Full article

Cryopreservation plays a critical role in animal breeding and the conservation of endangered species, but it often compromises sperm characteristics such as morphology, motility, and viability due to oxidative stress. This study explores the antioxidative effect of Mito-Tempo (MT) and Berberine (BER) to enhance post-thaw sperm quality in rabbits. Pooled rabbit sperm samples were supplemented with different concentrations (0.0, 0.5, 5, 10, 50 µmol/L) of MT and BER. Sperm motility was evaluated using computer-assisted semen analysis, while viability, apoptosis, reactive oxygen species (ROS) levels, acrosome integrity, and mitochondrial function were assessed through flow cytometry. The results revealed that MT at 5 and 10 µmol/L and BER at 10 µmol/L significantly improved total and progressive motility, mitochondrial activity, and sperm viability compared to the control group. Furthermore, 10 µmol/L BER enhanced acrosome integrity, while both 5 µmol/L MT and 10 µmol/L BER effectively reduced ROS levels and apoptosis. This study is the first to demonstrate the protective effects of MT and BER on rabbit sperm during cryopreservation. By mitigating oxidative stress and reducing apoptosis, these antioxidants markedly improved post-thaw sperm quality, positioning MT and BER as promising agents for improving sperm cryosurvival. Full article

The standardization of the semen cryopreservation technique could be an effective tool in poultry for the conservation of genetic resources. During this process, the production of reactive oxygen species increases, leading to oxidative stress that causes damage to the spermatozoa. To reduce this effect, the addition of exogenous antioxidants in the cryopreservation diluent has been reported to be effective. Multiple antioxidants such as catalase, vitamin E, cysteamine, ergothioneine, and serine have been studied in roosters. Therefore, the present investigation aims to perform a meta-analysis to determine if the use of the aforementioned antioxidants added to the cryopreservation extender produces an improvement in semen quality parameters in roosters after thawing. After collecting the data, a discriminant canonical analysis was performed to determine which of the selected semen quality traits provided the most information, with hypo-osmotic swelling test (HOST), viability, and total motility variables showing the highest discriminatory power. However, according to the descriptive statistics, catalase and serine are the antioxidants that improve a greater number of seminal quality parameters, and since catalase gives the most favorable results for most of the discriminating variables, it could be the antioxidant of choice. Full article

This study aims to investigate the impact of carvacrol and thymol on the quality of Beni Arouss buck semen stored in skim milk at 4 °C. Ejaculates were collected from eight Beni Arouss bucks weekly for 11 weeks, pooled, and then divided into three equal parts. Samples were diluted to 400 × 10⁶ sperm/mL in skim milk (control) and skim milk supplemented with a single dose of 200 µM carvacrol and thymol each. Evaluations of sperm motility, viability, abnormalities, membrane integrity, lipid peroxidation, and bacterial growth were conducted at 0, 6, 24, and 48 h of liquid storage at 4 °C. After 48 h of storage, the results indicate that the addition of carvacrol positively influences total and progressive motility and viability. However, it also leads to a decrease in lipid peroxidation and bacterial growth compared to the control group (p < 0.05). Thymol showed similar results to carvacrol, except for progressive motility (p > 0.05). Bacterial growth was negatively correlated with total and progressive motility and viability (p < 0.05), while no correlation between lipid peroxidation and these parameters was observed (p > 0.05). In conclusion, the addition of carvacrol and thymol to skim milk extender moderately improves the quality of Beni Arouss buck semen after 48 h storage at 4 °C due to its antimicrobial activity. Full article