Research Interests: Geography, Ecology, Habitat, Grassland, National Park, and 3 moreHome Range, Deciduous, and Biodiversitas
The global environment is under increasing pressure from expanding human activities and climate changes. The change in global environment, including increase environmental temperature, marine pollution, ocean acidification among others,... more
The global environment is under increasing pressure from expanding human activities and climate changes. The change in global environment, including increase environmental temperature, marine pollution, ocean acidification among others, has resulted in significant loss in biodiversity. To dates, the International Union for Conservation of Nature (IUCN) has estimated that 41% of amphibians, 33% of corals, 26% of mammals and 13% of birds are threatened by extinction (International Union for Conservation of Nature IUCN, 2015). Imminent extinction of wild species is often caused by multiple factors and may not always be due to failure of animals to breed. Nevertheless, reproductive sciences play critical roles in wildlife conservation, especially captive breeding program. A clear example of how reproductive biology contributes to species recovery program is the case of black footed ferret (Howard et al., 2003; Santymire et al., 2014), endemic to North America. In 1980s, the species unde...
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The global environment is under increasing pressure from expanding human activities and climate changes. The change in global environment, including increase environmental temperature, marine pollution, ocean acidification among others,... more
The global environment is under increasing pressure from expanding human activities and climate changes. The change in global environment, including increase environmental temperature, marine pollution, ocean acidification among others, has resulted in significant loss in biodiversity. To dates, the International Union for Conservation of Nature (IUCN) has estimated that 41% of amphibians, 33% of corals, 26% of mammals and 13% of birds are threatened by extinction (International Union for Conservation of Nature - IUCN, 2015). Imminent extinction of wild species is often caused by multiple factors and may not always be due to failure of animals to breed. Nevertheless, reproductive sciences play critical roles in wildlife conservation, especially captive breeding program. A clear example of how reproductive biology contributes to species recovery program is the case of black footed ferret (Howard et al., 2003; Santymire et al., 2014), endemic to North America. In 1980s, the species un...
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Reproduction in canids has been characterized by having some peculiar aspects, such as the extended reproductive cycle and ovulation of immature oocytes [...].
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The dhole (Cuon alpinus) is one of the least frequent studied endangered canid species and many aspects of ecological knowledge about this species are lacking. The objectives of this study were to investigate the spatial movement of... more
The dhole (Cuon alpinus) is one of the least frequent studied endangered canid species and many aspects of ecological knowledge about this species are lacking. The objectives of this study were to investigate the spatial movement of dholes, prey abundance, prey selection, and prey overlaps with other large carnivorous species in the Huai Kha Khaeng Wildlife Sanctuary, Thailand, during November, 2017 and October, 2018. Two adult female dholes were captured and fitted with GPS collars. Twenty camera trap sets were systematically used to survey the area. Scat collection was conducted along forest roads and trails. The home range sizes and activity radii of the two dholes were 3,151.63 ha. and 1,442.84 m, and 33.39 ha and 331.56 m, respectively. The sambar deer (Rusa unicolor) was the most abundant prey species (30.93%). However, dhole fecal analysis showed that the monitored dholes preferred red muntjac (Muntiacus muntjak) (57.1%). There was a high degree of prey overlap between dholes...
Research Interests: Geography, Ecology, Endangered Species, Habitat, Predation, and 3 moreWildlife, Leopard, and Camera Trap
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Reproductive success of endangered whooping cranes (Grus americana) maintained ex situ is poor. As part of an effort to identify potential causes of poor reproductive success in a captive colony, we used non-invasive endocrine monitoring... more
Reproductive success of endangered whooping cranes (Grus americana) maintained ex situ is poor. As part of an effort to identify potential causes of poor reproductive success in a captive colony, we used non-invasive endocrine monitoring to assess gonadal and adrenal steroids of bird pairs with various reproductive outcomes and evaluated the relationships of hormones and behaviors to reproductive performance. Overall, reproductively successful (i.e., egg laying) females had significantly higher mean estrogen levels but lower mean progestogen concentrations than did unsuccessful females. Other hormones, including glucocorticoids and androgens, were not significantly different between successful and unsuccessful individuals. Observations of specific behaviors such as unison calling, marching, and the number of copulation attempts, along with overall time spent performing reproductive behaviors, were significantly higher in successful pairs. Our findings indicate that overall reproduct...
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Cytoplasmic lipids play key roles during oocyte and embryo development. However, there is little information on the changes in lipid types during intraovarian follicular and oocyte growth. Here, we used matrix-assisted laser desorption... more
Cytoplasmic lipids play key roles during oocyte and embryo development. However, there is little information on the changes in lipid types during intraovarian follicular and oocyte growth. Here, we used matrix-assisted laser desorption ionization-time of flight (MALDI-TOF) mass spectrometry to understand lipid composition in the cat oocyte during differing stages of folliculogenesis. Follicles at different developmental stages were mechanically isolated from cat ovaries within 4 h after routine ovariohysterectomy. Oocytes with granulosa cells were recovered from secondary (preantral stage, n = 387), early antral (<0.5 mm diameter, n = 177), small antral (0.5–1 mm, n = 144), and antral (>1 mm, n = 120) follicles, then subjected to lipid extraction and MALDI-TOF analysis (n = 3 replicates). Resulting mass spectra data were evaluated using MALDIquant in R package to eliminate baseline (background) and to identify peak values. The latter maximal values for each follicle stage were...
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A previous study from our laboratory has demonstrated that preantral follicles from the dog that are cultured in alginate are able to grow and produce steroid hormones (Songsasen et al. 2011 Reproduction 142, 113–122). Here we... more
A previous study from our laboratory has demonstrated that preantral follicles from the dog that are cultured in alginate are able to grow and produce steroid hormones (Songsasen et al. 2011 Reproduction 142, 113–122). Here we investigated the influence of using a combination of alginate and a degradable biomaterial, fibrin, on dog follicle development in vitro. We hypothesised that the alginate and fibrin gel matrix would be superior to alginate alone because the former has dynamic mechanical properties that permit more expansive follicle development than the inert alginate-only system. Secondary follicles (128–220 μm in diameter) were collected from the ovaries of 4 prepubertal dogs (<6 months of age) and encapsulated in 0.5% alginate (n = 26) or 0.5% alginate + 12.5 mg mL–1 of fibrin (n = 22). Follicles were cultured for 12 days at 38.5°C in 100 μL of α-minimal essential medium + 2 mM of glutamine + 5.5 μg mL–1 of insulin + 5.5 μg mL–1 of transferrin + 6.7 ng mL–1 of selenium ...
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The reproductive physiology of canids is unique compared to other mammalian species. Specifically, the reproductive cycle of female canids is characterized by extended periods of proestrus and estrus followed by obligatory diestrus and... more
The reproductive physiology of canids is unique compared to other mammalian species. Specifically, the reproductive cycle of female canids is characterized by extended periods of proestrus and estrus followed by obligatory diestrus and protracted ovarian inactivity (anestrus). Although canid reproduction follows this general pattern, studies have shown variations in reproductive biology among species and geographic regions. Understanding of these differences is critical to the development of assisted reproductive technologies including estrus induction, gamete rescue, and embryo production techniques for canid conservation efforts. This review summarizes current knowledge of canid reproduction, including estrus cyclicity, seasonality, and seminal traits, with the emphasis on species diversity. The application of reproductive technologies in wild canid conservation will also be discussed.
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To derive a practical procedure to store canine somatic cells, fibroblasts isolated from testicular or ovarian tissues were cryopreserved in 1.2 M ethylene glycol or in 1.2 M dimethylsulfoxide prepared in Dulbecco's Modified Eagle... more
To derive a practical procedure to store canine somatic cells, fibroblasts isolated from testicular or ovarian tissues were cryopreserved in 1.2 M ethylene glycol or in 1.2 M dimethylsulfoxide prepared in Dulbecco's Modified Eagle Medium as cryoprotectants, and were frozen either in plastic straws or vials. Thawed cells were cultured for 24 hr at 38.5 degree C in a humidified atmosphere of 5 percent CO2 95 percent air, and then their membrane integrity was assayed with a double fluorescent stain, Fertilight. In addition, frozen-thawed fibroblasts were cultured for 4 days, and then their functional survival was measured after staining small colonies with trypan blue. After freezing and thawing, membrane integrity of testicular fibroblasts was 55-70 percent and functional survival ranged from 20-40 percent. With frozen-thawed ovarian cells, the average membrane integrity was 55-75 percent and the average functional survival was 35-40 percent. When frozen in ethylene glycol, functi...
Research Interests: Andrology, Cryopreservation, Dogs, Female, Animals, and 7 moreMale, Medical Physiology, tESTIS, Ovary, Cell Survival, Ethylene Glycol, and fibroblasts
To examine the effect of seeding to induce ice formation during cryopreservation on their survival, spermatozoa from B6D2F1 mice were cooled to and held at −4°C for 30 min in phosphate-buffered saline (PBS) alone, in egg yolk-supplemented... more
To examine the effect of seeding to induce ice formation during cryopreservation on their survival, spermatozoa from B6D2F1 mice were cooled to and held at −4°C for 30 min in phosphate-buffered saline (PBS) alone, in egg yolk-supplemented PBS, or in PBS with raffinose + glycerol as cryoprotective additives (CPAs). Seeding and holding spermatozoa at −4°C did not affect their viability as judged by vital staining. Egg yolk protected spermatozoa against chilling injury, as cooling them to −4°C in the presence of egg yolk yielded higher survivals than those cooled without egg yolk (34.4 ± 3.4 v 9.0 ± 1.3% in three replicates of >400 spermatozoa/replicate). To study effects of seeding on their fertilizing ability, spermatozoa in the raffinose–glycerol–egg yolk solution were frozen to −196°C either without seeding or after seeding at −4°C. Development of 222 oocytes into two-cell embryos afterin vitrofertilization (IVF) with spermatozoa frozen without seeding was 43%; development rates of 186, 186, and 207 oocytes after IVF with spermatozoa frozen after seeding and being held at −4°C for 5, 10, or 30 min were 46, 44, and 9%, respectively. In a direct comparison, after IVF with seeded or unseeded spermatozoa the respective cleavage rates into two-cell embryos were 83% of 275 oocytes and 69% of 304 oocytes, a difference that was small but significant by χ2analysis. An additional 925 oocytes were fertilized with spermatozoa after being seeded and frozen to −196°C in four separate batches of CPA solutions. Overall, after IVF with frozen sperm, 68% of those oocytes cleaved into two-cell embryos and 59% developed into 544 blastocysts. Based on these results, we concluded that embryo production by IVF seemed to be improved using spermatozoa frozen after being seeded. Mouse spermatozoa cryopreserved by the method described here are capable of fertilizing oocytes at a rather high rate.
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A total of 104 oocytes were aspirated from 11 mature ewes and 4 prepubertal lambs. After in vitro maturation, fertilization and culture, 11 of the 104 oocytes developed into blastocysts. These were cryopreserved in 1.5 M ethylene glycol.... more
A total of 104 oocytes were aspirated from 11 mature ewes and 4 prepubertal lambs. After in vitro maturation, fertilization and culture, 11 of the 104 oocytes developed into blastocysts. These were cryopreserved in 1.5 M ethylene glycol. After being thawed, all were transferred into four recipients, two of which became pregnant and delivered a normal lamb. Key words: Oocyte, cryopreservation, in vitro maturation and fertilization, sheep, embryo
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The red wolf is a critically endangered canid, with ~250 and ~20 individuals in the ex situ and reintroduced wild populations, respectively. Assisted reproductive technologies such as sperm cryopreservation and in vitro fertilization... more
The red wolf is a critically endangered canid, with ~250 and ~20 individuals in the ex situ and reintroduced wild populations, respectively. Assisted reproductive technologies such as sperm cryopreservation and in vitro fertilization therefore represent critically-needed tools to manage these populations. However, the motility of post-thaw red wolf sperm rapidly declines during in vitro incubation, hindering the ability to develop these technologies. In this study, we evaluated the influence of several culture media (a modified canine capacitation medium (mCCM), a modified North Carolina State University-23 medium (mNCSU-23), a synthetic oviductal fluid (SOF), a fertilization Tyrode’s medium base or Fert-TALP (FERT), and a TRIS-based buffer (TRIS)) on the survival and capacitation of red wolf sperm during extended (18 h) incubation at 38.5°C and 5% CO2. Red wolf sperm motility averaged (±s.e.m.) 73.8 ± 7.1% at the time of collection, and was better maintained over 4 h incubation in ...
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Extracellular vesicles (EVs) contain multiple factors that regulate cell and tissue function. However, understanding of their influence on gametes, including communication with the oocyte, remains limited. In the present study, we... more
Extracellular vesicles (EVs) contain multiple factors that regulate cell and tissue function. However, understanding of their influence on gametes, including communication with the oocyte, remains limited. In the present study, we characterized the proteome of domestic cat (Felis catus) follicular fluid EVs (ffEV). To determine the influence of follicular fluid EVs on gamete cryosurvival and the ability to undergo in vitro maturation, cat oocytes were vitrified using the Cryotop method in the presence or absence of ffEV. Vitrified oocytes were thawed with or without ffEVs, assessed for survival, in vitro cultured for 26 hours and then evaluated for viability and meiotic status. Cat ffEVs had an average size of 129.3 ± 61.7 nm (mean ± SD) and characteristic doughnut shaped circular vesicles in transmission electron microscopy. Proteomic analyses of the ffEVs identified a total of 674 protein groups out of 1,974 proteins, which were classified as being involved in regulation of oxidat...
Ovarian cancer is the fifth cause of cancer-related mortality in women, with an expected 5-year survival rate of only 47%. High-grade serous carcinoma (HGSC), an epithelial cancer phenotype, is the most common malignant ovarian cancer. It... more
Ovarian cancer is the fifth cause of cancer-related mortality in women, with an expected 5-year survival rate of only 47%. High-grade serous carcinoma (HGSC), an epithelial cancer phenotype, is the most common malignant ovarian cancer. It is known that the precursors of HGSC originate from secretory epithelial cells within the Fallopian tube, which first develops as serous tubal intraepithelial carcinoma (STIC). Here, we used gene editing by CRISPR-Cas9 to knock out the oncogene p53 in dog oviductal epithelia cultured in a dynamic microfluidic chip to create an in vitro model that recapitulated human STIC. Similar to human STIC, the gene-edited oviduct-on-a-chip, exhibited loss of cell polarization and had reduced ciliation, increased cell atypia and proliferation, with multilayered epithelium, increased Ki67, PAX8 and Myc and decreased PTEN and RB1 mRNA expression. This study provides a biomimetic in vitro model to study STIC progression and to identify potential biomarkers for ear...
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Local attitudes towards carnivores often reflect the degree of damage they are perceived to cause. Consequently, understanding the interactions between people and these species is essential to conservation efforts. This study investigated... more
Local attitudes towards carnivores often reflect the degree of damage they are perceived to cause. Consequently, understanding the interactions between people and these species is essential to conservation efforts. This study investigated local perceptions of three Cerrado canid species and current chicken management practices, to identify the potential damage they cause and how this relates to peoples’ attitudes towards these species. Results from structured interviews at 50 ranches in Goiás, Brazil, highlighted that general knowledge about Cerrado canids differed significantly by species, with interviewees unable to correctly answer questions about the hoary fox Lycalopex vetulus and crab-eating fox Cerdocyon thous in comparison to the maned wolf Chrysocyon brachyurus. Chicken coops were identified as the most effective method for preventing predation, yet only 44% of respondents employed this method. Using a perceived predation measure, interviewees reported chicken predation by ...
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The current in vitro maturation system (IVM) for dog oocytes is inefficient. On the average, only 15% of ovarian oocytes complete nuclear maturation in vitro. For unknown reasons, the ability of oocytes to develop to the metaphase II... more
The current in vitro maturation system (IVM) for dog oocytes is inefficient. On the average, only 15% of ovarian oocytes complete nuclear maturation in vitro. For unknown reasons, the ability of oocytes to develop to the metaphase II stage (MII) varies markedly among bitches (Songsasen et al., 2002, Mol. Reprod. Dev. 62, 407–415). The objective of this study was to identify the cause(s) underlying these significant variations in nuclear maturation. Initially, we retrospectively analyzed data obtained during the past 3 years;; 1661 oocytes were obtained from 74 bitches where stage of reproduction for the donor was known based on ovarian morphology. Oocytes were cultured in TCM 199+0.1% polyvinyl alcohol at 38.5°C in 5% CO2 in humidified air under various experimental conditions. Analysis of variance (ANOVA) was performed to compare differences in meiotic competence of oocytes obtained at various reproductive stages and during different seasons. Stage of reproduction did not influence...
Research Interests: Endocrinology, Genetics, Andrology, Art, Fertility, and 15 moreCell Biology, Cryopreservation, Oogenesis, Embryo, Biological Sciences, Educational, Cloning, Fertilization, Embryonic Development, Folliculogenesis, Embryogenesis, Gametogenesis, Fertilisation, Embryo Development, and Medical and Health Sciences
The ability to grow oocytes from immature ovarian follicles in vitro has significant potential for fertility preservation; yet, it has proved challenging in large mammalian species due to the complex metabolic needs and long-term culture... more
The ability to grow oocytes from immature ovarian follicles in vitro has significant potential for fertility preservation; yet, it has proved challenging in large mammalian species due to the complex metabolic needs and long-term culture requirements. Currently, follicular incubations are based on a "static" system with manual exchange of medium. Despite the numerous advantages of conventional culturing approaches, recapitulating the native microenvironment and supporting the survival of ovarian follicles from large mammalian species still represent challenges. In this study, we utilized an innovative, dynamic microfluidic system to support the in vitro survival of domestic cat and dog follicles enclosed within the ovarian cortex or isolated from ovarian cortex. Results indicate both species-specific and tissue type-specific differences in response to microfluidic culture. Domestic cat but not dog ovarian cortical tissues maintained viability under flow similar to conventi...
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The aims of the present study were to determine the effects of insulin, invitro, on: (1) the viability and growth of domestic cat ovarian follicles; (2) mRNA expression of genes regulating steroidogenesis (cytochrome P450 family 17... more
The aims of the present study were to determine the effects of insulin, invitro, on: (1) the viability and growth of domestic cat ovarian follicles; (2) mRNA expression of genes regulating steroidogenesis (cytochrome P450 family 17 subfamily, A polypeptide 1 (Cyp17a1), cytochrome P450 family 19 subfamily, A polypeptide 1 (Cyp19a1) and steroidogenic acute regulatory protein (Star)) and water transport (aquaporins (AQPs) Aqp1, Aqp3, Aqp7, Aqp9); and (3) steroid production (17β-oestradiol (E2), progesterone (P4), androstenedione (A4)). Cat secondary follicles were isolated from ovarian cortices and cultured in 0 (Control), 1 or 10µgmL-1 insulin for 14 days (Day 0=culture onset). Follicle and oocyte viability (based on neutral red staining), diameter and antrum formation were assessed every 72h and at the end of incubation (Day 14). Expression of steroidogenic and water transport genes was evaluated on Days 0, 6 and 12, and E2, P4 and A4 concentrations in the culture medium were determi...
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The capacity to cryopreserve semen from captive cranes facilitates production of offspring from behaviorally incompatible or geographically separated pairs, and allows for long-term preservation of valuable genetic materials. The present... more
The capacity to cryopreserve semen from captive cranes facilitates production of offspring from behaviorally incompatible or geographically separated pairs, and allows for long-term preservation of valuable genetic materials. The present study sought to develop effective cryopreservation protocols for whooping (Grus americana) and white-naped (Grus vipio) cranes, through examining the influences of two permeating (DMA and Me2SO) and one non-permeating (sucrose) cryoprotectants, as well as vitamin E on post-thaw sperm survival. In Study 1, ejaculates (whooping: n = 10, white-naped: n = 8) were collected and cryopreserved in one of six cryo-diluents (crane extender with: DMA; DMA+0.1M sucrose; Me2SO; Me2SO+0.1M sucrose; 0.1M sucrose; 0.2M sucrose) using a two-step cooling method. Frozen samples were thawed and assessed for overall motility, motion characteristics, membrane integrity, morphology, and ability to bind to the inner perivitelline membrane (IPVM). In Study 2, whooping crane...
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In the present study we examined the effects of stem cell factor (SCF; 50 vs 100 ng mL-1) alone or in combination with epidermal growth factor (EGF; 100 ng mL-1) on: (1) the in vitro viability and growth of cat follicles within ovarian... more
In the present study we examined the effects of stem cell factor (SCF; 50 vs 100 ng mL-1) alone or in combination with epidermal growth factor (EGF; 100 ng mL-1) on: (1) the in vitro viability and growth of cat follicles within ovarian cortices; (2) phosphatidylinositol 3-kinase (PI3K)/AKT and mitogen-activated protein kinase (MAPK) phosphorylation; and (3) c-kit and FSH receptor (FSHr) mRNA expression. At 100 ng mL-1, SCF increased (P ≤ 0.05) the percentage and size of secondary follicles after 14 days of in vitro culture and sustained AKT phosphorylation after 3 days incubation. EGF suppressed this beneficial effect and reduced (P ≤ 0.05) the percentage of structurally normal follicles and FSHr expression when combined with 100 ng mL-1 SCF. Expression of c-kit mRNA was higher (P ≤ 0.05) in the presence of 100 ng mL-1 SCF compared with fresh follicles and cohorts cultured under other conditions. A c-kit inhibitor suppressed follicle growth and reduced AKT phosphorylation. Collectiv...
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Primordial follicles dictate a female’s reproductive life span and therefore are central to fertility preservation for both endangered species and individuals with fertility-threatening conditions. Ovarian tissue containing primordial... more
Primordial follicles dictate a female’s reproductive life span and therefore are central to fertility preservation for both endangered species and individuals with fertility-threatening conditions. Ovarian tissue containing primordial follicles can be cryopreserved and later thawed and transplanted back into individuals to restore both endocrine function and fertility. Importantly, increasing numbers of human live births have been reported following ovarian tissue cryopreservation and transplantation. A current limitation of this technology is patient access to sites that are approved or equipped to process and cryopreserve ovarian tissue – especially in larger countries or low resource settings. Here, we review empirical evidence from both animal models and human studies that suggest that ovarian tissue can be transported at cold temperatures for several hours while still maintaining the integrity and reproductive potential of the primordial follicles within the tissue. In fact, se...
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To assist in genetic resource management and recovery efforts of the white-naped crane (Antigone vipio), we conducted two experiments to evaluate the effect of cooling condition, thawing rate, and cryoprotectant concentration on sperm... more
To assist in genetic resource management and recovery efforts of the white-naped crane (Antigone vipio), we conducted two experiments to evaluate the effect of cooling condition, thawing rate, and cryoprotectant concentration on sperm survival post-thaw. Semen was collected from four mature males during breeding season (March and April) and evaluated for volume, sperm concentration, motility, and membrane integrity. In Experiment 1, ejaculates (n = 8) were diluted with Beltsville Poultry Semen Extender (BPSE) containing 10% dimethylsulfoxide (Me2SO) and frozen using either one (average cooling rate = 2.5 °C/min) or two step (average cooling rate = 7 and 9 °C/min, respectively) cooling method. The frozen samples were thawed using one of two thawing rates: 37 °C 30 s vs. 4 °C 1 min. In Experiment 2, samples were diluted with crane semen extender containing either 6% or 10% Me2SO, frozen using two-step method and then thawed at 37 °C for 30 s. Both cooling condition (two-step > one-...
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The tufted deer is a small deer, listed as near threatened on the International Union for Conservation of Nature Red List, and there is no information on the fundamental reproductive biology of this species. In this study, we report for... more
The tufted deer is a small deer, listed as near threatened on the International Union for Conservation of Nature Red List, and there is no information on the fundamental reproductive biology of this species. In this study, we report for the first time, characterization of male reproductive traits and cryopreservation of semen in this species. Males were subjected to electroejaculation during each season (autumn, winter, spring, and summer), and ejaculates were assessed for motility and quality traits. Fecal samples were collected 3 to 5 times weekly for 2 years and analyzed for androgen metabolites using enzyme immunoassay. Ejaculates with greater than 70% motility were cryopreserved using Beltsville extender (BF5F) or Triladyl. Straws were thawed and assessed subjectively as well as swim-up processed to isolate motile spermatozoa for computer-assisted sperm analysis and acrosome integrity at hourly interval. Tufted deer male reproductive and semen traits peaked in autumn. Mean feca...
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Artificial insemination has served as a valuable tool for the genetic management of small, isolated populations of several wildlife species (Pukazhenthi B et al. 2004 Development 16, 33–46). The overall aim of the present project was to... more
Artificial insemination has served as a valuable tool for the genetic management of small, isolated populations of several wildlife species (Pukazhenthi B et al. 2004 Development 16, 33–46). The overall aim of the present project was to develop a successful protocol for AI in the Przewalski horse (Equus ferus przewalskii), which is formally listed on the IUCN Red List as “extinct in the wild.” Achieving the long-term goal requires a series of requisite studies to improve our fundamental understanding of reproductive biology in this rare species of equid; therefore, our specific objectives in the present project were to (1) characterize ejaculate traits and examine the influence of seasonality in stallions; and (2) determine the follicular dynamics in mares. Stallions (n = 7) were anesthetized and subjected to a standardized electroejaculation procedure (Collins CW et al. 2006 Anim. Reprod. Sci. 94, 46–49). Testicular volume (TTV) and seminal traits [total sperm concentration (TSC), ...
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Understanding stage-specific requirements of mammalian folliculogenesis is limited in the domestic dog. The present study examined the effects of two potential regulators of dog follicle growth and survival in vitro, namely the original... more
Understanding stage-specific requirements of mammalian folliculogenesis is limited in the domestic dog. The present study examined the effects of two potential regulators of dog follicle growth and survival in vitro, namely the original stage of the follicle (i.e. preantral (≤230 µm diameter) vs early antral (diameter from >230 to ≤330 µm) and FSH and/or LH concentrations. After isolation and alginate encapsulation, follicles were cultured in 0, 1, 10 or 100 µg mL–1 FSH and 0, 1 or 10 ng mL–1 LH for 20 days. Regardless of stage, FSH promoted growth, but LH did the same only in the absence of FSH. Production of 17β-oestradiol and progesterone was detectable, indicating theca cell activity. The greatest growth occurred in preantral (mean (± s.d.) 61.4 ± 25.9%) versus antral (42.6 ± 20.3%) follicles, but neither developmental stage nor gonadotropin affected survival. Antrum detection was minimal due, in part, to antral collapse, and oocytes exhibited an increasingly pale appearance ...