229 From head to tail: A red wolf sperm project

Development of assisted reproductive technologies for the critically endangered red wolf (Canis rufus) is crucial to the maintenance of genetic diversity to support species recovery. Towards this goal, a cryopreservation protocol has previously been developed for red wolf sperm; however, the ability of the gametes to undergo capacitation has not been assessed in this species. Previously, we have shown that oviductal extracellular vesicles (oEVs) improve cat sperm motility and fertilizing ability. The objectives were to (1) compare the effects of culture media on motility and acrosomal integrity of fresh sperm, and select the best medium that can be used in a capacitation protocol; (2) identify potential biomarkers for sperm cryo-tolerance; and (3) determine the influence of canine oEVs on sperm survival and motility post-thaw. In Study 1, sperm were collected by electro-ejaculation from adult red wolves (n=8) and immediately cryopreserved in TRIS-egg yolk buffer with 8% glycerol or incubated for 18h in 5% CO2 and 38.5°C in one of the following media: canine capacitation medium (CCM), FERT-TALP (FERT), NCSU, synthetic oviductal fluid (SOF) and TRIS. At 0, 1, 2, 3, 4, and 18h, sperm were evaluated for total motility and acrosome integrity (FITC-PNA). In Study 2, sperm with high (>80%, HM, n=2 wolves) and low (<15%, LM, n=2 wolves) motility post-incubation at 4°C in the cryopreservation medium for 18h were subjected to proteomic analysis. In Study 3, oviducts were collected from domestic dogs (1-9 years, n=12) after elective spaying, and oEVs from various stages of the oestrous cycle [early follicular (EF), late follicular (LF), early luteal (EL), and late luteal (LL)] were isolated using the Total Exosome Isolation kit (Invitrogen). Frozen-thawed red wolf sperm (n=4 males) were incubated with 30×106 oEVs in non-capacitating CCM, and assessed as in study 1 at 0, 0.5, 1, 2, 3, 4, 6, 8, and 10h. Data were analysed using a paired samples t-test with 95% CI (Prism8, GraphPad Inc.). Sperm incubated in CCM and NCSU had higher motility than those in FERT, SOF, and TRIS after 2h of incubation and onward (2 h: 65±6, 68±6, 42±10, 57±8, and 43±5; 3 h: 60±9, 63±8, 36±11, 46±9, and 34±6; 4 h: 60±9, 60±10, 30±10, 43±8, and 20±5; 18 h: 12±7, 15±7, 9±5, 3±2, and 0, respectively; P<0.05). After 1h of incubation, samples incubated in CCM, NCSU, and SOF had a higher number of sperm with intact acrosomal membranes (P>0.05) than other treatments. A total of 179 proteins were identified, of which 129, including those regulating energy metabolism and mitochondrial mediated apoptosis, were differentially expressed between HM and LM. Preliminary data from Study 3 suggested that thawing and incubating sperm in the presence of LF, EL, and LL oEVs improved sperm motility. In conclusion, CCM and NCSU sustained sperm survival after invitro incubation and could be candidates for invitro fertilization studies in the red wolf. Data generated from sperm proteomic analysis provided insights into cellular pathways regulating sperm cryo-sensitivity. Finally, we demonstrated the potential of oEVs in improving wolf sperm survival post-thawing.

230 Cryopreservation for Canis lupus conservation: Evaluating protocols to freeze grey wolf testicular tissue

Because of the severe decline in grey wolf (Canis lupus) abundance, preservation of genetic diversity within the species is essential to prevent inbreeding depression. Cryopreservation is a valuable tool in endangered species conservation, because it allows genetic material to be rescued from rare individuals for future use. The ability to preserve gonadal tissue is particularly useful in seasonal breeders, such as grey wolves, when mature gametes are not available during the non-breeding season. Optimization of species-specific cryopreservation protocols is necessary due to the toxicity of cryoprotectants. Here, we aimed to investigate three protocols to cryopreserve grey wolf testicular tissue, as a model for endangered canid species. Testicular tissue samples from four adult grey wolves were obtained and cryopreserved using slow-freezing (SF) and needle vitrification (nVT) techniques. Slow-frozen samples were exposed to 15% dimethylsulfoxide (DMSO) or 7.5% DMSO + 7.5% ethylene glycol (EG) in minimum essential medium (MEM) at room temperature, placed in a Mr. Frosty Freezing Container (Thermo Fisher Scientific) and cooled to −80°C overnight, before storage in liquid nitrogen. Needle-vitrified samples were equilibrated in a 7.5% DMSO + 7.5% EG solution in MEM for 10min at 4°C, then treated with 15% DMSO + 15% EG + 0.5M sucrose for 10min at 4°C before plunging into liquid nitrogen. Each sample was thawed using serial dilutions of sucrose (1, 0.5, and 0.25) into MEM at 37°C for 5min each, fixed in 4% paraformaldehyde, and embedded in paraffin wax. Five-micron-thick cross-sections of tissue samples were stained using haematoxylin and eosin. Tubule areas and quantity of each cell type (Sertoli cells, spermatogonia, spermatocytes, spermatids, and abnormal cells) were recorded and compared with a fresh control group for each wolf. Cell populations and tubule areas were analysed using a nonparametric Wilcoxon test through JMP statistical software (SAS Institute Inc.), and are presented as means±standard deviations. There was no difference in tubule areas between the treatment groups (fresh=5200±2870, nVT=5655±2370, SF DMSO=3607±814, SF DMSO+EG=3905±1450µm2; P>0.05). Although there was an increase in abnormal cells/tubule area (µm2) for nVT, SF DMSO, and SF DMSO+EG compared with the fresh samples (0.0015±0.0014, 0.0014±0.0013, 0.0016±0.0011, and 0.0007±0.0004, respectively; P>0.05), differences were not statistically significant. Moreover, the number of Sertoli cells, spermatogonia, and spermatocytes were reduced in the cryopreserved groups compared with fresh tissues, but the differences were not statistically different (P>0.05). The data suggest that the three tested protocols preserved testicular structure and cell populations of cryopreserved testicular tissue and could be useful in the genetic preservation of grey wolves.

Oviductal extracellular vesicles interact with the spermatozoon's head and mid-piece and improves its motility and fertilizing ability in the domestic cat

Fertilization and early embryo development are regulated by a unique maternal-gamete/embryo cross-talk within the oviduct. Recent studies have shown that extracellular vesicles (EVs) within the oviduct play important roles in mediating this developmental process. Here, we examined the influence of oviductal EVs on sperm function in the domestic cat. We demonstrated that (1) EVs are enriched in proteins related to energy metabolism, membrane modification, and reproductive function; (2) EVs bound and fused with the membranes of the acrosome and mid piece; and (3) incubating sperm with EVs improved motility, fertilizing capacity of cat spermatozoa and prevented acrosomal exocytosis in vitro. These findings indicated that oviductal EVs mediate sperm function and fertilization in the cat and provides new insights to improve sperm cryopreservation and in vitro fertilization in the domestic and wild felids and human.

The Domestic Dog Embryo: In Vitro Fertilization, Culture, and Transfer

Advances in embryo technologies in the domestic dog have made significant strides in the past decade. This progress has been spurred by interests in taking advantage of the dog as a biomedical research model for human and companion animal medicine, developing assisted reproductive technologies to manage genetic diversity in endangered canids maintained ex situ, and improving breeding in rare or working breeds of dogs. Here, we focus on recent advancements and techniques for collection of in vivo-matured oocytes, in vitro fertilization (IVF), in vitro culture of early (≤8-cell) and advanced stage (≥16-cell) embryos, and embryo transfer.

207 Cat oviductal exosomes as a tool to improve gamete rescue of endangered felids: effects on sperm capacitation and in vitro fertilization

Exosomes play important roles in reproduction, for example, facilitating fetal-maternal interaction and establishment of pregnancy. However, little is known about how oviductal exosomes affect sperm function. We investigated the effects of oviductal exosomes on sperm capacitation and fertilizing ability in domestic cats as a model for endangered felids. Oviducts were collected from cats (1-5 years) after elective spaying and flushed with 1mL of PBS. Exosomes (EX) were isolated using the Total Exosome Isolation kit (Invitrogen/Thermo Fisher Scientific, Waltham, MA, USA) and labelled with BODIPY dye (boron dipyrromethene). Unattached dye was removed by using Exosome Spin Columns (MW 3000, Invitrogen). Presence and purity of EX was confirmed by transmission electron microscopy (TEM). To investigate the effects of EX on sperm capacitation, semen was recovered from epididymis of 5 cats (3 replicates) after elective neutering. One million spermatozoa mL−1 were incubated with or without EX (1V sperm to 2V total exosomes from 2 oviducts) for 1h in PBS. The samples were then incubated at 38.5°C in 1 of the 2 conditions: (1) capacitation (SOF medium+1000IU of penicillin, 10μg mL−1 streptomycin, 10μg mL−1 heparin, 20 µM penicillamine, 10 µM hypotaurine, 1 µM epinephrine); and (2) non-capacitation (capacitation medium without heparin, penicillamine, or hypotaurine) for up to 24h. Total motility, hyperactive and progressive motility, and percentage of intact acrosomes (FITC-PNA) were assessed at 0, 1, 2, 18, and 24h. Data were analysed by using SPSS software (IBM Corp., Armonk, NY) using a paired samples t-test with 95% CI. Vesicles of 30-100nm were observed by TEM, indicating successful isolation of EX, which were found to bind to both acrosome and mid-piece (BODIPY labelling). Sperm incubated with EX exhibited higher motility than those without EX (P<0.05 for all comparisons) at 1h (capacitation: 80±3.7v. 70±3.5; non-capacitation: 78±1.6v. 66±2.5%), 2h (capacitation: 77±1.3v. 61±1.1; non-capacitation: 74±0.9v. 55±3.5%), 18h (capacitation: 53±1.5v. 40±4.7; non-capacitation: 30±1.2v. 21±3.7%), and 24h (capacitation: 30±2.5v. 12±1.1; non-capacitation: 21±2.1v. 8±0.9%). Regarding progressive and hyperactive motility and acrosome integrity, only hyperactive motility at 1h using capacitation medium was significantly higher in the presence of EX than without it (18±1.5v. 9±2.7%; P<0.05). Next, we performed IVF using sperm with or without 1h incubation with EX. After 18h IVF, presumptive zygotes were stained with Hoechst 33342 and observed under a fluorescence microscope to assess fertilization and polyspermy. Preliminary data (30 oocytes/group) revealed that sperm incubation with EX reduced polyspermy (6±4% v. 20±8%) and improved normal fertilization (28±14vs 8±4%), although the differences were not significantly different (P>0.05 for both groups). In conclusion, the findings indicate that oviductal EX play roles in regulating sperm function by enhancing sperm motility. Further studies are needed to confirm the impact of EX on fertilization and how this strategy can be applied to endangered felid conservation.

Time within reproductive season, but not age or inbreeding coefficient, affects seminal and sperm quality in the whooping crane (Grus americana)

All living whooping cranes (Grus americana) are descended from 16 or fewer birds that remained alive in the early 1940s, a bottleneck that puts the species at potential risk for inbreeding depression. Although AI is commonly used in the management of the captive population of this species, little is known about seminal traits or factors affecting sperm quality in the whooping crane. In the present study, semen samples were collected from 29 adult males (age 3–27 years) during the early (March), mid (April) and late (May) breeding season over 2 consecutive years. The effects of donor age, time within reproductive season and level of inbreeding on seminal characteristics were analysed using regression and information–theoretic model selection. Only time within reproductive season significantly affected seminal traits, with total numbers of spermatozoa and proportions of pleiomorphisms increasing across the season. We conclude that, even with a highly restricted number of founders, there is no discernible influence of inbreeding (at the levels described) on sperm output or quality. Furthermore, although there is variance in seminal quality, the whooping crane produces significant numbers of motile spermatozoa throughout the breeding season, similar to values reported for the greater sandhill crane (Grus canadensis tabida).

Short-term hypertonic exposure enhances in vitro follicle growth and meiotic competence of enclosed oocytes while modestly affecting mRNA expression of aquaporin and steroidogenic genes in the domestic cat model

Using the domestic cat as a non-rodent, larger animal model, the objective was to determine the impact of a brief incubation in a hypertonic microenvironment on (1) ovarian follicle and oocyte growth in vitro, (2) developmental capacity of the resident oocyte, and (3) expression of aquaporin (AQP) genes in parallel with genes involved in regulation of folliculogenesis. In Study 1: Secondary or early antral follicles encapsulated in 0.5% alginate were allocated to one of three treatment groups: 1) culture in standard medium at 290 mOsm for 15 d (Control); 2) incubation in 350 mOsm medium for 1 h followed by culture in standard medium for 15 d (Hypertonic-1h); or 3) incubation in 350 mOsm medium for 24 h followed by incubation in standard medium for additional 14 d (Hypertonic-24h). After measuring follicle and oocyte diameters on Day 15, in vitro-grown oocytes were incubated for 24 h before assessing nuclear status. In Study 2: secondary or early antral follicles were subjected to one of the three treatments: 1) culture in standard medium at 290 mOsm for 48 h; 2) incubation in 350 mOsm medium for 1 h followed by culture in standard medium for additional 47 h; or 3) incubation in 350 mOsm medium for 24 h followed by culture in standard medium for additional 24 h. At the end of the culture period, all follicles were assessed for mRNA level of Cyp17a1, Cyp19a1, Star, Aqp1, 3, 5, 7 and 8 as well as Fshr using qPCR. Freshly collected follicles also were subjected to gene expression analysis and served as the 'Non-cultured control'. Hypertonic-24h follicles grew larger (P < 0.05) than the control, whereas those in Hypertonic-1h group exhibited intermediate growth, especially when the culture started at the early antral stage. Oocytes in the Hypertonic-24h group were larger and resumed meiosis at a higher rate than in the other treatments. In vitro culture affected (P < 0.05) mRNA expression of Cyp19a1, Star, Aqp1, and Aqp7 in both the secondary and early antral stage while Fshr was only affected in the former compared to the non-cultured control. Pre-incubating follicles in 350 mOsm medium for 24 h enhanced (P < 0.05) Star and Aqp7 while decreasing (P < 0.05) Aqp1 expression compared to the control in secondary follicles, but not in the early antral stage. In summary, short-term hypertonic exposure promoted cat follicle development in vitro (including the meiotic competence of the enclosed oocyte) possibly through a mechanism that does not involve water transport genes.

Expression pattern of matrix metalloproteinases changes during folliculogenesis in the cat ovary

Matrix metalloproteinase (MMP) has been implicated as having roles in ovarian folliculogenesis. Here, we determined the expression pattern of six MMPs (MMP1, MMP2, MMP3, MMP7, MMP9 and MMP13) and their endogenous tissue inhibitor, TIMP1, during cat follicle growth. Different developmental stage follicles were mechanically isolated and gene expression analysed by real-time qPCR while MMP1, 2, 9 and 13 localization was determined by immunohistochemistry. With the exception of MMP13, the amount of MMP mRNA was lowest in primordial follicles and increased thereafter. Peak levels were detected in early antral follicles for MMP1 (72.2-fold increase above primordial follicle amount), MMP2 (10-fold), MMP3 (57-fold) and MMP9 (2.8-fold). MMP7 transcripts increased 2-fold by the primary follicle stage and then plateaued. MMP13 mRNA peaked in primary follicles (2.5-fold) and was lower in more advanced counterparts. TIMP1 sharply increased (6-fold) in secondary follicles and gradually declined in the later stages. MMP1 and MMP9 expression were expressed in the granulosa cells of all follicle stages. MMP2 was immunoreactive in early and antral follicles, especially at granulosa cells adjacent to the antral cavity. By contrast, the MMP13 was weakly detected in primary follicles onward. In summary, there are distinctive and consistent changes in MMPs and TIMP1 expression during follicle development, suggesting that these enzymes play one or more roles in cat folliculogenesis. In particular, high mRNA and protein expression levels of MMP1 and MMP2, especially at the antral stage, indicate that these enzymes likely are involved in antrum formation and expansion.

137 DYNAMIC SHIFT IN CYTOPLASMIC LIPIDS IN CAT OOCYTES DURING OVARIAN FOLLICLE DEVELOPMENT

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 selected and subjected to principal component analysis to identify similarities and differences in mass spectra profile among oocytes from varying developmental stages. Peaks were compared to those calculated molecular formulae available in the Lipid MAP database. Error estimates were calculated using Excel (Microsoft Corp., Redmond, WA), and lipid species identification performed using Lipid MS Predict. Twenty-nine lipid species from six glycerophospholipids groups (glycerophosphates, PA; glycerophosphoserines, PS; glycerophosphoinositols, PI; glycerophosphoglycerols, PG; glycerophosphoinositol monophosphates, PIP; and glycerophosphoethanolamines, PE) were identified, 15 being found in more than 1 developmental stage. Two species in particular, [PI(29:4)+Na]+ and [PIP(23:0)+Na]+, were the most abundant lipids and were identified in oocytes from all developmental stages. There were dynamic shifts in lipid species expressed at different follicle stages. Oocytes from secondary and antral follicles contained more lipid types (15 and 22, respectively) than early (10) and small antral (4) counterparts. Four (PA, PS, PI, and PIP) of the 6 glycerophospholipids were found only in oocytes from secondary and antral follicles. Oocytes from small antral follicles also lacked PA, PS, and PG, whereas PG was not found in early antral stage oocytes. In summary, we showed for the first time in the cat that, similar to goats and rats, there are temporal changes in lipid types within the oocyte during folliculogenesis. We suspect that these changing dynamics, including shifts in presence or absence of lipid species with follicle stage, may be playing key roles in oocyte growth and viability. Our findings also serve as in vivo benchmarks for parallel studies focused on enhancing an in vitro culture system for early-stage ovarian follicles to preserve fertility of genetically valuable domestic and wild felids.

120 IMPACT OF SEASON ON SEMINAL CHARACTERISTICS AND SPERM CRYOPRESERVATION IN THE TUFTED DEER (ELAPHODUS CEPHALOPHUS)

The Tufted deer (Elaphodus cephalophus), a small deer species native to China, is listed as near threatened on the IUCN Red List and >70 animals are managed in North American zoos as a hedge against extinction. In this study, we 1) characterized the seminal traits, 2) assessed the impact of season on ejaculate traits and testosterone level, and 3) examined sperm sensitivity to cryopreservation. Semen (24 ejaculates) were obtained from five males (1–2 ejaculates/male per season) by electro-ejaculation and evaluated for volume, osmolality, pH as well as sperm concentration, motility (%M), forward progression (FP, scale = 0–5) and acrosomal integrity (%AI). Ejaculates were divided into two aliquots and cryopreserved (4% vol/vol glycerol final concentration; 50–200 × 106 sperm mL–1) over liquid nitrogen vapor using Beltsville extender (BF5F; Howard et al. 1986) or Triladyl® (TRIL; Minitüb GmbH, Germany) extender. Sperm motility and %AI were assessed immediately (subjective) upon thawing and following swim-up processing (SU; 30 min) using computer-assisted semen analysis after 1, 2, 3, and 4 h of incubation (37°C). Fecal samples were collected 3–5 times weekly for 2 years and analyzed for testosterone (T) metabolites using enzyme immunoassay as a function of season (autumn, September–November; winter, December–February; spring, March–May; and summer, June–August). Data were analyzed using Proc GLM or ANOVA with Tukey multiple mean comparison. Significance was set at P < 0.05. Male reproductive and semen traits peaked in autumn (volume, 2.0 mL; concentration, 207.6 × 106 mL–1; pH, 7.6; osmolality, 310.8 mOsm; %M, 76%; FP, 3.5; and %AI, 82.3). Mean testicular length and neck girth in autumn were 4.9 and 43.2 cm, respectively. Mean T concentration (~1.23 µg g–1 of dry feces) was higher (P < 0.05) in summer compared with winter (1.07 µg g–1 of dry feces) or spring (1.06 µg g–1 of dry feces). Sperm motility and %AI were lower (P < 0.05) immediately after thawing (BF5F, 34.6 and 34.7%, respectively; and TRIL, 23.1 and 29.1%, respectively) compared with fresh semen (76.9 and 74.6%, respectively). Motility characteristics immediately after SU (computer-assisted semen analysis) were higher (P < 0.05) in BF5F compared with TRIL: %M (56.4 v. 44.9%), progressive motility (42.5 v. 21.9%), %AI (41.2 v. 31.3%), straight-line velocity (68.0 v. 53.2 µm s–1), straightness (85.1 v. 75.1%), and linearity (54.3 v. 45.0%). At the end of 4 h of incubation, sperm %M and FP declined (P > 0.05) in both BF5F and TRIL (47 and 30%, respectively) but the %AI was higher (P < 0.05) in BF5F (32%) than TRIL (21%). Results indicate that tufted deer ejaculates exhibit seasonal variations in reproductive traits and cryopreservation in BF5F better preserves sperm motility and acrosomal membrane integrity compared with TRIL.

Anti-Müllerian Hormone in the Domestic Dog during the Anestrus to Oestrous Transition

The reproductive cycle of the domestic dog features a long period of relative ovarian inactivity or anestrus. The mechanism of anestrous termination/oestrous resumption is not yet fully understood, which presents a challenge to the development of oestrous induction protocols. In this study, we assess the possibility that anti-Müllerian hormone (AMH) might play a role in this transition by characterizing its patterns of expression in the circulation during the transition from anestrus to oestrous and in all stages of ovarian follicular growth. Serum samples from five beagles (2.0-4.5 years) were collected three times per week at least 30 days prior to the onset of oestrous and assessed for AMH concentrations. Serum AMH concentration increased significantly during the transition from anestrus to proestrus and then declined back to the anestrous baseline beginning on day -4 before the luteinizing hormone surge, which was determined by changes in serum progesterone concentrations. Cortical sections of ovaries from females undergoing routine ovariohysterectomy (aged 8 months-5 years, n = 4) were evaluated for AMH by immunohistochemistry. Pre-antral and small antral follicles were most strongly immunoreactive for AMH. These data suggest that the increase in the number of antral follicles is associated with the rise in serum AMH as the anestrous period comes to an end. The rise in AMH might be useful in predicting the onset of oestrus and therefore assist with the optimization of oestrous induction protocols and possibly other assisted reproductive technologies.

184 FOLLICULOGENESIS AND DONOR AGE INFLUENCE MATRIX METALLOPROTEINASE-2 EXPRESSION IN THE DOMESTIC CAT

Matrix metalloproteinases (MMPs) and tissue inhibitor of metalloproteinases (TIMPs) are known to play key roles in the remodelling of extracellular matrix during ovarian folliculogenesis, especially during the final stage of follicle development. To date, little is known about the significance of MMPs and TIMPs during preantral follicle development. This study determined the expression of MMPs and TIMP-1 during various stages of cat folliculogenesis, largely for the purpose of securing information useful to improving in vitro follicle culture. Primordial (~10 follicles/cat), primary (~5 follicles/cat), secondary (~9 follicles/cat), early antral (~9 follicles/cat), and antral (~4 follicles/cat) follicles were physically isolated from ovaries recovered from 15 cats (5 months to 3 years old during follicular stage) undergoing ovariohysterectomy and assessed for expression of MMP-1, -2, -3, -7, -9, and -13 as well as TIMP-1 using real-time quantitative polymerase chain reaction (q-PCR; 2–4 replicates/follicle stage). Additional ovaries were obtained from three prepubertal (6 months old) and three adult (1 year old) cats and ovarian pieces were fixed in Bouin's solution and assessed for MMP-2 and -13 localization using immunohistochemistry. MMP expression data were analysed using the Kruskull-Wallis one-way ANOVA. Follicles from all stages of development expressed MMPs and TIMP-1. Specifically, expression of MMP-2 increased (P < 0.05) as folliculogenesis progressed (10-fold increases from primordial to early-antral and antral stage). There were no differences (P > 0.05) in the expression of other MMPs among follicular classes. For TIMP-1, there was a tendency (P = 0.07) for increased expression after antrum formation (early antral and antral stages). Immunohistochemistry analysis revealed that MMP-2 was expressed in both the oocyte and somatic cells of all follicular stages in prepubertal cats. However, MMP-2 expression was limited to granulosa and theca cells of antral follicles in adult females. MMP-13 was expressed in the granulosa and theca cells of primary, secondary, and antral stage follicles, and there were no differences (P > 0.05) in localization patterns for this protein between prepubertal and adult females. In summary, the study is the first to report the expression of MMPs as well as TIMP-1 in isolated cat follicles. The difference in MMP-2 expression between prepubertal and adult cats suggests that there may be age-specific requirements for in vitro follicle growth. We are keenly interested in this information for underpinning the development of new in vitro microenvironments for growing immature cat follicles. We suspect that such information will be crucial for understanding how to promote the remodelling of the extracellular matrix by creating degradable biomaterials containing MMP-sensitive peptides to allow optimal follicle expansion.

The domestic dog and cat as models for understanding the regulation of ovarian follicle development in vitro

The culture of ovarian follicles is an important tool for understanding the mechanisms controlling follicle development and differentiation of the oocyte. The benefit of recovering meiotically and developmentally competent oocytes from early stage follicles (primordial, primary, pre-antral and early antral) also would be significant, ranging from rescue of genomes from endangered species to preserving fertility in women facing cancer treatments. This research field is at an early stage of scientific discovery. To-date, live offspring from cultured primordial follicles that produced fertilizable oocytes has occurred only in the mouse. Progress in other more complex species has been limited because larger animals have longer durations of natural folliculogenesis, thereby requiring more culture time to generate fully grown follicles and oocytes. We believe the dog and cat are excellent models for understanding more about folliculogenesis in vitro. This review highlights what is known about this topic for these two species as well as future priorities. We have discovered that it is more challenging to maintain viability of primordial follicles within ovarian tissues in vitro in the dog than the cat. Nonetheless, it is possible to grow both isolated cat and dog pre-antral follicles in culture. Although the follicles of both species have the capacity to increase in size and produce steroids, only cat oocytes appear morphologically normal. The reason for this striking difference between these two species is an area of high research priority. While much more fundamental data are required, we envision advanced technology that will allow harvesting oocytes from the vast, unused follicle stores sequestered within carnivore ovaries. These gametes have utility for reproducing genetically valuable dogs and cats that are 'companions' or biomedical models for investigating human disorders as well as for salvaging the genomes of rare canid and felid species that die before contributing to genetic management programs.

Cat and dog primordial follicles enclosed in ovarian cortex sustain viability after in vitro culture on agarose gel in a protein-free medium

Our objective was to examine the influences of differing media, protein supplementation and the microenvironment on cat vs dog primordial follicle viability in vitro. Ovarian cortical slices were cultured for 3, 9 or 15 days in α-minimum essential medium (α-MEM) or MEM supplemented with 10% fetal bovine serum (FBS), 10% knock-out serum replacement (KSR) or 0.1% polyvinyl alcohol (protein free). In a separate study, cat and dog ovarian tissues were cultured in protein-free α-MEM and MEM, respectively, in cell culture inserts, on 1.5% agarose gel or in 24-well cell culture plates (control). Follicle viability was assessed in both studies using calcein AM/ethidium homodimer and histological evaluation with haematoxylin/eosin staining. No cat follicle sustained viability beyond 9 days of in vitro culture in α-MEM compared to 37.5% of those incubated for 15 days in MEM in protein-free condition (p < 0.05). In contrast, α-MEM was superior (p < 0.05) to MEM in maintaining dog follicle viability (32.7% vs 8.1%) in protein-free condition at 15 days. Serum was detrimental (p < 0.05) to follicle survival in both species. Knock-out serum replacement supplementation and a protein-free condition supported cat follicle viability, whereas the latter was superior (p < 0.05) to the former for sustaining dog follicle survival. Likewise, dog follicle viability was enhanced (p < 0.05) by the agarose gel compared to the cell culture insert and control groups after 3 and 9 days of culture. For the cat, the agarose gel better (p < 0.05) supported follicle viability compared to the control, but was equivalent to the cell culture insert. Therefore, sustaining primordial follicle survival from intracortical ovarian slices requires a different in vitro microenvironment for the cat vs the dog. A key factor to enhancing survival of these early stage follicles in culture appears to be the use of agarose gel, which enhances follicle viability, perhaps by promoting gas exchange.

121 ALGINATE-FIBRIN GEL MATRIX PROMOTES IN VITRO GROWTH OF DOG SECONDARY FOLLICLES

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 + 10 μg mL–1 of FSH and 1 ng mL–1 of LH + 3 mg mL–1 of polyvinyl alcohol. Follicle diameter was monitored and half of the medium exchanged every 48 h. Follicle survival was assessed based on ability to increase in size, as well as on oocyte and granulosa cell morphology. Comparisons of follicle growth rate for each culture day between the 2 treatments were conducted using Student's t-test and among culture days within the same group using ANOVA followed by a Holm-Sidak multiple comparison. Follicle survival was compared using a chi-square test. In both groups, follicles maintained the 3-dimensional structure and increased (P < 0.05) in size as culture period progressed. However, follicles encapsulated in alginate + fibrin grew larger (P < 0.05) than those in alginate alone. Specifically, follicles in alginate + fibrin were doubled in size by 12 days compared with a 60% increase for alginate alone. There were no differences (P > 0.05) in follicle survival between the 2 groups (27.0 and 38.1% for alginate and alginate-fibrin, respectively). Results demonstrate that a dynamic alginate-fibrin matrix enhances in vitro follicle growth. We suspect that the mechanism involved is related to facilitating expansion capacity. Specifically, it is likely that nondegradable alginate offers physical, but eventually restrictive, support to encapsulated cells. By contrast, in the gel combination, the fibrin degrades due to cell-secreted proteases that, in turn, permit more robust follicle expansion. Low follicle survival (<40%) in both treatments emphasises the need for more studies to identify influential endocrine/paracrine factors that enhance follicle growth and production of competent oocytes. Funded by NIH-KO1RR020564.

Activity pattern, reproductive behaviors and gonadal hormones in the raccoon dog (Nyctereutes procyonoides)

The objectives of this study were to (1) assess year-round behaviors and activity patterns of captive raccoon dogs (Nyctereutes procyonoides) and (2) characterize the species' reproductive endocrinology. Behaviors and activity patterns of 12 (5.7) animals were recorded over a 1-year period. During that time, fecal samples were collected 2-7 times/week from 16 (7.9) individuals (six of these were included in the behavioral study) for the analysis of testosterone, progesterone and estrogen metabolite concentrations. Activity pattern and excretion of gonadal steroids followed a seasonal pattern. Specifically, dogs were cathemeral in summer, and primarily nocturnal in winter. In the males, testosterone concentrations were at baseline from April through September, began to rise in October and reached peak concentrations in February (P<0.05). In the females, elevated estrogen (P<0.05) was observed in March followed by an increase in progestagen concentrations from March through May (P<0.05) in both pregnant and pseudopregnant animals. Gender significantly influenced monthly testosterone/estrogen ratio (P<0.01); values were higher in males than in females throughout the year with overall percentage of overlapping values between males and females being 28%. In summary, this study characterized cirannual fluctuations in behaviors and gonadal steroid metabolites in the raccoon dog maintained in captivity. Because there is no obvious sexual dimorphism, the differences in testosterone/estrogen ratio may be useful for gender differentiation (72% accuracy), especially among individuals living in the wild.

In vitro growth and steroidogenesis of dog follicles are influenced by the physical and hormonal microenvironment

The present study examined the influences of the physical and hormonal microenvironment on in vitro growth and steroidogenesis of dog follicles. Follicles were enzymatically isolated and individually encapsulated in 0.5% (w/v; n=17) or 1.5% (n=10) alginate and cultured with 0.5 IU/ml equine chorionic gonadotropin for 192 h. In a separate experiment, follicles were encapsulated in 0.5% alginate and cultured with 0 (n=22), 1 (n=23), 10 (n=20) or 100 (n=21) μg/ml FSH for 240 h. Follicle diameter and steroid production were assessed every 48 h in both studies. Follicles encapsulated in the 0.5% alginate grew faster (P<0.05) than those cultured in the 1.5% concentration. Oestradiol (E(2)) and progesterone (P(4)) increased consistently (P<0.05) over time, and follicles in the 1.5% alginate produced more (P<0.05) P(4) than those in the 0.5% solution. Follicles cultured in the highest FSH concentration (100 μg/ml) increased 100% in size after 240 h compared with 50 to 70% in lower dosages. E(2) concentration remained unchanged over time (P>0.05) across FSH dosages. However, P(4) increased (P<0.05) as culture progressed and with increasing FSH concentration. Results demonstrate that dog follicles cultured in alginate retain structural integrity, grow in size and are hormonally active. Lower alginate and increasing FSH concentrations promote in vitro follicle growth. However, the absence of an E(2) rise in follicles cultured in FSH alone suggests the need for LH supplementation to support theca cell differentiation and granulosa cell function.

231 SEMINAL QUALITY IN WHOOPING CRANE (GRUS AMERICANA) IS AFFECTED BY STAGE OF BREEDING SEASON BUT NOT BY AGE OF INDIVIDUAL

The whooping crane is one of the most critically endangered species in North America. The species underwent a severe genetic bottleneck with only 16 individuals remaining in the wild as of 1942. Captive breeding began in 1966 and continues to produce chicks for release in order to establish new wild populations. However, captive birds experience poor reproduction with approximately 40% of eggs being infertile. Males have been known to reach sexual maturity at 5 years of age and continue to reproduce almost as long as the duration of their adult life (i.e. 40 years). Understanding factors affecting seminal quality may assist in identifying and correcting causes of suboptimal reproduction. Our objectives were to determine the influence of age and reproductive seasonality on seminal quality. We hypothesised that seminal quality variations among whooping cranes and ejaculates within a given individual over time were due to bird age and stage of breeding season. In 2010, twenty-nine whooping cranes of 5 age groups housed at Patuxent Wildlife Research Center (Laurel, MD, USA) were studied: ≤5 years (n = 3); 6–10 years (n = 7); 11–15 years (n = 7); 16–20 years (n = 4); >20 years old (n = 8). Semen was collected using a manual manipulation technique at 3 stages of the breeding season: early (March, n = 29) mid (April, n = 24), and late (May, n = 14). Samples were evaluated for seminal volume and sperm concentration, motility, and morphology, with data evaluated by analysis of variance. Bird age had no influence on seminal quality, whereas stage of breeding season affected seminal volume and the proportion of sperm with normal morphology (95% confidence interval). Specifically, samples collected during Mid breeding season had the highest volume (mean ± SEM; early: 42.0 ± 8.0 μL; mid: 66.0 ± 15.2 μL; late: 39.7 ± 17.8 μL), but lowest proportions of structurally normal sperm (early: 78.4 ± 3.7%: mid: 61.5 ± 3.2%; late: 69.7 ± 3.4%). There was a significant difference (P = 0.06) in sperm concentration among stages of the breeding season (early: 66.3 ± 18.8 × 106 sperm mL–1; mid: 179.2 ± 46.2 × 106 sperm mL–1; late: 91.4 ± 47.8 × 106 sperm mL–1). Sperm motility was unaffected by season (early: 36.4 ± 3.5%; mid: 45.9 ± 4.1%; late: 48.0 ± 4.9%). In summary, there is a peak in seminal quality that corresponds with higher volume and more sperm during the mid stage of the season, although with higher instances of structural abnormalities. Despite the small founder base for this species, males in this population produce sperm with no variation in seminal quality across a wide variation in age.

12 INDUCTION OF OVARIAN ACTIVITY IN THE MANED WOLF (CHRYSOCYON BRACHYURUS) USING A GnRH-AGONIST

Induction of ovarian activity and ovulation is a valuable tool for the genetic management of ex situ populations of wildlife. Deslorelin, a gonadotropin releasing hormone (GnRH)-agonist, has been used earlier to induce oestrus in the grey wolf (Canis lupus). The objective of the present study was to determine the efficacy of Deslorelin (2.1 mg, Ovuplant®, Peptech Animal Health, Australia) for manipulating ovarian activity of the maned wolf, a species speculated to be an induced ovulator. Eight female (4–12 years old) maned wolves were (i) paired with a male (n = 3) or (ii) housed alone (n = 5). Of the 8 females, 1 (1 in a pair and 1 singleton) were implanted with Deslorelin under the vulvar mucosa for 12 days. The remaining 6 received implants in the subcutaneous layer of the ear for 7 days. Fresh fecal samples were collected 5 to 7 days/week for 1 month before Deslorelin treatment through 6 weeks after implant withdrawal. Reproductive steroid metabolites were extracted from the fecal samples and quantified using a validated enzyme immunoassay. Baseline progestagen concentrations for each individual were calculated by an iterative process, whereby high values exceeding the mean plus one standard deviation were excluded. Comparisons of oestrogen and progestagen concentrations among pre-, peri-, and post-Deslorelin implant periods were performed using analysis of variance. Site and duration of the GnRH agonist treatment had no effect (P > 0.05) on subsequent ovarian responses. In paired females, oestrogen metabolites reached the highest (P < 0.05) concentration during Deslorelin (i.e. peri-) treatment (441.7 ± 20.2 ng g–1 of feces) compared to pre- (174.9 ± 16.7) and post- (177.8 ± 9.1) treatment. Progesterone metabolites rose (P < 0.05) above the baseline (indicative of ovulation) starting on Day 10 after the onset of Deslorelin implantation and remained elevated throughout the study (pre-, 11 645 ± 4798; peri-, 31 521 ± 6444; post-, 55 843 ± 2924 ng g–1 of feces). In singleton females, oestrogen metabolites increased (P < 0.05) immediately after implantation (from pre-, 184.2 ± 45.3 to peri-, 334.2 ± 29.8 ng g–1 of feces) and then declined (post-, 192.3 ± 12.4). Progestagen metabolites exhibited a similar pattern with a rise (P < 0.05) during Deslorelin treatment (from pre-, 3870 ± 1336 to peri-, 10 546 ± 880 ng g–1 of feces) followed by a decline after implant withdrawal (post-, 6171 ± 366), indicating that ovulation did not occur. These results suggest that Deslorelin can induce ovarian activity in the maned wolf. However, administration of an ovulatory agent after Deslorelin treatment may be required in females managed in the absence of a male, further supporting the assertion that this species is an induced ovulator. Funded by the Morris Animal Foundation.

Advances in reproductive science for wild carnivore conservation

Knowledge about reproduction is critical for predicting the viability of wildlife populations in nature and for managing breeding programmes in captivity. Intensive species-based studies are the priority, because reproductive mechanisms are extraordinarily diverse, even within the same taxonomic family. Carnivores deserve more attention as such species are highly vulnerable to environmental change and human persecution. The present review provides contemporary illustrations of how reproductive science is contributing to understand unique reproductive mechanisms that are both of fundamental and applied interest. In the case of the endangered African wild dog (Lycaon pictus) free-living in South Africa, non-invasive faecal corticosteroid assessments have yielded new insights about the impact of animal relocation and reintroduction on adaptive responses, reproductive fitness and survival. For the maned wolf (Chrysocyon brachyurus), advances have been made in characterizing and comparing reproductive traits in free-ranging vs captive individuals. For the cheetah (Acinonyx jubatus), recent studies have focused on the cryosensitivity of sperm and the ability to develop a field-friendly sperm cryo-method. The by-product has been a large-scale frozen repository of sperm from wild-caught cheetahs useful for infusing new genes into ex situ populations. Finally, rigorous, multi-disciplinary and cross-institutional reproductive studies of the black-footed ferret (Mustela nigripes), including the use of artificial insemination, have contributed to the remarkable recovery and restoration of this species, once on the brink of extinction. In summary, advances in reproductive science are not necessarily related to 'assisted breeding'. However, understanding the unique ways of carnivore reproduction greatly contributes to species management and conservation.

Follicular morphology, oocyte diameter and localisation of fibroblast growth factors in the domestic dog ovary

Remarkably little is known about folliculogenesis in the dog. Objectives were to characterise (1) changes in follicle/oocyte diameter and granulosa cell number and (2) localisation of fibroblast growth factor (FGF)-2 and FGF-7 during dog ovarian follicle development. Fourteen ovarian pairs were excised and processed for histological evaluation. Two to four serial sections/bitch were stained with hematoxylin, and follicle/oocyte diameters and granulosa cell number were determined at each developmental stage. Mean follicle and oocyte size were compared among stages by one-way analysis of variance. Relationships between follicle and oocyte size and granulosa cell number were determined using correlation and regression analysis, respectively. Another eight serial sections/bitch were processed for immunostaining to determine FGF-2 and FGF-7 localisation. Primordial and primary follicles were similar in size, but smaller than the progressively increasing (p < 0.05) diameter of the later stages. Oocyte diameter gradually increased (p < 0.05) among oocytes derived from primordial, primary, secondary and early antral follicles with no difference (p > 0.05) thereafter. Oocyte size and granulosa cell number increased (p < 0.01) with follicular diameter. Except during anoestrus, FGF-2 occurred in oocytes and granulosa cells of primordial to secondary follicles. In adult bitches, FGF-7 was localised in granulosa cells of primary and secondary follicles and also occurred in the theca layer of antral follicles during prooestrus and oestrus. In summary, folliculogenesis in the domestic dog occurs in two phases: pre-antral phase characterised by increasing follicle size in association with oocyte growth and granulosa cell proliferation and antral phase linked with marked granulosa cell proliferation and accumulation of antral cavity fluid. Finally, the temporal localisation pattern of FGF-2 implies its role in follicular activation, whereas FGF-7 activities appear related to later folliculogenesis.

154 REPRODUCTIVE SEASONALITY AND FOLLICULAR DYNAMICS IN THE PRZEWALSKI'S HORSE

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), and total (TM) and progressive sperm motility (PM)] were assessed once each season (winter, January to March; spring, April to June; summer, July to September; fall, October to December) for 1 year, with data analyzed by repeated-measures ANOVA. Mares (n = 8) were examined by ultrasonography in a specialized chute system 3 days/week during breeding season (April to June) over 3 years. At each examination, ovarian structures [size of the dominant follicle and presence of corpora lutea (CL)] were assessed. Values for total ejaculate volume (mean ± SEM, 33.0 ± 22.2 mL), sperm motility (TM, 58 ± 19%; PM, 49 ± 18%), and TSC (2.8 ± 0.3 × 109) were highly variable among individuals. Seasonality significantly (P < 0.05) influenced TSC, which was highest in summer (4.41 ± 0.09 × 109) compared with spring (2.7 ± 0.5 × 109), fall (1.7 ± 0.4 × 109), and winter (2.5 ± 0.4 × 109). Season had no influence on TTV or other seminal traits (P > 0.05), with motile sperm being recovered at all ejaculation attempts. Ultrasonography revealed that the reproductive cycle of the Przewalski mare was composed of two phases. The follicular phase (4.3 ± 2.2 days; range, 3 to 7) was characterized by the presence of one dominant follicle that grew at a rate of 2.9 ± 0.2 mm (range, 1–6 mm) per day and ovulated at a size of 43.8 ± 1.5 mm in diameter (range, 30–57 mm). The luteal phase was distinguished by the presence of a CL that was sustained and evident on the ovary for 12.2 ± 3.3 days (range, 9–15) before regression. In summary, the basic reproductive physiology of the Przewalski horse is comparable with the domestic horse, including the ability of stallions to retain year-round spermatogenesis and ovarian follicular dynamics (including number, size, and growth rate) in the mare. These data allow us to suggest that established protocols for AI in the domestic horse (including estrus induction) likely will have relevance to adapting this technology to the genetic management of the rare Przewalski horse. Morris Animal Foundation (Grant No. D07ZO-403), Sichel Endowment Fund, Smithsonian Endowment Fund, Animal Management staff at CRC and The Wilds.

166 POTENTIAL OF URINARY RELAXIN AS A USEFUL INDICATOR OF PREGNANCY IN THE MANED WOLF

The maned wolf (Chrysocyon brachyurus), a neotropical canid, lives in habitats severely compromised by agricultural development. Therefore, maintaining a healthy and viable zoo population is crucial, because it serves as hedge against extinction. However, the North American ex situ population of maned wolves is far from self-sustaining, mainly due to low pregnancy success and high neonatal mortality. Currently, there is no non-invasive way to determine pregnancy in this species. Therefore, the goal is to determine whether urinary relaxin can be used as an indicator of pregnancy in this species. Objectives were to (1) determine the relationship between serum and urinary relaxin in canids, using pregnant domestic bitches as a model, and (2) evaluate the patterns of urinary relaxin in pregnant v. non-pregnant female maned wolves. Serum and urine samples were obtained weekly from six pregnant domestic bitches starting from the day of natural breeding until 3 weeks before the estimated whelping dates. For the maned wolf, urine and feces were obtained weekly during a breeding season (October to February) from six females, three of which were pregnant and gave birth. Concentrations of serum and urinary relaxin were measured using the double antibody canine relaxin radioimmunoassay (Steinetz et al. 1996 Biol. Reprod. 54, 1252–1260). Fecal progestagen were determined using an enzyme immunoassay (Songsasen et al. 2006 Theriogenology 66, 1743–1750). The relationship between serum and urinary relaxin concentrations was determined using the Pearson Product Moment Correlation Analysis. The relationship between urinary relaxin concentrations and days before whelping (for pregnant females) or time after the initial rise of progestagen for each individual were determined using a linear regression analysis. Serial dilutions of pooled dog urine produced displacement curves parallel to those of the appropriate synthetic canine relaxin standards, while wolf samples showed limited parallelism with low concentration of immunoactive antigen. Concentrations of urinary relaxin were significantly correlated with the serum counterpart in pregnant dogs (P < 0.01, r2 0.58). In pregnant maned wolves, relaxin level increased two- to six-fold as gestation progressed (P < 0.05, r2 ranged from 0.15 to 0.56). In contrast, urinary relaxin remained at the baseline in non-pregnant females throughout the diestrus period (P > 0.05). In conclusion, our findings suggest that urinary relaxin mirrors serum relaxin during pregnancy in domestic bitches and may have potential as a tool to diagnose pregnancy in the maned wolf. Further studies are required to improve the specificity and sensitivity of this non-invasive assay.

253 LACK OF ABILITY TO REGULATE KINASE ACTIVITIES MAY BE RESPONSIBLE FOR MEIOTIC INCOMPETENCE IN THE DOG OOCYTE

The size of donor follicles influences meiotic maturation of oocytes, including those of the domestic dog (Songsasen and Wildt 2005 Mol. Reprod. Dev. 72, 113–119). Maturation promoting factor (MPF, CDK1) and mitogen activating protein kinase (MAPK) play a pivotal role in regulating meiosis in several species (Abrieu et al. 2001 J. Cell Sci. 114, 257–267). Accordingly, we determined (1) MPF and MAPK activities, and (2) mRNA expression of cell cycle genes, including CDK1, CCNB1, and CDC25 in oocytes obtained from small (<1 mm diameter), medium (1 to 2 mm) and large (>2 mm) follicles. In Study 1, ovarian oocytes were classified into three groups (based on these sizes) and then cultured (38.5�C in 5% CO2) for 0, 24, or 48 h in TCM-199 (+25 µm β-mercaptoethanol, 10 ng mL–1 epidermal growth factor, 0.25 mm pyruvate, 2.0 mm glutamine, and 0.1% polyvinyl alcohol). Oocytes were denuded, assessed for nuclear status, and stored individually at –80�C until MPF and MAPK activities were assayed using a double kinase assay. Kinase activities of in vitro-matured (IVM) oocytes were expressed as a ratio of MPF and MAPK to that in metaphase I (MI) oocytes flushed from the oviducts of estrous bitches. In Study 2, oocytes (n = 20/follicular size class) were immediately frozen at –80�C; RNA was extracted, reverse transcribed, and subjected to quantitative real-time PCR analysis. Expression levels of each transcript were normalized to levels of endogenous glyceraldehyde-3-phosphate dehydrogenase (GAPDH). Statistical analyses were performed using ANOVA followed by the Holm-Sidak test for multiple comparisons. Both MPF and MAPK activities varied among follicular size classes. Kinase activities increased in oocytes from large follicles upon meiotic resumption, with germinal vesicle (GV) oocytes expressing the lowest levels compared to their metaphase II (MII) counterpart (GV: 25.9 � 5.2% v. MII: 211.5 � 19.5% and 36.4 � 9.1% v. 150.7 � 22.9% for MPF and MAPK, respectively; P < 0.01). For medium follicles, MPF increased (P < 0.01) as oocytes progressed from GV (23.3 � 6.3%) to MII (243.4 � 55.5%). However, MAPK levels remained constant until the MI stage, and then increased (P < 0.01) in MII oocytes. For small follicles, MPF increased (P < 0.05) at the MI stage and then remained constant until meiosis was completed, whereas MAPK activities remained constant after GVBD. Kinase activity levels were not different (P < 0.05) between MI and MII oocytes harvested from the three follicular classes. Interestingly, follicular size had no effect (P > 0.05) on expression levels of cell cycle transcripts. These findings suggest that the compromised developmental competence of dog oocytes from small follicles likely is related to the oocytes' inability to regulate MAPK activity during meiotic resumption.

Requirement for, and patterns of, pyruvate and glutamine metabolism in the domestic dog oocyte in vitro

Supplementation of energy substrates to culture medium is essential for resumption and completion of meiosis in vitro for many mammalian species. Objectives were to study the dog oocyte, specifically the influences of pyruvate and glutamine on maturation and the utilization of these two substrates at various developmental stages and incubation times. Ovarian oocytes (n=681) were obtained from spayed bitches and cultured for 48 hr in TCM 199 medium containing various concentrations of pyruvate (0-2.5 mM) and glutamine (0-4 mM) before being assessed for nuclear status. For analyzing metabolic activity, 259 dog oocytes were cultured for 0, 12, 24, 36, or 48 hr, assessed for pyruvate and glutamine metabolism using the hanging drop method and then evaluated for nuclear status. Neither pyruvate nor glutamine had influence (P > 0.05) on oocyte maturation in vitro (IVM). However, both culture interval and meiotic status influenced pyruvate uptake (P < 0.05). Specifically, pyruvate uptake declined as the oocyte progressed from the germinal vesicle (GV) to metaphase II (MII) stage. Glutamine oxidation decreased as culture duration progressed (P < 0.05). In summary, pyruvate or glutamine is not required to promote successful IVM of dog oocytes. But, both substrates are being metabolized, and in patterns different to the domestic cat, another carnivore species. Pyruvate played an important role earlier in the maturational process, and less glutamine was oxidized as the oocyte neared nuclear maturation. These variations emphasize the importance of defining species specificities in carnivores before expecting consistently successful IVM/IVF.

138 EFFECT OF SEMINAL PLASMA ON CHILLING AND FREEZING OF CANINE SPERMATOZOA

Seminal plasma (SP) is usually removed from semen that is to be cryopreserved. However, some reports indicate that SP has beneficial effects on spermatozoa during chilling and freezing (Barrios et al. 2000 Biol. Reprod. 63, 1531–1537; Moore et al. 2005 Theriogenology 63, 2372–2381; Vadnais et al. 2005 Anim. Reprod. Sci. 87, 121–132). The purpose of this study was to determine the effect on sperm survival of adding SP to the extender before cooling and freezing canine spermatozoa. In replicate experiments, ejaculates obtained from 4 healthy dogs (3–4 years old) of various breeds were pooled and centrifuged at 300g for 10 min at 25�C; the supernatant of seminal plasma was decanted. Spermatozoa were suspended in egg yolk-Tris (EYT) buffer. The study comprised 2 experiments: Exp. 1: Sperm were suspended in EYT extender containing 0%, 20%, 50%, 80%, or 100% SP, and were slowly cooled to 4�C for 2 h or held at 25�C as controls. Exp. 2: Sperm samples, each of which contained 1 � 108 sperm mL-1, were assigned to 5 groups to be frozen. In group 1, sperm in EYT + 20% SP were cooled to 4�C, diluted to contain final concentrations of 5% glycerol + 10% SP in EYT, and then frozen. In the 4 other groups, sperm in EYT alone were first cooled slowly to 4�C, then diluted to contain 5% glycerol plus 0%, 20%, 40%, or 50% SP in EYT, and then frozen. Spermatozoa were frozen at 25�C min in plastic straws that were suspended above liquid nitrogen and thawed in water at 38�C for 30 s. Sperm survival was assayed by determining progressive motility and integrity of plasma and acrosome membranes. Progressive motility was determined by microscopic examination at 400� magnification. Membrane integrity was assessed by use of a double fluorescent dye, and acrosome integrity by staining sperm with Pisum sativum agglutinin. The results of the first experiment showed that 20%, 50%, 80%, or 100% SP did not improve motility, membrane integrity, or acrosome integrity of spermatozoa chilled to 4�C compared to those chilled without SP (P &gt; 0.05). Survival of spermatozoa suspended in EYT + 20% SP and maintained at 25�C was significantly higher than for those that were chilled (P &lt; 0.05). The results of the second experiment showed that spermatozoa suspended in EYT + 20% SP and then diluted at 4�C to contain 5% glycerol + 10% SP exhibited the highest progressive motility and membrane integrity after being frozen and thawed (P &lt; 0.05). In summary, although seminal plasma did not affect spermatozoa that were only chilled, addition of seminal plasma did significantly improve survival of canine spermatozoa that were frozen and thawed.

Oocyte biology and challenges in developing in vitro maturation systems in the domestic dog

The oocyte of the domestic dog is unique from that of other mammalian species studied to date. Ovulation occurs either once or twice per year, with the oocyte released at the germinal vesicle stage, and then completing nuclear and cytoplasmic maturation within the oviduct under the influence of rising circulating progesterone. In vivo meiotic maturation of the bitch oocyte is completed within 48-72 h after ovulation, which is longer than 12-36 h required for oocytes from most other mammalian species. Due to these inherently novel traits, in vitro culture systems developed for maturing oocytes of other species have been found inadequate for maturation of dog oocytes. On average, only 15-20% of ovarian oocytes achieve the metaphase II stage after 48-72 h of in vitro culture. Thus far, no offspring have been produced in the dog (or other canids) by transferring embryos derived from in vitro matured oocytes. This review addresses current knowledge about dog reproductive physiology, specifically those factors influencing in vitro developmental competence of the oocyte. This summary lays a foundation for identifying the next steps to understanding the mechanisms regulating meiotic maturation and developmental competence of the dog oocyte.

Patterns of fecal gonadal hormone metabolites in the maned wolf (Chrysocyon brachyurus)

Ex situ populations of maned wolves are not viable due to low reproductive efficiency. The objective of this study was to increase knowledge regarding the reproductive physiology of maned wolves to improve captive management. Fecal samples were collected 3-5 d/wk from 12 females of various reproductive age classes (young, prime breeding and aged) and reproductive histories (conceived and raised pups, conceived but lost pups, pseudo-pregnant and unpaired). Ovarian steroids were extracted from feces and assessed by enzyme immunoassay. Concentrations of estrogen metabolites gradually increased, beginning 2-5 d before breeding, and declined to baseline on the day of lordosis and copulation. Fecal progestin metabolite concentrations increased steadily during the periovulatory period, when sexual receptivity was observed, and remained elevated during pregnancy and pseudo-pregnancy. During the luteal phase, young and prime breeding-age females excreted larger amounts of progestins than those of older age classes. Furthermore, progestin concentrations were higher during the luteal phase of pregnant versus pseudo-pregnant bitches. Profiles of fecal progestin metabolites for three singleton females were unchanged throughout the breeding season, suggesting ovulation is induced in this species. However, this finding could be confounded by age, as these females were either young or aged.

326FOLLICULAR SIZE, BUT NOT STAGE OF REPRODUCTION OR SEASON, INFLUENCES MEIOTIC MATURATION OF DOMESTIC DOG OOCYTES

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 meiotic abilities of oocytes. Percentages of oocytes obtained during proestrus/estrus (n=468 oocytes), diestrus/metestrus (n=333), anestrus (n=331) or prepuberty (6–8 months of age, n=479) and developing to MII were 17.9±2.9%, (mean±SEM), 24.0±6.0%, 20.8±4.7%, and 17.8±5.2%, respectively (P&gt;0.05). A similar analysis across seasons (spring, summer, fall, winter) also indicated no influence of time of year on nuclear maturation (P&gt;0.05). Because there is a known strong link between follicular growth and meiotic competence of goat oocytes (De Smedt et al., 1994 J. Exp. Zool. 269, 128–139), we also examined the impact of follicular size on nuclear maturation. The cortex of ovaries from 15 bitches was horizontally dissected (5mm thickness) so follicles could be observed and divided into three classes: (1) &lt;0.5mm diameter (n=60); (2) ≥0.5 to &lt;1mm (n=110); and (3) 1–2mm (n=72). Follicles were separated according to these size classes;; oocytes were recovered and cultured in TCM 199+0.25mM pyruvate, 2mM glutamine, 25mM β-mercaptoethanol, 10ng/mL epidermal growth factor (Basal TCM) supplemented with 0.5IU/mL equine chorionic gonadotropin for 1h. Oocytes then were cultured in Basal TCM for 48h before staining with 1% orcein to assess nuclear status. Follicular size influenced meiotic competence of the oocytes (ANOVA, P&lt;0.05). Mean percentages of MII oocytes were 14.2±7.2, 15.6±4.5, and 30.9±8.2, for oocytes recovered from &lt;0.5-mm, ≥0.5 to &lt;1-mm and 1–2-mm diameter follicles, respectively. This study revealed that stage of reproduction and season have no impact on in vitro nuclear maturation of the dog oocyte. However, the findings demonstrate that dog oocytes acquire meiotic competency during follicular development. Because the source of most dog oocytes for IVM are small follicles, results suggest that oocytes may be incapable of completing nuclear maturation under in vitro conditions that are designed for fully-grown oocytes.

213EFFECTS OF TIME OF MATURATION AND SHEEP SERUM ON IN VITRO FERTILIZATION IN THE ENDANGERED ELD'S DEER (CERVUS ELDI THAMIN) OOCYTES

The Eld’s deer, native to Southeast Asia, is threatened with extinction. Although artificial insemination is effective for offspring production, in vitro fertilization (IVF) would be more useful for rapidly disseminating genetic material from valuable founders. The objectives of this study were to: 1) determine if oocytes recovered from exogenous gonadotropin-treated hinds require additional in vitro maturation;; and 2) assess if fertilization is enhanced by supplementing Deer Synthetic Oviduct Fluid (DSOF;; Berg DK et al., 2003 Theriogenology 59, 189–205) with 1-day postestrus sheep serum (SS). Estrous cycles in Eld’s deer hinds (n=10) were synchronized with PGF2α analog (Lutalyse™, 500mg), followed by a 14-day intravaginal CIDR-G insertion;; ovine FSH (Ovagen™; 0.05 unit×8 injections) was administered at 12-h intervals beginning 84h before CIDR-removal. COCs (n=160) were retrieved laparoscopically 40–46h post-CIDR-removal and either fixed or matured in vitro (for 12h v. 24h) in TCM-199 (Earle’s salt) supplemented with 0.33mM pyruvate, 2mM glutamine, 100IUmL−1 penicillin, 100μgmL−1 streptomycin, 10% fetal calf serum, 5μgmL−1 FSH and LH and 1μgmL−1 E2 (5% CO2, 38.5°C). After 12- or 24-h IVM, cumulus cells were partially removed and oocytes (n=110) fertilized in DSOF with pooled frozen-thawed sperm (3 males;; 2×106 motile sperm mL−1), in the absence or presence of SS (20%, v/v). Additional oocytes (n=18) were used for parthenogenetic control. At 20-h postinsemination, presumptive zygotes were fixed and stained (Hoechst 33342) to assess fertilization success (presence of two pronuclei). Data were analyzed by ANOVA. Overall, 16.0±2.6 (mean±SEM) COCs were recovered/female. The majority of COCs were of excellent quality (grade I; 67.7±3.8%). At time of aspiration, 85% of the oocytes (n=11/13) were in metaphase I stage, 7.5% in telophase and 7.5% degenerate. No parthenogenic activation was observed. Likewise, no polyspermy was observed in any treatment. Fertilization was higher (P&lt;0.05) in oocytes matured for 24h and fertilized in the absence (64.4±3.1%) compared to presence (26.9±11.2%) of SS. In the absence of SS, a higher (P&lt;0.05) proportion of oocytes were fertilized after 24h (64.4±3.1%) compared to 12h (27.1±9.0%) IVM. There was no effect (P&gt;0.05) of SS on fertilization among oocytes subjected to 12-h IVM (27.1±9.0% v. 12.5±9.5%). When SS was present during fertilization, no difference (P&gt;0.05) was observed among oocytes matured for 12 or 24h. Results demonstrate that: 1) Eld’s deer oocytes require an additional 24-h IVM to complete maturation;; 2) DSOF supports sperm-oocyte interaction;; and 3) SS is not essential for successful fertilization. (Supported by Morris Animal Foundation.)

Effects of meiosis-inhibiting agents and equine chorionic gonadotropin on nuclear maturation of canine oocytes

Experiments were conducted to determine the effects of meiosis-inhibiting-agents and gonadotropins on nuclear maturation of canine oocytes. The culture medium was TCM199 + 10 ng/ml epidermal growth factor supplemented with 25 microM beta-mercaptoethanol, 0.25 mM pyruvate, and 1.0 mM L-glutamine (Basal TCM). Initially, oocytes were cultured in Basal TCM alone or in Basal TCM + dibutylryl cyclic adenosine monophosphate (0.5, 1, 5, or 10 mM dbcAMP) for 24 hr. Dibutylryl cAMP inhibited resumption of meiosis in a dose-dependent manner; 60% of oocytes remained at the germinal vesicle (GV) stage after being cultured for 24 hr in 5 mM dbcAMP. The meiosis-inhibitory effect of dbcAMP appeared to be reversible, as the oocytes resumed meiosis and completed nuclear maturation after being cultured for an additional 48 hr in its absence. Oocytes were then cultured in Basal TCM alone or in Basal TCM + roscovitine (12.5, 25, or 50 microM) for 24 hr. Although approximately 60% of oocytes cultured in 25 microM roscovitine remained at the GV stage, this percentage was not significantly different from the 48% that also remained at the GV stage when cultured in its absence. Oocytes were cultured in Basal TCM + 25 microM roscovitine for 17 hr, exposed briefly to equine chorionic gonadotropin (eCG), and then cultured in Basal TCM for 48 hr. Short exposure of oocytes to eCG was beneficial, as it significantly increased the proportion of oocytes developing beyond germinal vesicle breakdown (P < 0.05) with approximately 20-30% of these were metaphase I (MI) oocytes. Study of the kinetics of nuclear maturation demonstrated that large numbers of oocytes remained at MI even after being cultured for 52 hr following brief exposure to eCG. This study showed that in vitro maturation of canine oocytes can be somewhat improved by short exposure of oocytes to eCG. However, further studies are still required to derive effective methods to mature canine oocytes in vitro.

Permeability characteristics and osmotic sensitivity of rhesus monkey (Macaca mulatta) oocytes

BACKGROUND

Permeability characteristics and sensitivity to osmotic shock are principal parameters that are important to derive procedures for the successful cryopreservation of mammalian oocytes.

METHODS AND RESULTS

The osmotically inactive volume of rhesus monkey oocytes was determined by measuring their volumes in the presence of hypertonic solutions of sucrose from 0.2 to 1.5 mol/l, compared with their volume in isotonic TALP-HEPES solution. Boyle-van't Hoff plots at infinite osmolality indicated that the non-osmotic volumes of immature and mature oocytes were 20 and 17% respectively. Osmotic responses of oocytes exposed to 1.0 mol/l solutions of glycerol, dimethylsulphoxide (DMSO) and ethylene glycol (EG) were determined. Rhesus monkey oocytes appeared to be less permeable to glycerol than to DMSO or to EG. Sensitivity of oocytes to osmotic shock was determined by exposing them to various solutions of EG (0.1 to 5.0 mol/l) and then abruptly diluting them into isotonic medium. Morphological survival, as measured by membrane integrity, of oocytes diluted out of EG depended significantly on the concentration of EG (P < 0.01).

CONCLUSION

Determination of permeability characteristics and sensitivity to osmotic shock of rhesus oocytes will aid in the derivation of procedures for their cryopreservation.

Nuclear maturation of canine oocytes cultured in protein-free media

The objective of this study was to determine the ability of canine oocytes to complete nuclear maturation in a protein-free medium. Oocytes obtained from ovaries of bitches aged 6 months to 2 years were cultured either in TCM199 or CMRL1066 medium without protein supplementation in 5% or 20% O(2). Sixteen of 121 (13%) oocytes cultured in TCM199 reached metaphase II, but only 1 of 135 oocytes cultured in CMRL1066 did so (P < 0.05). Oxygen concentration did not affect nuclear maturation. An additional 103 oocytes were cultured in TCM199 for 48 hr, inseminated with chilled ejaculated spermatozoa, fixed in 1:3 acetic acid-ethanol and then stained with aceto-orcein; 34% of these oocytes were penetrated by spermatozoa. To determine developmental competence of oocytes cultured in a protein-free medium, 85 oocytes were cultured in TCM 199 for 48 hr, inseminated and then cultured; 7 early stage embryos were produced. The effects of growth hormone, beta-mercaptoethanol (betaME), luteinizing hormone (LH) and energy substrates, alone or in combination, on nuclear maturation of oocytes cultured in a protein-free medium were also determined. Growth hormone enhanced cumulus expansion, but did not improve nuclear maturation. beta-mercaptoethanol had no effect on nuclear maturation. However, percentages of MII oocytes significantly decreased when the oocytes were cultured for 48 hr in the medium containing LH or a high concentration of glucose (P < 0.05). In conclusion, canine oocytes are able to complete nuclear maturation in a protein-free medium. The specific type of medium and other supplements significantly influence the meiotic maturation of canine oocytes.

Effects of beta-mercaptoethanol on formation of pronuclei and developmental competence of swamp buffalo oocytes

This study was conducted to determine the effect of supplementing maturation medium with beta-mercaptoethanol (betaME) on pronuclei formation and developmental competence of swamp buffalo oocytes. Buffalo oocytes were matured in TCM199 medium either with 10mM betaME or without betaME supplementation for 24h. In Experiment 1, oocytes were fixed and stained for cytological evaluation after in vitro fertilization (IVF). In Experiment 2, presumptive zygotes were cultured and their developmental competency was assessed. It was found that betaME significantly improved the proportion of oocytes that exhibited synchronous pronuclei formation (31.8+/-5.1% versus 17.9+/-3.3%, P<0.05). There were no significant differences between oocytes matured with or without betaME in their capability of developing into blastocyst-stage embryos (3.0+/-1.3% versus 1.8+/-0.9%). However, blastocysts produced from oocytes matured in the presence of betaME appeared to develop faster than those from oocytes matured in the absence of betaME (P<0.05). Cavitation of embryos from oocytes matured in the presence of betaME occurred at 156 hpi, whereas those matured in the absence of betaME occurred at 180 hpi. Although in vitro production of blastocysts did not increase by addition of betaME to maturation medium, quality of blastocysts produced from oocytes matured in the presence of betaME was improved. This study provides information for further investigations on optimizing a system for in vitro production of swamp buffalo embryos.

Osmotic sensitivity of canine spermatozoa

The objective of this study was to determine osmotic tolerance of canine spermatozoa. The study comprised three experiments: (1) spermatozoa suspended either in an egg yolk-citrate (EYC) extender or in Kenney skim milk extender were exposed to NaCl solutions ranging from 290 to 1500 mOsm; (2) spermatozoa suspended in EYC were exposed to 550 to 1500 mOsm solutions of glucose, galactose, or fructose; and (3) spermatozoa suspended in EYC or glucose-bovine serum albumin (G-BSA) were exposed to 0.6 M (approximately 900 mOsm) or 1.2 M (approximately 1600 mOsm) solutions of glycerol, ethylene glycol (EG), or dimethyl sulfoxide (Me(2)SO). In all experiments, motility and membrane integrity of spermatozoa were assessed after they were diluted into isotonic medium at 37 degrees C. Exposure of canine spermatozoa to solutions of either NaCl or monosaccharides at osmolalities >500 mOsm caused a significant reduction of motility (P<0.01). Motility of spermatozoa was more affected by osmotic stress than their membrane integrity. Osmotic sensitivity of canine spermatozoa was dependent on the type of extender; spermatozoa suspended in the Kenney extender were more resistant to osmotic stress than those suspended in the EYC extender. Despite their sensitivity to exposure to high concentrations of nonpermeating agents, canine spermatozoa were rather resistant to exposure to glycerol and EG. However, Me(2)SO was toxic to canine spermatozoa; motility was substantially reduced after spermatozoa were exposed to 0.6 M Me(2)SO. The type of extender also affected the sensitivity of canine spermatozoa to Me(2)SO; spermatozoa suspended in the EYC extender were more resistant than those suspended in G-BSA. It was concluded that canine spermatozoa are sensitive to osmotic stress, but are tolerant to shrinking and swelling caused by exposure to permeating cryoprotectants.

Differences among dogs in response of their spermatozoa to cryopreservation using various cooling and warming rates

Spermatozoa collected from the caudae epididymides of 16 dogs of various breeds were suspended in an isotonic salt solution (DIMI medium) containing 0.6 M glycerol, frozen in liquid nitrogen, and their "survival" was measured after thawing. In the first experimental series, duplicate samples of spermatozoa from each of 11 dogs were cooled at rates of 0.5, 3, 11, 58, or 209 degrees C/min, stored in liquid nitrogen, and the frozen samples warmed at approximately 830 or at 33 degrees C/min. Sperm "survival" was judged by microscopic assessments of motility and of membrane integrity, the latter as assayed with Fertilight, a double fluorescent stain. Motility of frozen spermatozoa that were thawed rapidly, averaged for 11 dogs, was low at low rates, increased to a maximum at 11 degrees C/min, and then decreased significantly at higher rates (P<0.01). This inverted V-shaped curve was also observed with slow thawing, although the apparent optimum cooling rate ranged from 3 to 11 degrees C/min. The integrity of sperm plasma membranes showed a similar dependence on cooling rate, although the percentages of spermatozoa with intact plasma membranes were higher than the percentages of motile spermatozoa. Motility of spermatozoa, as a function of cooling rate, varied considerably from male to male (P<0.01), whereas membrane integrity was much more consistent among the 11 dogs. In the second experimental series with spermatozoa from 5 dogs, motility of spermatozoa frozen at 0.5 degrees C/min and warmed at 3.6, 33, 140, or 830 degrees C/min also exhibited an inverted V-shaped survival curve, in this case as a function of warming rate. In summary, high survival of frozen-thawed canine epididymal spermatozoa depended on both cooling and warming rates, but spermatozoa from each dog exhibited their own sensitivity to cooling and warming rates.

Cryopreservation of gametes and embryos of non-domestic species

Many species of mammals are threatened or endangered. Methods of assisted reproduction that are being used with increasing frequency to produce offspring of domestic animals and humans are often viewed as offering innovative ways to reproduce non-domestic species as well. Uncounted millions of live young of domestic or laboratory species have been produced from gametes and embryos stored at -70 degrees C or below, sometimes for as long as 25 to 35 yrs. Such methods of cryopreservation are now being applied with increasing frequency and urgency to preserve gametes and embryos of non-domestic and threatened species to establish "genome resource banks" or "frozen zoos." But levels of success to produce live young from such cryopreserved gametes or embryos vary considerably from species to species, as well as from individual to individual. It is sometimes thought that differences among species in fundamental characteristics of their gametes may determine the efficacy of cryopreservation and the production of live young. However, it may not be that ineffective cryopreservation is responsible for low success rates. Rather, the limiting factor may be insufficient information and knowledge of the most basic reproductive biology of such non-domestic species. Even standard methods of cryopreservation may be completely adequate to act as a "temporary" expedient to preserve germplasm of non-domestic species to permit time to acquire a fuller understanding of the biology and behavior of non-domestic species.

Effects of cooling and warming conditions on post-thawed motility and fertility of cryopreserved buffalo spermatozoa

The principal objective of this study was to derive an improved procedure for cryopreservation of swamp buffalo (Bubalus bubalis) spermatozoa. Experiments were conducted to determine effects of cooling rate, intermediate plunge temperature and warming rate on motility and acrosome integrity of spermatozoa. Spermatozoa were obtained from three bulls (three ejaculates/bull) and were subjected to nine cooling conditions before being frozen in liquid nitrogen: cooling at 10, 20, or 30 degrees C/min each to -40, -80, or -120 degrees C before being plunged into liquid nitrogen. The spermatozoa frozen under a given condition were then thawed either at 1000 or 200 degrees C/min. Cooling rate, intermediate temperature and warming rate significantly affected survival of spermatozoa obtained from the three bulls. Cooling spermatozoa from 4 to -120 degrees C either at 20 or 30 degrees C/min yielded better progressive motility compared to other cooling conditions (50 versus 30%). Rapid warming was superior to slow warming. In an additional study, motility and fertility of spermatozoa frozen after being cooled to -120 degrees C at 20 degrees C and 30 degrees C/min and those frozen by a standard protocol used routinely for semen processing were assessed. Progressive motility of cryopreserved spermatozoa cooled at 20 degrees C and 30 degrees C/min was 40%, while that of spermatozoa cryopreserved using a standard protocol was 25%. A total of 178 buffalo cows were inseminated with cryopreserved spermatozoa obtained from one bull, and their pregnancy status was assessed 60 days later by rectal palpation. Out of the 60, 26 (43%) and 23 of 58 (40%) cows inseminated with sperm cooled at 20 and 30 degrees C/min, respectively, became pregnant, whereas 17 of 60 (28%) cows inseminated with sperm frozen by a standard protocol became pregnant. This study demonstrates that an effective cryopreservation procedure for buffalo spermatozoa can be derived by systematic examination of various cryobiological factors.

Effect of treatment with recombinant bovine somatotropin on responses to superovulatory treatment in swamp buffalo (Bubalus bubalis)

The objective of this study was to determine the effect of treatment with recombinant bovine somatotropin (rBST) on the response to superovulatory treatment in swamp buffalo. Estrous cycles of 16 buffalo cows were synchronized by intravaginal administration of progesterone and estradiol benzoate, and the cows were then randomly divided into 2 groups. The rBST-treated group received 250 mg of a sustained-release formula of rBST on Day 4 after progesterone implantation, whereas the control group did not receive rBST. Both groups were then given a superovulatory regimen of twice daily injections of FSH for 3.5 d (total dose of 260 mg, i.m.), between Days 9 and 11 after administration of progesterone. The cows were bred naturally 1 d after the last FSH injection, then 6 d after breeding they were slaughtered, and their reproductive tracts were removed. The numbers of corpora lutea (CL) and follicles were recorded, and embryos were flushed out of the uterine horns. There were no significant differences between the rBST-treated and control cows for the mean numbers (+/- SEM) of CL (6.0 +/- 2.2 vs 4.3 +/- 1.1), follicles (15.9 +/- 4.1 vs 19.8 +/- 2.9), or total embryos recovered per collection (4.5 +/- 1.6 vs 2.3 +/- 1.0). However, there were significant differences between rBST-treated and control cows for the numbers of transferable embryos per collection (3.0 +/- 1.0 vs 0.8 +/- 0.3; P < or = 0.05) and the overall proportion of transferable embryos (75 vs 33%; P < or = 0.01). The results of this study show that pretreatment of swamp buffalo with rBST significantly increases the production of transferable embryos in response to superovulation.

Live mice from cryopreserved embryos derived in vitro with cryopreserved ejaculated spermatozoa

This study was undertaken to try to reduce the number of animals required to maintain mouse strains by banking of embryos or spermatozoa. The principal objective was to cryopreserve ejaculated mouse spermatozoa, using a method recently developed for epididymal spermatozoa. Within 30 min after mating, ejaculated spermatozoa were flushed from the uterus of mated females; shortly afterwards, epididymal spermatozoa were also collected from the same males that had mated with the females. The average values for spermatozoal motility and viability of ejaculated specimens of nine males were 43 and 46%, respectively, and for epididymal specimens, the corresponding values were 60 and 52%. In experiment 1, ejaculated or epididymal spermatozoa were incubated with oocytes for 0.5 to 4 h. As evidenced by development into two-cell embryos within 24 h, kinetics of fertilization of the two spermatozoa types were similar. In experiment 2, ejaculated and epididymal spermatozoa of three males were separately cryopreserved in medium containing raffinose, glycerol, and egg yolk. Samples were cooled and seeded at -4 degrees C, cooled to -70 degrees C at 20 degrees C/min, and then were placed into liquid nitrogen for storage. When cryopreserved epididymal or ejaculated spermatozoa were thawed at > 1,000 degrees C/min and used for in vitro fertilization, > 60% of oocytes cleaved, and approximately 95% of cleaved embryos developed into morulae or blastocysts. When embryos produced with cryopreserved spermatozoa were transferred into recipients, 18 and 22 live pups were obtained from 62 and 54 embryos resulting from ejaculated or epididymal spermatozoa, respectively. This study documented the feasibility of cryopreserving ejaculated spermatozoa as an effective alternative to preserving germ plasm from genetically valuable mice.

Birth of live mice derived by in vitro fertilization with spermatozoa retrieved up to twenty-four hours after death

The objective of this study was to determine the viability and fertility of mouse spermatozoa obtained at various postmortem intervals. Male mice were euthanized, and the bodies were kept at approximately 22 degrees C for up to 24 hr. The epididymides were removed and spermatozoa were allowed to swim out into Minimum Essential Medium supplemented with bovine serum albumin. Motility of spermatozoa retrieved within 12 hr postmortem was approximately 60%, whereas motility of those obtained 6 to 12 hr later decreased significantly (P < 0.05). There appeared to be no differences in the percentages of spermatozoa with intact plasma and acrosomal membranes regardless of the time after death. After in vitro fertilization of oocytes with spermatozoa collected immediately after death or at 6, 12, 18, or 24 hr postmortem, the cleavage rates were 81%, 70%, 64%, 34%, and 19%, respectively. Once oocytes were fertilized, more than 65% developed into morulae/blastocysts. Transfer of a total of 166 embryos produced in vitro with postmortem spermatozoa resulted in the birth of 44 live pups (26.5%). Of these 44, 3 live mice were derived by transfer of 11 embryos (27.3%) produced with 24-hr postmortem spermatozoa. Histological examination of the testes and epididymides obtained at various postmortem intervals revealed that degenerative changes of the testes occurred within 6 hr, whereas those of the epididymides were less obvious until 6 hr later. These changes included pyknosis, release of intracellular contents, and disruption of intercellular bridges of the germ cells. This study has demonstrated that spermatozoa recovered from a dead animal as long as 24 hr after death can be used to fertilize oocytes, and that the resulting zygotes can develop into live young.

Cryopreservation of mouse spermatozoa. I. Effect of seeding on fertilizing ability of cryopreserved spermatozoa

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 degrees 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 degrees C did not affect their viability as judged by vital staining. Egg yolk protected spermatozoa against chilling injury, as cooling them to -4 degrees 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 degrees C either without seeding or after seeding at -4 degrees C. Development of 222 oocytes into two-cell embryos after in vitro fertilization (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 degrees 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 chi2 analysis. An additional 925 oocytes were fertilized with spermatozoa after being seeded and frozen to -196 degrees 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.

Cryopreservation of mouse spermatozoa. II. Relationship between survival after cryopreservation and osmotic tolerance of spermatozoa from three strains of mice

A procedure to cryopreserve mouse spermatozoa has been derived to bank the genetics of valuable strains of mice in a practical way. The primary objective of this study was to apply the cryopreservation method developed for spermatozoa of strain B6D2F1 to those of strains 129/J and C57BL6/J. Using the capability of spermatozoa to fertilize oocytes in vitro as the criterion of survival, we found differences in survival after cryopreservation among the three strains. Blastocysts were obtained after in vitro fertilization of oocytes with frozen spermatozoa from B6D2F1 (51%) and 129/J (12%); none was obtained from C57BL6/J. Transfer of embryos into recipients resulted in the birth of 69 live pups from 164 embryos produced with frozen B6D2F1 spermatozoa and 11 pups from 35 embryos produced with 129/J spermatozoa. To seek an explanation of these differences among the three strains, spermatozoa were exposed to anisotonic solutions ranging from 5 to 3200 mOsm; viability of spermatozoa was assessed by a double stain using flow cytometry. Mouse spermatozoa tolerated exposure to solutions of osmolalities between 200 and 400 mOsm, but were damaged when exposed to solutions exceeding this range. Spermatozoa from C57BL6/J were the most sensitive: 20, 35, and 40% of C57BL6/J, 129/J, and B6D2F1 spermatozoa survived exposure to an 800 mOsm solution, respectively. This study suggests that there is a genetic basis for sensitivity of mouse spermatozoa to osmotic shock and freezing injury. Nevertheless, the birth of live pups produced with frozen spermatozoa from 129/J as well as with spermatozoa from B6D2F1 mice indicates that cryopreservation of spermatozoa can be used to preserve the genetics of valuable strains of mice.

Birth of live mice resulting from oocytes fertilized in vitro with cryopreserved spermatozoa

The objective of this study was to develop a reliable method to cryopreserve mouse spermatozoa, using in vitro fertilization (IVF) of oocytes, development of resultant zygotes into blastocysts, and the birth of live young after embryo transfer as criteria of sperm survival. Epididymal sperm were frozen in a raffinose-glycerol solution containing either egg yolk (EY) or BSA. Sperm frozen in the presence of EY yielded higher survivals than those frozen in the presence of BSA; when used for IVF, the former resulted in more blastocysts (26% vs. 5%). Comparison between one-step and stepwise dilution of the cryoprotectant revealed no differences in sperm viability as assayed by a vital stain. Nevertheless, IVF using frozen sperm recovered by one-step or stepwise dilution resulted in 33% and 17% blastocyst formation, respectively. When embryos produced with cryopreserved sperm were transferred into recipients, pregnancies (12 of 15 recipients) and the birth of live young (57 pups from 167 embryos transferred) resulted. These results were comparable to those obtained from transferral of embryos produced by IVF with fresh sperm (17 pregnancies from 19 recipients, 87 live young from 197 embryos). Thus, this study has resulted in the development of a simple and efficient cryopreservation procedure for mouse sperm.