Universal DNA methylation age across mammalian tissues

Aging, often considered a result of random cellular damage, can be accurately estimated using DNA methylation profiles, the foundation of pan-tissue epigenetic clocks. Here, we demonstrate the development of universal pan-mammalian clocks, using 11,754 methylation arrays from our Mammalian Methylation Consortium, which encompass 59 tissue types across 185 mammalian species. These predictive models estimate mammalian tissue age with high accuracy (r > 0.96). Age deviations correlate with human mortality risk, mouse somatotropic axis mutations and caloric restriction. We identified specific cytosines with methylation levels that change with age across numerous species. These sites, highly enriched in polycomb repressive complex 2-binding locations, are near genes implicated in mammalian development, cancer, obesity and longevity. Our findings offer new evidence suggesting that aging is evolutionarily conserved and intertwined with developmental processes across all mammals.

Estrous cycle characterisation and artificial insemination using frozen–thawed spermatozoa in the bottlenose dolphin (Tursiops truncatus)

The reproductive endocrinology of the bottlenose dolphin,Tursiops truncatus,was characterized to facilitate the development of artificial insemination using cryopreserved spermatozoa. Specific objectives were: (i) to determine the excretory dynamics of urinary luteinizing hormone (LH) and ovarian steroid metabolites during the estrous cycle; (ii) to evaluate the effect of an exogenously administered synthetic progesterone analog (altrenogest) on reproductive hormone excretion; (iii) to correlate follicular growth and ovulation (as determined by transabdominal ultrasound) to urinary LH and ovarian steroid metabolites; (iv) examine thein vivofertilisation capacity of cryopreserved semen, and (v) to develop an intrauterine insemination technique. Based on urinary endocrine monitoring of natural estrous cycles (2 consecutive cycles) and nine post altrenogest cycles in ten females, estrous cycles were found to be 36 days long and comprised of an 8 day and 19 day follicular and luteal phase, respectively. Peak estrogen conjugates (EC; 5.4 ± 3.8 ng/mg creatinine (Cr)) occurred 8 h prior to the LH surge (70.9 ± 115.7 ng/mg Cr). The time of ovulation, as determined by ultrasonography, occurred 32.1 ± 8.9 h and 24.3 ± 7.0 h after the onset of the LH surge and LH peak, respectively. Mean preovulatory follicular diameter and circumference were 2.1 ± 0.5 cm and 6.5 ± 1.5 cm, respectively. Of the 27 estrous synchronisation attempts, 13 resulted in an ovulatory cycle, with ovulation occurring 21 days post-altrenogest treatment. Intrauterine (4 of 5) and intracornual (1 of 3) inseminations conducted across eight estrous cycles resulted in five pregnancies (63%), one pregnancy resulted from the use of liquid stored semen, whereas four were achieved using cryopreserved semen. These data provide new information on female bottlenose dolphin reproductive physiology, and demonstrate that the combination of endocrine monitoring and serial ultrasonography contributed to successful AI using liquid-stored and cryopreserved semen.

Development of sperm sexing and associated assisted reproductive technology for sex preselection of captive bottlenose dolphins (Tursiops truncatus)

Research was conducted to develop sperm sorting and novel sperm preservation methodologies for sex predetermination in the bottlenose dolphin (Tursiops truncatus) using artificial insemination. In Study 1, the effect of seminal plasma (SP), sperm concentration and freezing rate (FR) on in vitro sperm quality of liquid-stored, non-sorted spermatozoa was examined. There was no effect (P > 0.05) of prefreeze SP addition on post-thaw quality (progressive motility, kinetic rating, sperm motility index (SMI), viability and acrosome integrity). Post-thaw motility parameters and viability were higher (P < 0.05) for slow FR than fast FR samples. In Study 2 investigating the effects of liquid storage and sorting on sperm quality, motility and SMI after sorting and centrifugation were lower (P < 0.05) than those of the initial ejaculate. The sort rate for enrichment (91 ± 4% purity) of X- and Y-bearing spermatozoa was 3400 ± 850 spermatozoa sex−1 s−1. In Study 3, compared with a modified straw method, directional freezing resulted in enhanced in vitro quality of sorted and non-sorted spermatozoa derived from liquid-stored semen (P < 0.05). In Study 4, endoscopic insemination of three dolphins with sorted, frozen–thawed X-bearing spermatozoa resulted in one conception and the birth of a female calf. High-purity sorting of dolphin spermatozoa, derived from liquid-stored semen, can be achieved with minimal loss of in vitro sperm quality and samples are functional in vivo.

Reproductive Physiology and Development of Artificial Insemination Technology in Killer Whales (Orcinus orca)1

Research was conducted to define the basic reproductive physiology of killer whales (Orcinus orca) and to use this knowledge to facilitate the development of artificial insemination procedures. The specific objectives were 1) to determine the excretory dynamics of urinary LH and ovarian steroid metabolites during the estrous cycle; 2) to evaluate the effect of an exogenously administered, synthetic progesterone analog on reproductive hormone excretion; 3) to validate the use of transabdominal ultrasound for ovarian evaluation and timing of ovulation; 4) to examine the quality of semen after liquid storage and cryopreservation; and 5) to develop an intrauterine insemination technique. Based on urinary endocrine monitoring of 41 follicular phases and 26 complete cycles from five females, estrous cycles were 41 days long and comprised a 17-day follicular phase and a 21-day luteal phase. A consistent temporal relationship was observed between peak estrogen conjugates and the LH surge, the latter of which occurred approximately 0.5 days later. Two animals placed on oral altrenogest (three separate occasions for 30, 17, and 31 days, respectively) excreted peak urinary estrogen concentrations 25 days after withdrawal that were followed by sustained elevations in urinary pregnanediol-3alpha-glucuronide excretion. Mean preovulatory follicle diameter was 3.9 cm (n = 6), and ovulation occurred 38 h (n = 5) after the peak of the LH surge. Based on visual estimates of motility, liquid-stored semen maintained 92% of its raw ejaculate sperm motility index (total progressive motility x kinetic rating [0-5 scale, where 0 = no movement and 5 = rapid progressive movement]) when held at 4 degrees C for 3 days postcollection. Semen cryopreserved using a medium freezing rate demonstrated good postthaw total motility (50%), progressive motility (94%), and kinetic rating (3.5). Insemination during eight estrous cycles resulted in three pregnancies (38%), two from liquid-stored and one from cryopreserved semen. Two calves were delivered after gestation lengths of 552 and 554 days, respectively. These data demonstrate the potential of noninvasive endocrine monitoring combined with serial ultrasonography to improve our understanding of the reproductive biology of cetaceans. This fundamental knowledge was essential for ensuring the first successful conceptions, resulting in live offspring, using artificial insemination in any cetacean species.

Seasonality, estrous cycle characterization, estrus synchronization, semen cryopreservation, and artificial insemination in the Pacific white-sided dolphin (Lagenorhynchus obliquidens)

The reproductive physiology of the Pacific white-sided dolphin, Lagenorhynchus obliquidens, was characterized to facilitate the development of artificial insemination (AI) using cryopreserved spermatozoa. Specific objectives were to: 1) describe reproductive seasonality of the Pacific white sided dolphins; 2) describe urinary LH and ovarian steroid metabolites during the estrous cycle; 3) correlate LH and ovarian steroidal metabolite patterns to ultrasound-monitored follicular growth and ovulation; and 4) assess the efficacy of synchronizing estrus, sperm collection/cryopreservation, and intrauterine insemination. Ovulations (64%, n=37) and conceptions (83%, n=18) occurred from August to October. Peak mean serum testosterone (24 ng/ml), cross-sectional testicular area (41.6 cm2), and sperm concentration (144.3×107 sperm/ml) occurred in July, August, and September respectively. Spermatozoa were only found in ejaculates from July to October. Estrous cycles (n=22) were 31 d long and were comprised of a 10 d follicular and 21 d luteal phase. Ovulation occurred 31.2 h after the onset of the LH surge and 19.3 h after the LH peak. Follicular diameter and circumference within 12 h of ovulation were 1.52 and 4.66 cm respectively. Estrus synchronization attempts with altrenogest resulted in 17 (22%) ovulatory cycles with ovulation occurring 21 d post-altrenogest. Ten AI attempts using cryopreserved semen resulted in five pregnancies (50%). The mean gestation length was 356 days (range 348–367). These data provide new information on the Pacific white-sided dolphin's reproductive physiology and collectively enabled the first application of AI in this species.

Effect of Cryopreservation Methods and Precryopreservation Storage on Bottlenose Dolphin (Tursiops truncatus) Spermatozoa1

Research was conducted to develop an effective method for cryopreserving bottlenose dolphin (Tursiops truncatus) semen processed immediately after collection or after 24-h liquid storage. In each of two experiments, four ejaculates were collected from three males. In experiment 1, three cryopreservation methods (CM1, CM2, and CM3), two straw sizes (0.25 and 0.5 ml), and three thawing rates (slow, medium, and fast) were evaluated. Evaluations were conducted at collection, prefreeze, and 0-, 3-, and 6-h postthaw. A sperm motility index (SMI; total motility [TM] x % progressive motility [PPM] x kinetic rating [KR, scale of 0-5]) was calculated and expressed as a percentage MI of the initial ejaculate. For all ejaculates, initial TM and PPM were greater than 85%, and KR was five. At 0-h postthaw, differences in SMI among cryopreservation methods and thaw rates were observed (P < 0.05), but no effect of straw size was observed. In experiment 2, ejaculates were divided into four aliquots for dilution (1:1) and storage at 4 degrees C with a skim milk- glucose or a N-tris(hydroxymethyl)methyl-2-aminoethane sulfonic acid (TES)-TRIS egg yolk solution and at 21 degrees C with a Hepes-Tyrode balanced salt solution (containing bovine albumin and HEPES) (TALP) medium or no dilution. After 24 h, samples were frozen and thawed (CM3, 0.5-ml straws, fast thawing rate) at 20 x 10(6) spermatozoa ml(-1) (low concentration) or at 100 x 10(6) spermatozoa ml(-1) (standard concentration). The SMI at 0-h postthaw was higher for samples stored at 4 degrees C than for samples stored at 21 degrees C (P < 0.001), and at 6-h postthaw, the SMI was higher for samples frozen at the standard concentration than for samples frozen at the low concentration (P < 0.05). For both experiments, acrosome integrity was similar across treatments. In summary, a semen cryopreservation protocol applied to fresh or liquid-stored semen maintained high levels of initial ejaculate sperm characteristics.

Semen collection, characterisation and artificial insemination in the beluga (Delphinapterus leucas) using liquid-stored spermatozoa

Ejaculates were collected from a beluga (Delphinapterus leucas) to gain an understanding of sperm biology and develop a short-term sperm preservation method for use in artificial insemination (AI). Ejaculate parameters and biochemistry, semen production and serum testosterone concentrations of an adult male were characterised for 21 months. Sperm viability, acrosome integrity and morphology did not change (P > 0.05) but ejaculate volume, sperm concentration and total spermatozoa per ejaculate were higher (P < 0.05) from January to June than from July to December. Peak testosterone concentrations (P < 0.05) were observed from October to April (8.0 ± 1.6 ng mL–1). The effects of hyaluronic acid (HA), antioxidants, storage temperature and time on in vitro sperm characteristics were examined. Motility parameters and viability were improved (P < 0.05) when semen was stored at 5°C compared with 21°C. During the first 24 h of storage sperm agglutination was absent only at 5°C in the presence of HA. A nulliparous 28-year-old female was inseminated endoscopically with liquid-stored semen. A pregnancy and birth of a calf was achieved following AI for the first time in this species, thereby validating both the AI technique and the fertility of beluga spermatozoa after chilled storage in a specialised diluent.

Characterization of male killer whale (Orcinus orca) sexual maturation and reproductive seasonality

Longitudinal serum testosterone concentrations (n=10 males) and semen production (n=2 males) in killer whales were evaluated to: (1) characterize fluctuations in serum testosterone concentrations with respect to reproductive maturity and season; (2) compare morphologic changes to estimated age of sexual maturity, based on changes in serum testosterone concentrations; and (3) evaluate seasonal changes in sperm production. Classification of reproductive status and age class was based on differences (P < 0.05) in serum testosterone concentrations according to age; juvenile males ranged from 1 to 7 years (mean+/-S.D. testosterone, 0.13+/-0.20 ng/mL), pubertal males from 8 to 12 years (2.88+/-3.20 ng/mL), and sexually mature animals were 13 years and older (5.57+/-2.90 ng/mL). For captive-born males, serum testosterone concentrations, total body length and height to width ratio of the dorsal fin were 0.7+/-0.7 ng/mL, 495.6+/-17.5 cm and 1.14+/-0.13c m, respectively, at puberty; at sexual maturity, these end points were 6.0+/-3.3 ng/mL, 548+/-20 cm and 1.36+/-0.1cm. Serum testosterone concentrations were higher (P<0.05) from March to June than from December to February in pubertal animals (4.2+/-3.4 ng/mL versus 1.4+/-2.6 ng/mL) and than from September to December in sexually mature animals (7.2+/-3.3 ng/mL versus 4.0+/-2.0 ng/mL). Ejaculates (n = 90) collected from two males had similar (P > 0.05) sperm concentrations across all months. These data represent the first comprehensive study on male testosterone concentrations during and after sexual maturation, and on reproductive seasonality in the killer whale.

Preservation of beluga (Delphinapterus leucas) spermatozoa using a trehalose-based cryodiluent and directional freezing technology

A beluga (Delphinapterus leucas) sperm preservation method was developed for use in genome banking and AI. In Study 1, glycerol-based cryodiluents (modified BF5F and modified Platz Diluent Variant (PDV)) were unable to maintain adequate progressive motility using straws (fast and slow freezing rate (FR)) or pellets (slow FR). Neither freezing method nor FR affected in vitro sperm characteristics (P > 0.05), but retention of prefreeze progressive motility following thawing was greater (P < 0.05) for BF5F (21%) than PDV (15%). In Study 2, examining the effects of straw freeze–thawing using BF5F with glycerol (1 and 3%, v/v) or trehalose (46 and 91 mM) on sperm characteristics, samples cryopreserved in trehalose exhibited superior (P < 0.05) in vitro parameters compared with their glycerol-treated counterparts. In Study 3, compared with a straw method, directional freezing using 91 mM trehalose enhanced (P < 0.05) sperm characteristics, with samples retaining 38%, 75% and 61% of their prefreeze progressive motility, curvilinear velocity and viability, respectively. A higher (P < 0.05) proportion of motile spermatozoa displayed rapid velocity after directional (21 ± 1%) compared with straw (12 ± 3%) freezing. Systematic development of a cryodiluent and the use of directional freezing resulted in beluga spermatozoa exhibiting adequate post-thaw quality for genome banking and use in AI.

Saksenaea vasiformis and Apophysomyces elegans zygomycotic infections in bottlenose dolphins (Tursiops truncatus), a killer whale (Orcinus orca), and pacific white-sided dolphins (Lagenorhynchus obliquidens)

During a 10-yr period, a killer whale (Orcinus orca), two Pacific white-sided dolphins (Lagenorhynchus obliquidens), and two bottlenose dolphins (Tursiops truncatus), all housed at SeaWorld of Texas from 1991 to 2001, were infected with fungi from the class Zygomycetes. In four out of five cases, the fungi were identified as either Saksenaea vasiformis or Apophysomyces elegans. All fungi in the class Zygomycetes aggressively invade the vascular system. Death occurred within 23 days after the initial clinical signs. The primary site of infection involved the s.c. tissue and skeletal musculature. In one case, infection originated in the placenta and uterus of a periparturient animal. All cases exhibited systemic spread of the organisms, including two to the central nervous system. The fifth and most recent case, a bottlenose dolphin, was treated with liposomal nystatin, an antifungal formulation with reduced nephrotoxicity. This animal initially responded to therapy; however, 14 days after cessation of therapy, fungal growth reoccurred. Thus, the animal was euthanatized 39 days after the initial clinical signs. This drug represents a promising treatment option if combined with early disease detection and aggressive tissue resection.

Characterization of the estrous cycle in female beluga (Delphinapterus leucas) using urinary endocrine monitoring and transabdominal ultrasound: Evidence of facultative induced ovulation

Recent, successful application of assisted reproductive technologies in captive beluga has resulted from the extensive study of male beluga reproductive biology. Optimization of assisted reproduction requires additional detailed knowledge of the female estrous cycle. Our specific objectives were to: (1) validate urinary immunoassays for use in this species; (2) elucidate annual ovarian cycle dynamics through the combined use of hormone excretion patterns and transabdominal ultrasound; and (3) establish whether ovulation in this species is spontaneous or induced by male factors. Ovulation was observed in four of 15 estrous cycles monitored in four adult female beluga maintained in a single-sex group. After introduction of a breeding male, ovulation was observed in six of seven estrous cycles. All estrous cycles occurred from March through June. For spontaneous ovulations (n=4), the inter-estrous interval was 34d (range 33-35d), with a follicular phase length (FPL) of 25±8d (mean±SD). For all ovulatory estrous cycles (with and without a breeding male), urinary estrogen conjugates (EC, 15.3±7.9ng/mg Cr) and ovulatory luteinizing hormone (ovLH, 17.1±6.6ng/mg Cr) concentrations both peaked on Day 0, and EC concentrations returned to baseline 8±7d later. For non-conceptive cycles, urinary progestagen (Pg) concentrations increased on Day 0 (3.5±1.7ng/mg Cr), peaked on Day+19 (19.7±17.1ng/mg Cr), and were elevated above baseline for 27±4d. Preovulatory follicular diameter and circumference on Day -2±2 (range: Day -4 to -1) from peak EC were 2.5±0.7 and 7.8±1.3cm, respectively. The FPL in non-ovulatory estrous cycles (n=11) lasted 24±10d and EC concentrations gradually declined to baseline over a 21±10d interval following the EC peak (27.8±28.8ng/mg Cr). Non-ovulatory estrous cycles were characterized by the absence of an ovLH surge and no concomitant increase in Pg concentrations above baseline excretion; the mean follicular diameter at or near peak EC was 3.1±0.8cm on Day 2 ±3d from peak EC (range: -1 to +5days from peak EC). Overall, these data confirm that captive beluga exhibit reproductive seasonality and demonstrate that the species is a facultative-induced ovulator.

Evaluation of motility, membrane status and DNA integrity of frozen–thawed bottlenose dolphin (Tursiops truncatus) spermatozoa after sex-sorting and recryopreservation

Artificial insemination (AI) with sex-sorted frozen–thawed spermatozoa has led to enhanced management of ex situ bottlenose dolphin populations. Extended distance of animals from the sorting facility can be overcome by the use of frozen–thawed, sorted and recryopreserved spermatozoa. Although one bottlenose dolphin calf had been born using sexed frozen–thawed spermatozoa derived from frozen semen, a critical evaluation of in vitro sperm quality is needed to justify the routine use of such samples in AI programs. Sperm motility parameters and plasma membrane integrity were influenced by stage of the sex-sorting process, sperm type (non-sorted and sorted) and freezing method (straw and directional) (P<0.05). After recryopreservation, sorted spermatozoa frozen with the directional freezing method maintained higher (P<0.05) motility parameters over a 24-h incubation period compared to spermatozoa frozen using straws. Quality of sperm DNA of non-sorted spermatozoa, as assessed by the sperm chromatin structure assay (SCSA), was high and remained unchanged throughout freeze–thawing and incubation processes. Though a possible interaction between Hoechst 33342 and the SCSA-derived acridine orange was observed in stained and sorted samples, the proportion of sex-sorted, recryopreserved spermatozoa exhibiting denatured DNA was low (6.6±4.1%) at 6 h after the second thawing step and remained unchanged (P>0.05) at 24 h. The viability of sorted spermatozoa was higher (P<0.05) than that of non-sorted spermatozoa across all time points after recryopreservation. Collective results indicate that bottlenose dolphin spermatozoa undergoing cryopreservation, sorting and recryopreservation are of adequate quality for use in AI.

Deep intra-uterine artificial inseminations using cryopreserved spermatozoa in beluga (Delphinapterus leucas)

Artificial insemination (AI) with liquid-stored spermatozoa and sperm cryopreservation using directional freezing (DF) have been successful in the beluga. This study built on this foundation to develop a deep intra-uterine AI technique with frozen-thawed semen in beluga. Forty-two ejaculates from one male were cryopreserved using DF technology and subsequently used for 10 insemination attempts with seven females. Percentage pre- and post-thaw progressive motility and viability were (mean +/- SD) 73.0 +/- 12.2, 38.4 +/- 8.8, 88.0 +/- 0.1, and 59.3 +/- 15.7%, respectively. A series of GnRH injections (3 x 250 microg, IV, 1.5 to 2 h apart) were used to induce ovulation, once a growing follicle >2.5 cm in diameter was visualized via trans-abdominal ultrasonography. Artificial insemination was performed at 30.1 +/- 3.8 h post-initial GnRH injection with semen deposited in the uterine horn, 92.6 +/- 16.2 cm beyond the genital opening using a flexible endoscope. The external cervical os (cEOS) was located beyond a series of 5 to 10 vaginal rings, 44.8 +/- 9.3 cm from the external genital opening. The internal bifurcation of the uterus was 27 +/- 6.8 cm beyond the cEOS. Ovulation occurred at 8.5 +/- 7.6 h post-AI. Two of 10 inseminations (20%) resulted in pregnancy. The first pregnancy resulted in twins; both calves were born 442 d after AI, with one surviving. The second pregnancy is ongoing. These findings represent the first successful application of AI using frozen-thawed semen in beluga, and are important examples of how assisted reproductive technologies can provide tools for the global management of threatened species.

Sperm DNA fragmentation and morphological degeneration in chilled elephant (Elephas maximus and Loxodonta Africana) semen collected by transrectal massage

Ejaculates from nine Asian and two African elephants were analysed to gain a further understanding of mechanisms underlying variable semen quality after transrectal massage. Semen analysis was performed after collection (0 h; subjective motility parameters only) and after 24 h of chilled storage at 10 °C (24 h; all ejaculate and sperm characteristics). Ejaculates with ≤50% total motility (TM) at 24 h, which represented >90% of collection attempts, contained a sperm population with a high degree of DNA damage (64.2 ± 19.2% fragmented DNA) and an elevated incidence of detached heads (43.3 ± 22.5%). In contrast, good quality ejaculates designated as those with >50% TM at 24 h displayed higher (p < 0.05) values of sperm kinetic parameters, DNA integrity and normal morphology. Fertility potential was high for good quality ejaculates from two males (one Asian and one African bull) based on in vitro characteristics after chilled storage for up to 48 h post-collection. Urine contamination of semen, as assessed quantitatively by creatinine concentration, was confirmed as a significant factor in reduced elephant ejaculate quality. However, the identification of considerable DNA damage and morphological degeneration in the majority of ejaculates after only 24 h of chilled storage indicates that sperm ageing could be a primary contributor to inconsistent semen quality in the elephant.

Reproductive physiology of the female Magellanic penguin (Spheniscus magellanicus): Insights from the study of a zoological colony

Eight captive female Magellanic penguins (Spheniscus magellanicus) were monitored over a 10week period, commencing at 5weeks prior to egg lay (EL), to increase our understanding of the species' reproductive biology. Females in cordoned nest sites underwent cloacal artificial insemination (AI) every 4-7days with different semen donors for each insemination. The EL interval was 97.9±3.6h (range: 84-108h) and paternity analyses revealed that conceptive inseminations occurred from 11.5 to 4.5days before oviposition. A biphasic pattern of estradiol, testosterone, progesterone and the biochemical analytes triglyceride, iron, calcium and phosphorus occurred in relation to EL, with values increasing (P<0.05) to maximal concentrations during the three weeks preceding oviposition, then decreasing (P<0.05) rapidly after oviposition completion. In comparison with post-lay (baseline) values, concentrations of estradiol and testosterone relative to the first oviposition were elevated at Week-5, and those of triglyceride, a yolk formation index, as well as iron, calcium and phosphorus, became elevated at Week-4 (P<0.05). Collective data indicate an estimated total egg formation interval of 29days, with oviducal transit of the ovulated ovum occurring over the majority of the ∼4day EL interval. These findings indicate that egg formation is prolonged with folliculogenesis initiated at 5weeks or more prior to oviposition. Consequently, the period of folliculogenesis and egg formation is estimated to overlap with the final ∼3weeks that wild females spend at sea prior to returning to land for breeding.

Characteristics of high-quality Asian elephant (Elephas maximus) ejaculates and in vitro sperm quality after prolonged chilled storage and directional freezing

The in vitro quality of spermatozoa from one elephant (Elephas maximus) was examined after chilled storage and directional freezing (DF). High-quality, non-contaminated ejaculates (77.6 ± 6.0% progressive motility, 3.9 ± 1.5 µg creatinine mL–1 raw semen, 2.7 ± 0.6% detached heads) were cryopreserved after 0 (0hStor), 12 (12hStor) and 24 h (24hStor) of chilled storage. At 0 h and 6 h post-thawing, total motility, plasma membrane integrity, acrosome integrity, mitochondrial activity and normal morphology were similar (P > 0.05) across treatments. In contrast, progressive motility, rapid velocity and several kinematic parameters were lower (P < 0.05) for 24Stor compared with 0hStor at 0 h post-thaw. By 6 h post-thaw, amplitude of lateral head displacement and velocity parameters (average pathway, straight-line and curvilinear velocity) were lower (P < 0.05) for 24hStor compared with 0hStor and 12hStor. DNA integrity was high and remained unchanged (P > 0.05) across all groups and processing stages (1.6 ± 0.6% of cells contained fragmented DNA). Results indicate that DF after up to 12 h of chilled storage results in a post-thaw sperm population of acceptable quality for artificial insemination. These findings have implications for the cryopreservation of sex-sorted spermatozoa, which typically undergo more than 12 h of chilled storage prior to sorting and preservation.

Alkaline phosphatase as an indicator of true ejaculation in the rhinoceros

The objective was to determine if seminal alkaline phosphatase (ALP) can serve as an indicator of true ejaculation in the rhinoceros. Concentrations of ALP activity were determined in seminal fractions collected from African black rhinos (Diceros bicornis), an African white rhino (Ceratotherium simum), and an Indian rhino (Rhinoceros unicornis) during electroejaculation. In addition, seminal fractions collected during penile massage of a Sumatran rhino (Dicerorhinus sumatrensis) were assessed. Correlations between ALP activity and sperm concentration, fraction pH, and fraction osmolality were evaluated in the Indian rhino and black rhino. Concentrations of ALP activity in rhino ejaculate fractions ranged from < 5 to 11,780 U/L and were positively correlated (P < 0.05) with sperm concentration for both Indian rhino (r = 0.995) and black rhino (r = 0.697), but did not exhibit a strong correlation with either pH or osmolality (P > 0.05). Data were insufficient for establishing meaningful correlation coefficients in the Sumatran rhino and white rhino, but preliminary results were in accordance with findings in the Indian rhino and black rhino. We concluded that ALP was present in rhinoceros semen, likely originated from the epididymides and/or testes, and could serve as a useful tool for assessing the production of ejaculatory versus pre-ejaculatory fluid in the rhinoceros.

Thyroid hormone concentrations associated with age, sex, reproductive status and apparent reproductive failure in the Amazon river dolphin (Inia geoffrensis)

This study was conducted to characterize immunoreactive thyroid hormone concentrations in wild Amazon river dolphins, also called boto (Inia geoffrensis) by age group, sex, pregnancy and lactation status, and to determine if thyroid hormone concentration differences could be detected between pregnant females with and without successful parturition outcomes. Radioimmunoassays were used to analyse total T 3 and total T 4 in 182 serum samples collected from 172 botos living in the Mamirauá Sustainable Development Reserve, in the Brazilian Amazon from 2003 through 2015. Age significantly affected tT 3 and tT 4 concentrations in males, with values in immature males and females being significantly lower than those in adult males, whereas no age effects were noted between immature females and adult non-pregnant, non-lactating females. Significant sex differences were noted in tT 3 concentrations between immature males and females and in tT 4 concentrations between adult males and females. These resulted in significant differences in the tT 3:tT 4 ratio between males and females within the immature and adult groups. Lactating and non-pregnant adult females had significantly higher tT 3 concentrations than pregnant females, and this difference was primarily driven by a 12% drop in tT 3 concentrations during the last two-thirds of pregnancy. No differences in thyroid hormone concentrations were detected between females diagnosed as pregnant and later found to have or not have a live calf. These results are the first to define thyroid hormone reference intervals and normal physiological variations in a wild population of river dolphins.

Establishing models of corticosteroid patterns during the life history of killer whales (Orcinus orca) under human care

The use of corticosteroids and their metabolites as a physiologic measure of stress in wildlife species is increasing in both in and ex situ populations. However, factors such as season, circadian rhythm, sex and age are also known to influence corticosteroid production in wildlife. Our objective was to evaluate the influence of these variables on serum cortisol, corticosterone, aldosterone and their fecal metabolites in zoo-based killer whales (Orcinus orca). For evaluation of season, sex and age, we examined 30 animals (21 females, 9 males), and for circadian rhythm, we studied 18 animals (10 females, 8 males). Season did not influence corticosteroids (P ≥ 0.19). Circadian rhythm influenced all corticosteroids (P ≤ 0.012). Serum cortisol and corticosterone were highest in the morning and lower by mid-day and evening. Serum aldosterone was lowest during mid-day and highest in the evening. Excreted corticosteroid metabolites were higher in the morning and mid-day compared to evening (P ≤ 0.002). Serum cortisol was higher in males than females (P = 0.011). The inverse was observed for fecal corticosterone metabolites (P = 0.03). Serum corticosterone increased with age in all animals (P = 0.002), but serum cortisol increased with age in males only (P < 0.001). Finally, combining previously published data and these data reported herein, we developed models of corticosteroid patterns for zoo-based killer whales during life history events, including circadian variation, pregnancy and acute stress that may serve as a guide for evaluating stress physiology and animal welfare in this species.

The steroid metabolome of pregnancy, insights into the maintenance of pregnancy and evolution of reproductive traits

Modes of mammalian reproduction are diverse and not always conserved among related species. Progesterone is universally required to supports pregnancy but sites of synthesis and metabolic pathways vary widely. The steroid metabolome of mid-to late gestation was characterized, focusing on 5α-reduced pregnanes in species representing the Perissodactyla, Cetartiodactyla and Carnivora using mass spectrometry. Metabolomes and steroidogenic enzyme ortholog sequences were used in heirarchial analyses. Steroid metabolite profiles were similar within orders, whales within cetartiodactyls for instance, but with notable exceptions such as rhinoceros clustering with goats, and tapirs with pigs. Steroidogenic enzyme sequence clustering reflected expected evolutionary relationships but once again with exceptions. Human sequences (expected outgroups) clustered with perissodactyl CYP11A1, CYP17A1 and SRD5A1 gene orthologues, forming outgroups only for HSD17B1 and SRD5A2. Spotted hyena CYP19A1 clustered within the Perissodactyla, between rhinoceros and equid orthologues, whereas CYP17A1 clustered within the Carnivora. This variability highlights the random adoption of divergent physiological strategies as pregnancy evolved among genetically similar species.

284 IN VITRO FUNCTION OF FROZEN - THAWED BOTTLENOSE DOLPHIN (TURSIOPS TRUNCATUS) SPERM UNDERGOING SORTING AND RECRYOPRESERVATION

Artificial insemination (AI) using sex-selected sperm of bottlenose dolphins is currently used for the reproductive and social management of captive populations, but distance of males to the sorting facility represents a limitation of the procedure. Sorting and recryopreservation of previously frozen–thawed (FSF) sperm would facilitate the global application of this technology. Although a calf has been produced using FSF sperm (O’Brien et al. 2009 Theriogenology 71, 98–107), a comprehensive examination of the in vitro quality of such samples is needed. The objective was to compare the in vitro quality of nonsorted (CNTR) and sorted (FSF) dolphin sperm before and after recryopreservation using straw (STR) and directional freezing (DF) methods. At all assessment intervals, sperm were evaluated for 1) motility parameters with computer-assisted sperm analysis (CASA); 2) plasma membrane integrity (viability) and acrosome integrity using propidium iodide/fluorescein isothiocyanate-labeled peanut agglutinin (PI/FITC-PNA) staining and 3) DNA denaturation using the sperm chromatin structure assay (SCSA). Semen from 3 ejaculates × 3 males was cryopreserved by DF. After thawing, samples were divided into CNTR and FSF. The CNTR sperm were recryopreserved using STR and DF methods with assessments performed after the first thaw (PT1) and before recryopreservation (PF2). The FSF sperm were prepared for sorting using a density gradient centrifugation (DGC) method, stained with Hoechst 33342, sorted (SX MoFlo®, Dako, Fort Collins, CO, USA), then recryopreserved using STR and DF methods. The FSF sperm were assessed post-PT1, post-DGC, post-stain, post-sort, and at PF2. After the second thaw (PT2), CNTR and FSF samples were diluted (1:0.1, vol/vol) with Androhep Enduraguard™ (AE; Minitube of America, Verona, WI, USA), incubated at room temperature, and assessed at 0, 6, 12, 18, and 24 h PT2. The PT1 samples retained high proportions of their PF1 total motility (TM) and progressive motility (PM) (mean ± SD; 87.9 ± 7.3% and 92.2 ± 5.9%, respectively). The FSF sperm had improved (ANOVA; P < 0.05) motility (TM, PM, VAP, VCL, VSL) and viability at PF2 compared with PF1. The FSF sperm recryopreserved using DF had higher (P < 0.05) motility over the 24-h post-thaw incubation period compared with STR. The CNTR sperm DNA fragmentation remained unchanged throughout the process. The DNA fragmentation of FSF samples increased after staining (P < 0.05), then decreased during the PT2 incubation period, stabilising at lower values (P < 0.05) than CNTR from 6 to 24 h PT2. This unusual pattern indicates a possible interaction between Hoechst 33342 and acridine orange. After recryopreservation, the viability of FSF sperm was higher (P < 0.05) than that of CNTR sperm. Results indicate that bottlenose dolphin sperm undergoing cryopreservation, sorting, and recryopreservation are of adequate quality for use in AI.

Topographic Variations in Mobilization of Blubber in Relation to Changes in Body Mass in Short-Finned Pilot Whales (Globicephala macrorhynchus)

AbstractFat-level measurements used to indicate individual body condition and fitness are useful only when taken at a region along the body where fat responds to variations in caloric intake. Investigations to identify appropriate species-specific regions are limited, especially for cetaceans that have a specialized fat (blubber) that serves as an energy reserve and provides insulation. Over 18 mo, body mass of six pilot whales varied (range: 50-172 kg), and although caloric intake increased when water temperatures were lower, generally the best-fitting state-space model for length-adjusted mass was based on a single factor, caloric intake. After correcting for body length (range: 330-447 cm), the slope for blubber thickness and "blubber ring" thickness (average blubber thickness along a girth) in relation to body mass was positive and had a P value of <0.10 at six of 16 blubber measurement sites and one of five girth measurement sites, respectively. The slope for body girth (a reflection of changes in underlying blubber thickness) in relation to body mass was positive and had a lower P value ([Formula: see text]) at three of five girth measurement sites. Results indicate that blubber from the anterior insertion of the pectoral fins to the posterior insertion of the dorsal fin is the most metabolically active region. This region includes the midflank site, a location where blubber thickness measurements have historically been taken to monitor cetacean body condition. Conversely, blubber in the peduncle region was comparatively inert. These findings must be considered when measuring blubber thickness and body width (i.e., photogrammetry) to monitor the condition of free-ranging cetaceans.