Adrenal-testicular-pituitary relationships in the cheetah subjected to anesthesia/electroejaculation

Reptile assisted reproductive technologies: can ART help conserve 300million years of evolution by preserving extant reptile biodiversity?

Biodiversity loss is the greatest environmental problem threatening ecosystem, animal, and human health. Anthropogenic induced changes to climate, habitat, disease, species distributions, poaching, and unsustainable trade have accelerated extinction rates in all vertebrates, including reptiles. Preventing reptile extinctions will require humans to acknowledge these losses and develop ex situ and in situ plans to preserve them. Assisted reproductive technologies (ART) are management tools used to protect numerous vertebrate taxa; however, progress in developing ART for reptiles has lagged. Creating functional and sustainable reptile ART will strengthen our conservation capacity by capturing genetic material from select individuals to overcome natural or manmade boundaries. Utilising short-term gamete storage and genome resource banking, in conjunction with timed artificial insemination (AI) or ex ovo incubation, could lead to profound advances in reptile conservation, mitigating the loss of reptile biodiversity. In this article, we review ART reptile research completed since the 1970s. Topics include AI, hormonal control of reproduction, gamete collection, gamete storage, and genome resource banking. Additionally, we review the potential application of advanced reproductive methodologies, including in vitro/ex ovo fertilisation, intracytoplasmic sperm injection, cloning (somatic cell nuclear transfer), and genetic editing.

Semen collection and ejaculate characteristics of the Leopard Tortoise (Stigmochelys pardalis)

The preservation of spermatozoa is an important tool used in conservation programs to increase the genetic diversity of threatened and endangered species. Although routinely used to manage conservation programs for higher vertebrates, there have been limited attempts to establish reproductive assistance programs for tortoises. The purpose of this study was to develop a model for collecting and characterizing semen in Testudinidae. Semen was collected from 13/16 (81.2%, 95% CI: 62-100) adult male leopard tortoises (Stigmochelys pardalis) via electroejaculation under propofol anesthesia. Semen samples were collected most frequently after the second series of electrostimulations (6/13, 46.1%), with fewer animals producing semen after the first (5/13, 38.5%) or third (2/13, 15.4%) electrostimulations. The average volume of a semen sample in the tortoises was 0.26 ml (standard deviation: 0.16, minimum-maximum: 0.1-0.6), the average spermatozoal concentration was 101.62 × 10⁶/ml, and the average motility at time of collection was 57.3%. A rapid decrease in motility was observed in refrigerated samples over 24 h resulting in a median motility of 0% at 24 h post-collection. The results of this study suggest that electroejaculation is a safe and efficient method for collecting semen from leopard tortoises.

CARDIORESPIRATORY EFFECTS OF DEXMEDETOMIDINE-BUTORPHANOL-MIDAZOLAM (DBM): A FULLY REVERSIBLE ANESTHETIC PROTOCOL IN CAPTIVE AND SEMI-FREE-RANGING CHEETAHS (ACINONYX JUBATUS)

Multiple anesthesia protocols have been used in the cheetah ( Acinonyx jubatus ). Twenty healthy, captive cheetahs were immobilized with dexmedetomidine (15.8 ± 1.9 μg/kg), butorphanol (0.22 ± 0.03 mg/kg), and midazolam (0.18 ± 0.03 mg/kg) by intramuscular injection. Induction, recumbency, and recovery times were recorded, and physiologic parameters were monitored. Anesthesia was antagonized with atipamezole (0.125 ± 0.02 mg/kg) and naltrexone (0.1 ± 0.014 mg/kg) intramuscularly. All cheetahs were safely anesthetized with this protocol. Cheetahs were laterally recumbent by 8 ± 3.5 min. Cardiorespiratory values were stable throughout the length of anesthesia. Moderate hypertension, with systolic blood pressure ranging from 178 ± 19.8 mm Hg, was initially observed but decreased over time. There was a statistical decreasing trend in temperature; SpO2; and systolic, mean, and diastolic blood pressure, but not in heart rate and end-tidal CO₂. Recoveries were rapid, with cheetahs standing by 11.3 ± 5.7 min postreversal administration. This is the first report of a dexmedetomidine-butorphanol-midazolam anesthetic combination in cheetahs. Overall, this anesthetic protocol proved to be safe and effective.

Intrinsic factors, adrenal gland morphology, and disease burden in captive cheetahs (Acinonyx jubatus) in South Africa

Adrenal gland weight (AW) and corticomedullary ratio (ACMR) are used as indicators of stress in animals. Captive cheetahs (Acinonyx jubatus) have higher ACMRs than free-ranging ones and stress has been linked to gastritis, amyloidosis, glomerulosclerosis, and myocardial fibrosis. We reviewed age, sex, body weight (BW), kidney weight (KW), and left AW and ACMR with necropsy findings in 51 South African captive cheetahs. Eleven common histopathologic lesions were counted for each animal as measure of its disease burden. Adrenal corticomedullary hyperplasia was significantly correlated with left AW and ACMR. Males had significantly higher AWs than females; other parameters showed no difference between the sexes. Disease burden, gastritis, and myocardial fibrosis were moderately correlated with adrenal morphology supporting prior evidence that gastritis and myocardial fibrosis are linked to stress. Glomerulosclerosis was not correlated with adrenal morphology and neither kidney nor liver amyloidosis contributed significantly to variation in AW or ACMR on multivariate analyses. Interstitial nephritis showed much stronger correlations with kidney and liver amyloidosis than gastritis. All three adrenal parameters were correlated with age; age was the only significant variable affecting ACMR on the multivariate analyses; and disease burden as well as systemic amyloidosis and kidney disease (except for fibrosis) showed moderate correlations with age. Age may, therefore, be important in the pathogenesis of disease in captive cheetahs, particularly of amyloidosis and kidney disease. None of the intrinsic measurements or adrenal parameters were sufficiently closely linked to disease to be used as ante-mortem proxies for disease burden or specific diseases. Zoo Biol. 36:40-49, 2017. © 2016 Wiley Periodicals, Inc.

A review of the pharmacology and clinical application of alfaxalone in cats

Alfaxalone-2-hydroxpropyl-β-cyclodextrin (alfaxalone-HPCD) was first marketed for veterinary use in Australia in 2001 and has since progressively became available throughout the world, including the USA, where in 2012 Food and Drug Administration (FDA) registration was granted. Despite the growing body of published works and increasing global availability of alfaxalone-HPCD, the accumulating evidence for its use in cats has not been thoroughly reviewed. The purpose of this review is: (1) to detail the pharmacokinetic properties of alfaxalone-HPCD in cats; (2) to assess the pharmacodynamic properties of alfaxalone-HPCD, including its cardiovascular, respiratory, central nervous system, neuromuscular, hepatic, renal, haematological, blood-biochemical, analgesic and endocrine effects; and (3) to consider the clinical application of alfaxalone-HPCD for sedation, induction and maintenance of anaesthesia in cats. Based on the published literature, alfaxalone-HPCD provides a good alternative to the existing intravenous anaesthetic options for healthy cats.

Development and evaluation of electroejaculation techniques in the Tasmanian devil (Sarcophilus harrisii)

Electroejaculation (EEJ) has been used successfully to collect samples suitable for genome resource banking from a variety of endangered wildlife species. Ejaculates can also be used to evaluate the reproductive potential of individuals and provide information on seminal characteristics to aid in the development of sperm cryopreservation techniques. Electroejaculation techniques used for marsupial and eutherian species were tested on Tasmanian devils (n = 35). Spermic ejaculates were collected in 54% (19/35) of EEJ attempts. Spermic ejaculates were low in volume (3.9 ± 6.5 × 102 µL, range 10–3000 µL) and contained low numbers of spermatozoa (3.3 ± 7.8 × 103 spermatozoa per ejaculate, range 6–33 000). The osmolality and pH of presumptive urine-free ejaculates were 389 ± 130 mOsm kg–1 (range 102–566) and 7.0 ± 0.9 (range 6.0–8.0), respectively. Prostatic bodies were observed in 79% (26/33) of ejaculates. Episodic fluctuations in serum testosterone concentrations were not detected during the EEJ procedure (P > 0.05). Increases observed in serum cortisol concentrations during EEJ were less (P < 0.05) than those observed after an adrenalcorticotropic hormone challenge and diurnal variation suggested that cortisol concentrations are greater during the day than at night (P < 0.05). This information can be used to provide range values for the future examination of basic endocrine responses and the adrenal–pituitary axis of this species. This study also demonstrated that spermatozoa-rich devil electroejaculates are more difficult to obtain and poorer in quality than those of other marsupials.

Changes in the fecal concentrations of cortisol and androgen metabolites in captive male jaguars (Panthera onca) in response to stress

In the present study we determined the efficacy of the measurement of fecal cortisol and androgen metabolite concentrations to monitor adrenal and testicular activity in the jaguar (Panthera onca). Three captive male jaguars were chemically restrained and electroejaculated once or twice within a period of two months. Fecal samples were collected daily for 5 days before and 5 days after the procedure and stored at -20 degrees C until extraction. Variations in the concentrations of cortisol and androgen metabolites before and after the procedure were determined by solid phase cortisol and testosterone radioimmunoassay and feces dry weight was determined by drying at 37 degrees C for 24 h under vacuum. On four occasions, fecal cortisol metabolite levels were elevated above baseline (307.8 +/- 17.5 ng/g dry feces) in the first fecal sample collected after the procedure (100 to 350% above baseline). On one occasion, we did not detect any variation. Mean (+/- SEM) fecal androgen concentration did not change after chemical restraint and electroejaculation (before: 131.1 +/- 26.7, after: 213.7 +/- 43.6 ng/g dry feces). These data show that determination of fecal cortisol and androgen metabolites can be very useful for a noninvasive assessment of animal well-being and as a complement to behavioral, physiological, and pathological studies. It can also be useful for the study of the relationship between adrenal activity and reproductive performance in the jaguar.

Noninvasive monitoring of adrenocortical activity in carnivores by fecal glucocorticoid analyses

Measurement of glucocorticoid metabolites in feces has become an accepted method for the noninvasive evaluation of adrenocortical activity. The objective of this study was to determine if a simple cortisol enzyme immunoassay (EIA) was suitable for monitoring adrenocortical activity in a variety of carnivore species. Performance of the cortisol EIA was gauged by comparison to a corticosterone radioimmunoassay (RIA) that has been used for measuring glucocorticoid metabolites in feces of numerous species. Tests for parallelism and extraction efficiency were used to compare the cortisol EIA and corticosterone RIA across eight species of carnivores (Himalayan black bear, sloth bear, domestic cat, cheetah, clouded leopard, black-footed ferret, slender-tailed meerkat, and red wolf). The biological relevance of immunoreactive glucocorticoid metabolites in feces was established for at least one species of each Carnivora family studied with an adrenocorticotropic hormone (ACTH) challenge. High performance liquid chromatography (HPLC) analysis of fecal extracts for each species revealed (1) the presence of multiple immunoreactive glucocorticoid metabolites in feces, but (2) the two immunoassays measured different metabolites, and (3) there were differences across species in the number and polarities of metabolites identified between assay systems. ACTH challenge studies revealed increases in fecal metabolite concentrations measured by the cortisol EIA and corticosterone RIA of approximately 228-1145% and approximately 231-4150% above pre-treatment baseline, respectively, within 1-2 days of injection. Concentrations of fecal glucocorticoid metabolites measured by the cortisol EIA and corticosterone RIA during longitudinal evaluation (i.e., >50 days) of several species were significantly correlated (P<0.0025, correlation coefficient range 0.383-0.975). Adrenocortical responses to physical and psychological stressors during longitudinal evaluations varied with the type of stimulus, between episodes of the same stimulus, and among species. Significant elevations of glucocorticoid metabolites were observed following some potentially stressful situations [anesthesia (2 of 3 subjects), restraint and saline injection (2 of 2 subjects), restraint and blood sampling (2 of 6 episodes), medical treatment (1 of 1 subject)], but not in all cases [e.g., gonadotropin injection (n=4), physical restraint only (n=1), mate introduction/breeding (n=1), social tension (n=1), construction (n=2) or relocation (n=1)]. Results reinforced the importance of an adequate baseline period of fecal sampling and frequent collections to assess adrenocortical status. The corticosterone RIA detected greater adrenocortical responses to exogenous ACTH and stressful exogenous stimuli in the Himalayan black bear, domestic cat (female), cheetah, clouded leopard, slender-tailed meerkat, and red wolf, whereas the cortisol EIA proved superior to resolving adrenocortical responses in the black-footed ferret and domestic cat (male). Overall results suggest the cortisol EIA tested in this study offers a practical method for laboratories restricted in the usage of radioisotopes (e.g., zoological institutions and field facilities) to integrate noninvasive monitoring of adrenocortical activity into studies of carnivore behavior and physiology.

Conservation of feline semen. Part II: Cold-induced damages on spermatozoal fertilizing ability

During the conservation of feline semen, the freeze-thaw procedure in particular is responsible for inducing severe spermatozoal damage, which diminishes fertilizing ability. Therefore, cold-induced damage represents a limiting factor for the conservation of semen, particularly semen from felids, which are often affected by teratospermia. In this article, feline sperm characteristics are reported, with special reference to motility and morphology, which are more likely to be affected by conservation protocols; and moreover, the causes of cold-induced damages are described. Attention has been focused on methods to evaluate functional integrity of spermatozoa, and those applied to cat semen are reviewed. Among these, a rather recently developed technique involves fluorescent staining methods, and in particular chlortetracycline. The chlortetracycline assay applied to cryopreserved cat epididymal sperm shows that it is suitable to evaluate the functional status of cat sperm.

Characterization of semen collected from beagles and captive Japanese black bears (Ursus thibetanus japonicus)

This study characterized semen collected from the Japanese black bear, Ursus thibetanus aponicus, to provide information on semen cryopreservation for artificial breeding. Preliminary studies using a beagle dog as the model species showed that sperm concentration and total sperm count were lower in semen collected by electroejaculation than in semen collected by digital manipulation, but that sperm motility, viability and morphology were similar. Characterization of semen obtained from Japanese black bears by electroejaculation under general anesthesia revealed that semen volume and total number of spermatozoa collected were lower; but that sperm concentration, motility, viability and morphology were equivalent to those reported in other ursids. When semen was collected via a catheter inserted into the urethra during the stimulation for ejaculation, the sperm concentration, total sperm count and motility were relatively higher than when semen was collected directly in a test tube. Specific normal semen characteristics (mean +/- SEM) were pH, 7.6 +/- 0.0; volume, 0.212 +/- 0.038 mL; sperm concentration, 361 +/- 100 x 10(6)/mL; total sperm count, 84.0 +/- 32.2 x 106; +++ motility, 30 +/- 5%; motility, 77 +/- 3%; viability 77 +/- 2%; and abnormal morphology, 11+/- 2%. These results suggest that semen can be collected from Japanese black bears by electroejaculation.

Conservation strategies for the long-term survival of the Cheetah Acinonyx jubatus by the Cheetah Conservation Fund, Windhoek

The Cheetah Acinonyx jubatus is declining throughout its range because of loss of habitat, a declining prey base and competition with livestock interests. Throughout Africa there are less than 15 000 animals remaining. The largest wild population of Cheetahs is in Namibia, although in the last 12 years numbers have been reduced by half to c. 2500 animals. Significant declines have continued as farmers capture and remove Cheetahs as ‘pests’. Established in 1990, the Cheetah Conservation Fund aims to secure habitats for the long‐term survival of the species and its ecosystems. The primary focus of the Fund is working outside of the protected reserves with the local livestock farming communities to develop ways to reduce conflict between humans and Cheetahs. The Fund also conducts independent and collaborative research, disseminates information and recommends management techniques to farmers.

Seasonality of serum testosterone levels and sperm density in Tursiops truncatus

We trained a mature male bottlenose dolphin, Tursiops truncatus, to provide semen samples on command. After completion of the 10-week training period, semen was collected twice weekly and blood was sampled twice monthly for a period of 28 months. Total sperm per ejaculate ranged from near 0 to 54.6 x 10(9) (n = 1332). Sperm densities from each session ranged from no sperm to 1,587 x 10(6)/ml (n = 241). Testosterone levels ranged from 1.1 to 54.4 ng/ml (n = 79). Seasonal variations were observed in total sperm per ejaculate, sperm density per ml of ejaculate, and in serum testosterone levels. Peak sperm densities were detected during September and October of three consecutive breeding seasons. Serum testosterone levels peaked in June, decreased during July and August, and were lowest in September and October, the period of greatest sperm density. Peak sperm production and density were coincident with the peak period of breeding activity but at a time when serum testosterone levels were lowest.

The effects of different anesthetics on blood steroid concentrations in domestic tom-cats

Testosterone and androstenedione were measured in the plasma of mature tom-cats before, during and after anesthesia with thiopentone, ketamine, xylazine and alphaxolone/alphadolone. Samples were collected via an indwelling jugular catheter at 30 min intervals before anesthesia (5 samples) and during the recovery phase (8 samples), and at intervals of 15 min during anesthesia (7 samples). Thiopentone and ketamine anesthesia significantly depressed testosterone and androstenedione concentrations during and after anesthesia. Xylazine significantly increased testosterone concentrations during anesthesia but they returned to pre-anesthetic concentrations during recovery. Androstenedione concentrations were significantly depressed during the recovery phase from xylazine anesthesia. Alphaxolone/alphadolone anesthesia had no significant effect of testosterone concentrations but significantly increased and androstenedione concentrations during anesthesia and recovery. Testosterone and androstenedione concentrations in cats were significantly altered by these 4 commonly used anesthetics and this must be taken into account if hormone concentrations are measured while cats are anesthetised.

Reproductive and genetic consequences of founding isolated lion populations

Species survival is critically dependent on reproductive performance, a complex physiological process under rigorous genetic control. Classical studies of inbreeding in laboratory animals and livestock have shown that increased homozygosity can adversely affect spermatogenesis, ovulation and perinatal mortality and morbidity^1–3. For wild populations, the consequences of inbreeding depression have not been examined intensively, although our recent studies of the African cheetah revealed a striking degree of genetic uniformity^4,5 combined with an extremely high incidence of structurally abnormal spermatozoa (>70%) in captive⁶ as well as free-ranging⁷ males. In this study, we report definitive evidence that the reproductive function of free-ranging mammals can be impaired as a result of demographic contraction followed by inbreeding. In an examination of three distinct lion populations (two from the Serengeti ecosystem in East Africa and a third descended from lions in the Gir Forest of western India), a direct correlation was observed between genetic variability and two physiological traits, incidence of abnormal sperm and circulating testosterone, a critical hormone for spermatogenesis.

East African cheetahs: evidence for two population bottlenecks?

A combined population genetic and reproductive analysis was undertaken to compare free-ranging cheetahs from east Africa (Acinonyx jubatus raineyi) with the genetically impoverished and reproductively impaired south African subspecies (Acinonyx jubatus jubatus). Like that of their south African counterparts, the quality of semen specimens from east African cheetahs was poor, with a low concentration of spermatozoa (25.3 X 10(6) per ejaculate) and a high incidence of morphological abnormalities (79%). From an electrophoretic survey of the products of 49 genetic loci in A. jubatus raineyi, two allozyme polymorphisms were detected; one of these, for a nonspecific esterase, shows an allele that is rare (less than 1% incidence) in south African specimens. Estimates of polymorphism (2-4%) and average heterozygosity (0.0004-0.014) affirm the cheetah as the least genetically variable felid species. The genetic distance between south and east African cheetahs was low (0.004), suggesting that the development of genetic uniformity preceded the recent geographic isolation of the subspecies. We propose that at least two population bottlenecks followed by inbreeding produced the modern cheetah species. The first and most extreme was ancient, possibly late Pleistocene (circa 10,000 years ago); the second was more recent (within the last century) and led to the south African populations.