Abstract
The remaining wild population of Amur leopards (Panthera pardus orientalis) is estimated to be about 40 individuals. An additional 208 individuals are present within the captive Europaisches Erhaltungszucht-Programm (EEP) and Species Survival Plans (SSP).5 Captive breeding programs have therefore become increasingly important for the conservation of this species. In addition, the development of reliable methods for reproductive assessment is needed to optimize breeding management. Although ultrasonography and laparoscopy are widely used techniques for reproductive assessment, more recently transrectal ultrasonagraphy has also shown great promise in non-domestic felids.2,4 On behalf of the EEP an international team representing six European institutions performed an interdisciplinary project on captive Amur leopards, consisting of general health screening, interchange of husbandry and management ideas, collection of tissue samples for genetic and taxonomic work, and the assessment of reproductive soundness.1 In Europe a total of 102 Amur leopards (53 males, 49 females) are held in captivity from which only 11 animals are classified as pure-bred. In this paper, we present the data on reproductive health assessments of the genetically most valuable individuals.
Four females (7–14 years old) were evaluated by transrectal ultrasonography. One female was examined twice, with a 0.5-year interval. Blood samples were collected for steroid hormone analysis. Additionally, fecal samples of three animals were available for noninvasive determination of estrogen and progesterone profiles over a time period of 3 months. One female showed a healthy but inactive genital tract which was confirmed by the hormonal data, too. In the remaining females (n=3) pathologic findings in their urogenital tracts ranged from vaginitis and cystitis to myometrial cysts, focal fibrosis in the myometrium, single or multiple myomas, luteal and follicular cysts. Although the ovarian disorders could be confirmed by the hormonal data, uterine pathology could not be diagnosed by the same methods. Fecal analysis of progesterone and estradiol of females (n=3) housed without a male indicated the capability of spontaneous ovulation in Amur leopards, which is in contrast to many other felid species. The detected cycle length was 14–17 days.
Nine male Amur leopards (seven purebred, two hybrids) were investigated by transcutaneous (testes) and transrectal (accessory sex glands) ultrasonography. Six of them were examined twice with a 0.5-year interval. In addition, semen collection was performed by rectal electro stimulation in each individual. The semen was assessed for motility and morphology by light and scanning electron microscopy (SEM).
The transrectal ultrasound indicated normal development of urogenital tract in eight males. In one purebred male an incomplete descensus of one testis was diagnosed. This 2-year-old male had an aspermatic ejaculate. In the remaining purebred males (n=6) it was possible to collected semen of variable quantity and quality (volume: 250–1,500 µl; total sperm number: 8–300x106 motility: 5–70%). The semen samples of both hybrid males were characterized by significantly higher sperm concentration (>2000x109 sperm/ml) and sperm motility (>80%). Morphology assessment indicated a high percentage of defect sperm cells in the purebreds. The hybrids showed abnormal shaped acrosomes only detectable by SEM. In comparison of ejaculates obtained to different times of the year it was hypothesized that a seasonal spermatogenesis exists in the Amur leopard.
In conclusion the presented data on the reproductive status provided basic information about Amur leopards and will be of great benefit of both genome banking and future assisted breeding programs. The application of ultrasonography offered additional information to endocrine monitoring and is a reliable tool for nonsurgical assessment of reproductive soundness. This species most threatened to extinction in the wild is also characterized by a very limited number of reproductively healthy purebred individuals in captivity and has only a chance to survive if assisted reproduction will be applied.
Acknowledgments
This study was supported by a grant from the EEP. Special thanks to Sarah Christie and Tanya Arzhanova, EEP coordinators. We also like to thank Prof. Klaus Eulenberger (head veterinarian of Leipzig Zoo, Germany), Dr. Bernd Seidel (veterinarian of Berlin Tierpark, Germany) and Pavel Brandl (curator, Prague Zoo, Czech Republic) for cooperation as well as Dagmar Viertel, Christiane Franz and Marlies Rohleder (all IZW, Berlin, Germany) for technical assistance.
Literature Cited
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