The jaguar (Panthera onca) is the largest wild cat native to the Americas and a focal species for in situ conservation efforts. Its name is derived from the South American Tupi-Guarani word jaguaretê, which means “he who kills with one leap,” highlighting the jaguar’s phenomenally strong bite and preference to hunt by stalk and ambush rather than engaging in a lengthy chase.
Due to poaching and habitat loss and fragmentation, jaguars have declined substantially throughout their natural range. The species has been classified as ‘near threatened’ with a declining population trend in Latin America, and as ‘vulnerable’ in Brazil. The most robust wild populations are found in the Amazon and the Pantanal. However, even jaguars in these areas are subject to restricted gene flow, increasing their risk of inbreeding, reduced genetic variation, and extinction.
Assisted reproductive technologies, such as semen banking and artificial insemination, represent one way to link fragmented jaguar populations and maintain genetic diversity. Semen cryopreservation permits long-term storage of genetic resources within liquid nitrogen tanks, allows transport of frozen semen as an alternative to translocating live animals, and—when paired with artificial insemination—potentially facilitates gene exchange between different isolated populations.
Recently, Drs. Lindsey Vansandt and Bill Swanson from the Cincinnati Zoo’s Center for Conservation and Research of Endangered Wildlife (CREW) traveled to Brazil to work with colleagues from the Associação Mata Ciliar and the Federal University of Mato Grosso to help save this iconic cat through the development of assisted reproductive technologies. This was actually their third trip to Brazil for the project (see previous blogs http://blog.cincinnatizoo.org/2016/02/09/bom-dia-from-brasil/ and http://blog.cincinnatizoo.org/2016/02/16/crew-scientists-in-brazil-wild-times-with-pumas-snakes/ to read more about their other adventures).
The first part of the project is focused on improving and simplifying semen banking. More specifically, the team is (1) assessing the feasibility of a new method of semen collection (urethral catheterization) and sperm cryopreservation (vitrification) with captive jaguars (both of the aforementioned techniques represent field-friendly alternatives to methods currently in use), and (2) comparing a soy lecithin-based cryomedium to the standard egg yolk-based cryomedium for sperm cryopreservation (the use of egg yolk presents several problems such as variability in composition and microbial contamination). Their most recent trip was very successful in that semen was banked from all four of the males that were collected. Thanks to the efforts of previous trips, each male has now been banked at least twice. Lindsey is currently at the Universidade de São Paulo performing the final steps of the research: assessing the quality of the frozen sperm after it has been thawed.
The second leg of the project is aimed at optimizing artificial insemination in the jaguar. One of the major challenges of artificial insemination in any felid species is ensuring the procedure is performed during the appropriate stage of the female’s estrous cycle. One strategy to more precisely time ovulation induction is to administer a progestin (a class of synthetic progesterones that can temporarily suppress ovarian activity) beforehand. As a first step in this process, fecal hormone analysis was used to non-invasively monitor the jaguar females’ responses to two different doses of oral progestin. Using that information, the scientists were able to more finely tune the progestin dose in preparation for the four artificial inseminations performed on this trip. The good news is that all four females did respond (i.e., the ovaries displayed follicles and/or ovulations) and were inseminated with fresh semen collected from three of the four males mentioned above. Future studies will be performed to assess the fecal hormone response of the females. As for the penultimate determinate of success (which is to say jaguar cubs) we will have to cross our fingers and wait!