• 117 Cryopreservation of snake semen: Are we frozen in time?

      Zacariotti, R.; Guimarães, M.; Jensen, Thomas; Durrant, Barbara S. (2011)
      The increasing number of endangered snake species, isolation of small fragmented populations with associated inbreeding and mating or conception problems in captivity underscore the need to develop assisted reproductive techniques such as semen cryopreservation and artificial insemination to enhance conservation efforts. However, no efficient protocols for semen evaluation, cooling, or freezing are described in the 4 known publications on snake semen cryopreservation. In this initial study, semen was collected noninvasively from 4 live adult red diamond rattlesnakes (Crotalus ruber) by ventral massage....
    • Characterization of cultured adult Corturnix japonica testicular germ stem cells using seven stem cell markers.

      Jensen, Thomas; Poling, Matthew; Charter, Suellen; Durrant, Barbara S.; (2010)
      ...The large avian oocyte and the inability to consistently superovulate birds make techniques such as cloning and oocyte cryopreservation unlikely tools for avian conservation. Instead, the use of domestic birds as hosts to produce sperm of exotic species for use in artificial insemination may be a practical approach to conserve avian germplasm....
    • Chelonian perivitelline membrane-bound sperm detection: A new breeding management tool

      Croyle, Kaitlin E.; Gibbons, Paul; Light, Christine; Goode, Eric; Durrant, Barbara S.; Jensen, Thomas (2016)
      Perivitelline membrane (PVM)-bound sperm detection has recently been incorporated into avian breeding programs to assess egg fertility, confirm successful copulation, and to evaluate male reproductive status and pair compatibility. Due to the similarities between avian and chelonian egg structure and development, and because fertility determination in chelonian eggs lacking embryonic growth is equally challenging, PVM-bound sperm detection may also be a promising tool for the reproductive management of turtles and tortoises....
    • Detection of oocyte perivitelline membrane-bound sperm: A tool for avian collection management

      Croyle, Kaitlin E.; Durrant, Barbara S.; Jensen, Thomas (2015)
      The success and sustainability of an avian breeding programme depend on managing productive and unproductive pairs. Given that each breeding season can be of immeasurable importance, it is critical to resolve pair fertility issues quickly. Such problems are traditionally diagnosed through behavioural observations, egg lay history and hatch rates, with a decision to re-pair generally taking one or more breeding seasons. In pairs producing incubated eggs that show little or no signs of embryonic development, determining fertility is difficult. Incorporating a technique to assess sperm presence on the oocyte could, in conjunction with behaviour and other data, facilitate a more timely re-pair decision. Detection of perivitelline membrane-bound (PVMbound) sperm verifies successful copulation, sperm production and sperm functionality. Alternatively, a lack of detectable sperm, at least in freshly laid eggs, suggests no mating, lack of sperm production/function or sperm–oviduct incompatibility. This study demonstrated PVM-bound sperm detection by Hoechst staining in fresh to 24-day-incubated exotic eggs from 39 species representing 13 orders. However, a rapid and significant time-dependent loss of detectable PVM-bound sperm was observed following incubation of chicken eggs. The PCR detection of sperm in seven species, including two bacterially infected eggs, demonstrated that this method was not as reliable as visual detection using Hoechst staining. The absence of amplicons in visually positive PVMs was presumably due to large PVM size and low sperm count, resulting in DNA concentrations too low for standard PCR detection. In summary, this study demonstrated the feasibility and limitations of using PVM-bound sperm detection as a management tool for exotic avian species. We verified that sperm presence or absence on fluorescence microscopy can aid in the differentiation of fertile from infertile eggs to assist breeding managers in making prompt decisions for pair rearrangements. This protocol is currently used to manage several breeding pairs in San Diego Zoo global avian conservation programmes.
    • Remote touch prey-detection by Madagascar crested ibises Lophotibis cristata urschi

      Cunningham, Susan J.; Castro, Isabel; Jensen, Thomas; Potter, Murray A.; (2010)
      Birds that forage by probing must often rely on sensory systems other than vision to detect their buried prey. Such senses may include hearing (e.g. Australian magpies (Atramidae), American robins (Turdidae)) or chemical senses/olfaction (e.g. kiwi (Apterygidae) and some shorebirds (Scolopacidae)). Probe foraging kiwi and shorebirds are also able to use vibrotactile cues to locate prey buried in the substrate at some distance from their bill‐tips (‘remote touch’). These birds possess an organ consisting of a honey‐comb of sensory pits in bone of the bill‐tips, packed with mechanoreceptive nerve ending (Herbst corpuscles). Such a bill‐tip organ has recently also been described in ibises (Threskiornithinae), but its function not elucidated. We designed a foraging experiment presenting mealworm prey to three captive Madagascar crested ibises Lophotibis cristata urschi under a variety of trial conditions to discover whether they were using remote touch, mediated by their bill‐tip organ; chemosense/olfaction; or hearing to locate buried prey. The ibises were reliant on remote touch for prey detection – the first time this sensory system has been demonstrated for this group of birds. They did not appear to use hearing or chemical senses/olfaction to aid in prey detection.
    • Serum prolactin and testosterone levels in captive and wild brown kiwi (Apteryx mantelli) during the prebreeding, breeding, and incubation periods

      Jensen, Thomas; Jamieson, Sarah E.; Castro, Isabel; Gartrell, Brett; Cockrem, John F.; Durrant, Barbara S. (2019)
      In brown kiwi (Apteryx mantelli), the male is the primary incubator, a trait that is relatively rare among birds. The maintenance of avian incubation behavior is controlled by the protein hormone prolactin (PRL)....
    • Sexing of mid-incubation avian embryos as a management tool for zoological breeding programs

      Jensen, Thomas; Mace, Michael E.; Durrant, Barbara S. (2012)
      …The ability to selectively incubate and hatch eggs of a desired sex represents a significant improvement in the long-term management of avian species. This study describes a successful method for in ovo sexing of embryos from stage 30 through 42 of incubation (Hamburger and Hamilton [1951] J Morphol 88:49–92).…
    • Transfer and detection of freshly isolated or cultured chicken (Gallus gallus) and exotic species' embryonic gonadal germ stem cells in host embryos

      Imus, Nastassja; Roe, Mandi; Charter, Suellen J.; Durrant, Barbara S.; Jensen, Thomas (2014)
      The management of captive avian breeding programs increasingly utilizes various artificial reproductive technologies, including in ovo sexing of embryos to adjust population sex ratios….. This project evaluated the possibility of using xenotransfer of embryonic gonadal germline stem cells (GGCs) for future reintroduction of their germplasm into the gene pool…..
    • Xenogeneic transfer of adult quail (Coturnix coturnix) spermatogonial stem cells to embryonic chicken (Gallus gallus) hosts: a model for avian conservation

      Roe, Mandi; McDonald, Nastassja; Durrant, Barbara S.; Jensen, Thomas (2013)
      ...This is the first study to suggest that it is feasible to rescue adult germ stem cells of deceased birds to prolong the reproductive lifespan of critically endangered species or genetically valuable individuals by transferring them to an embryonic chicken host.