Reproduction in Domestic Animals

Reprod Dom Anim 43 (Suppl. 2), 74–82 (2008); doi: 10.1111/j.1439-0531.2008.01145.xISSN 0936-6768Non-invasive Monitoring of Hormones: A Tool to Improve Reproduction inCaptive Breeding of the Eurasian LynxHormone Monitoring in Breeding Programmes of MammalsM Dehnhard 1 , S Naidenko 2 , A Frank 1 , B Braun 1 ,FGo¨ritz 1 and K Jewgenow 11 Leibniz-Institute for Zoo Biology and Wildlife Research, Berlin, Germany; 2 A.N. Severtzov Institute of Ecology and Evolution, Moscow, RussiaContentsThe survival of many critical endangered mammal species isoften depending on successful captive breeding programmeswhich include the future option of reintroduction to the wild.Breeding in captivity also demands the application of modernassisted reproductive techniques to ensure maximal biodiversity,but knowledge on reproductive physiology is oftenlimited. Therefore, non-invasive monitoring of urinary andfaecal hormones has become an important tool for reproductivemanagement. To exemplify the importance of noninvasivehormone monitoring, we choose the Eurasian lynxas a model for the world’s most endangered felid species, theIberian lynx. We analysed faecal samples of pregnant andpseudo-pregnant female Eurasian lynxes during a 3-year studyperiod. Compared to pre-mating levels faecal progesteronemetabolite profiles revealed a tendency towards higher levels inpregnant and pseudo-pregnant females with no differencebetween both categories. Oestrogen levels raised in bothpregnant and pseudo-pregnant females with a tendency to bemore elevated and prolonged in pregnant females. Surprisinglyboth E2 and P4 metabolites were highly correlated (r 2 =0.8131, p < 0.0001) showing a postpartum increase both inpregnant and pseudo-pregnant females. The results from theEurasian lynx revealed that the measurement of faecalprogesterone metabolites led to profiles dissimilar to profilesshown in other felid species, but similar to those from faecalgestagen metabolite analysis in the Iberian lynx. To identifyfaecal gestagen and oestrogen metabolites a radio-metabolismstudy was performed. Using the progesterone immunoassaytwo major progesterone metabolites were detected demonstratingthat the assay indeed tracks the relevant metabolites.The oestrogen assay measured authentic 17b-oestradiol andoestrone, and their conjugates. The analysis of the faecalmetabolite composition in samples from early and latepregnancy and lactation particularly revealed a distinct shiftin the relation between 17b-oestradiol and oestrone thatchanged in favour of oestrone. This might indicate differenthormone sources during and after pregnancy (corpus luteum,placenta). We hypothesize, that placental steroid analysis incombination with other highly sophisticated analytical techniques,like liquid chromatography mass spectrometry orurinary relaxin analysis may led to analytical options toconfirm pregnancy and to differentiate this from pseudopregnancyin lynx species.IntroductionThe main threat of mammalian species is human activityand many in situ populations are critically endangeredbecause of landscape development has reduced andfragmented their habitat (Ceballos et al. 2005; Cardilloet al. 2006). Due to the rapid decline of the species, it isapparent that some mammal populations will alreadynot be able to recover on its own. Therefore, successfulcaptive breeding programmes of managed zoo populationsmight result in animals that could be returned topart of their original range under protected regimes asdescribed for several species; notably the Arabian andscimitar horned oryx (Mesochina et al. 2003) and thePrzewalski horse (Ryder 1993). To achieve these objectivesnew approaches to improve the success of mammalconservation is urgently required and captive populationshave become of prime importance for the conservationof species in terms of research and education.Concomitantly there is a high priority in maintaining orincreasing genetic diversity in small populations to avoidinbreeding (Earnhardt et al. 2004). Thus, successfulcaptive breeding programmes of endangered speciesmust be performed on scientific basis and depend moreand more on modern assisted reproduction techniques(ART). The last 20 years are characterized by sporadicapplication of artificial insemination, gamete bankingand ⁄ or embryo production in non-domestic species(Masui et al. 1989; Hermes et al. 2001, 2007; Penfoldet al. 2005; Pukazhenthi et al. 2006; Swanson 2006;Hildebrandt et al. 2007; Stoops et al. 2007; Swansonet al. 2007). However, the most striking limitation ofusing ART in breeding programmes is limited knowledgeon reproduction biology, in particular knowledgeon hormone regulation of female reproductive cycle andpregnancy. Therefore, the purpose of the first part of thepaper is to give a brief outline on the current state of theart regarding non-invasive hormone monitoring techniques.Hormones control reproductive success. Knowing ananimal’s hormone patterns allows understanding itsbiology, and diagnosing and correcting infertility. Whilemany hormones interact in the reproductive process, thesteroid hormones oestradiol, progesterone and testosteroneare the most important regulators of reproductivebehaviours and functions across vertebrates. They areproduced by ovaries and testes, and their concentrationin blood serum is used to validate reproductive activityof mammals. Single blood samples, which are usuallyavailable from captive animals, however, can hardly beused to assess reproductive status of an exotic species.Hormone values depend on many factors, like seasonality,reproductive silence, reproductive suppression,pseudo-pregnancy, which are simply not known orstudied before in several exotic species.Presuming the knowledge of a particular reproductivepattern of a mammalian species, the analysis ofÓ 2008 The Authors. Journal compilation Ó 2008 Blackwell Verlag