Plains zebra (Equus quagga) adrenocortical activity increases during times of large aggregations in the Serengeti ecosystem.

Adverse environmental stimuli (stressors) activate the hypothalamic-pituitary-adrenal axis and contribute to allostatic load. This study investigates the contribution of environmental stressors and life history stage to allostatic load in a migratory population of plains zebras (Equus quagga) in the Serengeti ecosystem, in Tanzania, which experiences large local variations in aggregation. We expected higher fGCM response to the environmental stressors of feeding competition, predation pressure and unpredictable social relationships in larger than in smaller aggregations, and in animals at energetically costly life history stages. As the study was conducted during the 2016 El Niño, we did not expect food quality of forage or a lack of water to strongly affect fGCM responses in the dry season. We measured fecal glucocorticoid metabolite (fGCM) concentrations using an enzyme immunoassay (EIA) targeting 11ß-hydroxyetiocholanolone and validated its reliability in captive plains zebras. Our results revealed significantly higher fGCM concentrations 1) in large aggregations than in smaller groupings, and 2) in band stallions than in bachelor males. Concentrations of fGCM were not significantly higher in females at the energetically costly life stage of late pregnancy/lactation. The higher allostatic load of stallions associated with females, than bachelor males is likely caused by social stressors. In conclusion, migratory zebras have elevated allostatic loads in large aggregations that probably result from their combined responses to increased feeding competition, predation pressure and various social stressors. Further research is required to disentangle the contribution of these stressors to allostatic load in migratory populations.

Metabolism of prostaglandin F2alpha in Eurasian lynx (Lynx lynx) and Asian leopard cat (Prionailurus bengalensis euptilura).

Methods for monitoring endocrine status are useful tools for reproduction management. In particular, successful captive breeding of endangered feline species requires reliable methods for pregnancy diagnosis. In many species, uterine and placental prostaglandin-F2α (PGF2α) is involved in the regulation of reproductive processes. PGF2α is metabolized to 13,14-dihydro-15-keto-PGF2a (PGFM) during the first passage through the lungs. Immunoreactive PGFM is elevated in pregnant felids during the last trimester and is used for pregnancy diagnosis, although authentic PGFM is excreted in negligible amounts. To investigate the metabolism of PGF2α, a radiometabolism study was performed in two individuals of two feline species, Eurasian lynx and leopard cats, by injection of tritiated PGF2α and collection of faecal and urinary samples. All samples were extracted and subjected to HPLC separation. Radioactivity and immunoreactivity towards PGFM were determined in each HPLC fraction. The radio- and immunogramms differ slightly between the two species, and radiolabelled PGFM was present only in minor amounts. One major eicosanoid metabolite was found in all urine and faecal samples analysed, and also in previous studies in faecal samples of several pregnant feline species. Its polarity was similar, but not identical to PGF2α. We hypothesized that PGF2α is metabolized to more polar dinor and tetranor metabolites. First mass spectrometric analyses favoured a dinor metabolite as major compound of PGF2α metabolism in felids. Following identification and validation in the studied species, we aim to use these metabolites to improve pregnancy detection in other felids and probably other carnivores.

Research on reproduction is essential for captive breeding of endangered carnivore species.

Assisted reproductive technology (ART) has great potential for conservation, but its successful application in captive breeding programmes of endangered species is often compromised by limited background on species' biology. Although carnivore species benefit from knowledge obtained in domesticated species (dogs, cats and ferrets), the focus of research is different. In pet animals, research in reproduction has mainly been focused on ovarian function and contraception, although substantial progress has also been made in the field of in vitro embryo production, transgenic embryos and cloning to aid relevant medical models. In endangered species, however, research should focus on characterizing reproductive traits (cyclicity and seasonality) to unravel species-specific endocrine principles of reproduction physiology. Based on this knowledge, it is crucial to enhance the ability to manipulate female reproductive cycles, especially those of embryo recipients. Furthermore, research conducted on molecular and cellular mechanisms of gamete and embryo development, as well as on cryopreservation protocols of gametes and embryos, is required for successful implementation of advanced ART to wild carnivores. This review will provide a summary on the state of the art with focus on ART contributing to conservation breeding of endangered carnivores.

Characterisation and validation of an enzyme-immunoassay for the non-invasive assessment of faecal glucocorticoid metabolites in cheetahs (Acinonyx jubatus).

The non-invasive measurement of adrenocortical function in cheetahs is an important tool to assess stress in captive and free-ranging individuals, because stress has been suggested to be one of the causes of poor reproductive performance of captive cheetahs. We tested four enzyme immunoassays (EIA) in two captive cheetahs in Germany using adrenocorticotropic hormone (ACTH) challenges and identified the corticosterone-3-CMO EIA to be most sensitive to the increase in faecal glucocorticoid metabolite (fGCM) concentrations after the ACTH challenge. This EIA performed also well in five captive cheetahs in South Africa. The fGCM concentrations across all seven cheetahs increased within 24h by 681% compared to the baseline levels prior to ACTH. Storage of faecal samples at 0-4°C did not strongly affect fGCM concentrations within 24h, simplifying sample collection when immediate storage at -20°C is not feasible. The two cheetahs in Germany also received an injection of [(3)H]cortisol to characterise fGCMs in faecal extracts using high-performance liquid chromatography (HPLC) immunograms. HPLC fractions were measured for their radioactivity and immunoreactive fGCM concentrations with the corticosterone-3-CMO EIA, respectively. The results revealed a polar peak of radiolabelled cortisol metabolites co-eluting with the major peak of immunoreactive fGCMs. Thus, our EIA measured substantial amounts of fGCMs corresponding to the radioactive peaks. The peaks were of higher polarity than native cortisol and corticosterone, suggesting that the metabolites were conjugated, which was confirmed by solvolysis of the HPLC fractions. Our results show that the corticosterone-3-CMO EIA is a reliable tool to assess fGCMs in cheetahs.

Life cycle of feline Corpora lutea: histological and intraluteal hormone analysis.

The corpus luteum (CL) is a transient hormone gland on the ovary that produces progesterone (P4) for the maintenance of pregnancy. It develops from residual follicular granulosa and theca cells after ovulation. Very little is known about the cellular and hormonal processes within CLs obtained from pregnant and pseudopregnant felids. Therefore, our aim was to review the luteal function in feline CLs of different reproductive stages in conjunction with our data obtained in domestic cats and Eurasian lynxes. Corpus luteum function in lynxes is of particular interest, as a post-partum luteal activity was suggested based on repeated ultrasonography and endocrine examinations. Histology of CL from pregnant and pseudopregnant domestic cats clearly reflects the luteal function. The formation of the CL after ovulation is characterized by transforming of theca and granulosa cells into steroidogenic luteal cells and is accompanied by increased intraluteal and circulating P4 levels. Luteal regression is steadily progressive; the first signs (coarsed vacuolization, increased proportion of non-steroidogenic cells) are visible already in CL from the second trimester of pregnancy.

Embryo retrieval after hormonal treatment to control ovarian function and non-surgical artificial insemination in African lions (Panthera leo).

Assisted reproduction technologies are essential for propagating endangered wild felids. Artificial insemination (AI) has been reported in several wild feline species, but pregnancy rates are low, partially owing to failures of current hormonal stimulation protocols. Therefore, this study describes the application of reliable methods to monitor ovarian activity and the development of an effective hormonal protocol to induce oestrus and ovulation in African lions. Application of porcine FSH and porcine LH was shown to be effective for inducing follicular growth and ovulation, and this regimen appeared to be superior to protocols described earlier in terms of ovulation and fertilization rates. Furthermore, non-surgical AI was performed successfully in lions, and uterine-stage embryos were collected and cryopreserved. African lions may serve as a valuable model to develop assisted reproduction for propagation of relic zoo populations in the critically endangered Asian lion or Barbary lion.

Comparative metabolism of gestagens and estrogens in the four lynx species, the Eurasian (Lynx lynx), the Iberian (L. pardinus), the Canada lynx (L. canadensis) and the bobcat (L. rufus).

With the increasing prevalence of faecal hormone metabolite analysis, it is important to develop a better understanding of the dynamics of faecal metabolite composition. The aim of this study was to compare the quantitative faecal gestagen and estrogen metabolite composition in the four lynx species: Eurasian lynx, Iberian lynx, Canada lynx and bobcats. Comparative HPLC immunograms were generated from faecal samples collected before, during, and after pregnancy from individual females of each lynx species. Gestagens and estrogens revealed three similar classes of immunoreactive faecal metabolites: (1) polar metabolites which were enzyme-hydrolysable and thus may be designated as conjugates, (2) non-hydrolysable polar metabolites, and (3) non-polar metabolites or free steroids. For both hormones, strong similarities in the HPLC immunograms across species suggests that steroid metabolism is relatively conserved among Lynx species. Gestagens were primarily excreted as polar conjugates or unknown metabolites, whereas estrogen metabolism revealed a huge proportion (approximately 50%) consisting of 17beta-estradiol and estrone. These results are consistent with patterns of steroid metabolism in other felid species. Only two minor species-specific patterns emerged. In bobcats, we observed an exceptionally high proportion of gestagen conjugates, and in Iberian lynx, there was an exceptionally high proportion of estrone. The comparison of HPLC immunograms within individuals revealed that intra-individual variations in steroid metabolite composition are considerably high. However, changes in metabolite composition did not correlate with specific reproductive stages; rather, they seemed to occur at random. We assume that these differences may reflect changes in liver metabolism and/or qualitative and quantitative variations in gut bacteria composition, resulting in differences in faecal metabolite composition.

Pregnancy diagnosis in urine of Iberian lynx (Lynx pardinus).

Diagnosis of pregnancies is an important management tool for the Iberian lynx Conservation Breeding Program, a program geared to recover the world's most endangered felid. Non-invasive methods such as fecal hormone analyses are not applicable to the lynx, since fecal progestin does not follow the typical pregnancy pattern of felids. Therefore, we aimed to test whether urine can be used as an alternative substance for pregnancy diagnosis in the Iberian lynx. Progesterone immunoreactive metabolites were determined in urine samples of pregnant and non-pregnant females before and during breeding season. Additionally, we used the Witness Relaxin test to determine relaxin in blood and urine. No differences were found in progestin concentrations determined in urine samples collected from pregnant and non-pregnant animals between day 1 and 65 following mating. Although the Witness Relaxin test was positive in serum samples collected from animals between day 32 and 56 of pregnancy, it failed in both fresh and frozen urine samples collected from the same stage of pregnancy. A weak relaxin reaction in urine samples collected from animals between day 29 and 46 of pregnancy was detectable after urines were concentrated by ultrafiltration (>50x). Concentrated samples obtained from non-pregnant and early pregnant animals yielded negative test results. In conclusion, the Witness Relaxin test can be applied for pregnancy diagnosis in Iberian lynx in both serum and concentrated urine samples obtained during the second half of pregnancy. A positive relaxin test indicates an ongoing pregnancy, whereas negative tests must be judged carefully as hormone concentrations might be below detection thresholds.

Seasonal profiles of ovarian activity in Iberian lynx (Lynx pardinus) based on urinary hormone metabolite analyses.

The Iberian Lynx Ex-Situ Conservation Programme is an essential part of a co-ordinated action plan to conserve the most endangered felid species of the world. Successful captive breeding demands reliable methods for reproduction monitoring including reliable non-invasive pregnancy diagnosis. During a 3-year study, urine samples from six captive Iberian lynx females were obtained (one non-pregnant, one pseudo-pregnant and 11 pregnant cycles). Progesterone, pregnanediol and oestradiol were determined in urinary extracts and relevant urinary oestrogen metabolites were characterized by high-performance liquid chromatography (HPLC). Urinary progestins did not follow the typical pregnancy-related course of felids. In the lynx, we failed to demonstrate an urinary progestin elevation during pregnancy. In contrast, urinary oestrogens increased from 3.8 +/- 0.6 to 8.6 +/- 0.5 ng/mg creatinine (p < 0.001) during the pregnancy. A comparison of pseudo-pregnant with pregnant cycles revealed a further increase of oestrogens caused by implantation (p < 0.05). In one female, which refused to mate, no difference was estimated between oestrogens levels during the breeding and non-breeding seasons. Almost 10-fold higher oestrogen concentrations were measured in urines of females that shared enclosures with males. HPLC analysis of oestrogens in urine samples collected from Iberian lynx during the pregnancy revealed that lynx urine is composed of two polar oestrogen metabolites in addition to oestrone and minor amounts of oestradiol. Oestrone was detectable in all urinary extracts (8-12% of metabolites), whereas oestradiol was elevated only during late pregnancy (18%). Thus, seasonal luteal activity in Iberian lynx can be monitored by urinary oestrogens. The increase of urinary oestradiol during late pregnancy might indicate an oestradiol secretion by the lynx placenta.

Gonadal activity in male and female captive fossas (Cryptoprocta ferox) during the mating season.

The fossa is an endangered, mongoose-like carnivore species endemic to Madagascar with a breeding season (BS) in the southern hemisphere spring. For the present study, faecal samples of captive fossas were collected for over 1 year for five males and four non-pregnant females, and for two pregnant animals during the reproductive period. The goal was to assess gonadal activity using non-invasive hormone measurements of faecal testosterone (T) and gestagen metabolites using assays previously established in our laboratory and further validated in this study. All study animals were housed in northern hemisphere zoos. In males, the seasonal T metabolite profile revealed a peak in spring (March). High performance liquid chromatography (HPLC) analysis was used to characterize the faecal hormone metabolite composition. The highest immunoreactivity was detected in the position of dihydrotestosterone, whereas native T was not detected. In the two pregnant females, gestagen metabolite concentrations increased 4-9 days after the initial matings and remained elevated throughout gestation with concentrations dramatically higher than those of the non-pregnant females during the BS. In these females, gestagen metabolite analyses did not reveal a seasonal pattern similar to the males. The HPLC-analysis revealed that the major proportion of immunoreactivity was associated with an unknown metabolite, whereas native progesterone was undetectable. The seasonal hormone pattern of male fossas gives proof of the reproductive seasonality of this species. The elevated 5alpha-pregnan-3beta-ol-20-one levels in pregnant animals allows for the characterization of pregnancy in the fossa based on analysis of faecal steroid metabolite concentrations.

Non cat-like ovarian cycle in the Eurasian and the Iberian lynx - ultrasonographical and endocrinological analysis.

The Iberian lynx is considered the most endangered felid species. Therefore, an ex situ conservation program was initiated to protect this species from extinction. Additional knowledge on lynx reproduction biology and reliable methods for reproductive monitoring are important for developing a captive breeding program. The aim of this study in lynx was to implement transrectal ultrasonography to visualize ovarian structures (follicles, corpora lutea) and to assess ovarian activity in addition to analysis of serum progesterone and oestradiol. Because of limited access to Iberian lynxes, the less-endangered Eurasian lynx and bobcat were also studied in this comparative study. Recent endocrinological studies based on faecal and urinary progesterone and oestrogen metabolites revealed that steroid profiles in both these species were alike and did not follow the typical pattern of other felids. Pregnancy diagnosis was not possible, since progesterone concentrations did not differ between pregnant and pseudopregnant animals. Progesterone was also detected after parturition as well as after weaning until the onset of a new oestrous cycle. In the present study, the presence of corpora lutea during the non-breeding season was confirmed by ultrasonography and by elevated serum levels of progesterone averaging 3.56 +/- 1.3 ng/ml in Eurasian and 6.1 +/- 0.26 ng/ml in Iberian lynx, respectively. The ultrasonographical findings on the ovarian structures suggest strongly that corpora lutea developed after ovulation stay active until November and regress before the onset of the next oestrus.

Non-invasive monitoring of hormones: a tool to improve reproduction in captive breeding of the Eurasian lynx.

The survival of many critical endangered mammal species is often depending on successful captive breeding programmes which include the future option of reintroduction to the wild. Breeding in captivity also demands the application of modern assisted reproductive techniques to ensure maximal biodiversity, but knowledge on reproductive physiology is often limited. Therefore, non-invasive monitoring of urinary and faecal hormones has become an important tool for reproductive management. To exemplify the importance of non-invasive hormone monitoring, we choose the Eurasian lynx as a model for the world's most endangered felid species, the Iberian lynx. We analysed faecal samples of pregnant and pseudo-pregnant female Eurasian lynxes during a 3-year study period. Compared to pre-mating levels faecal progesterone metabolite profiles revealed a tendency towards higher levels in pregnant and pseudo-pregnant females with no difference between both categories. Oestrogen levels raised in both pregnant and pseudo-pregnant females with a tendency to be more elevated and prolonged in pregnant females. Surprisingly both E2 and P4 metabolites were highly correlated (r(2) =0.8131, p < 0.0001) showing a postpartum increase both in pregnant and pseudo-pregnant females. The results from the Eurasian lynx revealed that the measurement of faecal progesterone metabolites led to profiles dissimilar to profiles shown in other felid species, but similar to those from faecal gestagen metabolite analysis in the Iberian lynx. To identify faecal gestagen and oestrogen metabolites a radio-metabolism study was performed. Using the progesterone immunoassay two major progesterone metabolites were detected demonstrating that the assay indeed tracks the relevant metabolites. The oestrogen assay measured authentic 17beta-oestradiol and oestrone, and their conjugates. The analysis of the faecal metabolite composition in samples from early and late pregnancy and lactation particularly revealed a distinct shift in the relation between 17beta-oestradiol and oestrone that changed in favour of oestrone. This might indicate different hormone sources during and after pregnancy (corpus luteum, placenta). We hypothesize, that placental steroid analysis in combination with other highly sophisticated analytical techniques, like liquid chromatography mass spectrometry or urinary relaxin analysis may led to analytical options to confirm pregnancy and to differentiate this from pseudo-pregnancy in lynx species.

Model for Hormonal Emergency Contraception (HEC) in cycling and mated guinea pigs - Studies with the Progesterone Receptor Modulators (PRM) Ulipristal Acetate (UPA/CDB2914) and EC317.

A guinea pig model for new HEC methods is proposed. Two targets for HEC (Hormonal Emergency Contraception), ovulation and conception (post-mating study), were investigated using adjusted PRM treatments: (a) Ovulation inhibition study: Injections on cycle days 10-17, study of ovarian histology on day 18; (b) post-mating study: Injections on cycle days 1 and 2; rate of pregnant females was recorded at autopsy on day 18. P plasma levels permitted assessment of effects on ovulation in non-conceiving animals. RESULTS: (a) All controls had recently ovulated. Statistically significant anti-ovulatory effects (p < 0.05, Fisher's Exact Test) were seen at 10 mg UPA (ulipristal acetate, CDB2914) and ≥0.3 mg EC317; 100% inhibition was found for EC317 at 10, 3, and 1 mg/day. No dosage of UPA was 100% effective. (b) In post-mating studies, 16 of 30 controls were pregnant. Both PRMs (progesterone receptor modulator) exerted inhibitory effects on conception, none on imminent ovulation; 1 of 10 animals had living conceptuses after 10 mg UPA, none following 10 and 1 mg EC317/day, respectively. At pairwise comparison with controls, 10 mg was the lowest effective dosage for UPA (p < 0.05), and 1 mg for EC317 (p < 0.01). P plasma levels: Significantly lower P (p < 0.05) in subsequently pregnant vs non-pregnant controls was found on cycle day 3 or 4; this difference disappeared on day 8 or 9. This stage thus appears vulnerable to hormonal constellations and possibly PRM effects. HEC model: Effects on ovulation and conception were seen at the same dose levels of both PRM. Superior and more consistent effects of EC317 vs UPA (factor ≥10) suggest higher efficacy using EC317 for HEC.

Comparative endocrine investigations in three bear species based on urinary steroid metabolites and volatiles.

In order to improve breeding of in situ populations of bears, a comprehensive study of reproductive physiology in Brown (Ursus arctos), Spectacled (Tremarctos ornatus) and Giant panda bears (Ailuropoda melanoleuca) was performed. The objective was to perform non-invasive analyses of urinary and fecal steroid metabolites. In addition, we investigated the presence of reproduction-related urinary volatile substances of these bears that might trigger the reproductive behavior. Urinary estrogen concentrations, routinely used to monitor follicular activity in Giant panda, were inappropriate for monitoring follicular activity in Spectacled bear. In addition, no estrogen peak related to mating activity was observed in Brown bear. Further contrasting Giant panda, although urinary pregnanediol analyses failed to indicate luteal activity in either Spectacled or Brown bears, urinary (Spectacled bear) and fecal (Brown bear) concentrations of progesterone were an appropriate indicator of luteal activity. The Giant panda had volatile components (medium-chain fatty acids) in their urine that increased simultaneously with the seasonal increase of estrogens. These fatty acids were also detected in the Brown during estrus and Spectacled bear. Further studies on the behavioral relevance of these fatty acids are required to determine if they are pheromones.

Headspace solid-phase microextraction (SPME) and gas chromatography-mass spectrometry (GC-MS) for the determination of 5alpha-androst-2-en-17-one and -17beta-ol in the female Asian elephant: application for reproductive monitoring and prediction of parturition.

Asian elephants are not self-sustaining in captivity. The main reasons for this phenomenon are a low birth rate, an aging population, and poor calf-rearing. Therefore, it is essential that reproductive rates had to be improved and there is need for rapid quantitative measures to monitor reproductive functions focussing on estrous detection and the prediction of the period of parturition. The objective of this study was to develop a method which combines headspace solid-phase microextraction (SPME) and gas chromatography-mass spectrometry (GC-MS) for analyses of 5alpha-androst-2-en-17beta-ol and -17-one to prognose estrous and to predict the period of parturition. SPME was carried out with a CTC Combi Pal system. The course of the luteal phase-specific substance 5alpha-androst-2-en-17beta-ol and -17-one followed a cyclic pattern in which the follicular and luteal phases could be clearly distinguished (mean estrous cycle length, 15+/-1.4 weeks). Based on daily urine samples, estrous prognosis might be possibly based on the initial 5alpha-androst-2-en-17beta-o1 increase at the end of the follicular phase. Parturition prognosis was performed in three elephant cows based on the 5alpha-androst-2-en-17beta-o1 drop to baseline levels 5-4 days prior parturition. Experiments revealed that 5alpha-androst-3alpha-ol-17-one and probably 5alpha-androst-3alpha-ol-17beta-ol are generated from sulfate conjugates by a thermal process.

Effect of pheromones from male goats on LH-secretion in anoestrous ewes.

Pheromones from ram's wool or buckhairs lead to an increase in the LH pulse frequency, thus inducing ovulations in seasonally anoestrous sheep and goats, respectively. Indications exist that pheromones from one species may be active in the other one. The changes of the LH secretion pattern were used as a bioassay to demonstrate such an interspecies effect of either ram's wool or buckhairs. A clear increase in the LH pulse frequency was obvious in ewes after stimulation with buckhairs (p less than or equal to 0.001, n = 11), but was absent in does after application of ram's wool or its extracts. Organic solvent extracts from buckhairs were split into a neutral (FN) and an acid fraction (FA). The latter one was further divided into two subfractions (FA-I, FA-II) according to the chain length of the fatty acids. The most pronounced effect was found after FN (p less than or equal to 0.001, n = 12), but FA still remained significantly active (p less than or equal to 0.05, n = 9). The subfractions FA-I and FA-II, however, had largely lost the pheromonal activity. It is concluded that buck pheromones are active in sheep. The neutral fraction is likely to contain the bulk of pheromonally active substances.

Reliability criteria of a bioassay using rats trained to detect estrus-specific odor in cow urine.

An odor discrimination apparatus was used to quantify the reaction of rats against odor differences of estrous and diestrous urine of cows. Rats were trained to release impulses from a microswitch when they came into contact with estrous but not diestrous urine. After training, the discrimination ability was highly significant (P< or = 0.001) between both urine types. The reaction was specific for cow urine, and no significant discrimination occurred for estrous and diestrous urine from pigs or goats, or that of women. The discrimination of urine diluted with water was still highly significant up to 1:25. Another group of rats was trained to detect camphor. Decreasing concentrations were detected down to 0.1/microg/ml when diluted in water, and down to 1/microg/ml when diluted in estrous urine. Once trained to discriminate between estrous and diestrous urine, rats maintained this ability for 12 mo. Thus, a bioassay was set up to accompany fractionation steps in the laboratory which could lead to the isolation of estrous pheromones in cow urine.

Variation in estrus-related odors in the cow and its dependency on the ovary.

Urine samples were collected from 10 cows during the estrous cycle (Day 0=day of observed estrus) and investigated for pheromone activity using a quantitative rat bioassay. Pheromone activity in this assay was given in impulses/45 sec. Progesterone was measured in milk fat to verify the stage of cycle. The maximal response of rats was found on Day -1 (20.0 +/- 3.5 impulses/45 sec; x +/- SEM), and impulse rates were clearly higher (P

Comparative metabolism of PGFM (13,14-dihydro-15-keto-PGF2α) in feces of felids.

Methods for monitoring endocrine activities are useful tools for reproduction management. In particular, captive breeding of endangered felid species is considered to be an important part of the species conservation efforts. Within breeding programs, reliable methods for pregnancy diagnosis are highly demanded to prevent peri- and postpartal losses, but pregnancy diagnosis based on gestagen metabolites in felids is hampered by pseudopregnancies. Recently, we described fecal PGFM as an indicator for pregnancy in several feline species, but peak levels of PGFM secretion differed dramatically between species. It is believed that prostaglandin composition and metabolism pathways may differ as well. Therefore, a study was devised to both compare various fecal immunoreactive PGFM metabolites and to identify prostaglandins in fecal extracts by liquid chromatography-mass spectrometry (LCMS). Our results confirmed that fecal metabolite patterns differ between feline species. The identity of PGFM was confirmed in six of eight felids. In Iberian lynx and the Sumatran tiger, PGFM did not exceed 5% of all immunoreactivities. The total number of immunoreactivities varied between two (e.g., domestic cat) and four (e.g., oncilla). Several prostaglandins were identified by LCMS; apart from PGFM, all LCMS-identified prostaglandins, including tetranor-PGFM, did not show any cross-reactivity with our PGFM-specific antibody. This indicates the existence of still unknown eicosanoids and further studies are needed to clarify the origin of the different metabolites. Although differing stages of pregnancy did not reveal significant differences in the composition of metabolites, we could not exclude the possibility that metabolites from other prostaglandins (e.g. PGE2) contributed to the fecal metabolite patterns.

Using PGFM (13,14-dihydro-15-keto-prostaglandin F2α) as a non-invasive pregnancy marker for felids.

Understanding the complex endocrine interactions that control reproduction in felids is essential for captive breeding management. The most important demand is a quick and reliable pregnancy diagnosis. However, the occurrence of pseudopregnancies in felids complicates matters. We investigated whether the fecal prostaglandin metabolite (PGFM) recently suggested for pregnancy diagnosis in the lynx is suitable for all felid species. We found that increased levels of PGFM during the last trimester indicate pregnancy in seven of the eight main lineages of the carnivore family Felidae. PGFM levels in a sand cat (domestic cat lineage) were basal at mating and remained so until Day 40 post-mating. Day 41 marked the beginning of a distinct increase culminating in peak levels of 6.5 µg/g before parturition and decreasing again to baseline thereafter. Similar pregnancy profiles were obtained from the domestic cat, the leopard cat, the lynx, the ocelot and the caracal lineage, whereas in pseudopregnant individuals (sand cat, Iberian and Eurasian lynx) fecal PGFM remained at basal levels. In pregnant cheetahs (puma lineage) PGFM increased above basal following day ∼48 peaking before pregnancy but remained at baseline in pseudopregnant females. Discrepancies existed in the Panthera lineage. While Chinese leopard, Sumatran tiger, and the black panther showed marked increases of PGFM during the last weeks of pregnancy, only moderate increases in PGFM levels were found in the Indochinese tiger and the Persian leopard. Altogether, PGFM as tool for pregnancy diagnosis has been proven to be useful in breeding management of felids.