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Sergio A. Estay - One of the best experts on this subject based on the ideXlab platform.
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Correspondence between the habitat of the threatened pudú (Cervidae) and the national protected-area system of Chile
BMC ecology, 2016Co-Authors: Melissa A. Pavez-fox, Sergio A. EstayAbstract:Background Currently, many species are facing serious conservation problems due to habitat loss. The impact of the potential loss of biodiversity associated with habitat loss is difficult to measure. This is particularly the case with inconspicuous species such as the threatened Pudu (Pudu puda), an endemic Cervidae of temperate forests of Chile and Argentina. To evaluate the effectiveness of the Chilean protected-area system in protecting the habitat of the Pudu, we measured the congruence between this specie’s potential distribution and the geographical area occupied by the protected areas in central and southern Chile. The measurements of congruency were made using the Maxent modeling method.
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Correspondence between the habitat of the threatened pudú (Cervidae) and the national protected-area system of Chile
BMC ecology, 2016Co-Authors: Melissa A. Pavez-fox, Sergio A. EstayAbstract:Currently, many species are facing serious conservation problems due to habitat loss. The impact of the potential loss of biodiversity associated with habitat loss is difficult to measure. This is particularly the case with inconspicuous species such as the threatened Pudu (Pudu puda), an endemic Cervidae of temperate forests of Chile and Argentina. To evaluate the effectiveness of the Chilean protected-area system in protecting the habitat of the Pudu, we measured the congruence between this specie’s potential distribution and the geographical area occupied by the protected areas in central and southern Chile. The measurements of congruency were made using the Maxent modeling method. The potential habitat of the Pudu was found to be poorly represented in the system (3–8 %) and even the most suitable areas for the species are not currenly protected. According to these results, the protected area network cannot be considered as a key component of the conservation strategy for this species. The results presented here also serve as a guide for the reevaluation of current Pudu conservation strategies, for the design of new field studies to detect the presence of this species in human-disturbed areas or remaining patches of native forest, and for the implementation of corridors to maximize the success of conservation efforts.
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Correspondence between the habitat of the threatened pudú (Cervidae) and the national protected-area system of Chile
BMC Ecology, 2016Co-Authors: Melissa Pavez-fox, Sergio A. EstayAbstract:Background Currently, many species are facing serious conservation problems due to habitat loss. The impact of the potential loss of biodiversity associated with habitat loss is difficult to measure. This is particularly the case with inconspicuous species such as the threatened pudú ( Pudu puda ), an endemic Cervidae of temperate forests of Chile and Argentina. To evaluate the effectiveness of the Chilean protected-area system in protecting the habitat of the pudú, we measured the congruence between this specie’s potential distribution and the geographical area occupied by the protected areas in central and southern Chile. The measurements of congruency were made using the Maxent modeling method. Results The potential habitat of the pudú was found to be poorly represented in the system (3–8 %) and even the most suitable areas for the species are not currenly protected. According to these results, the protected area network cannot be considered as a key component of the conservation strategy for this species. Conclusions The results presented here also serve as a guide for the reevaluation of current pudú conservation strategies, for the design of new field studies to detect the presence of this species in human-disturbed areas or remaining patches of native forest, and for the implementation of corridors to maximize the success of conservation efforts.
G. A. Bubenik - One of the best experts on this subject based on the ideXlab platform.
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Effect of antiandrogen cyproterone acetate on the development of the antler cycle in Southern Pudu (Pudu puda).
The Journal of experimental zoology, 2002Co-Authors: G. A. Bubenik, Eugenia Reyes, D. Schams, A. Lobos, Ludĕk Bartos̆, Fernando KoernerAbstract:The antler cycle of Pudu is similar to other cervids, but unlike most boreal deer, male Southern Pudu (Pudu puda) exhibits two seasonal peaks of LH and testosterone. In that respect, Pudu is similar to roe deer. Whereas the antler cycle in some deer species, such as roe deer or white-tailed deer, is very sensitive to variation of testosterone, in other cervids, such as fallow deer or reindeer, a blockade of androgens with cyproterone acetate (CA) has little or no effect on the timing of the antler casting. In order to test the sensitivity of Pudu antlers to variations of androgens, CA (administered 2× weekly at 50 mg/buck) was injected intramuscularly for 3 weeks in 5 adult male Pudu, starting February 19 (late summer). Four other males of similar age served as controls. The experiment was performed at the University of Concepcion, Chile, latitude 36.6°S. Blood samples were taken once a week between January 19 and April 3. In CA-treated bucks, the antlers were cast approximately 3 weeks after the initiation of CA treatment and a new antler growth began almost immediately. The antlers reached about 5 cm in length, before ceasing to grow at the end of April, when they became mineralized and were subsequently polished. CA had no effect on the already declining levels of LH. Plasma levels of testosterone in controls increased from February 15, whereas in CA-treated bucks remained depresses until March 21. It is concluded that similarly to white-tailed deer, the antler cycle of Southern Pudu is very sensitive to manipulation of androgen levels. J. Exp. Zool. 292:393–401, 2002. © 2002 Wiley-Liss, Inc.
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Pudu, the smallest deer of the world: 10 years of endocrine studies of Southern Pudu (Pudu puda) in Chile
Zeitschrift für Jagdwissenschaft, 2000Co-Authors: G. A. Bubenik, Eugenia Reyes, D. Schams, A. Lobos, L. BartošAbstract:Die ersten 10 Jahre der Forschung über Physiologie und Verhalten der Pudu konzentrierten sich auf Untersuchungen der männlichen Hormonprofile. Grund- und jahreszeitliche Gehalte von LH (Luteotropin), FSH (Follikelstimulierendes Hormon), Testosteron, Prolaktin, IGF-1 (insulin-like growth factor 1), Kortisol und Trijodthyronin wurden bestimmt. Zusätzlich wurde über die Grundgehalte und die Werte nach Stimulation von Kortisol, Wachstumshormon (GH), LH, FSH und Testosteron nach ACTH (Adrenocorticotropes Hormon) und GnRH (Gonadotropin-Releasing Hormon) Challenge-Tests berichtet. Die meisten Hormonwerte im Blut der männlichen Pudu sind in den unteren Bereichen häufig um die Hälfte geringer als die Hormongehalte eines anderen kleinen Cerviden, dem Rehwild. Der Pudu antwortet schnell auf stimulierten Stress und GnRH löst einen heftigen Anstieg von LH und Testosteron bei dominanten Männchen aus. Die nächste Phase der Forschung wird sich nun auf die weibliche Endokrinologie konzentrieren. Derzeit erfolgt die Bestimmung saisonaler Gehalte weiblicher Fortpflanzungshormone. The first ten years of research on Pudu physiology and behavior concentrated on the investigation of hormone profiles in males. Basic and seasonal levels of LH, FSH, testosterone, prolactin, IGF-1, cortisol and triiodothyronine were determined. The seasonal fluctuations of reproductive and other hormones are related to the reproductive and the antler cycles and the social rank of individual males. In addition, basal and poststimulatory levels of cortisol, growth hormone (GH), LH, FSH and testosterone were reported after ACTH and GnRH challenge tests. Most blood levels of hormones in male Pudu are in the low range often less than half of hormonal levels of another small cervid, the roe deer. Pudu responds quickly to simulated stress and GnRH elicits a vigorous increase of LH and T in the dominant males. The next phase of our research is now concentrated on the reproductive physiology of the female Pudu, where a delayed implantation of the embryo is suspected. Les 10 premières années de recherche sur la physiologie et sur le comportement du Pudu ont été consacrées à l'étude des profils hormonaux chez les mâles. Les niveaux de base et les variations saisonnières ont été déterminées en ce qui concerne la LH, la FSH, la testostérone, la prolactine, l'IGF-1, le cortisol et la triiodothyronine. Les variations saisonnières des hormones gonadotropes et d'autres hormones sont liées aux cycles de la reproduction et du développement des bois ainsi qu'au rang social des différents mâles. En outre, les niveaux de base et post-stimulatoires de cortisol, des hormones de croissance (GH), LH, FSH et testostérone ont été renseignés après des tests de challenge à l'hormone adrénocorticotrope (ACTH) et à l'hormone de déclenchement gonadotrope (GnRH). La plupart des niveaux hormonaux sanguins chez le Pudu sont faibles : ils sont souvent de moitié inférieurs à ceux d'un autre cervidé de petite taille tel que le Chevreuil. Le Pudu répond rapidement au stress simulé et le GnRH déclenche une forte augmentation de LH et de testostérone chez les mâles dominants. La phase suivante de notre recherche se concentre à présent sur la physiologie de la reproduction chez la femelle du Pudu où une nidation différée est suspectée.
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Pudu, the smallest deer of the world: 10 years of endocrine studies of Southern Pudu (Pudu puda) in Chile
Zeitschrift für Jagdwissenschaft, 2000Co-Authors: G. A. Bubenik, Eugenia Reyes, D. Schams, A. Lobos, Ludek BartosAbstract:The first ten years of research on Pudu physiology and behavior concentrated on the investigation of hormone profiles in males. Basic and seasonal levels of LH, FSH, testosterone, prolactin, IGF-1, cortisol and triiodothyronine were determined. The seasonal fluctuations of reproductive and other hormones are related to the reproductive and the antler cycles and the social rank of individual males. In addition, basal and poststimulatory levels of cortisol, growth hormone (GH), LH, FSH and testosterone were reported after ACTH and GnRH challenge tests. Most blood levels of hormones in male Pudu are in the low range often less than half of hormonal levels of another small cervid, the roe deer. Pudu responds quickly to simulated stress and GnRH elicits a vigorous increase of LH and T in the dominant males. The next phase of our research is now concentrated on the reproductive physiology of the female Pudu, where a delayed implantation of the embryo is suspected.
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Rank dependent seasonal levels of IGF-1, cortisol and reproductive hormones in male Pudu (Pudu puda)
Comparative Biochemistry and Physiology A-molecular & Integrative Physiology, 1998Co-Authors: Ludek Bartos, G. A. Bubenik, Eugenia Reyes, D. Schams, A. LobosAbstract:Abstract We tested the following hypothesis: when two Pudu males share a single pen throughout the year, the dominant animal will have a higher level of IGF-1 than its subordinate pen mate, particularly during the period of increased social friction (e.g. rut and establishment of territories). To test this hypothesis, we used data from six adult males maintained at the University of Concepcion, Chile (latitude 36.6° S), and analysed them from the males' dominance point of view. Two males plus eight to ten females were kept in one pen and although we did not specifically measure dominance, the rank position was obvious from frequent encounters between the bucks. Three consecutive blood samples were taken monthly over the period of 1 year. In addition to IGF-1, we also analysed seasonal levels of testosterone, cortisol, prolactin, LH and FSH. The analysis revealed that IGF-1 levels of dominant males were significantly higher than those of subordinate males from September to November (the second part of the antler growing period and time of establishing territories). Testosterone levels were higher and FSH levels were lower in dominant males during the rut. Levels of prolactin were higher in dominant animals in November (summer). Cortisol and LH did not show any significant differences between dominant and subordinate males. This data provides the first evidence indicating the possible link between dominance and blood levels of IGF-1. The functional explanation of such links is discussed.
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Seasonal changes of testicular parameters in southern Pudu Pudu puda in relationship to circannual variation of its reproductive hormones
Acta Theriologica, 1997Co-Authors: Eugenia Reyes, G. A. Bubenik, D. Schams, A. Lobos, Rosa EnriquezAbstract:Seasonal variation of testicular and epididymal parameters in the smallest deer, the southern Pudu Pudu puda Molina, 1782 were related to the circannual fluctuation of plasma levels of its reproductive hormones. The diameter and the length of testes, the diameter of epididymis as well as the diameter and the heights of epithelium of seminiferous and epididymal tubules were measured. Morphological evaluation of spermatogenesis were performed on histological sections of testicular and epididymal tissues. Most of these gonadal parameters exhibit a seasonal variation which is in accordance with the reproductive pattern as well as the variation of reproductive hormones. Seasonal fluctuations of LH and testosterone indicate two seasonal activations of the reproductive system, one in the spring (antler mineralization), the other in the fall (rut). FSH exhibit one prolonged peak (summer to fall) whereas prolactin follows the expected, photoperiodically-dependant time course with peak levels around the summer solstice. The measurements of testicular parameters indicate a prolonged period of gonadal activity in southern Pudu but the period of maximal reproductive stimulation is limited to the time around the rut.
Daniel González-acuña - One of the best experts on this subject based on the ideXlab platform.
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Subcutaneous abscess caused by Trueperella pyogenes in a Southern Pudu (Pudu puda)
Austral journal of veterinary sciences, 2020Co-Authors: Sebastián Llanos-soto, Paulina González-muñoz, Alexis Opazo-capurro, Gerardo González-rocha, Daniel González-acuñaAbstract:ABSTRACT: A case of an abscess on the head of a captive Southern Pudu (Pudu puda) caused by Trueperella pyogenes is described. A diagnosis was done based on bacterial culture and MALDI-TOF MS identification. Traumatic inoculation of the bacterium in the subcutaneous tissue is speculated.
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Infection with Borrelia chilensis in Ixodes stilesi ticks collected from Pudu puda deer.
Ticks and tick-borne diseases, 2017Co-Authors: Claudio Verdugo, Omar Jiménez, Carlos Hernandez, Pedro Álvarez, Angelo Espinoza, Daniel González-acuñaAbstract:Abstract Lyme borreliosis is a vector-borne zoonosis caused by Borrelia burgdorferi sensu lato species complex spirochetes, which are maintained in transmission cycles among vertebrates and Ixodes ticks. Recently, a new genospecies within this complex, Borrelia chilensis , was described in Ixodes stilesi collected from the environment and from rodents in Chile. This tick also infests the native Southern Pudu deer ( Pudu puda ). The objectives of this study were to investigate the prevalence, intensity of infestation, and aggregation of hard ticks on this deer species, and to determine the presence of borrelial pathogens in the ticks. Sixty-six deer were examined over a two-year period. A total of 179 ticks of two species, I. stilesi and Ixodes taglei , were collected. Of those, 100 were adults, 78 were nymphs, and one was a larva . Ixodes stilesi was the most prevalent tick (47%) and was highly aggregated (D = 0.77) on the deer. Deer body weight was positively associated with tick burden. Borrelia spirochetes were detected in two (6.45%) of the examined I. stilesi ticks. Phylogenetic analyses of 16S and flaB gene sequences positioned these samples in the same clade with Borrelia chilensis VA1 previously described from Chile. These findings suggest that I. stilesi may play a role in the local persistence of B. chilensis . Further studies are required to fully understand the mechanisms of natural transmission of B. chilensis and the risk of infection in humans.
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Molecular divergence between insular and continental Pudu deer (Pudu puda) populations in the Chilean Patagonia
Studies on Neotropical Fauna and Environment, 2011Co-Authors: Marcelo Fuentes-hurtado, Claudio Verdugo, Daniel González-acuña, Fernando Vidal, Juan Carlos Marín, Juliana A. ViannaAbstract:Island–continent isolation scenarios have played major roles in the understanding and development of evolutionary theories. During the last glacial maximum (LGM) in southern Chile, ice sheet advances and retreats formed the Patagonian archipelago along the southern Pacific Ocean. Chiloe Island is the largest island from the archipelago isolated from the continent by a narrow and shallow stretch of ocean. Pudu puda is a species endemic to Chile and part of Argentina, distributed along the Valdivian Temperate rainforest. We used mtDNA control region (654 bp) and cytochrome b (734 bp) sequences to understand the consequences in the evolutionary history and population structure of Pudu puda island–continent isolation. Bayesian and Maximum Likelihood phylogenetic analysis revealed two divergent clades corresponding to the continent and Chiloe Island. The Median Joining Network also supports these findings with an isolation of 10 mutational steps between Chiloe and the continent. We also found a significant hig...
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First report of paratuberculose in Southern Pudu deer (Artyodactila: Cervidae)
Arquivo Brasileiro de Medicina Veterinária e Zootecnia, 2011Co-Authors: Daniel González-acuña, V. Neira-ramirez, L. Moreno-salas, M. QuezadaAbstract:Descreve-se o primeiro caso de paratuberculose em veado Pudu-do-sul (Pudu Pudu). O animal foi encontrado na cidade de Concepcion, centro sul do Chile, em pessimas condicoes e com sinais claros de diarreia. Internamente apresentava seria atrofia de gordura no coracao, lesoes histologicas nos pulmoes, figado, baco e rins, e injurias intestinais. Diferentes amostras foram preparadas com Ziehl-Neelsen, e os linfonodos mesentericos presentes no ileo foram fortemente positivos para a bacteria resistente ao acido.
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Evaluating mortality sources for the Vulnerable Pudu Pudu puda in Chile: implications for the conservation of a threatened deer
Oryx, 2009Co-Authors: Eduardo Silva-rodriǵuez, Alejandro Aleuy, Gabriel Ortega-Solís, Felipe Osorio-Zúñiga, J Sanderson, Claudio Verdugo, Daniel González-acuñaAbstract:Weassessed the importance of potential sources of mortality for the Vulnerable southern Pudu Pudu puda in southern Chile using the clinical records of wildlife re- habilitation centres, necropsies of animals found in the field and a review of the diet of potential predators. To assess whether the identified mortality sources operate in nomi- nally protected areas, we conducted a camera-trap survey in two areas to determine the presence of Pudus and their potential predators. Predation by domestic dogs Canis lupus familiaris and car collisions were the commonest causes of Pudu admissions to rehabilitation centres (35 of 44) and of deaths of animals encountered opportunistically in the field (seven of 14). Field data suggest that poaching could also be an important threat to Pudus. Pudus were detected in both areas surveyed, accounting for 15.6%of mammal detections. Dogs accounted for 47.8% of all detections of potential predator species, followed by pumasPuma concolor (17.4%), guignas Leopardus guigna (17.4%) and chilla foxes Lycalopex griseus (17.4%). The literature survey implicated onlypumas as important Pudu predators among native carnivores. Our data suggest that, aside from forest loss, dogs, road kills and probably poaching are important concerns for Pudu con- servation. Our frequent detections of free-ranging dogs associated with roads within nominally protected areas suggest that long-term efforts to conserve Pudu will require not only the protection of remnant native forest but also substantive environmental education to modify dog man- agement near protected areas.
Melissa A. Pavez-fox - One of the best experts on this subject based on the ideXlab platform.
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Correspondence between the habitat of the threatened pudú (Cervidae) and the national protected-area system of Chile
BMC ecology, 2016Co-Authors: Melissa A. Pavez-fox, Sergio A. EstayAbstract:Currently, many species are facing serious conservation problems due to habitat loss. The impact of the potential loss of biodiversity associated with habitat loss is difficult to measure. This is particularly the case with inconspicuous species such as the threatened Pudu (Pudu puda), an endemic Cervidae of temperate forests of Chile and Argentina. To evaluate the effectiveness of the Chilean protected-area system in protecting the habitat of the Pudu, we measured the congruence between this specie’s potential distribution and the geographical area occupied by the protected areas in central and southern Chile. The measurements of congruency were made using the Maxent modeling method. The potential habitat of the Pudu was found to be poorly represented in the system (3–8 %) and even the most suitable areas for the species are not currenly protected. According to these results, the protected area network cannot be considered as a key component of the conservation strategy for this species. The results presented here also serve as a guide for the reevaluation of current Pudu conservation strategies, for the design of new field studies to detect the presence of this species in human-disturbed areas or remaining patches of native forest, and for the implementation of corridors to maximize the success of conservation efforts.
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Correspondence between the habitat of the threatened pudú (Cervidae) and the national protected-area system of Chile
BMC ecology, 2016Co-Authors: Melissa A. Pavez-fox, Sergio A. EstayAbstract:Background Currently, many species are facing serious conservation problems due to habitat loss. The impact of the potential loss of biodiversity associated with habitat loss is difficult to measure. This is particularly the case with inconspicuous species such as the threatened Pudu (Pudu puda), an endemic Cervidae of temperate forests of Chile and Argentina. To evaluate the effectiveness of the Chilean protected-area system in protecting the habitat of the Pudu, we measured the congruence between this specie’s potential distribution and the geographical area occupied by the protected areas in central and southern Chile. The measurements of congruency were made using the Maxent modeling method.
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Muzzle morphology and food consumption by Pudu (Pudu puda Molina 1782) in south-central Chile
Studies on Neotropical Fauna and Environment, 2015Co-Authors: Melissa A. Pavez-fox, Mario Pino, Paulo CortiAbstract:The southern Pudu (Pudu puda) is one of the smallest living deer of the world. It inhabits the temperate rainforest of Chile and Argentina, where it is considered vulnerable due to decreasing populations. To improve the existing information concerning its feeding ecology, we performed morphometric measurements on skulls and jaws (n = 22), and observed feeding behavior on individual deer (n = 14). The Pudu presented an oral morphology adapted to select specific parts of plants, and a brachyodont molar type, which is consistent with the selective browsing style and consumption of primarily dicotyledonous plants. This information can be used to infer habitat relationships and needs of the Pudu during the growth season.
A. Lobos - One of the best experts on this subject based on the ideXlab platform.
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Effect of antiandrogen cyproterone acetate on the development of the antler cycle in Southern Pudu (Pudu puda).
The Journal of experimental zoology, 2002Co-Authors: G. A. Bubenik, Eugenia Reyes, D. Schams, A. Lobos, Ludĕk Bartos̆, Fernando KoernerAbstract:The antler cycle of Pudu is similar to other cervids, but unlike most boreal deer, male Southern Pudu (Pudu puda) exhibits two seasonal peaks of LH and testosterone. In that respect, Pudu is similar to roe deer. Whereas the antler cycle in some deer species, such as roe deer or white-tailed deer, is very sensitive to variation of testosterone, in other cervids, such as fallow deer or reindeer, a blockade of androgens with cyproterone acetate (CA) has little or no effect on the timing of the antler casting. In order to test the sensitivity of Pudu antlers to variations of androgens, CA (administered 2× weekly at 50 mg/buck) was injected intramuscularly for 3 weeks in 5 adult male Pudu, starting February 19 (late summer). Four other males of similar age served as controls. The experiment was performed at the University of Concepcion, Chile, latitude 36.6°S. Blood samples were taken once a week between January 19 and April 3. In CA-treated bucks, the antlers were cast approximately 3 weeks after the initiation of CA treatment and a new antler growth began almost immediately. The antlers reached about 5 cm in length, before ceasing to grow at the end of April, when they became mineralized and were subsequently polished. CA had no effect on the already declining levels of LH. Plasma levels of testosterone in controls increased from February 15, whereas in CA-treated bucks remained depresses until March 21. It is concluded that similarly to white-tailed deer, the antler cycle of Southern Pudu is very sensitive to manipulation of androgen levels. J. Exp. Zool. 292:393–401, 2002. © 2002 Wiley-Liss, Inc.
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Pudu, the smallest deer of the world: 10 years of endocrine studies of Southern Pudu (Pudu puda) in Chile
Zeitschrift für Jagdwissenschaft, 2000Co-Authors: G. A. Bubenik, Eugenia Reyes, D. Schams, A. Lobos, L. BartošAbstract:Die ersten 10 Jahre der Forschung über Physiologie und Verhalten der Pudu konzentrierten sich auf Untersuchungen der männlichen Hormonprofile. Grund- und jahreszeitliche Gehalte von LH (Luteotropin), FSH (Follikelstimulierendes Hormon), Testosteron, Prolaktin, IGF-1 (insulin-like growth factor 1), Kortisol und Trijodthyronin wurden bestimmt. Zusätzlich wurde über die Grundgehalte und die Werte nach Stimulation von Kortisol, Wachstumshormon (GH), LH, FSH und Testosteron nach ACTH (Adrenocorticotropes Hormon) und GnRH (Gonadotropin-Releasing Hormon) Challenge-Tests berichtet. Die meisten Hormonwerte im Blut der männlichen Pudu sind in den unteren Bereichen häufig um die Hälfte geringer als die Hormongehalte eines anderen kleinen Cerviden, dem Rehwild. Der Pudu antwortet schnell auf stimulierten Stress und GnRH löst einen heftigen Anstieg von LH und Testosteron bei dominanten Männchen aus. Die nächste Phase der Forschung wird sich nun auf die weibliche Endokrinologie konzentrieren. Derzeit erfolgt die Bestimmung saisonaler Gehalte weiblicher Fortpflanzungshormone. The first ten years of research on Pudu physiology and behavior concentrated on the investigation of hormone profiles in males. Basic and seasonal levels of LH, FSH, testosterone, prolactin, IGF-1, cortisol and triiodothyronine were determined. The seasonal fluctuations of reproductive and other hormones are related to the reproductive and the antler cycles and the social rank of individual males. In addition, basal and poststimulatory levels of cortisol, growth hormone (GH), LH, FSH and testosterone were reported after ACTH and GnRH challenge tests. Most blood levels of hormones in male Pudu are in the low range often less than half of hormonal levels of another small cervid, the roe deer. Pudu responds quickly to simulated stress and GnRH elicits a vigorous increase of LH and T in the dominant males. The next phase of our research is now concentrated on the reproductive physiology of the female Pudu, where a delayed implantation of the embryo is suspected. Les 10 premières années de recherche sur la physiologie et sur le comportement du Pudu ont été consacrées à l'étude des profils hormonaux chez les mâles. Les niveaux de base et les variations saisonnières ont été déterminées en ce qui concerne la LH, la FSH, la testostérone, la prolactine, l'IGF-1, le cortisol et la triiodothyronine. Les variations saisonnières des hormones gonadotropes et d'autres hormones sont liées aux cycles de la reproduction et du développement des bois ainsi qu'au rang social des différents mâles. En outre, les niveaux de base et post-stimulatoires de cortisol, des hormones de croissance (GH), LH, FSH et testostérone ont été renseignés après des tests de challenge à l'hormone adrénocorticotrope (ACTH) et à l'hormone de déclenchement gonadotrope (GnRH). La plupart des niveaux hormonaux sanguins chez le Pudu sont faibles : ils sont souvent de moitié inférieurs à ceux d'un autre cervidé de petite taille tel que le Chevreuil. Le Pudu répond rapidement au stress simulé et le GnRH déclenche une forte augmentation de LH et de testostérone chez les mâles dominants. La phase suivante de notre recherche se concentre à présent sur la physiologie de la reproduction chez la femelle du Pudu où une nidation différée est suspectée.
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Pudu, the smallest deer of the world: 10 years of endocrine studies of Southern Pudu (Pudu puda) in Chile
Zeitschrift für Jagdwissenschaft, 2000Co-Authors: G. A. Bubenik, Eugenia Reyes, D. Schams, A. Lobos, Ludek BartosAbstract:The first ten years of research on Pudu physiology and behavior concentrated on the investigation of hormone profiles in males. Basic and seasonal levels of LH, FSH, testosterone, prolactin, IGF-1, cortisol and triiodothyronine were determined. The seasonal fluctuations of reproductive and other hormones are related to the reproductive and the antler cycles and the social rank of individual males. In addition, basal and poststimulatory levels of cortisol, growth hormone (GH), LH, FSH and testosterone were reported after ACTH and GnRH challenge tests. Most blood levels of hormones in male Pudu are in the low range often less than half of hormonal levels of another small cervid, the roe deer. Pudu responds quickly to simulated stress and GnRH elicits a vigorous increase of LH and T in the dominant males. The next phase of our research is now concentrated on the reproductive physiology of the female Pudu, where a delayed implantation of the embryo is suspected.
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Rank dependent seasonal levels of IGF-1, cortisol and reproductive hormones in male Pudu (Pudu puda)
Comparative Biochemistry and Physiology A-molecular & Integrative Physiology, 1998Co-Authors: Ludek Bartos, G. A. Bubenik, Eugenia Reyes, D. Schams, A. LobosAbstract:Abstract We tested the following hypothesis: when two Pudu males share a single pen throughout the year, the dominant animal will have a higher level of IGF-1 than its subordinate pen mate, particularly during the period of increased social friction (e.g. rut and establishment of territories). To test this hypothesis, we used data from six adult males maintained at the University of Concepcion, Chile (latitude 36.6° S), and analysed them from the males' dominance point of view. Two males plus eight to ten females were kept in one pen and although we did not specifically measure dominance, the rank position was obvious from frequent encounters between the bucks. Three consecutive blood samples were taken monthly over the period of 1 year. In addition to IGF-1, we also analysed seasonal levels of testosterone, cortisol, prolactin, LH and FSH. The analysis revealed that IGF-1 levels of dominant males were significantly higher than those of subordinate males from September to November (the second part of the antler growing period and time of establishing territories). Testosterone levels were higher and FSH levels were lower in dominant males during the rut. Levels of prolactin were higher in dominant animals in November (summer). Cortisol and LH did not show any significant differences between dominant and subordinate males. This data provides the first evidence indicating the possible link between dominance and blood levels of IGF-1. The functional explanation of such links is discussed.
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Seasonal changes of testicular parameters in southern Pudu Pudu puda in relationship to circannual variation of its reproductive hormones
Acta Theriologica, 1997Co-Authors: Eugenia Reyes, G. A. Bubenik, D. Schams, A. Lobos, Rosa EnriquezAbstract:Seasonal variation of testicular and epididymal parameters in the smallest deer, the southern Pudu Pudu puda Molina, 1782 were related to the circannual fluctuation of plasma levels of its reproductive hormones. The diameter and the length of testes, the diameter of epididymis as well as the diameter and the heights of epithelium of seminiferous and epididymal tubules were measured. Morphological evaluation of spermatogenesis were performed on histological sections of testicular and epididymal tissues. Most of these gonadal parameters exhibit a seasonal variation which is in accordance with the reproductive pattern as well as the variation of reproductive hormones. Seasonal fluctuations of LH and testosterone indicate two seasonal activations of the reproductive system, one in the spring (antler mineralization), the other in the fall (rut). FSH exhibit one prolonged peak (summer to fall) whereas prolactin follows the expected, photoperiodically-dependant time course with peak levels around the summer solstice. The measurements of testicular parameters indicate a prolonged period of gonadal activity in southern Pudu but the period of maximal reproductive stimulation is limited to the time around the rut.
