Update of Cestodes Parasitizing Neotropical Hystricomorphic Rodent.

This review aims at identifying cestodes that are present in hunted rodent species in the neo-tropical region. The rodent species that was investigated were the capybara (Hydrochoerus hydrochaeris, Linnaeus, 1766), lappe (Cuniculus paca, Linnaeus, 1766), agouti (Dasyprocta leporina, Linnaeus, 1758), chinchilla (Chinchilla chinchilla, Lichtenstein, 1829), Trinidad spiny rat (Proehimys trinitatus, Allen and Chapman, 1893), nutria (Myocastor coypus, Molina, 1782), and vizcacha (Lagostomus maximus, Desmarest, 1817). These rodent species are utilized for their meats in many rural communities in the Caribbean and South America. These rodents belong to the hystricomorphic group. Raillietina demerariensis Daniels, 1895 was commonly found in the gastrointestinal tract of D. leporina, C. paca and P. trinitatus. Similarly, in the liver, muscle and subcutaneous tissue the metacestodes on Echinococcus vogeli Daniels, 1895 and Echinococcus oligarthrus was found in the lappe and agouti. The capybara was found to have the most species of cestodes in its gastrointestinal tract when compared to the agouti and lappe. However, metacestodes were not recorded in the tissues of the capybara. This surprising feature shows the effect of the difference in feeding habits between the capybara and the agouti and lappe. The literature reviewed in this study includes scientific publications on cestodes and metacestodes of Hystricomorphic rodents. An exhaustive search was performed using the digital repositories in Google Scholar, Scielo, Redalyc, Scopus and Pubmed. Literature searched spanned the years 1970-2021. Cestodes of zoonotic significance were E. vogeli and E. oligarthrus, with humans becoming infected when consuming eggs of contaminated food and water. The agouti and lappe act as intermediate host in the life cycle of E. vogeli and E. oligarthrus, the definitive host (canids and felids) become infected by consuming of tissue infected with metacestodes. Humans become infected through the ingestion of eggs from the definitive host where cystic lesions develop in the liver, lungs and other abdominal organs.

Trichuris spp. in Animals, with Specific Reference to Neo-Tropical Rodents.

Trichuriasis is the clinical disease of animals infected with the parasite of the genus Trichuris. This review attempts to present information on Trichuris spp. infestation in neo-tropical rodents that are utilized for meat consumption by humans. Neo-tropical rodents utilized for meat production can be divided into two categories: those that have been domesticated, which include the guinea pig (Cavia porcellus), and those that are on the verge of domestication, such as the capybara (Hydrochoerus hydrochaeris), lappe (Cuniculus paca/Agouti paca), and agouti (Dasyprocta leporina). This document reviews the literature on the species of Trichuris that affects the rodents mentioned above, as well as the clinical signs observed. The literature obtained spans over sixty years, from 1951 to 2020. Trichuris spp. was found in these neo-tropical rodents mentioned. However, there is a dearth of information on the species of Trichuris that parasitize these animals. The capybara was the only rodent where some molecular techniques were used to identify a new species named T. cutillasae. In most cases, Trichuris spp. was found in combination with other endoparasites, and was found at a low prevalence in the lappe and guinea pig. The presence of Trichuris spp. ranged from 4.62-53.85% in the agouti, 4.21-10.00% in the lappe, 50% in the capybaras, and 1-31% in guinea pigs. Further work must be done towards molecular identification of various Trichuris spp. present in these rodents, as well as the clinical effect of infection on the performance of agouti, lappe, capybara, and guinea pigs.

Reproductive Technologies Used in Male Neo-Tropical Hystricomorphic Rodents.

This review, which is the first of two, focuses on the male reproductive anatomy and reproductive technologies used in Neo-tropical hystricomorphic rodents with the potential for domestication, which are the agouti (Dasyprocta leporina), the capybara (Hydrochoerus hydrochaeris) and the paca (Cuniculus paca). We consider over seventy references spanning from 1965 to 2020, with the majority of work being done in the past twenty years. Knowledge of the reproductive tract and reproductive technologies is critical to the conservation and preservation of these species. Although all three animals had similarities in their anatomy, such as no overt scrotums and testes located intra-abdominally in the inguinal region, some had unique features-for example, the agouti and the paca had penile spines, and two lateral penile cartilages. High spermatogenic efficiency was noted in the agouti and the paca, making them good candidates for increasing their reproductive performance in conservation programs. A review of the literature has shown that there is increasing work taking place on the reproductive technologies used in these animals; however, a lot of work is still lacking, as, to the author's knowledge, standard protocols and artificial insemination procedures are yet to be established.

Nutritive Value and Physical Properties of Neo-Tropical Rodent Meat-with Emphasis on the Capybara (Hydrochoerus hydrochaeris).

This review will focus on the nutritive characteristics of meat from neo-tropical rodents which have not yet been domesticated. These rodents include the capybara (Hydrochoerus hydrochaeris), agouti (Dasyprocta leporina), and the lappe (Agouti paca). Information about the meat characteristics of these rodents were obtained from peer reviewed journal articles. Literature was obtained using search engines such as Google Scholar, Uwi linc, and Pub Med Central. Keywords used in the searches were "capybara", "Hydrochoerus hydrochaeris", "agouti", "Dasyprocta leporina", "Agouti paca/Cuniculus paca", lappe", and "meat proximate analysis". Over four decades of literature was searched, spanning from the 1970s to 2020. There is a vast amount of information on the meats of the capybara, but limited information on the lappe, and there is a dearth of information on the agouti. Capybara meat is considered to be highly nutritious, with high levels of polyunsaturated fatty acids (PUFA), low levels of saturated fatty acids (SFA), low levels of fats and cholesterol. The animals that were reared in conditions which were similar to their habitat had lower levels of SFA. Diet, age, confinement, and sex had an effect on the chemical composition of the meat of the capybara. On average, capybara meat had a moisture content of 75%, protein 22%, ash 1.5%, and lipid 1%. During the authors' search of the literature, no information was found on the proximate composition of the lappe or agouti meat. Information regarding the fatty acid profile of lappe meat was found, as well as a description of the physical characteristics of agouti and lappe meat. The physical parameter shows that the lappe has the most tender meat of the three rodent species, while the agouti has the least tender meat, and the capybara being intermediary. Neo-tropical rodent meat is highly nutritious, and is an excellent protein alternative for the growing population of the world. These animals are adapted to challenging environments and can grow well using locally available feed resources. However, further research needs to be conducted on the proximate analysis on lappe and agouti meat to fully inform consumers about its nutrient value.

Endoparasites of Selected Native Non-Domesticated Mammals in the Neotropics (New World Tropics).

In this review, information was summarized on endoparasites found in six non-domesticated neotropical animals. These mammals have the potential to be domesticated. The animals included three rodents, agouti (Dasyprocta leporina), lappe (Agouti paca), and capybara (Hydrochoerus hydrochaeris); a marsupial, manicou (Didelphis marsupialis insularis); and an artiodactyl, the collared peccary (Tayassu tajacu/Peccari tajacu) and a ruminant (the red brocket deer, Mazama americana). While there are many descriptions of the parasites present, the majority of publications failed to note the effect of them on the animals. Most information is available on endoparasites of capybara, while the endoparasites of the red brocket deer were the least reported. The manicou was reported to have had the most number of endoparasites, 44 species of parasites were reported, while there were only 24 endoparasites reported in the lappe. The most common parasites found in these neotropical animals were Paraspidodera uncinata, Strongyloides spp., Eimeria spp., Moniezia benedeni, Trichuris spp., Physocephalus spp., and Giardia spp. A large majority of the studies concluded that these animals were reservoirs for parasites that could affect domesticated livestock. Endoparasites of zoonotic significance were Echinoccocus spp., Trichuris spp., Giardia spp., and Cryptosporidium spp.

Nutrition of Six Selected Neo-Tropical Mammals in Trinidad and Tobago with the Potential for Domestication.

This review highlights the available literature on the nutrition of six neo-tropical animals with the potential for domestication-the agouti (Dasyprocta leporina/D. aguti), lappe (Agouti paca), capybara (Hydrochoerus hydrochaeris), manicou/opossum (Didelphis marsupialis insularis), collared peccary (Peccary tajucu) and the red brokcet deer (Mazama americana). Over 100 references were used, spanning over 100 years. The earliest being 1915 and the most recent being 2018. The references used in this review were synthesized to give a detailed look of the dentition, anatomy of the gastrointestinal tract and type of feed these animals consume. Nutritional requirements of the animals are required to understand what is needed for growth, maintenance and reproduction of each physiological stage. The agouti (D. leporina/D. aguti) was observed to be a monogastric mammal that fed primarily on fruits, seeds, animal matter and practiced caecotrophy. The lappe/paca (C. paca/A. paca) was described as a strict herbivore and a frugivore which practiced caecotrophy, with a diet that varied throughout the year, according to food availability. The capybara (H. hydrochaeris) was found to be the largest known rodent and was described as a semiaquatic hindgut fermenter that practiced caecotrophy. The manicou/opossum (D. marsupialis insularis) was found to be an omnivore with a simple stomach. The collared peccary (T. tajacu) was found to be frugivorous. Their unique stomach enabled them to consume a wide variety of feedstuff, allowing them to be found in a wide range of habitats. The red brocket deer (M. americana), a ruminant, was described as a browser that consumed mainly fruits and seeds and they frequented mineral lick. Knowledge of what they consume in the wild is important, so that we know what to feed in captivity. There is also the need to evaluate captive diets while trying to domesticate these mammals and develop nutrient requirement tables for these neo-tropical animals. Finally, an understanding of the dentition and gastrointestinal tract is important to increase efficiency (nutritional and cost). These six neo-tropical mammals were chosen due to their prevalence as game species in Trinidad and Tobago.

Hidatidose policística no norte do Brasil: abordagem parasitológica e histopatológica de pacas e casos humanos / Polycystic hydatid in northern Brazil: parasitological and histopathological approach from human and pacas cases

A hidatidose policística é uma zoonose causada pelo cestóide Echinococcus vogeli, amplamente distribuído no norte do Brasil. Os hospedeiros definitivos são Speothos venaticus (cachorro-vinagre) e Canis familiaris (cães domésticos), enquanto Agouti paca (paca) é hospedeiro intermediário. Tanto as pacas quanto o homem (hospedeiro acidental) desenvolvem a forma larvar (metacestóide), principalmente na superfície e no interior do fígado. Esta tese tem como objetivo geral estudar as características parasitológicas e histopatológicas de metacestóides de E. vogeli, originários de pacas e humanos da região norte do Brasil, visto o conhecimento insuficiente ou mesmo o seu desconhecimento. Os fígados e mesentérios foram obtidos de oito pacientes com hidatidose policística durante ato cirúrgico na Fundação Hospital Estadual do Acre. Pacas foram capturadas no Município de Bujari, Floresta Estadual do Antimary, Acre. Durante a necropsia das pacas, foram observadas lesões macroscópicas (massas esbranquiçadas ou amareladas, semelhantes a bolhas na superfície dos fígados). Para a análise parasitológica foram aplicadas as microscopias de luz, contraste interferencial de Normaski (DIC) e varredura laser confocal. A análise morfométrica foi realizada com o auxílio do Programa Image Pro Plus Media Cybernetics. Os órgãos de pacas e humanos foram submetidos à análise histopatológica. Os pequenos e grandes ganchos rostelares apresentaram polimorfismo morfológico, enquanto a organização dos protoescólices acompanhou o padrão descrito para Echinococcus sp. Todas as pacas apresentavam cistos hepáticos, porém em apenas duas encontramos líquido hidático, comprovados pela presença dos ganchos e protoescólices. A análise histopatológica dos tecidos hepáticos das pacas confirmou a hidatidose policística e evidenciou, pela presença de agrupamentos de ovos, a coinfecção com Calodium hepaticum. As características morfológicas dos ganchos rostelares dos casos humanos não diferiram...

Polycystic hydatidosis is a zoonotic disease caused by the cestode Echinococcus vogeli, largely distributed in northern Brazil. The definitive hosts are Speothos venaticus (bush dogs) and Canis familiaris (domestic dogs), while Agouti paca (paca) is the intermediate host. Both the pacas and man (accidental host) develop the larval form (metacestodes), mainly on the surface and inside the liver. This thesis aims to study histopathological and parasitological characteristics of metacestodes of E. vogeli, from pacas and humans of the north region of Brazil, seen the insufficient knowledge or lack of it. The mesentery and livers were recovered from eight patients with polycystic hydatidosis during surgery in the Acre State Hospital Foundation. Pacas were captured in the municipality of Bujari, Antimary State Forest, Acre. During the pacas necropsy, macroscopic lesions were observed (whitish or yellowish masses, similar to blisters on the surface of the liver). Identification analyses were applied to light microscopy, interferential contrast microscopy of Normaski (DIC) and confocal laser scanning microscopy. Morphometric analysis was performed by Image Pro Plus Media Cybernetics program. The pacas and human organs were subjected to histopathological analysis. The small and large rostellar hooks presented morphological polymorphism while protoscoleces organisation accompanied the pattern described in Echinococcus sp. All pacas presented liver cysts, however in only two found proven by the presence of hydatid fluid, hooks and protoscoleces. Histopathological analysis of pacas’ hepatic tissues confirmed polycystic hydatidosis and evidenced by the presence of eggs clusters the Calodium hepaticum coinfection. The morphological characteristics of human cases rostellar hooks did not differ from described to the pacas; however, the hooks were greater than the mesenteric ones. Already in relation to protoscoleces, the mesenteric ones were larger than the liver...

Características regionais sobre a ultra-estrutura das células principais do epitélio do ducto epididimal de Agouti paca / Regional ultra structural features of principal cells from the epididymal epithelium lining of Agouti paca

As células principais (P) do epitélio de revestimento do epidídimo de paca foram relacionadas com processos citofisiológicos de endocitoses do tipo adsortiva e de fase fluida, respectivamente, aparentemente realizando também secreção apócrina. Essas funções foram propostas embasando-se em características de ultra-estrutura das células P, em cujos citoplasma observaram-se um expressivo número de vesículas, com diferentes formas, tamanhos e presença de conteúdo internalizado em algumas das vesículas revestidas por endomembranas, ocorrendo ainda caveolas e vesículas diminutas localizadas junto à borda apical de microvilos. Ademais, observaram-se vesículas grandes e revestidas e/ou com superfícies lisas; endossomos, e lisossomos de localização predominantemente apical. Uma via de secreção apócrina foi sugerida com base na ocorrência de expansões (protrusões), citoplasmáticas intraluminais nas células P.

The principal (P) cells of epididymidis surface epithelium of Agouti paca were related to processes of adsorptive endocytosis and phase-fluid endocytosis, as well as protein secretion apparently also occur.These findings had been proposed on the base the cytoplasmic ultrastructural features of P cells in which were seen an expressive number of vesicles with several shapes, sizes and internalized content occurring also smaller pits and pale small vesicles located next to the apical brush border of microvilli. Moreover, occurred coated vesicles, smooth surface vesicles and great vesicles; multivesicular bodies, endosomes and lysosomes mainly viewed on supranuclear and apical positions. Presence of an appocrine secretory pathway was characterized in P cells through the occurrence of apical cytoplasmic expansions, protruding into the ducts epididymidis luminal compartment.

Familial osteopetrosis in Agouti paca: report of nine cases / Osteopetrose familiar em Agouti paca: relato de nove casos

Nine cases of familial osteopetrosis were studied in Agouti paca rodents maintained in captivity. Animals were distributed in three groups depending on the severity of their skeletal lesions. Based upon clinical, radiological, and microscopic findings, it was concluded that one animal had level I lesions, three animals had level II lesions, and five animals had level III osteopetrosis and osteonecrosis. Throughout the entire axial and appendicular skeleton, there was an increased amount of both trabecular and cortical bone tissue. All analyzed bones showed thickened cortex and reduced medullary canals. Bone trabeculae were thick and confluent. Cortex showed a narrowing of Haversian canals. Numerous cementing lines resulted in typical mosaic patterns. Osteocytes were pycnotic. Osteonecrosis was characterized by the disappearance of osteocytes and bone matrix decomposition.

Descreveram-se nove casos de osteopetrose familiar em Agouti paca mantidas em cativeiro. Os animais foram distribuídos em três grupos de acordo com a gravidade das lesões do esqueleto. Com base nos exames clínico, radiológico e microscópico, foi concluído que um animal apresentou lesões de nível I, três animais tiveram lesões de nível II e cinco animais tiveram osteopetrose de nível III. Por todo o esqueleto axial e apendicular, a quantidade de osso trabecular e osteônico estava aumentada. Todos os ossos analisados mostraram córtex espesso e canais medulares reduzidos. As trabéculas ósseas eram espessas e confluentes. No córtex, verificou-se um estreitamento de canais de Havers. Numerosas linhas de cimentação resultaram em um padrão de mosaico típico. Osteócitos estavam picnóticos e a osteonecrose foi caracterizada pela morte dos osteócitos, com desintegração da matriz óssea.

Aspectos morfológicos do saco vitelino em roedores da subordem Hystricomorpha: paca (Agouti paca) e cutia (Dasyprocta aguti) / Morphological aspects of yolk sac from rodents of Hystricomorpha subordem: paca (Agouti paca) and agouti (Dasyprocta aguti)

Este trabalho visou caracterizar macro e microscopicamente o saco vitelino em pacas (Agouti paca) e cutias (Dasyprocta aguti) no início de gestação. Três embriões/fetos de pacas e três de cutias foram utilizados para a análise do saco vitelino, durante as fases iniciais de gestação. Fragmentos do saco vitelino foram removidos do embrião/feto e rotineiramente processados para inclusão em parafina (técnica histológica rotineira) e em resina Spurr (análise ultra-estrutural). Macroscopicamente, a placenta vitelínica em ambas as espécies inseria-se na superfície da placenta principal, com suas margens projetando-se completamente sobre o embrião/fetos. Na microscopia de luz, a placenta vitelínica apresentava-se constituída pelo epitélio endodérmico e um mesenquima com inúmeros vasos vitelínicos. Ultraestruturalmente, a placenta vitelínica visceral da paca era formada por células endodérmicas com núcleos na região mediana e da cutia por núcleos dispostos apicalmente; outra característica foi o grande número de mitocôndrias, vesículas de conteúdo eletrodenso e com microvilosidades. Com base nos resultados concluímos, que (1) a placenta vitelínica das duas espécies apresenta inserção na superfície da placenta principal; (2) a placenta vitelínica de paca se apóia na membrana de Reichert, diferentemente da cutia, que não possui tal membrana; (3) o cório e alantóide apresentam-se fusionados, formando a placenta corioalantoídea; e (4) o saco vitelino em ambas as espécies é invertido e vascularizado.

The study aimed to characterize gross and microscopic features of the yolk sac in paca (Agouti paca) and agouti (Dasyprocta aguti) in early gestation. Fragments of the yolk sac of 3 paca and 3 agouti fetuses at early gestation were taken and processed for histological and ultrastructural analyses. Gross features of the vitelline placenta in both species showed its insertion over the main placenta surface and projections to the embryos/fetuses. Microscopically, the vitelline placenta was constituted by endoderm epithelium and mesenchyme, in which vitelline vessels are abundant. The ultrastructure of the samples showed that the visceral yolk sac of the paca was formed by endodermic cells with nuclei in the median region, and that the visceral yolk sac of the agouti was formed by nuclei arranged apically; other characteristic was the large number of mitochondrias, eletrodense vesicles with microvilosities We conclude that (1) the vitelline placenta of the two species presents insertion in the surface of the main placenta; (2) the vitelline placenta of paca rests on the Reichert's membrane, whereas the agouti vitelline placenta does not have this membrane; (3) the chorion and allantoic are fusioned; and (4) the chorioallantoic placenta and the yolk sac in both species are reversed and vascularized.

Características reprodutivas da paca fêmea (Agouti paca) criada em cativeiro / Reprodutive characteristics of the female paca (Agouti paca) raised in captivity

O objetivo do trabalho foi estudar a biologia reprodutiva da Agouti paca criada em cativeiro. Os resultados demonstraram que, a duração média do ciclo estral foi de 32,5 + 3,7 dias e o período gestacional de 148,6 + 4,8 dias. O intervalo entre partos foi de 224,5 + 52,2 dias e o primeiro cio pós-parto foi de 25,6 + 8,8 dias. A maioria (55,6 por cento) das fêmeas apresentou dois partos por ano, com o nascimento de um filhote por parto, sendo 44,7 por cento fêmeas e 55,3 por cento machos. Ao nascer o peso médio das fêmeas foi de 605,9 + 87,5 g e dos machos 736,7 + 108,4 g (P < 0,05). A puberdade das fêmeas ocorreu entre o 8º e 12º mês, porém neste aspecto são necessárias investigações mais detalhadas.

The objective of this paper was to study the reproductive biology of the Agouti paca raised in captivity. It was observed that the estrous cycle average was 32.5 + 3.7 days, gestation length 148.6 + 4.8 days, parturition interval 224.5 + 52.2 days, and the first post-partum 25.6 + 8.8 days. It was also observed that 55.5 percent of the females presented two parturitions per year with one young per parturition, of which 44.7 percent were females and 55.3 percent were males. The birth weight was 605.9 + 87.8 g for females and 736.7 + 108.4 g for males (P<0.05). Puberty in females occurred between 8 to 12 months; for this, however, more detailed investigations are necessary.

Variaciones nucleotídicas de dos grupos de tepezcuintles, Agouti paca (Rodentia: Agoutidae), en cautiverio provenientes de dos localidades de Yucatán, México / Nucleotidic variations of two captive groups of tepezcuintle, Agouti paca (Rodentia: Agoutidae), from two sites in Yucatan, Mexico

The objective of this work was to estimate the nucleotidic variation between two groups of tepezcuintles (Agouti paca) from the states of Campeche and Quintana Roo, Mexico and within members of each group. Blood samples were collected from eleven A. paca kept in captivity. DNA from leukocytic cells was used for Ramdom Amplification of DNA Polimorphism (RAPD). The primers three 5'-d(GTAGACCCGT)- 3' and six 5'-d(CCCGTCAGCA)- 3' were selected from de Amersham kit (Ready.To.Go. RAPD Analysis Beads, Amersham Pharmacia Biotech), because they produced an adequate number of bands. The electrophoretic pattern of bands obtained was analyzed using software for phylogenetic analysis based on the UPGMA method, to estimate the units of nucleotidic variation. The phylogenetic tree obtained with primer three reveals a dicotomic grouping between the animals from both states in the Yucatan Peninsula showing a divergent value of 1.983 nucleotides per hundred. Animals from Quintana Roo show a grouping with primer six; an additional grouping was observed with animals from Campeche. Nucleotidic variation between both groups was 2.118 nucleotides per hundred. The nucleotidic variation for the two primers within the groups from both states, showed fluctuating values from 0.46 to 1.68 nucleotides per hundred, which indicates that nucleotidic variation between the two groups of animals is around two nucleotides per hundred and, within the groups, less than 1.7 nucleotides per hundred.

Estimamos las variaciones nucleotídicas entre dos grupos de tepezcuintles (Agouti paca) provenientes de los estados de Campeche y Quintana Roo, México y, dentro de cada grupo. Se colectaron muestras sanguíneas de once A. paca mantenidos en cautiverio. El ADN de leucocitos se utilizó para efectuar la amplificación aleatoria de polimorfismos de ADN (RAPD). Se seleccionaron los iniciadores número tres 5’ -d(GTAGACCCGT)-3’ y seis 5’ -d(CCCGTCAGCA)-3’ del estuche (Ready.To.Go. RAPD Analysis Beads, Amersham Pharmacia Biotech), porque produjeron un adecuado número de bandas. Los patrones electroforéticos de bandas fueron procesados con el software para análisis filogenético basado en el método de UPGMA para estimar la variación nucleotídica. El árbol filogenético obtenido con el iniciador tres reveló una agrupación dicotómica entre los animales de ambos estados de la Península de Yucatán, con un valor de divergencia de 1.983 nucleótidos de cada cien. Los animales de Quintana Roo mostraron un agrupamiento con el iniciador seis y, otro grupo más con animales procedentes de Campeche. La variación nucleotídica entre estos dos grupos fue de 2.118 nucleótidos por cada cien. Las variaciones nucleotídicas dentro de los grupos procedentes de ambos estados, para los dos iniciadores, mostraron valores que fluctuaron entre 0.46 y 1.68 nucleótidos de cada cien, lo cual indica que la variación nucleotídica entre los dos grupos de animales es alrededor de dos nucleótidos por cada cien y, dentro de grupos es menor a 1.7 nucleótidos por cada cien.

Actividad ovárica del tepezcuintle Agouti paca (Rodentia: Agoutidae) en cautiverio / Ovarian activity of Agouti paca (Rodentia: Agoutidae) under captivity

The ovarian activity of Agouti paca was characterized by hormonal profiles and ovarian structures. Samples of blood were taken from eight females (seven adults and one juvenile) at the breeding grounds of the Facultad de Medicina Veterinaria y Zootecnia in Yucatsn, Mexico. Sampling lasted approximately two months and was done every three and six days. Blood was collected from anesthetized animals, and the levels of progesterone (P4) and 17 beta estradiol (E2) were analized by radioimmunoassay technique. Macroscopic and microscopic analyses were carried out in ovaries of dead animals. The estrous cycle lasted 29+/-8.4 days, levels of 1.61+/-0.65 ng/ml for P4 and 39+/-24 pg/ml for E2 were observed for a follicular phase, 6.18+/-3.70 ng/ml and 29+/-16 pg/ml for P4 and E2 respectively in the luteal phase. Statistically significant differences were found between phases for P4 but not for E2. The presence of extragonadal steroids with levels of P4 of 1.9+/-0.77 ng/ml and E2 of 22+/-17 pg/ml were observed, which are not produced by the effects of managing stress. The changes in the levels of P4 during the cycle are indicators of luteal activity, with the intersticial tissue acting probably as active steroids-producing gland. Follicular growth was observed during the entire cycle.

Se caracterizó la actividad ovárica de A. paca por medio de perfiles hormonales y estructuras ováricas. Se muestrearon ocho hembras (siete adultas y una juvenil) en el criadero de la Facultad de Medicina Veterinaria y Zootecnia en el estado de Yucatán, México, durante aproximadamente dos meses. Se recolectaron muestras sanguíneas cada 3 y 6 días en animales anestesiados. Se estimaron los niveles de progesterona (P4) y 17 beta estradiol (E2) sanguíneos por radioinmunoanálisis. Las estructuras ováricas de animales muertos durante el periodo de muestreo fueron analizadas macro y microscópicamente. El ciclo ovárico duró 29±8.4 días, con niveles de 1.61±0.65 ng/ml para P4 y de 39±24 pg/ml para E2 durante la fase folicular, y de 6.18±3.70 ng/ml y 29±16 pg/ml para P4 y E2 respectivamente, en la fase luteal. Hubo diferencias (p<0.05) en los niveles de P4 entre las fases folicular y luteal, no así para E2. Se detectó la presencia de esteroides extragonadales, con niveles de 1.9±0.77 ng/ ml para P4 y de 22±17 pg/ml para E2, los cuales no son secretados por efecto del estrés por manejo. Los cambios en los niveles de P4 durante el ciclo son indicadores de actividad luteal, funcionando el tejido intersticial probablemente como una glándula productora de esteroides. De igual forma se observó que el crecimiento folicular ocurre durante todo el ciclo.