Ovum pick-up and in vitro maturation in spotted paca (Cuniculus paca-Linnaeus, 1766).

We tested FSHp, eCG and FSHp + eCG to establish ovum pick-up (OPU) and in vitro maturation method in spotted paca. Eight healthy adult females were subjected to each of four treatments to stimulate ovarian follicular growth. All females were subjected to a hormonal protocol using a single dose of 45 mg of injectable progesterone and single intramuscular injection of 0.075 mg d-cloprostenol on day 6. Ovarian stimulation was carried out as follows: in Group TFE (FSHp and eCG), animals were treated with a single dose of 80 mg of FSHp and 200 IU of eCG intramuscularly on day 6 after the application of progesterone; in Group TF (FSHp), they were treated with a single dose of 80 mg of FSHp intramuscularly on day 6 after application of progesterone; in Group treatment eCG, they were treated with 200 IU of eCG intramuscularly on day 6 after application of progesterone; and in Group TC (saline solution), 1 ml of saline solution was administered to control does. The OPU was performed between 22 and 26 hr after gonadotropin treatments. All recovered oocytes were placed into maturation media and incubated for 24 hr. There were no differences among the mean number of observed follicles, aspirated follicles and oocytes recovered per treatment. Oocyte maturation rates did not differ among groups, except, TF and treatment eCG oocytes had greater maturation rates than TC oocytes. In this study, gonadotropin administration failed to superovulate treated does and increase oocyte retrieval efficiency. Despite the feasibility of the procedure, further studies are needed to develop and refine hormonal protocols for oocyte recovery and in vitro maturation in this species.

Age at sexual maturity, first parturition and reproductive senescence in wild lowland pacas (Cuniculus paca): Implications for harvest sustainability.

Generation length (GL) of a mammal, calculated through the age at sexual maturity, first reproduction and reproductive senescence can be used to assess the capacity of a population of a species to withstand differing amounts of hunting pressure by humans without depletion of animal numbers. Due to the lack of reproductive data for wild mammals, the GL is often difficult to determine for most species. In the present study, the GL parameters were assessed for the wild lowland paca (Cuniculus paca) from a sample of 119 female genitalia obtained during a 15-year hunter participatory program in the Amazon. The probability of female pacas being sexually active, with observable ovarian functionality or pregnancy, increased as both body and genitalia masses increased. The average body mass at puberty was 5.46 kg. Puberty was estimated to occur at 4 months of age, from which there was estimation when age at first parturition would occur 9 months after birth. Additionally, there was no indication that there was a decrease in parturition rate at more advanced ages. The estimated age of first reproduction for pacas was much less than previous estimates, most from assessments of captive animals. In addition, because there was no evidence of reproductive senescence, it is suggested that the average age of mature hunted pacas should be used to determine optimal harvesting rates of pacas by humans. The present study highlights the importance of in situ studies on reproduction of animals in their natural habitat because these will yield more accurate reproductive variable estimates than those obtained from captive animals. It is suggested that similar methods be used to accurately assess reproductive parameters of other tropical species that are hunted by humans.

Effect of different feeding regimes on cecotrophy behavior and retention of solute and particle markers in the digestive tract of paca (Cuniculus paca).

Many small herbivores practice cecotrophy - the ingestion of special feces enriched in microbial protein by colonic separation mechanisms (CSM). In digesta passage experiments, secondary marker excretion peaks in feces are considered indicative of marker-reingestion via cecotrophy, but corroboration by behavioral observation was lacking so far. The paca (Cuniculus paca), a Neotropical hystricomorph rodent, produces two different kinds of feces (hard and soft) and practices cecotrophy either directly (from the anus) or indirectly (from a pile of defecated feces, mostly when hard and soft feces are defecated together). To investigate effects of diet on cecotrophy, we monitored cecotrophy behavior and digesta passage marker excretion of solute and particle markers in four adult pacas, at constant food intake, on four diets varying in protein and fiber content. Marker excretion patterns suggested a 'mucus-trap' CSM typical for hystricomorph rodents, and showed secondary peaks of a similar time lag after cecotrophy as the primary marker peak after marker feeding. However, not every cecotrophy event was followed by a secondary marker peak. On higher fiber/lower protein diets, the number of cecotrophy bouts, the duration of cecotrophy, the number of secondary marker peaks and the difference between solute and particle marker retention increased, whereas the proportion of indirect cecotrophy decreased, indicating a higher degree of digesta phase separation on these diets. Compared to hard feces, soft feces were particularly enriched in solute marker concentration. Cecotrophy depends on a CSM that varies in its efficiency with the nutrient composition of the diet.

Direct and indirect caecotrophy behaviour in paca (Cuniculus paca).

The colonic separation mechanism in lagomorphs and some rodents, associated with caecotrophy, serves to retain microbial protein. As tropical fruits have low protein concentrations, caecotrophy could be an important microbial protein source in frugivorous rodents such as the paca (Cuniculus paca). Due to conflicting reports on the occurrence of caecotrophy in this species, we obtained digestive tracts of three adult animals and observed the behaviour of four specimens maintained on a diet of a pelleted feed (P) and a supplemental mix of fruits and sweet potato (S, a source of structural fibre). In a Latin square design, P and S were both offered either in the morning (M) or in the afternoon (A), or with one item in the morning and the other in the afternoon (SP or PS). The paca's proximal colon is characterized by a distinct furrow typical for the colonic separation mechanism of hystricomorph rodents. Caecotrophy, both "direct" (from the anus) and "indirect" (from a pile of defecated faeces), was a regular component of the paca's behavioural repertoire, and caecotrophs contained more nitrogen and less fibre than hard faeces. Higher food intake led to less overall caecotrophy. With afternoon feeding of S, the onset of caecotrophy was delayed and the proportion of indirect caecotrophy increased, with hard faeces and caecotrophs often defecated together. No indirect caecotrophy occurred on treatment M. The results suggest that the time available after ingestion of structural fibre determines the efficiency of the colonic mechanism for the separation of hard faeces and caecotrophs.

Ophthalmic parameters in adult lowland paca (Cuniculus paca) raised in captivity.

OBJECTIVE: To investigate the ophthalmic parameters of lowland pacas, including the anatomic features, tear production, intraocular pressure, central corneal thickness, and morphology of the corneal endothelium. ANIMALS STUDIED: Thirteen adult, anesthetized Cuniculus paca. PROCEDURE: Eyes were evaluated using slit-lamp biomicroscopy, the Schirmer tear test I, digital applanation tonometry, binocular indirect ophthalmoscopy, and noncontact specular microscopy. RESULTS: The biomicroscopy findings showed blue/brown pigmented bulbar conjunctivae, well-developed cilia (only in the upper eyelid margin), superior and inferior lacrimal puncta, brown irides, round pupils, and vestiges of the nictitating membrane. The results of the Schirmer tear test I revealed (mean ± SD) a lacrimation rate of 4.10 ± 0.44 mm/min. The intraocular pressure was 6.34 ± 0.43 mmHg. Central corneal thickness measured by specular microscopy was 0.35 ± 0.01 mm. The mean values of density, hexagonality, and the area of the endothelial cells were 2083.15 ± 42.47 cells/mm2 , 67.07 ± 3.30%, and 486.30 ± 9.56 µm2 , respectively. CONCLUSIONS: The ocular parameters defined in this study may be used for reference in future studies and might also contribute to therapeutic approaches appropriate to this species.

First evidences of Amazonian wildlife feeding on petroleum-contaminated soils: A new exposure route to petrogenic compounds?

Videos recorded with infrared camera traps placed in petroleum contaminated areas of the Peruvian Amazon have shown that four wildlife species, the most important for indigenous peoples' diet (lowland tapir, paca, red-brocket deer and collared peccary), consume oil-contaminated soils and water. Further research is needed to clarify whether Amazonian wildlife's geophagy can be a route of exposure to petrogenic contamination for populations living in the vicinity of oil extraction areas and relying on subsistence hunting.

Convergence characteristics between a rodent, the South American lowland paca, and a ruminant, the African water chevrotain: An exemplary case study.

The level of convergence between a rodent, the South American lowland paca Cuniculus paca, and a ruminant, the African water chevrotain Hyemoschus aquaticus, is analysed using 231 characteristics belonging to different biological sectors. A convergence index is established based on the degree of rarity of each characteristic in each species compared to other members of its zoological group. Although the divergent characteristics are as numerous as the convergent ones, the two species are globally similar. Convergent characteristics occur in all biological categories, but their rate varies a great deal among them. From internal anatomy and osteology, through behaviour and ecology to the external appearance of the body, convergent characteristics are all the more frequent since the biological category is directly implicated in the adaptation of animals to their external environment (lowland rainforest). However, only the individuals' characteristics are concerned and not those of their population or social organisation. This could be due to differences between the communities of terrestrial mammals to which they belong.

Synchronization of estrus in paca (Cuniculus paca L. ): possible impacts on reproductive and productive parameters / Sincronização do estro em pacas (Cuniculus paca L. ): possíveis impactos sobre parâmetros reprodutivos e produtivos

Estrus synchronization is a reproductive biotechnology used to improve artificial insemination or pairing through the manipulation of the estrous cycle at a desirable time. Employing this technique in captive pacas (Cuniculus paca L.) is important because it creates expectation of meeting the demand for paca meat and, consequently, reduces poaching. Thus, this research aims to verify the effect of a progestogen implant associated with two doses of eCG on the synchronization and induction of fertile estrus. Twenty-seven adult pacas were used, 18 non-pregnant females and nine males, divided into three groups. G1 and G2 females groups (treatments) received 1.5 mg Norgestomet and were injected intramuscularly, seven days later, with 0.13 mg of prostaglandin. After 24 hours the implants were removed and the animals immediately received 25 IU and 50 IU of ECG intramuscularly, respectively. The mating of the three groups took place on the same days. G3 females' group (control) showed estrus on different days after D0. Females under treatment displayed estrus only after removing the implant (D8). G1, G2, and G3 pregnancy rates were 100%, 66%, and 50%, respectively. Regarding births per parturition, 100% of G1 and G3 produced one offspring, while 50% of G2 produced two. Progestogen in the form of subcutaneous implants was effective in mimicking the luteal phase of the estrous cycle. After removal, implants favored the occurrence of a fertile estrus. As a conclusion, further studies must be conducted in order to establish in-depth possible association between 50 IU of eCG, and the occurrence of twin pregnancies.(AU)

A sincronização é uma biotécnica reprodutiva que melhora a porcentagem de cobertura por meio da manipulação do ciclo estral. Empregar esta biotécnica em pacas de cativeiro (Cuniculus paca L.) é importante, pois cria-se a expectativa de que a demanda pela carne seja atendida e a caça ilegal diminua. O objetivo da pesquisa foi verificar o efeito de implantes de progestágenos associados a duas doses de gonadotrofina coriônica equina (eCG) na sincronização e indução de cios férteis de pacas. Foram utilizadas 18 fêmeas não prenhas e nove machos, divididos em três grupos. Fêmeas do G1 e G2 receberam implantes com 1,5mg de Norgestomet e, sete dias depois, 0,13mg de prostaglandina via intramuscular (IM). No dia 8 (D8), foram retirados os implantes e G1 e G2 receberam 25 UI e 50 UI de eCG, IM, respectivamente; G3 foi o controle. O pareamento nos três grupos aconteceu nos mesmos dias. As fêmeas do G3 apresentaram cio alguns dias após o dia zero (D0). Fêmeas que receberam tratamento apresentaram cio só após a retirada do implante no dia 8 (D8). As taxas de prenhez de G1, G2 e G3 atingiram 100%, 66% e 50%, respectivamente. Em relação a filhotes por parto, 100% do G1 e G3 produziram uma cria, enquanto 50% do G2 produziram duas crias. O progestágeno do implante foi eficaz em mimetizar a fase lútea do ciclo estral. Após a remoção, o tratamento hormonal favoreceu a ocorrência de cio fértil. Outros estudos devem ser realizados a fim de estabelecer uma possível associação entre 50 UI de eCG e a ocorrência de gestações gemelares.(AU)

Serological evaluation of ovarian steroids of red-rumped agouti (Dasyprocta leporina) during the estrous cycle phases.

The objective of this study was to evaluate serum progesterone (P4) and 17ß estradiol (E2) concentrations throughout the estrous cycle in the red-rumped agouti (Dasyprocta leporina). A total of eight multiparous, captive-bred females were bled throughout their estrous cycle via saphenous venipuncture, with E2 and P4 concentrations being measured via ELISA of the serum collected. Serum E2 ranged from 1212 to 3500pg/ml with a peak value coinciding with observed estrus. However, two additional peak values for E2 were also recorded, one each in metestrus and proestrus respectively. P4 concentrations reached a maximum of 4.23ng/ml, and increases in P4 immediately followed the second E2 peak in metestrus. The highest concentrations of P4 were recorded in mid diestrus; between days 23-25 of the 31-day cycle. This phase was the longest in the agouti, consisting of approximately 19days and accounted for 61% of the cycle. This study increased the basal scientific reproductive knowledge of this potentially valuable neo-tropical species.

Electrocardiographic exam in female spotted pacas (Cuniculus paca) / Exame eletrocardiográfico em pacas fêmeas (Cuniculus paca)

Considering the limited physiological information available on neotropical rodents and the importance of this information for pathophysiological and conservation studies of these species, the aim of this study was to evaluate the cardiac electric physiology of healthy captivity spotted pacas (Cuniculus paca) under chemical restraint, due to wild nature of these animals. Eleven adult female pacas were evaluated by blood count and biochemical dosage to rule out any associate disease. Each animal was evaluated in three periods every 15 days. After chemical restraint with intramuscular midazolam 0.5mg/kg and ketamine 25mg/kg, animals were subjected to a computerized electrocardiogram, where bipolar (DI, DII and DIII) and augmented unipolar leads (aVR, aVL, aVF) were obtained. Descriptive statistics were calculated for each parameter and built the confidence interval (CI) at significance level of 95%. The electrocardiographic examination was performed without difficult. ECG tracing in DII represents a QRS complex with positive polarity, preceded by a P wave of the same polarity and proceeded by T wave of variable polarity. Heart rate mean was 150±17 bpm, and cardiac electrical axis 33.4±21.9°. All animals showed sinusal rhythm. The ECG recording technique associated with chemical restraint was well tolerated, allowing quick acquisition of reliable ECG tracings with high repeatability, which produced sufficient results to determine the heart rhythm and suggest measures of ECG complexes duration and amplitude.(AU)

Considerando a limitada informação sobre a fisiologia cardíaca em roedores neotropicais e a importância desta informação para estudos fisiopatológicos e de conservação desta espécie, objetivou-se com este estudo avaliar a atividade elétrica cardíaca de pacas saudáveis mantidas em cativeiro, sob restrição química, devido à natureza selvagem destes animais. Onze fêmeas adultas foram avaliadas clinicamente e por meio do hemograma e testes bioquímicos no intuito de descartar qualquer co-morbidade associada. Cada animal foi submetido a três períodos experimentais a cada 15 dias. Após a restrição química com 25mg/kg de cetamina e 0,5mg/kg de midazolam pela via intramuscular, os animais eram submetidos a eletrocardiografia (ECG) computadorizada, aonde as derivações bipolares (DI, DII E DIII) e unipolares aumentadas (aVR, aVL, aVF) foram obtidas. A estatística descritiva foi calculada para cada parâmetro e o intervalo de confiança (CI), construído a um nível de significância de 95%. O exame eletrocardiográfico foi realizado sem dificuldade. O traçado eletrocardiográfico em DII apresentou QRS com polaridade positiva, precedido por onda P da mesma polaridade e seguida por onda T de polaridade variável. A frequência cardíaca média foi de 150±17 bpm e o eixo elétrico cardíaco de 33.4±21.9°. Todos os animais mostraram ritmo sinusal. A técnica eletrocardiográfica associada com restrição química foi bem tolerada permitindo a pratica aquisição de traçados de confiança e alta reprodutibilidade, que produziram resultados suficientes para determinar o ritmo cardíaco e sugerir medidas de duração e amplitude dos complexos de ECG.(AU)

Subsistence hunting of Cuniculus paca in the middle of the Solimões River, Amazonas, Brazil.

Ungulates, large primates and caviomorfs are cited by Amazonian hunters as preferred species. In this research, paca (Cuniculus paca) hunting was investigated in relation to water levels and the lunar cycle. In eight years of monitoring in the Amanã Sustainable Development Reserve, the killing of 625 pacas was registered in five monitored communities. Paca hunting took place mainly at night and the most commonly used method is "spotlighting". A positive correlation between the number of pacas killed and water level (rs=0.890; p<0.0001) was found. At least 37% of the pacas were hunted when moon illumination level was less than 10%, before moonrise or after moonset. In the Boa Esperança community, capture of paca tended to decrease on nights with high moon illumination (rs= -0.663; p=0.067). At the same time, an expressive catch-per-unity-effort decrease was also observed in this community (r2= -0.881; p<0.001), allowing us to predict unsustainable hunting levels for the next decade. The stock of animals in these areas could be continuously replaced if surrounding areas consisted of continuous forests. However, continuous hunting and deforestation force local hunters to travel longer distances to kill prey such as pacas. The confirmation of the relation between paca habits and lunar illumination and water level, a pattern described by local hunters, demonstrates the potential value of participatory research and the possibility of integrating traditional knowledge into scientific knowledge.

Subsistence hunting of Cuniculus paca in the middle of the Solimões River, Amazonas, Brazil / Caça de subsistência de Cuniculus paca no Médio Solimões, Amazonas, Brasil

Ungulates, large primates and caviomorfs are cited by Amazonian hunters as preferred species. In this research, paca (Cuniculus paca) hunting was investigated in relation to water levels and the lunar cycle. In eight years of monitoring in the Amanã Sustainable Development Reserve, the killing of 625 pacas was registered in five monitored communities. Paca hunting took place mainly at night and the most commonly used method is “spotlighting”. A positive correlation between the number of pacas killed and water level (rs=0.890; p<0.0001) was found. At least 37% of the pacas were hunted when moon illumination level was less than 10%, before moonrise or after moonset. In the Boa Esperança community, capture of paca tended to decrease on nights with high moon illumination (rs= −0.663; p=0.067). At the same time, an expressive catch-per-unity-effort decrease was also observed in this community (r2= −0.881; p<0.001), allowing us to predict unsustainable hunting levels for the next decade. The stock of animals in these areas could be continuously replaced if surrounding areas consisted of continuous forests. However, continuous hunting and deforestation force local hunters to travel longer distances to kill prey such as pacas. The confirmation of the relation between paca habits and lunar illumination and water level, a pattern described by local hunters, demonstrates the potential value of participatory research and the possibility of integrating traditional knowledge into scientific knowledge.

Ungulados, primatas de grande porte e caviomorfos são citados por caçadores amazônicos como espécies preferenciais. Neste trabalho, a caça de paca (Cuniculus paca) foi investigada em relação ao nível d'água e ao ciclo lunar. O abate de 625 pacas foi registrado em oito anos de monitoramento em cinco comunidades da Reserva de Desenvolvimento Sustentável Amanã. A caça de paca ocorre principalmente à noite e o método mais utilizado é a “focagem”. Encontrou-se uma correlação positiva entre o número de pacas abatidas e o nível d'água (rs=0.890; p<0.0001). Pelo menos 37% dos indivíduos foram abatidos quando o nível de iluminação lunar era menor do que 10%, antes do nascer da lua ou após seu ocaso. Na comunidade da Boa Esperança, a captura de paca tendeu ao decrescimento em noites com altos níveis de iluminação lunar (rs=−0.663; p=0.067). Ao mesmo tempo, uma expressiva redução da captura por unidade de esforço foi observada nessa comunidade (r2=−0.881; p<0.001), permitindo-nos prever níveis de caça insustentáveis para a próxima década. Frente a extensas áreas contínuas de floresta, o estoque de animais nas áreas de caça poderia ser continuamente substituído, mas os efeitos combinados de caça constante e desmatamento forçam caçadores locais a se locomoverem por longas distâncias para abater presas como as pacas. A confirmação dos padrões descritos por moradores locais sobre a relação entre pacas e os níveis de iluminação lunar e de água demonstra o potencial de pesquisa participativa e a possibilidade de integração entre os conhecimentos tradicionais e científicos.