Abstract The objectives of the study were to (1) describe the kinematic parameters of spermatozoa (2) compare methods of evaluating sperm viability (3) validate assays of functionality and integrity of the sperm membrane and (4) evaluate possible changes between spermatozoa from the epididymis and the vas deferens of the greater rhea. Semen samples were recovered from 7 adult individuals. Sperm motility was characterized by adjusting the set-up for Computer-assisted semen analysis (CASA) to that new species. For sperm viability evaluation, smears of bromophenol blue and eosin-nigrosine dyes were used. Five solutions of different osmolarities were then tested for the hypoosmotic swelling test (HOST). The combination of fluorescent probes (propidium iodide - IP and Hoechst 33342) was also used to assess plasma membrane integrity. Data were presented as mean ± SEM. Rhea spermatozoa from the vas deferens had an overall motility of 14.6 ± 2.5%. The bromophenol blue staining technique revealed that 64.6 ± 5.2% sperm were viable, while that proportion was 72.1 ± 2.5% using eosin-nigrosine. An average of 77.6 ± 4.8% of spermatozoa reacted to the HOST with distilled water at 0 mOsm/l. Fluorescent probes indicated that 65.3 ± 2.6% of spermatozoa had intact membranes. Interestingly, no statistical differences were observed between the parameters analyzed in the epididymal spermatozoa and the vas deferens. These new assays set reference values that can now be used to further exploration of sperm handling conditions and freezing protocols in rheas.

Abstract Spix's yellow-toothed cavies are rodents displaying high biological and farming potential. Knowledge of cavy reproductive aspects is paramount for satisfactory breeding. This study aimed to determine the gestation length and characterize the reproductive cycle phases of Spix's yellow-toothed cavies, also investigating potential male effects on these processes. The investigated animals were categorized into three groups: Gestational follow-up (G1), with a 5:1 female-to-male enclosure ratio; estrous cycle (G2), with a 5:1 female-to-male ratio with a male confined to a cage; and G3, consisting of five females and no male. Daily colpocytological examinations were performed, with the presence of spermatozoa on the microscopy slides indicative of copulation. G1 females were separated from the male immediately after copulation, with this being considered day "zero" of the pregnancy. G2 and G3 females were evaluated for two complete estrous cycles and qualitatively assessed through vaginal smears. The gestation length of the Spix's yellow-toothed cavies averaged 59 ± 2.24 days, with a continuous polyestrous cycle lasting 14.8 ± 0.73 days in G2 and 14.6 ± 0.75 days in G3. The proestrus phase was characterized by the dominance of parabasal cells, dyes, bacteria, and leukocytes; the estrus phase, by superficial cells with the predominance of anucleate cells with and without the presence of bacteria; the metestrus phase, by parabasal cells and numerous genuine cells, neutrophils, and bacteria; and the diestrus phase, mainly by basal, parabasal, and mutant cells, as well as high amounts of vaginal mucus, neutrophils, and bacteria. The presence of a male cavy significantly influenced diestrus duration, prolonging this phase, which is potentially attributed to female progesterone production effects.

Resumo O preá é um roedor com elevado potencial biológico e zootécnico a ser explorado, sendo o conhecimento sobre os aspectos reprodutivos fundamentais para que sua criação seja satisfatória. Objetivou-se determinar a duração da gestação em preás, e a caracterização das fases do ciclo reprodutivo, verificando, se existe influência da presença do macho neste processo. Os animais foram separados em três grupos: Acompanhamento gestacional (G1), 5:1, proporção de fêmea e macho no box; Ciclo estral, 5:1, com o macho preso em gaiola (G2) e cinco fêmeas em outro box sem o macho (G3). O exame colpocitológico ocorreu diariamente, identificado o espermatozoide na lâmina como cópula. As fêmeas do G1 foram separadas assim que copulavam e contadas como dia “zero” da gestação. As fêmeas do G2 e G3 foram avaliadas ao longo de dois ciclos estrais completos, avaliados qualitativamente pelo o esfregaço vaginal. O período de gestação em preás foi de 59±2,24 dias, com um ciclo poliéstrico contínuo, com duração de 14,8±0,73 dias no G2 e 14,6±0,75 dias no G3. O proestro caracterizou-se pelo predomínio de células parabasais, intermediárias, bactérias e leucócitos; o estro, células superficiais, com predomínio das anucleadas com presença ou não de bactérias; metaestro, células parabasais e grande quantidade de células intermediárias, neutrófilos e bactérias; diestro, predomínio de células basais, parabasais e intermediárias e grande quantidade de muco vaginal, neutrófilos e bactérias. A presença do macho influenciou significativamente a duração do diestro, tornando-se mais longa, fato que pode estar atrelado a influência sobre a produção de progesterona na fêmea.

Abstract Heterologous in vitro fertilization (IVF) is an important tool for assessing fertility of endangered mammals such as the jaguar, considering difficult access to females for artificial insemination and to obtain homologous oocytes. We aimed to evaluate the fertility of jaguar sperm cryopreserved with different extenders, using domestic cat oocytes to assess the development of hybrid embryos. Semen from four captive jaguars was obtained by electroejaculation. Samples were cryopreserved in powdered coconut water (ACP-117c) or Tris extender containing 20% egg yolk and 6% glycerol. Thawed spermatozoa were resuspended (2.0 × 106 spermatozoa/mL) in IVF medium and co-incubated with cat oocytes matured in vitro for 18 h. Presumptive zygotes were cultured for 7 days. After 48 h, cleavage rate was evaluated, and non-cleaved structures were stained for IVF evaluation. On days 5 and 7, the rate of morula and blastocyst formation was assessed. Data were analyzed using the Fisher exact test (p < 0.05). No difference was observed between ACP-117c and Tris extenders, respectively, for oocytes with 2nd polar body (2/51, 3.9 ± 2.9% vs. 2/56, 3.6 ± 3.1%), pronuclear structures (5/51, 9.8 ± 4.7% vs. 8/56, 14.3 ± 8.0%), and total IVF rates (7/36, 19.4 ± 5.0% vs. 10/37, 27.0 ± 13.8%). All the samples fertilized the oocytes, with 22.9 ± 3.2% (16/70) and 16.7 ± 3.6% (12/72) cleavage of mature oocytes for ACP-117c and Tris extenders, respectively. Morula rates of 4.3 ± 2.3% (3/70) and 5.6 ± 2.2% (4/72) were observed for ACP-117c and Tris, respectively. Only the Tris extender demonstrated blastocyst production (2/12, 16.7 ± 1.5% blastocyst/cleavage). We demonstrated that jaguar ejaculates cryopreserved using ACP-117c and Tris were suitable for IVF techniques, with blastocyst production by ejaculates cryopreserved in Tris. This is a first report of embryos produced in vitro using jaguar sperm and domestic cat oocytes through IVF.

Abstract Sex steroid hormones are critical in gonadal differentiation in turtles. The gonads are not the only organs responsible for producing these hormones during this phase. Mesonephros play an important role in steroidogenesis. The present study aimed to investigate the presence of steroidogenic cells in mesonephros of Podocnemis expansa during gonadal differentiation and to evaluate their morphology and ultrastructure. Ten embryos of P. expansa were collected from 5 nests on day 36 of incubation, during spawning period on an artificial beach. Embryos were extracted from eggs by slicing the shell and euthanized. They were dissected under a stereoscopic microscope to collect the gonad-mesonephro complex, in which were fixed and subsequently processed for light microscopy, immunohistochemistry and transmission electron microscopy analysis. During histological analysis was observed mesonephros has typical morphological structure. Immunohistochemistry showed immunoreaction to aromatase in cells of intertubular space. Confirming these findings, it was possible to observe a type of intertubular cell in several regions of mesonephro, being more predominant in region close to blood vessels, distal and proximal tubules. In ultrastructural analysis these cells were characterized by having a clear, large, and rounded nucleus with evident nucleolus and cytoplasm rich in electron-dense droplets. This study demonstrated for the first time the presence of cells with morphological, immunohistochemical and ultrastructural characteristics similar to steroid-producing cells in P. expansa mesonephrons, suggesting that this organ may contribute to gonadal differentiation in this species.

Abstract Duchenne Muscular Dystrophy (DMD) reproductive alterations and the influence of antioxidant treatments may aid in understanding morphometry testicular quantification. In this context, the aim of the present study was to characterize the intertubular compartment (ITC) morphometry of animal testes in mdx mice supplemented with ascorbic acid (AA). Sixteen mice were used, namely the C57BL/10 (non-dystrophic) and C57BL/10Mdx (dystrophic) lineages, distributed into the following groups: Control (C60), Dystrophic (D60), Control supplemented with AA (CS60), Dystrophic supplemented with AA (DS60). A total of 200 mg/kg of AA were administered to mice for 30 days. Subsequently, the testicles were collected, weighed, and fragmented. The obtained fragments were fixed in Karnovsky's solution (pH 7.2) and embedded in historesin for morphometric and transmission electron microscopy assessments. Leydig cells were hypertrophic in the D60 group, but was reverted by AA supplementation in the DS60 group. The DS60 group also exhibited increased intertubular volume compared to the CS60 group. The ultrastructural images identified multilamellar bodies in dystrophic animals (lipid storage) and telocyte cells (transport substances) in both control and dystrophic animals. Morphometric alterations were, therefore, noted in the intertubular compartment due to Duchenne muscular dystrophy (DMD), with AA administration capable of altering Leydig cells in this condition.

Abstract Estrogens and progestogens are hormones produced by maternal organs and it is required for recognition and maintenance of pregnancy. In addition, the embryo may also be a source. For this, the aim was to identify steroidogenic expression on Galea spixii embryos early in the embryonic period. Embryos were collected on Days 10 and 15 of gestation; some were fixed in 4% paraformaldehyde for morphological and immunohistochemical analysis (P450arom), whereas others had RNA extracted to determine presence of CYP19a1 gene. In addition, for immunochemistry, maternal ovaries were collected as positive control tissues. Maternal tissues had positive staining for aromatase, whereas none of the embryos stained for P450 aromatase. Based on qPCR reactions, CYP19a1 gene were expressed in all embryos. Galea spixii embryos expressed steroidogenic genes during the post-implantation period, indicating they have the potential to produce steroid hormones.

Abstract Letrozole is used as a therapeutic agent in reproductive disorders caused by high estrogen levels. Letrozole inhibits cytochrome P450 aromatase and reduces estrogen levels. However, the effects of long-term use on reproductive traits are unknown. The aim of this study was to evaluate the prolonged use of letrozole in the gonads of rodents (Spix's yellow-toothed cavy; Galea spixii). Forty-eight rodents (24 males and 24 females) were randomly divided into the treated and control groups. Letrozole administration started at 15 days of age and continued weekly until 30, 45, 90, and 120 days of age. The body, testis, and ovary weights were analyzed, as well as the morphological progression of spermatogenesis and folliculogenesis. Macroscopically, body weight gain and gonads weight were increased in the letrozole group. Microscopically, the ovaries of treated females showed stratified epithelium and a cellular disorder of the tunica albuginea. In the testes of treated males, the development of seminiferous tubules was delayed and sperm was absent. The collective findings indicate that the prolonged use of letrozole alters secondary sexual characteristics, and causes weight gain, reproductive changes, and male infertility.

ABSTRACT Several authors have underscored the importance of establishing parameters in morphological development by gender comparison to establish clinical and pre-clinical assays through the use of experimental models. Current research compares the morphometry of right and left adrenal glands of males and females and describes differentiation of the cortex and medulla tissue during the embryonic, pre-puberty and puberty phases in Spix´s yellow-toothed cavies. Embryos aged 22 (22D), 25 (25D), 30 (30D), 40 (44D) and >50 (50D) days of gestation and neonates aged 15 (15DPN) (DPN= Days postnatal), 30 (30DPN) and 90 (90DPN) days after birth were analyzed. Comparisons included morphometric and histological analysis in all periods described. When compared the right and left adrenal glands, results show that the length and width have statistical differences (p<0.05). Statistical difference between right and left glans for weight occurred only after 30D in males and after 50D in females. When compared male and females, no statistical difference in the right and left glands was extant. In the case of tissue differences, the glomerular zone is the first to emerge after 22D, followed by the fasciculate zone after 25D and by the reticular zone during the post-natal period. Medullar tissue was spread between the cortical tissue at the onset of development, establishing itself at the center of the organ since the end of pregnancy (>50D) up to puberty. Considering tissue differentiation, there was no difference between the adrenal glands of male and female cavies or between the right and left adrenal glands.

Resumo Para o estudo foram utilizados 20 animais, que estavam em freezer no Centro de Multiplicação de Animais Silvestres (CEMAS/UFERSA). Os animais foram descongelados, a cavidade abdominal aberta e a aorta torácica canulada no sentido caudal para injeção de solução de látex Neoprene 650 corado de vermelho e, em seguida, fixados em solução de formaldeído a 10%, por um período mínimo de 48 horas, para que pudessem ser dissecados, fotografados e os resultados analisados. A artéria celíaca originou-se da aorta abdominal e emitiu as artérias gástrica esquerda, lienal e esplênica. A artéria gástrica esquerda emitiu de dois a três ramos à região da curvatura menor do estômago. A artéria lienal emitiu quatro ramos ao parênquima do baço, de seis a doze ramos pancreáticos e a artéria gastroepiplóica esquerda. A artéria hepática emitiu de um a dois ramos pancreáticos e bifurcou-se em um curto tronco formado pelas artérias gástrica direita e hepática própria e ainda na artéria gastroduodenal, que originava a pancreaticoduodenal cranial e gastroepiplóica direita. O comportamento de trifurcação da artéria celíaca do preá assemelha-se ao encontrado em roedores, como o nutria, a cutia, o hamster e os ratos, o que sugere que este seja o padrão para a ordem.

Abstract For this study we used 20 animals that were in the freezer at the Wild Animals Multiplication Center (CEMAS/UFERSA). The animals were thawed, the abdominal cavity was opened, and the thoracic aorta cannulated caudally for the injection of red-stained latex Neoprene 650, and then fixed in formaldehyde solution 10%, for a minimum of 48 hours. Then the animals were dissected, photographed, and the results analyzed. The celiac artery originated from the abdominal aorta and issued the left gastric, splenic, and hepatic arteries. The left gastric artery issued two to three branches to the lesser curvature of the stomach. The splenic artery emitted four branches to the parenchyma of the spleen, six to twelve pancreatic branches and the left gastroepiploic artery. The hepatic artery emitted from one to two pancreatic branches and forked in a short trunk formed by right gastric and own hepatic arteries and in the gastroduodenal artery, which originated the cranial pancreaticoduodenal and right gastroepiploic. The trifurcation behavior of the celiac artery of the yellow-toothed cavy is similar to that found in rodents such as nutria, agouti, hamsters and mice, suggesting that this is the standard for the order.

RESUMO: Buscou-se estudar o desenvolvimento do pulmão do preá ( Galea spixii ) com ênfase nas características macroscópicas, histológicas e imunohistoquimicas, bem como acompanhar a proliferação celular. Para tanto, foram utilizados 8 fetos, os quais, de acordo com o tamanho (crown-rump - CR), foram divididos em 3 grupos: Grupo I (33-35 dias), Grupo II (38-40 dias) e Grupo III (43-45 dias). Macroscopicamente, não houve diferenças quanto à morfologia do pulmão entre os grupos. Em relação à maturação pulmonar, no grupo I, observou-se o início da formação dos brônquios e bronquíolos, os quais estavam rodeados por grande quantidade de mesênquima e vasos sanguíneos de pequeno calibre, caracterizando o estágio pseudoglandular. Os indivíduos do Grupo II apresentaram maior quantidade de formações tubulares no parênquima pulmonar, assim como redução da quantidade de mesênquima, atingindo, dessa forma, a fase canalicular. No Grupo III, os pulmões apresentaram-se completamente formados, atingindo a fase alveolar. Nas análises de imunohistoquimica, os pulmões dos indivíduos dos Grupos I e II apresentaram marcação para Pcna, Oct-4 e VEGF. Por outro lado, não houve marcação no Grupo III. A anatomia do pulmão do preá se assemelha ao pulmão da cutia ( Dasyprocta sp.) quanto ao número de lobos e fissuras. No que se refere ao desenvolvimento pulmonar, o pulmão do preá apresentou maior similaridade com o pulmão de fetos humanos, visto que ambos, ao nascer, encontram-se na fase alveolar, contrário a outras espécies de roedores.

ABSTRACT: The aim of this research was to study the development of the lung in Galea spixii , by gross anatomy, histological analysis and immunohistochemical techniques. Totally, 8 fetuses were used and allocated into three groups of age: Group I (33-35 days), Group II (38-40 days), and Group III (43-45 days) with given crown-rump - CR lenghts. According to the gross morphology, there were no differences in relation to the lung morphology among groups. In relation to lung maturation, the Group I showed early formation of the bronchi and bronchioles, which were richly surrounded by mesenchyme and small blood vessels, typical features of the pseudoglandular stage. Individuals from Group II showed higher amounts of tubular formations in the lung parenchyma and reduced mesenchyme, reaching the canalicular stage. The lung from individuals of the Group III was completely formed, reaching the alveolar phase. In the immunohistochemical analysis, the lung of individuals from both Groups I and II were positive for Pcna, Oct-4, and VEGF. In contrast, there was not labbeling on samples from Group III. Thus, the G. spixii lung anatomy resembles the agouti ( Dasyprocta sp.) lung, in relation to the number of lobes and fissures. In regard to the lung development, G. spixii showed more similarity with the human fetal lung, since both are born in the stage of the alveolar phase, different to other rodent species.

Glycosaminoglycans (GAGs) are heteropolysaccharides in mammalian tissue and consist of repeated disaccharide units with mono-sulfated or non-sulfated monosaccharides. GAGs are important components of the Extracellular Matrix (ECM) with several physiological roles, in the recognition, migration, adhesion, proliferation and differentiation processes. They are also important in angiogenesis, blood homeostasis, immune reactions, follicule development and also in the development of pathologies such as infertility, tumors and metastases. It has been shown that the profile of glycosaminoglycans in the uterine and placental tissues is highly variable throughout the reproductive cycle and during pregnancy. It may be directly related to their physiological or pathological functions in the tissue. The latter has recently triggered special clinical interest. Current review collaborates for a deeper knowledge on the profile and importance of GAGs in uterine and placental tissues throughout the reproductive cycle and pregnancy. It also covers information on the involvement of these molecules in pathological processes.

O estudo morfométrico de piolhos que acometem Galea spixii auxilia na compreensão da taxonomia desse Phithraptera. O trabalho objetivou realizar a morfometria de espécimes de Gliricola quadrisetosa recuperados em G. spixii. As análises foram realizadas com auxílio de microscópio óptico de luz. Os dados foram apresentados na forma de média simples e desvio padrão. Os machos e fêmeas apresentaram um comprimento médio corporal de 98,01±2,43 e 117,97±4,75 µm; da face inferior da cabeça de 16,42±3,41 e 18,43±2,61 µm; do protórax de 12,43±0,91 e 13,79±1,13 µm e do pterotórax de 13,57±1,07 e 14,88±1,84 µm, respectivamente. A genitália do macho apresentou em sua placa basal comprimento respectivo da margem lateral externa e interna de 28,86±1,29 e 21,88±1,91 µm; do ramo externo e interno de 2,94±0,38 e 7,25±0,72 µm. Na genitália da fêmea, o comprimento da porção superior e inferior foi respectivamente de 25,35±2,32 e 28,18±2,86 µm. As 11 cerdas apresentaram comprimento médio de 2,99±0,17 µm. As medidas obtidas contribuirão para padronização da taxonomia de Gliricola quadrisetosa recuperados em Galea spixii.

The morphometric study on lice affecting Galea spixii helps in understanding the taxonomy of this Phithraptera. The study aimed to perform morphometry of Gliricola quadrisetosa specimens recovered in G. spixii. Analyses were performed using light optical microscope. Data were presented as simple average and standard deviation. Males and females showed an average length of body of 98,01 ± 2,43 and 117,97 ± 4,75 µm; from the underside of the head 16,42 ± 3,41 and 18,43 ± 2,61 µm; prothorax 12,43 ± 0,91 and 13,79 ± 1,13 µm and pterothorax 13,57 ± 1,07 and 14,88 ± 1,84 µm, respectively. The male genitalia lodged in their basal plate showed length of its external and internal lateral margin of 28,86± 1,29 and 21,88 ± 1,91 µm; external internal branch of 2,94 ± 0,38 and 7, 25 ± 0,72 µm. In the female genitalia, the length of the upper and lower portions were, respectively, 25,35 ±2,32 and 28,18 ± 2,86 µm. The 11 bristles had an average length of 2,99±0,17 µm. The measurements will help to standardize the taxonomy of Gliricola quadrisetosa recovered in Galea spixii.

As emas são aves ratitas nativas do continente sul americano, são consideradas aves primitivas do ponto de vista filogenético que constituem um grupo altamente especializado. Este estudo buscou caracterizar macro e microscopicamente o fígado e pâncreas de emas. O material foi coletado no Centro de Multiplicação de Animais Silvestres (CEMAS), na cidade de Mossoró-RN, Brasil, (Registro IBAMA n° 14.78912). Utilizaram-se 20 animais jovens com idade entre dois e seis meses independente do sexo. Em emas, o fígado se relacionava cranialmente com o ápice do coração, dorsalmente com os pulmões, esôfago e o proventrículo gástrico, caudalmente, com o ventrículo gástrico, o baço, o duodeno e parte do jejuno. Apresentava coloração vermelha escura e possuía apenas dois lobos, sendo o direito ligeiramente menor que o esquerdo. Histologicamente, era revestido por uma cápsula de tecido conjuntivo delgada e cada lóbulo hepático pôde ser identificado pela presença evidente de veias centrais, com muitos sinusoides comunicando-se com elas. O pâncreas, ventralmente, apresentava-se como uma fita fina, formado por um lobo dorsal e um lobo ventral. Longitudinalmente o pâncreas em emas localiza-se no mesentério dorsal desde o fígado até a flexura cranial do duodeno, mantendo-se preso às alças duodenais por ligamentos. Histologicamente, era composto por uma cápsula delgada de tecido conjuntivo denso, com discretos lóbulos separados por tecido conjuntivo capsular, compostos por estruturas tubuloalveolares e ductos. O fígado e pâncreas de emas apresentam padrão morfológico similar ao descrito para aves domésticas.

The rhea are ratites birds native of the South American continent, which are considered primitive birds from the standpoint of the phylogenetic group that is highly specialized .This study aimed to characterize gross and microscopically the liver and rhea pancreas. The material was collected in a Wild Animals Multiplication Center, Mossoró-RN, Brazil, (Registration n° 14.78912 IBAMA). It was used 20 young animals aged between two and six months independent of sex. In the rhea the liver is related to the cranial apex of the heart, dorsally with the lungs, esophagus and gastric proventriculus, caudally with the gastric ventricle, the spleen, the duodenum and part of the jejunum. It was dark red color and had only two lobes, being the right lobe slightly smaller than the left. Histologically was lined by a thin connective tissue capsule and each lobe liver could be clearly identified by the presence of central veins, with sinusoids communicating with the veins. The pancreas, ventrally, showed a thin tape formed by a dorsal lobe and a ventral lobe. Longitudinally the pancreas in rhea is located in the dorsal mesentery since the liver until the cranial duodenal flexure, remaining connected the duodenal handles by ligaments. Histologically was composed of a thin capsule of dense connective tissue, with discrete lobules separated by capsular connective tissue, composed of tubuloalveolares structures and pipelines. The liver and pancreas of rhea have morphology similar to that described for domestic poultry.

O preá do semiárido nordestino (Galea spixii Wagler, 1831) é um roedor pertencente à família Caviidae. Pouca literatura é encontrada sobre essa espécie em relação a sua morfologia e seu comportamento ambiental e reprodutivo. Com o objetivo de entender a morfologia geral, em foco, na inervação do membro pélvico dessa espécie, neste trabalho, foi explorado o nervo isquiático, o qual é o maior de todos os nervos do organismo. Foram utilizados 10 preás (cinco machos e cinco fêmeas) que vieram a óbito por causas naturais, oriundos do Centro de Multiplicação de Animais Silvestres da Universidade Federal Rural do Semiárido (CEMAS/UFERSA). Os animais foram fixados após o óbito em solução aquosa de formaldeído 10% e, após 48 horas de imersão nessa solução, foram dissecados para exposição do nervo isquiático. Dessa forma, os dados obtidos foram compilados em tabelas e expressos em desenhos esquemáticos e fotografias. Os pares de nervos isquiáticos originaram-se de raízes ventrais de L6L7S1 (70%) e de L7S1S2 (30%) e distribuíram-se pelos músculos glúteo profundo, bíceps femural, semitendinoso e semimembranoso.

The Galea of the semi-arid northeast (Galea spixii Wagler, 1831) is a rodent belonging to the family Caviidae. Little literature is found on this species in relation to morphology, environmental and reproductive behavior. With a view to understanding the general morphology, particularly, in the innervation of the pelvic limb of this species, ponder the sciatic nerve, which is the largest of all the nerves of the body. 10 cavies were used (five males, five females) that they had died of natural causes, originating from breeders scientific, legally licensed by IBAMA, the UFRSA, Mossoró, RN. The animals were fixed after the death in an aqueous solution of formaldehyde 10% and after 48 hours of immersion in it, were dissected to expose the sciatic nerve. Thus, the data were compiled in tables and expressed in drawings and photographs. The pairs of sciatic nerves were derived from ventral roots L6L7S1 (70%) and L7S1S2 (30%) and were distributed by the deep gluteal muscles, biceps femural, semitendinosus and semimembranosus muscles.