Diva Anelie Guimarães

Spermatogenic Cycle Length and Sperm Production in a Feral Pig Species (Collared Peccary, Tayassu tajacu)

Although the collared peccary (Tayassu tajacu) is found throughout the Americas, with a high potential for domestication and commercial exploitation, there are few data on the reproductive biology of this mammalian species. The aim of the present study was to investigate testis structure, spermatogenic cycle length, Sertoli cell efficiency, and spermatogenic efficiency. Twelve adult peccaries were used for biometrical, histological, and stereological analyses; 3 of these peccaries received intratesticular injections of (3)H-thymidine for the determination of the duration of spermatogenesis. Testis weight and gonadosomatic index were 23.7 +/- 1.8 g and 0.2% +/- 0.1%, respectively. Seminiferous tubule volume density was 77.4% +/- 1.7%. Leydig cells occupied 12.8% +/- 1.8% of the testis parenchyma and presented a peculiar cytoarchitecture in the periphery of the seminiferous tubule lobes. The premeiotic, meiotic, and postmeiotic stage frequencies were very similar to those found for wild and domestic boars. The spermatogenic cycle and entire spermatogenic process (based on 4.5 cycles) lasted approximately 12.3 +/- 0.2 and 55.1 +/- 0.7 days, respectively. Daily sperm production per gram of testis in the collared peccary was approximately 23.4 +/- 2 x 10(6), which is similar to that of domestic and wild boars. The knowledge generated in the present study could be used in reproduction and animal improvement programs and provides important information that may be used for comparative reproductive biology with previously investigated mammalian species.

Duration of Spermatogenesis and Spermatogenic Efficiency in 2 Large Neotropical Rodent Species: The Agouti (Dasyprocta leporina) and Paca (Agouti paca)

The agouti (Dasyprocta leporina) and paca (Agouti paca) are among the largest extant rodent species. Although these species have considerable economic potential, there are few reports in the literature concerning male reproductive biology in sexually mature agoutis and pacas. The objectives of the present study were to perform detailed stereologic and histologic analyses of the testis and estimate spermatogenic cycle length in these 2 Neotropical rodent species as well as to compare the data with those from other well-studied rodent members of the Hystricomorpha and Myomorpha suborders. Eight adult agoutis and 6 adult pacas were used. The spermatogenic cycle in agoutis and pacas lasted 9.5 ± 0.03 and 11.5 ± 0.16 days, respectively, whereas the total duration of spermatogenesis for these 2 species was 42.8 ± 0.16 and 51.6 ± 0.7 days, respectively. Most of the parameters investigated were similar to those obtained for the other members of the Hystricomorpha suborder. As a result of the combination of high values of seminiferous tubule volume density, number of Sertoli cells per gram of testis, Sertoli cell efficiency, and a relatively short duration of spermatogenesis, the spermatogenic efficiency found in agoutis (52 ± 2 × 10(6)) and pacas (39 ± 2 × 10(6)) was particularly high when compared with that of previously investigated mammalian species. The data presented in this investigation would be useful for studies related to animal production as well as improvement and conservation programs involving these 2 large Neotropical rodent species.

DETERMINAÇÃO DO CICLO REPRODUTIVO DA CUTIA (Dasypwcta prymnolopha) ATRAVÉS DO DIAGNÓSTICO COLPOCITOLÓGICO

Foram realizadas analises colpocitologicas das diferentes fases do ciclo estral em 20 femeas adultas de cutias (Dasyprocta prymnolopha), assim como a determinacao da duracao da gestacao em outros seis animais. As cutias foram mantidas em regime de cativeiro, nas condicoes climatologicas encontradas no tropico umido da Amazonia. Os animais apresentaram reproducao do tipo poliestral continua, portanto nao foi observada estacao reprodutiva. A duracao media dos ciclos estrais de 30,69 ± 4,65 dias e periodo medio de gestacao de 104,33 + 0,57 dias. Com relacao ao estudo da citologia esfoliativa, notou-se que no proestro houve frequencia maior de celulas superficiais anucleadas, intermediarias e parabasals; no estro observou-se em numero elevado, as celulas superficiais (anucleadas e nucleadas) e ausencia de leucocitos; na fase de metaestro houve aumento de celulas intermediarias e leucocitos; no diestro, as celulas parabasals foram observadas em numero maior de vezes.

Características reprodutivas da paca fêmea (Agouti paca) criada em cativeiro

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% of the females presented two parturitions per year with one young per parturition, of which 44.7% were females and 55.3% 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.

Derivation of sperm from xenografted testis cells and tissues of the peccary (Tayassu tajacu).

Because the collared peccary (Tayassu tajacu) has a peculiar Leydig cell cytoarchitecture, this species represents a unique mammalian model for investigating testis function. Taking advantage of the well-established and very useful testis xenograft technique, in the present study, testis tissue and testis cell suspensions from immature collared peccaries (n=4; 3 months old) were xenografted in SCID mice (n=48) and evaluated at 2, 4, 6, and 8 months after grafting. Complete spermatogenesis was observed at 6 and 8 months after testis tissue xenografting. However, probably due to de novo testis morphogenesis and low androgen secretion, functionally evaluated by the seminal vesicle weight, a delay in spermatogenesis progression was observed in the testis cell suspension xenografts, with the production of fertile sperm only at 8 months after grafting. Importantly, demonstrating that the peculiar testicular cytoarchitecture of the collared peccary is intrinsically programmed, the unique Leydig cell arrangement observed in this species was re-established after de novo testis morphogenesis. The sperm collected from the xenografts resulted in diploid embryos that expressed the paternally imprinted gene NNAT after ICSI. The present study is the first to demonstrate complete spermatogenesis with the production of fertile sperm from testis cell suspension xenografts in a wild mammalian species. Therefore, due to its unique testicular cytoarchitecture, xenograft techniques, particularly testis cell suspensions, may represent a new and very promising approach to evaluate testis morphogenesis and to investigate spermatogonial stem cell physiology and niche in the collared peccary.

Functional morphology of the genital organs in the wild paca (Cuniculus paca) female

Functional morphology of the genital organs is a key knowledge component for enhanced understanding of physiological patterns and for the determination of the reproductive performance in wild species. This study examines the morphology of genital organs of 133 paca females in the wild. Estimated conceptions and parturitions were mostly (83.7% and 75.5%, respectively) localized in the wet season. The pregnancy rate between 57.1% and 61.4% suggests an estimated yearly production of 1.37-1.48 parturitions and a long estimated farrowing interval of 247-266 days. Although large antral follicles were observed in all females, pregnant females had a greater number of antral follicles than females in the luteal phase. The average litter size was 1.03 foetuses per pregnant female, and mean ovulation rate was 1.33 follicles, resulting in a rate of reproductive wastage of 28.7%. The constituent active luteal tissues of the ovary were oestrous cyclic, pregnancy and accessory CL. The 50% of pregnant females in the late pregnancy stage lacked pregnancy CL, suggesting that placenta may become the mean source of progesterone during late stages of pregnancy. Results of the present study suggest that the observation of the vaginal closure membrane should not be an accurate tool for diagnosing oestrus in the paca female.

Biometria testicular, eletroejaculação e características seminais de caititus, Tayassu tajacu Linnaeus, 1758 (Mammalia, Artiodactyla, Tayassuidae) mantidos em cativeiro na Amazônia Oriental

Estudos relacionados a obtencao e avaliacao de semen de Tayassu tajacu sao escassos, sendo necessarias pesquisas a respeito. Os objetivos do estudo foram avaliar a biometria testicular de caititus adultos cativos, testar a eficiencia da eletroejaculacao para obtencao de semen e avaliar suas caracteristicas seminais ao longo do ano. Procedeu-se a eletroejaculacao em oito animais adultos e as amostras de semen colhidas foram avaliadas quanto as caracteristicas fisicas e morfologicas. Os animais tinham testiculo esquerdo com 3,8 ± 0,4 cm X 2,6 ± 0,3 cm e 2,3 ± 0,2 de consistencia, e testiculo direito com 3,8 ± 0,5 cm X 2,7 ± 0,3 cm e 2,3 ± 0,2 de consistencia. A taxa de sucesso nas colheitas foi de 75,21%. O semen possuiu: volume 0,81 ± 0,86 mL, concentracao 137,44 ± 153 x 106 sptz mL-1, pH 7,92 ± 0,73, motilidade 52,66 ± 28,79%, vigor 2,2 ± 0,8, integridade de membrana plasmatica 55,84 ± 28,55%, defeitos maiores 22,87 ± 12,93%, defeitos menores 9,11 ± 5,88% e defeitos totais 31,52 ± 13,81%. Os animais apresentaram simetria testicular, a eletroejaculacao se mostrou eficiente para a obtencao de ejaculados em caititus e as flutuacoes observadas na producao seminal nao foram suficientes para caracteriza-los como animais de reproducao sazonal.

The stimulatory effect of male agouti (Dasyprocta prymnolopha) on the onset of female puberty

The objective of this research was to analyze female agouti puberty. We did not observe the onset of puberty when the females were raised without males. When an adult male was put together with other adults and no cycling females, the onset of estrous cycle was observed after 10 to 60 days. When the young females were raised with a male, the onset of puberty was reached at 9 months. We concluded that the male agouti influences the onset of puberty in females, and that the dominant female, apparently, inhibits or delays the puberty of the other agouti females of the group. We suggest further studies be made concerning the social control of the reproduction of these animal.

Intensive production system of collared peccary ( Pecari tajacu ) in Brazilian Amazon

good quality. The mating season extends from mid-February to June, with several males in the herd. According to the breeders, the Moka cows have good reproductive capacity and great longevity: they produce one calf per year, on average, along a productive life which can last 15 years. Calving is easy, without supervision or intervention. Marketing is done mostly by direct sale of live or slaughtered animals. Threehundred twenty-five animals were listed on the survey, on 11 farms, with an average of 30 animals per herd. Thirty-three animals typed as Moka by their owners were the subject of a phenotypical description and measurements. The mean value for the thoracic perimeter, the height at withers and the rump width are respectively 1626 15.2 cm, 1166 8.3 cm and 1206 17.6 cm; the mean liveweight of males and females are 4306 85 kg and 3406 45 kg respectively. These results constitute the initial values of a zootechnical description of the breed. They show the underaverage development of the animals, which can be qualified as medium sized. A photographic database of individual animals was created and could be used for the definition of the standard of the breed. The genetic analysis showed that the population presents a good allelic richness (6.7 alleles/locus) and genetic diversity (measured by an unbiased heterozygocity of 0.75), and a low estimated consanguinity (3.3%). Some specific features have been identified, such as the presence of zebu specific alleles, but few admixtures of taurine cattle. The relationship of this breed with African breeds, especially from Madagascar, or with European or Creole cattle will be studied in more detail in the future.

Puberty in male collared peccary (Pecari tajacu) determined by quantitative analysis of spermatogenic cells

Biological studies are necessary for the management of wildlife in captivity, and knowledge of reproduction is one of the important features for increasing production. The objective of the research was to determine the age at which male collared peccaries reach puberty. Testicular samples of 15 animals, aged 7 to 16 months, distributed into five groups (G1, G2, G3, G4 and G5) were used. The testes showed considerably increased weight, length and width (p < 0.05) from G1 to G3, whereas, from this group onward, the development of this organ was slower. There was positive correlation (p < 0.001) between the following testicular parameters: weight and length (r = 0.97), weight and width (r = 0.88), length and width (r = 0.92). Regarding the diameter of seminiferous tubules, an increase was observed (p < 0.05) from G1 to G4. The total number of spermatogenic cells increased significantly (p < 0.05) until G3 and then it stabilized. There was also positive correlation between testis weight and tubular diameter (r = 0.99, p < 0.001), and testis weight and spermatogenic cells (r = 0.98, p < 0.001). The number of Sertoli cells decreased significantly (p < 0.05) from G1, when they were undifferentiated as support cells, to G5, when they occurred together with the complete line of spermatic cells. The results demonstrate that the reproductive development of peccaries can be classified into the following stages: impuberty (G1, 7-8 months); pre-pubertal (G2, 9-10 months); pubertal (G3, 11-12 months); post-pubertal 1 (G4, 13-14 months); and post-pubertal 2 (G5, 15-16 months). Based on the histological analyses, puberty in the male collared peccary was determined to occur between 11 and 12 months of age.