Avaliação morfofuncional do processo espermatogênico de pacas (Cuniculus paca, Linneus 1766) adultas

• Ano de defesa: 2008
• Autor(a) principal: Carretta Junior, Moacir
• Orientador(a): Paula, Tarcízio Antônio Rego de
• Banca de defesa: Lino Neto, José , Guimarães, José Domingos , Fonseca, Cláudio César
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal de Viçosa
• Programa de Pós-Graduação: Mestrado em Medicina Veterinária
• Departamento: Biotecnologia, diagnóstico e controle de doenças; Epidemiologia e controle de qualidade de prod. de
• País: BR
• Palavras-chave em Português: Espermatogênese; Avaliação morfofuncional; Paca
• Palavras-chave em Inglês: Spermatogenesis; Morphofunctional evaluation; Cuniculus paca
• Área do conhecimento CNPq: CNPQ::CIENCIAS BIOLOGICAS::MORFOLOGIA
• Link de acesso: http://locus.ufv.br/handle/123456789/4950

This research aims to evaluate the spermatogenic process of sexually mature pacas. Five animals bred in captivity were used, one of them from the Centro de Triagem de Animais Silvestres ( Wild animals selection center ) of Universidade Federal de Viçosa and the other ones from the Um sonho a mais farm. Morphometric analyses were performed from fragments of testicles collected by means of hemicastration. The analyzed data concern the volume of the testicles, the proportion of different components of the testicular parenchyma, qualitative and quantitative morphometry of the seminiferous tubules and of the intertubular space, with greater emphasis on Leydig cells. It was observed that approximately 0.28% of the body weight is placed in the gonads, which represents its gonadosomatic index (GSI). Regarding the volumetric proportion of the components of the testicular parenchyma, it shows 90.87% of its mass placed in seminiferous tubules: 2.62% in Leydig cells and the remaining of the intertubular space corresponded to 6.51%. The tubulosomatic index (TSI), i.e. the percentage of body mass placed in seminiferous tubules, was 0.24%. The height of the seminiferous epithelium and the diameter of the seminiferous tubule were, respectively, 63,05µm and 202,05µm, and the length of the seminiferous tubules per testicle gram was 29.71. The relative population of Sertoli cells and reproduction cells in transversal sections of the seminiferous tubules in the first stage of the seminiferous epithelium cycle (SEC) was calculated. These data were crossed so as to determine the general yield of the spermatogenesis of 19.80 cells. Each Sertoli cell endured an average of 24.34 reproduction cells. Regarding Leydig cells, a leydigosomatic index (LSI) of 0.007% was observed. The average nuclear volume and total volume of the adult paca s Leydig cells are, respectively, 222 μm³ and 690μm³. It was possible, with this data, to calculate an average of 35.88 million Leydig cells per testicle gram; the quantity found in the amplitute average of the mammals observed ranges from 20 to 40 million. It is thus concluded that pacas show one of the greatest values of tubule length per testicle gram ever reported for a mammal and that the functional yield of Sertoli cells in these animals is higher than what is reported for most studied species so far.