Uso de sondas fluorescentes para avaliação seminal de ejaculado de gato do mato pequeno (Leopardus tigrinus) e ensaio de ligação à membrana perivitelina de ovo de galinha (Gallus gallus) como ferramenta de predição de fertilidade espermática

• Autor(a) principal: Garay, Rafael de Morais
• Data de Publicação: 2012
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: LOCUS Repositório Institucional da UFV
• Texto Completo: http://locus.ufv.br/handle/123456789/5101
• topic: Sondas fluorescentes; Membrana perivitelínica; Felinos; Fluorescent probes; Perivitelline layer; Cats; CNPQ::CIENCIAS AGRARIAS::MEDICINA VETERINARIA::REPRODUCAO ANIMAL

Several populations of wild carnivores are threatened with extinction, mainly due to fragmentation of habitats and low genetic variability of geographically isolated populations. Ex situ conservation strategies, like assisted reproduction and cryopreservation of gametes intended to assist the maintenance of viable populations. Cryopreservation process of male gametes, however, causes damages to cells, which are measured in order to evaluate methodologies and handling techniques to, therefore, increase the viability of reproduction with endangered species in captivity, using assisted reproduction. The study aimed to assess qualitatively the fresh and thawed semen of oncilla (Leopradus tigrinus) using a combination of fluorescent probes and tests of sperm binding to heterologous oocytes of domestic cats and the perivitelline layer of chicken egg. It was used a single individual of oncilla which was anesthetized by anesthesic of ketamine (10 mg / kg) and xylazine (1.2 mg / kg). The semen was collected by electroejaculation and evaluated to the physical aspects (color, appearance and volume) and were also carried out routine tests as follows: sperm motility, spermatic vigor, concentration of spermatozoa in the ejaculate, morphology and hypoosmotic test. Subsequently, the semen was cryopreserved in French straws at a concentration of 20 x 106 motile sperm / ml in TRIS medium based on citrate, 20% of egg yolk and final concentration of 6% glycerol and 0.5% Equex. To asses the integrity of the plasma and acrosomal membrane it was used a combination of three fluorescent probes, propidium iodide, Hoechst 33342 and agglutinin Pisium sativum isoticionato conjugated (FITC-PSA). For binding tests of sperm it was used oocytes of domestic cat and perivitelline layer of chicken eggs, semen was co-incubated at 0.5 x 106 mobile spermatozoa / ml in maintenance medium TCM 199 modified and incubated at 38 ° C at atmospheric pressure of 5% CO 2 for one hour. The ejaculates obtained presented satisfactory medial values for vigor and motility (4.33% and 80.0%, respectively), however, decreased this values in frozen-thawed semen (p <0.05). The fresh ejaculate was presented with values of sperm pathologies below in relation of values observed in other studies with fresh semen of oncilla (19%), the thawed semen increased values of defective cells (p <0.05), due exclusively to the increase in larger defects. The percentage of cells reactive to the hypoosmotic test was lower (p <0.05) in frozen-thawed semen compared to fresh semen (13.0% and 71.66%, respectively). The probes association of propidium iodide, Hoescht 33342 and FITC-PSA was effective to distinguish different subpopulations of sperm in one ejaculation, but there was a difficulty in identifying the staining by FITC-PSA in combination with H342. The population with the intact plasmatic and acrosomal layers decreased (p <0.05) in frozen-thawed semen compared to fresh semen and increased the population with damaged plasmatic layer and intact acrosome layer, which was inversely proportional to motility between these two treatments. For binding tests of oncilla sperm to heterologous oocyte and periviteline layer, both fresh and thawed semen showed adhesion to the substrates and decrease (p <0.05) in number of sperm adhered to the oocyte membrane of the thawed semen. The qualitative methods of sperm evaluation using fluorescent probes associations and binding assays of sperm with heterologous oocytes and perivitelline layers of chicken´s egg proved useful in the evaluation of fresh and thawed semen of oncilla.