Reproductive biotechnology as an important tool in the management and conservation of wild cats: Leopardus pardalis and Leopardus tigrinus.

Author(s)

Regina Celia Rodrigues da Paz

• Document type: Doctoral Thesis
• Press: São Paulo.
• Institution: Universidade de São Paulo (USP). Faculdade de Medicina Veterinária e Zootecnia (FMVZ/SBD)
• Defense date: 2004-09-17

Examining board members

Renato Campanarut Barnabe; José Luiz Catão Dias; Marcelo Alcindo de Barros Vaz Guimarães; Maria Denise Lopes; Nei Moreira

• Advisor: Renato Campanarut Barnabe

Abstract

This study represents the first assessment of ovarian, immunological and hormonal responses of two endangered Brazilian felids: L. pardalis (n=5) and L. tigrinus (n=4), treated with two exogenous gonadotropin regimens eCG/hCG and pFSH/pLH. Females were treated with four to six times alternating eCG/hCG and pFSH/pLH protocols using an interval of four months between each treatment. Ovarian follicular development and oocytes recovery were performed through laparoscopy. Recovered oocytes were submitted to the cytogenetical analysis and to the electron microscopy in order to evaluate the maturation (metaphase II) and the morphological and ultrastructural status, respectively. Blood samples were collected before each treatment and during the laparoscopy in order to measure progesterone and estradiol by RIA and to evaluate the immunological response to the exogenous gonadotropins by ELISA. Our results suggest that L. pardalis and L. tigrinus do not show a decrease (p>0.05) in ovarian response after repeated and alternate exposure to different gonadotropin treatments. In both L. pardalis and L. tigrinus, no differences were found regarding to the number of total ovarian structures (p>0.05) during successive gonadotropin treatments. When comparing the eCG/hCG and the pFSH/pLH treatments, there were no differences (p>0.05) regarding to the total number of ovarian structures in L. pardalis (5.7 ± 1.2 and 7.9 ± 0.9, respectively) or L. tigrinus (2.6 ± 0.7 and 2.0 ± 0.5, respectively). Despite the fact that the L. pardalis showed a higher number of follicles and CLs per stimulation (p<0.05) when compared to the L. tigrinus, no differences were found when analyzing the percentage of mature oocytes (p>0.05). Within species, both gonadotropin regimens were equally effective (p>0.05) to induce the follicular growth. No decreases (p>0.05) on the total number of ovarian structures and on the oocyte maturation percentages were observed between the sequential stimulations, but. L. pardalis showed a higher number of mature and total oocytes when treated with pFSH/pLH (p<0.05). L. Tigrinus didn’t show any differences regarding to the number of total and mature oocytes (p>0.05) when comparing both gonadotropin regimens. No oocytes in metaphase II were observed in the cytogenetic analyses. Oocytes histological evaluation showed that morphological characteristics were the same observed in others mammals. Hormonal analyses showed increased estradiol levels after superovulations. Higher levels of progesterone were observed before and after superovulations. Although some of these cats do demonstrate the development of anti-gonadotropin immunoglobulin titers, these humoral immune responses do not appear to interfere with gonadotropininduced ovarian stimulation. In this study, animals treated repeatedly with alternating regimens of eCG/hCG and pFSH/pLH showed no decrease in total ovarian structures after four to six successive treatments. These findings are potentially valuable for the ongoing efforts to develop and apply assisted reproductive technologies to the management and conservation of endangered felid populations. (AU)