Avances en la producción in vitro e in vivo de embriones porcinos

Abstract

The general objectives of this work were to enhance the efficiency of the IVP of porcine embryos and to improve the porcine ET technology. With this propose, the specific objectives contained in this thesis were: (1) To study the effectiveness of two combinations of CPAs, EG+DMSO or EG+PG, for the vitrification of GV stage porcine oocytes and their effects on the oocyte viability, fertilization ability, and the subsequent developmental competence (2) To evaluate the effect of three MINs (dbcAMP, cycloheximide and cilostamide) and their interactions with Gns on the meiotic maturation and developmental competence of porcine oocytes (3) To determine the effects of AsA supplementation to the IVM, IVF and IVC media, on the maturation, fertilization and embryonic developmental parameters, and to assess the effects of adding AsA to vitrification and warming defined media on the vitrification survival of IVP-porcine blastocysts (4) To investigate the effects of parity, season and WEI on the reproductive and embryonic parameters at day 6 after insemination of donor sows superovulated at postweaning estrus (5) To explore the possibility of re-vitrify in vivo-derived porcine embryos (6) To assess if the DSs is adequate for maintaining the viability and quality of vitrified in vivo-derived porcine embryos for a 3-day storage period (7) To investigate the effects of the recipients' parity on their reproductive performance after NsDU-ET. Methodology: For the in vitro system, production of porcine embryos was performed using ovaries from prepubertal gilts at a local slaughterhouse. Fertilization and embryo development parameters were assessment. Vitrification and warming of oocytes and embryos was performed by SOPS system. For in vivo techniques, after estrus detection and artificial insemination, embryos were recovered and evaluated. Embryos were transferred by non-surgical deep uterine embryo transfer. The conclusions of this thesis were: 1. In the absence of vitrification, the toxic effects of the vitrification media on the GV oocytes were minimal and similar for both CPA combinations. 2. High-quality blastocysts can be produced from SOPS vitrified immature oocytes. However, the blastocyst rate remained very low, and the developmental competence of the vitrified oocytes was reduced compared with the non-vitrified controls. 3. The interaction of Gns with the three MINs tested (dbcAMP, cycloheximide and cilostamide) accelerated meiotic progression to the MII stage. The presence of dbcAMP during the first period maturation increased or even doubled the capacity for oocyte development to the blastocyst stage. 4. Under our experimental conditions, the supplementation of IVM/IVF/IVC media with AsA (50 ?g/mL) failed to improve the IVP-outcomes. In contrast, the addition of AsA to chemically defined vitrification and warming media enhanced the blastocysts survival. 5. The parity of donor multiparous sows did not affect the pregnancy and fertilization rates and the number and quality of 6-day-old embryos, regardless of the time of the year (from fall to spring) or the WEI (3 or 4 days). 6. 6. Porcine blastocysts derived from vitrified and warmed embryos could be re-vitrified with quite good survival rates. 7. The DS is an efficient system for the storage of vitrified embryos for a storage period of three days, without affecting their viability after warming. 8. The pregnancy and farrowing rates and litter sizes were not affected by the recipients' parity after NsDU-ET.