Browsing by Author "Perea Brugal, Mariana Sofia"

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Intraovarian influence of bovine corpus luteum on oocyte morphometry and developmental competence, embryo production and cryotolerance.
(2020) Argudo Garzon, Daniel Ernesto; Tenemaza Cumbe, Milton Alejandro; Merchan Vargas, Shirley Lissette; Balvoa Tenelema, Jose Agustin; Méndez Álvarez, María Silvana; Soria Parra, Manuel Elías; Galarza Alvarez, Luis Rodrigo; Ayala Guanga, Luis Eduardo; Hernandez Fonseca, Hugo Jose; Perea Brugal, Mariana Sofia; Perea Ganchou, Fernando Pedro
Three experiments were conducted to determine influence of the bovine corpus luteum (CL) on morphometric and functional characteristics of oocytes, and subsequent embryonic development. Cumulus-oocyte complexes were aspirated from two types of cows: 1) with a CL in one ovary (CL+) and without a CL in the contralateral ovary (CL-), 2) and from cows without CL in either ovary (C). Intracellular activity of the enzyme glucose-6-phosphate dehydrogenase (G6PDH), oocyte diameter and thickness of the zona pellucida were determined (Experiment 1). Then, the rate of in vitro oocyte maturation for each ovarian category was evaluated and oocyte diameter and zona pellucida thickness were measured after maturation (Experiment 2). In Experiment 3, in vitro embryo production and cryotolerance were assessed. The oocyte diameter was greater (P 0.05) or C (P = 0.0131) ovaries. Activity of G6PDH was lower in oocytes from CL+ than CL- (P < 0.01) and C (P = 0.0148) ovaries. Rate of oocyte maturation, oocyte diameter and thickness of the zona pellucida after maturation did not differ among groups. Rate of cleavage was greater in zygotes from CL+ than from CL- or C (P < 0.01); and CL+ ovaries produced more total embryos on day 7 (P < 0.05) and more blastocysts (P < 0.01) than CL- and C ovaries. Rate of expansion and hatching of day-7 vitrified-warmed blastocysts at 24 and 48 h of culture did not differ among groups. In conclusion, oocytes collected from CL+ ovaries were larger and metabolically more prepared to continue maturation than those from ovaries lacking a CL. Also, rates of cleavage and yield of blastocysts were greater for oocytes from CL+ ovaries than from CL- and C ovaries. These findings indicate that a CL influenced oocyte developmental competence and embryonic development, presumably through intraovarian interactions.
The time interval between ovarian stimulation with FSH/LH and ovum-pick up affects the quantity, quality and developmental competence of oocytes retrieved from ecuadorian creole heifers
(2020) Ayala Guanga, Luis Eduardo; Samaniego Campoverde, Jorge Xavier; Argudo Garzón, Daniel Ernesto; Perea Brugal, Mariana Sofia; Perea Ganchou, Fernando Pedro; Rodas Carpio, Ermes Ramiro; Nieto Escandón, Pedro Emilio
The aim of this study was to evaluate the effects of gonadotropin treatment and the interval between ovarian stimulation with FSH/LH and the follicular aspiration session, on the quantity and quality of the cumulus oocyte complexes (COCs) obtained by ovum pick up (OPU)) in Ecuadorian Creole heifers. Four heifers were randomly assigned to four groups (FHS/LH 40h; FSH/LH 48h; control 40h; control 48h). In two groups a dose (0.011 mg, IM) of GnRH was applied on day 0, followed by 500 IU, IM, of FSH/LH on day 2, and the OPU session at 40 (FSH/LH 40 h) or 48 hours (FSH/LH 48h) after the application of gonadotropin. In the other two groups, FSH/LH was replaced by a physiological solution. There was no statistical difference in the recovery rate of COCs between FSH/LH 40h and FSH/LH 48h, but approximately twice as many COCs (p<0.05) were obtained than in those who did not receive ovarian stimulation. In addition, 2.4 times more COCs of quality A were achieved in the treatment of FSH/LH 48h than in that of FSH/LH 40h. All (100%) of these structures reacted positively to Brilliant Cresyl Blue (BCB+), which means that they finished the growth and were competent to initiate in vitro maturation. It is concluded that the treatment with FSH/LH 48h allowed to obtain a greater number of COCs competent for in vitro maturation.