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Méndez Álvarez, María Silvana

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Birth Date

1978-10-12

ORCID

0000-0001-5139-7173

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57217092296

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Universidad de Cuenca, Cuenca, Ecuador
Universidad de Cuenca, Facultad de Ciencias Agropecuarias, Cuenca, Ecuador
Universidad de Cuenca, Facultad de Ciencias Agropecuarias, Laboratorio de Biotecnología de La Reproducción Animal, Cuenca, Ecuador

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Ecuador

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Facultad de Ciencias Agropecuarias
El 21 de abril de 1982, por resolución del Honorable Consejo Universitario se establece la Facultad de Ciencias Agropecuarias, de la Universidad de Cuenca. La Facultad de Ciencias Agropecuarias es una institución formadora de talento humano en el área agronómica, a través de una educación de calidad, centrada en la investigación y vinculación con la colectividad. Los futuros profesionales médicos veterinarios zootecnistas e ingenieros agrónomos, durante su permanencia en las aulas y estudio de campo, desarrollan conocimientos científicos-tecnológicos, competencias y destrezas en procesos de producción agropecuaria. Se los prepara con el fin de preservar la salud de los animales y recursos naturales, fomentando la seguridad alimentaria, respetando el medio ambiente dentro del marco del Buen Vivir, englobado en las necesidades de la región y el país.

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Profesor (T)

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Méndez Álvarez

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María Silvana

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2019 - 201912020 - 20231
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  • Thumbnail Image
    Publication
    Methods of collection, extender type, and freezability of semen collected from creole bulls raised in the tropical highlands of Ecuador
    (2019) Argudo Garzon, Daniel Ernesto; Galarza Lucero, Diego Andrés; Bueno Leon, Hernan Patricio; Iñiguez Gutierrez, Carlos Ulises; Méndez Álvarez, María Silvana; Soria Parra, Manuel Elías; Torres Inga, Carlos Santiago; Perea Ganchou, Fernando Pedro; Alberio Null, Ricardo Horacio
    This study was conducted to determine the best combination between two collection method and two extenders in the cryopres-ervation of semen from creole bulls adapted to highlands of the Ecuadorian Andes. Sixty ejaculates from three adult Creole bulls were evaluated after collection by artificial vagina (AV) and electroejaculation (EE). Semen samples were split into two aliquots and diluted with a soy lecithin extender (Andromed®; A) or an egg yolk-containing extender (Triladyl®; T) and packed in straws of 0.25 ml with 20 × 106 sperms. Optical microscopy and computer-assisted semen analysis system (CASA) were used to evaluate semen quality characteristics. The effects of collection methods and extender type as well as its interaction were evaluated by a factorial ANOVA and Bonferroni’s test. Semen samples collected with EE and frozen with T (EE-T) and A (EE-A) had greater proportion of spermatozoa with optical assessed individual progressive motility (IPM), plasmatic membrane intact (HosT), and lower tail abnormalities than those obtained with AV and frozen with the same extenders (AV-T and AV-A);however, differences were significant only between EE-A and AV-T. CASA assessment indicated that the total mobility (TM) was greater (P < 0.05) in semen samples diluted with T, although these samples had a greater proportion (P < 0.05) of sperms with local motility (LM) and fewer immobile sperms (IS), than those extended with A. Generally, semen samples obtained with EE or AV and diluted with T seems to be the best option to ciopreserve gametes of Creole bulls raised in highlands of Ecuadorian Andes.
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    Publication
    Cryopreservation of Domestic and Wild Animal Spermatozoa: Update of Knowledge
    (Intechopen, 2023) Samaniego Campoverde, Jorge Xavier; Galarza Lucero, Diego Andrés; Méndez Álvarez, María Silvana; Duma Pauta, José Mauricio
    Current sperm cryopreservation protocols for domestic and wild mammals aim to minimize the cryogenic damage caused by cell dehydration, ice formation, and osmotic stress. The optimization of sperm cryopreservation include the use of different synthetic and nonsynthetic-based extenders supplemented with additives (e.g., egg yolk, coconut water, etc.) and antioxidants (e.g., melatonin, L-carnitine, caffeine, resveratrol, etc.) that protect the plasmalemma, acrosome, and mitochondria against the detrimental effects caused by the cryopreservation process. Furthermore, the use of penetrating (e.g., glycerol, ethylene glycol, dimethylformamide, etc.) and nonpenetrating (e.g., sucrose and trehalose) cryoprotectant agents (CPAs) or their combination should be investigated to protect sperm during the freezing process in slow and ultra-rapid freezing procedures. Finally, new cryopreservation protocols should focus on freezing curves and initial cooling rates that allow optimal dehydration during freezing and adequate hydration during thawing. The suitable interaction of all these factors will allow a sperm subpopulation to survive cryopreservation with integrity and fertilizing capacity, contributing to the improvement of the efficiency of genetic resource management and the development of germplasm banks that support the preservation of genetic diversity in domestic and wild animals.