Browsing by Author "Ayala Guanga, Luis Eduardo"

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Accuracy of ultrasound and visual inspection in antral follicular count in crossbred Holstein cows raised under grazing systems at high altitude
(2023) Astiz, Susana
The objective of this research was to investigate the diagnostic accuracy of post- mortem ultrasound in antral follicle count (AFC) determination and compare it with visual AFC in grazing crossbred Holstein cows, at high altitude in Ecuador. Pre- mortem blood from 80 cows was collected, and AFC and ovarian characteristics were ana-lysed post- mortem by ultrasound and visual techniques. AFC counts were stratified as high, medium or low by terciles. Mean AMH concentration in pre- mortem blood was 280.1 ± 15.53 pg/mL. The AFC obtained by visual inspection (26.9 ± 9.49 follicles) was 23.8% higher than by ultrasound (20.5 ± 7.53 follicles) in all ovaries. Body condi-tion score, age and weight of the cattle did not interact with the count technique. In the low AFC group, visual inspection and ultrasound provided similar AFC results. However, in the Medium- and High-AFC groups, AFC by ultrasound was 14.9% lower than AFC by visual inspection. We confirm that ultrasound can be used with great accuracy for AFC >3 mm (close to the resolution limit) in grazing crossbred Holstein cows at high altitude.
Adición de fluido folicular en la maduración de ovocitos de cerdas prepúberes
(Asociación Latinoamericana de Producción Animal, 2018) Argudo Garzon, Daniel Ernesto; Borja Tello, Diana Carolina; Wilches Correa, Veronica Elizabeth; Agurto Miranda, Valewska Andrea; Ayala Guanga, Luis Eduardo; Perea Ganchou, Fernando Pedro; Méndez Álvarez, María Silvana; Soria Parra, Manuel Elías; Argudo Garzon, Daniel Ernesto
La producción in vitro de embriones en los porcinos y otras especies de interés zootécnico es indispensable para el desarrollo productivo e investigativo. Diariamente se faenan cientos de cerdos en el camal municipal de Cuenca, Ecuador; donde sería posible rescatar material genético (complejos cúmulos ovocitos; Coc´s) valioso si se recuperan los ovarios de las cerdas; sin embargo, estos animales son beneficiados antes de la pubertad (<5 meses de edad) en cuyo caso la maduración de los Coc´s es deficiente. Se estableció como objetivo del estudio determinar el efecto del fluido folicular porcino (FFP) en maduración de Coc´s de cerdas prepúberes. Se obtuvieron ovarios (n=30) de cerdas faenadas en el camal municipal de Cuenca, los cuales fueron transportados al Laboratorio de Biotecnología de la Reproducción Animal de la Universidad de Cuenca, Ecuador. Inmediatamente se puncionaron los folículos antrales de 2-8mm con una aguja 18x1.5 pulgadas acoplada a una jeringa. El líquido folicular resultante fue filtrado para posteriormente realizar la búsqueda y recuperación de los Coc´s. Adicionalmente, se recuperó FFP, que fue centrifugado a 2000g x 20 minutos, esterilizado por doble filtración con filtros de jeringa estériles de 0.22µm y congelado hasta su uso. Para la maduración, los Coc´s de excelente y buena calidad (n=245) se dividieron aleatoriamente en tres grupos a los que se adicion diferentes porcentajes de FFP: 0% (n=79) ,10% (n=94) y 20%(n=72). Los Coc´s fueron incubados por 48hs en medio de maduración compuesto por TCM199, suero fetal bovino, FSH-p, HCG, piruvato de sodio, L-glutamina, gentamicina y FFP en una estufa con 5% de CO2, 38.5°C y 90%rh. Luego de madurados, los Coc´s fueron denudados por pipeteo en una solución dehialuronidasa 0.1% (p/v), inmediatamente teñidos conHoechst 33342 y observados en un microscopio de fluorescencia. Aquellos que presentaron la expulsión del corpúsculo polar fueron consideraron maduros y el resultado se expresó en porcentaje. Se aplicó un análisis de varianza (ANOVA) seguido de un test de Tukey. El grupo de Coc´s que no fue suplementado con FFP (0%) tuvo menor tasa de maduración (21,33+1,4 %) que los grupos suplementados con 10 (51,53+3,4%) y 20 % (52,93+5,7%) (P<0.05). Se concluye que, irrespectivamente del porcentaje adicionado el FFP fue necesario para mejorar la maduración de Coc´s de cerdas prepúberes
Adición de suero de cobaya en celo a un medio de maduración in vitro
(Universidad de Cuenca, 2023-09-21) Quizhpi Bueno, Paul Geovanny; Zuña Ortuño, Domenica Yamara; Ayala Guanga, Luis Eduardo
The work was carried out in the Biotechnology laboratory of the Faculty of Agricultural Sciences of the University of Cuenca. The objective of this study was to evaluate the effect of different percentages of guinea pig serum in heat (SCC) as a supplement in an in vitro maturation medium (IVM) for guinea pig oocytes from slaughterhouse ovaries. For this, in the first instance, 10 crossbred guinea pigs were synchronized, the day they showed heat, blood serum was obtained. In the second instance, slaughterhouse ovaries were collected and COC's were obtained from these using the Slicing technique, these were classified into type A, B and C based on their morphology. Three treatments were evaluated: T0=control (base maturation medium), T1=base medium + 5% SCC supplementation, T2= base medium + 10% SCC supplementation, T3= base medium + 20% supplementation. % of SCC it was determined that the addition of SCC caused a greater degree of expansion of cumulus cells 5% (84.65 ± 3.98), 10% (84.49 ± 3.63) and 20% (87.43 ± 3.98) with respect to control (69.7 ± 3.63; p<0.005). The percentage of oocytes that reached metaphase II in T1 (25.91 ± 2.79), T2 (26.9 ± 2.79) and T3 (32.48 ± 3.06), were higher compared to the T0 (8.65 ± 2.79; p<0.05). In conclusion, the oocytes that were matured in medium supplemented with SCC presented a better percentage of morphological maturation than cumulus cells and oocytes that reached metaphase II.
Adición del líquido folicular como suplemento al medio de maduración in vitro de ovocitos de cobaya provenientes de ovarios de matadero
(Universidad de Cuenca, 2023-06-26) Aguinsaca Yauri, Nidia Nataly; Motoche Castro, Mishel Stefanía; Ayala Guanga, Luis Eduardo
In recent years, the in vitro maturation (IVM) process of guinea pig oocytes has been trying to improve. However, the results obtained until now are contradictory. Therefore, the present study sought to validate a protocol for obtaining follicular fluid (FL) from guinea pigs in estrus and then, to evaluate the effect of supplementing it in different percentages in a conventional medium in vitro maturation of guinea pig oocytes. For the first experiment, ten mestizo guinea pigs were used, which received a heat synchronization protocol based on oral progesterone for 15 consecutive days as a result 200µl of LF was obtained. In the second experiment, cumulus oocyte complexes (COC´s) were obtained from guinea pig ovaries using the slicing technique. The COC´s were distributed randomly in four IVM media containing different percentages of FL (T0= control, T1= 5%, T2= 10%, and T3 = 20%). After 24 hours, greater expansion of cumulus cells (CC) was observed in T1 (68.1 ± 3.01%) and T3 (66.6 ± 3.39%). It compared to T2 (54.35 ± 2 .72%) and T0 (43.19 ± 2.43%) with p<0.05, between groups. In addition, when evaluating the restart of meiosis progression, it was observed that the oocytes from T3 (33.46 ± 2.4%) and T2 (31.06% ± 1.93%) presented a higher percentage of oocytes in metaphase II, without a statistical difference between these two treatments; compared to the oocytes from T1 (24.52 ± 2.13%) and T0 (14.07 ± 1.72%). In brief, the supplementation of 10% guinea pig the follicular fluid in a conventional maturation medium resulted in a higher percentage of cumulus expansion, it improves the percentage of oocytes that reach metaphase II.
Agrupamiento en base a tamaño, registros, manejo alimentario, estado reproductivo y salud de unidades bovinas de producción lechera en la provincia de Cuenca, Ecuador
(Universidad de Cuenca, 2015) Chuma, J.; Chilpe, M. I.; Pesántez, J. L.; Ayala Guanga, Luis Eduardo; Guevara, G.; Serpa García, Víctor Guillermo; Universidad de Cuenca; Dirección de Investigación de la Universidad de Cuenca
Bovine corpus luteum affects embryo developmental competence and production
(CSIRO, 2019) Alvarado Ulloa, Jhonatan Marcelo; Tenemaza Cumbe, Milton Alejandro; Merchan Vargas, Shirley Lissette; Argudo Garzón, Daniel; Méndez Álvarez, María Silvana; Soria Parra, Manuel Elías; Galarza Alvarez, Luis Rodrigo; Ayala Guanga, Luis Eduardo; Hernandez Fonseca, Hugo Jose; Perea Ganchou, Fernando Pedro; Merchan Vargas, Shirley Lissette
This study was conducted with the aim to determine the effect of bovine corpus luteum on in vitro embryo production. Immature cumulus–oocyte complexes (COCs) were aspirated from abattoir ovaries from cows with (ipsilateral; CL+) and without (contralateral; CL-) corpus luteum (CL), and from cows without CL in any of the ovaries. The experiment was completed within 12 replicates (100 ovaries per group). COCs were cultured in maturation medium (TCM-199 supplemented with 10% fetal bovine serum, 100 µg/ml sodium pyruvate, 0.75 mg/ml L-glutamine, 4 µg/ml FSH-p, 2 µM cysteamine and 250 µg/ml gentamicin) followed by in vitro fertilization (hepes synthetic oviductal fluid medium supplemented with 10 µg/ml heparin) and in vitro culture (citrate synthetic oviductal fluid medium). On day 7 after in vitro fertilization the embryos were evaluated and classified into morulae (M), early blastocysts (EB), blastocysts (B), expanded blastocysts (ExB) and hatched blastocysts (HB), and the embryos with better quality were recorded. Data were analyzed by logistic regression and general linear model of the SAS, and means compared by least-squares means method. Results of cleavage, embryo rate at day 7, and rates of M + EB, B, ExB and HB are shown in Table 1. The number of embryos per ovary was greater (P < 0.01) in CL+ (1.16 ± 0.11) than in CL- (0.45 ± 0.15) and C (0.55 ± 0.15). Also, the number of embryos per cultured oocyte was significantly greater in CL + than in CL- and C (0.27 ± 0.02 vs 0.14 ± 0.03 and 0.15 ± 0.03 respectively, P < 0.01). The results of this study reveal that the presence of the corpus luteum in the ovary at the time of the oocytes recovery affects the developmental capacity of the bovine embryos, and such influence probably occur through intraovarian interactions.
Capacidad de reinicio de la meiosis de ovocitos provenientes de folículos de varios tamaños obtenidos de ovarios de camal
(2019) Ayala Guanga, Luis Eduardo; Palacios Cedeño, Tito Emmanuel; Calle Ortiz, Guido Rigoberto; Rodas Carpio, Ermes Ramiro; Dutan Sanango, Jorge Bolivar; Murillo Apolo, Yury Agapito; Samaniego Campoverde, Jorge Xavier
The competence of oocytes according to follicle size to restart meiosis was evaluated. The follicles were measured and classified as Group 1 (G1 <4 mm), Group 2 (G2 4-8 mm) and Group 3 (G3 >8 mm). The aspiration was performed by group with a 21G needle connected to a vacuum pump, with a pressure of 65 mmHg. The complex oocyte clusters (COCs) recovered were classified as suitable and unsuitable to produce embryos in vitro, according to the characteristics of the cumulus and the cytoplasm. Eligible and unsuitable COCs were assessed with the Brilliant Cresyl Blue (BCB) and were classified into BCB+ and BCB-. In vitro maturation (IVM) was carried out in microdroplets, incubated in a 5% CO2 chamber, 38.5 °C and 90% humidity for 24 hours. The meiotic progression was determined by extrusion of the polar corpuscle by epifluorescence under an inverted microscope. Oocyte morphometry was established using a high definition camera (Excelis AU-600-HD) and software (AmScope v.3.7). The recovery percentage of oocytes was greater than 63%. The G2 follicles provided a higher percentage of eligible COCs (65.7%), where 59% of this group was classified as BCB+. The fit oocytes of G1 and G2 resumed meiosis by 75%. In addition, it was observed that oocytes after IVM reduced their diameter. It is concluded that follicle oocytes between 4-8 mm (G2) provide a higher percentage of mature COCs; however, 50% of follicles <4 mm (G1) are a promising source of viable oocytes, so they should be used for in vitro embryo production.
Características morfométricas de las razas criollas encerado, colorado, atigrado y pintado de la región interandina del Ecuador
(ALPA, 2018) Dután Sanango, Jorge Bolívar; Murillo Apolo, Yury Agapito; Rodas Carpio, Ermes Ramiro; Vázquez Mosquera, Juan Mesías; Calle Ortiz, Guido Rigoberto; Nieto Escandón, Pedro Emilio; Ayala Guanga, Luis Eduardo; Ortega Herrera, Vanessa Viviana; Dutan Sanango, Jorge Bolivar
Se caracterizó la morfometría de las razas Criollas Encerado, Colorado, Atigrado y Pintado de la región interandina del Ecuador, donde se evaluaron 106 vacas multíparas, edad promedio 5,3±0,19 años, número de partos 2,9±0,21 y condición corporal 3,1±0,11. Para establecer las características morfométricas se analizaron 21 medidas corporales, 4 caracteres de ubre, con el bastón zoométrico, cinta bovinométrica, calibrador, para determinar el peso se utilizó el método de Quetelet; además, 9 variables fanerópticas por observación directa. El análisis estadístico se realizó a través del Paquete Estadístico SPSS®, versión 22, en el cual se analizaron frecuencias, estadígrafos principales, análisis de varianza y chi cuadrado. Para la determinación de los biotipos se aplicó clúster bietápico basado en el color de capa, altura a la cruz, perímetro torácico y peso. Se estableció que el ganado criollo tiene una representatividad del 4% en la zona de estudio. Dentro de este genotipo se establecieron 4 biotipos; Encerada (28%), Colorada (14%), Atigrada (9%) y Pintada (55%), con características morfoestructurales similares entre sí (P>0,05), como altura a la cruz entre 120,9±1,11 - 121,5±0,80cm, peso 334,2±11,13 - 356,0±23,33kg; perímetro torácico 163,39±1,79 - 168,33±3,43cm y perímetro de caña 16,0 ±0,34 - 17,2 ±0,67cm. Los biotipos Encerada y Pintada presentaron tendencia lechera (96,4%) con un perfil rectilíneo de 75,0% y 88,5% respectivamente y proporciones longilíneas, superiores al 92,9%, a diferencia de la Colorada (42,9%) y Atigrada (33,3%) con un perfil convexilineo y caracteres de producción mixta de 14,3% y 33,3% para cada uno de ellos. Se concluye que los biotipos criollos tienen tendencia productiva lechera y doble propósito y la única diferencia entre ellos es el color de capa.
Características ováricas y hormonales de la cobaya en diferentes etapas del ciclo estral
(Universidad de Cuenca, 2023-09-26) Iglesias Barahona, Karen Paulina; Guamán Garzón, Pamela Michelle; Ayala Guanga, Luis Eduardo
The objective of this research was to evaluate the ovarian and hormonal characteristics of the guinea pig after heat synchronization with oral progesterone. The study was carried out in the Biotechnology laboratory of the Faculty of Agricultural Sciences of the University of Cuenca. Forty-three guinea pigs between 4 and 5 months of age were used, with an average weight of 886,2 ± 12,80 grams, they were synchronized for 15 days with oral progesterone (P4) (Altrenogest) for the subsequent assessment of the vaginal membrane, cytology, blood sampling, evaluation of ovarian morphology, antral follicle count and corpus luteum, as well as the classification of COC's obtained at five moments of the estrous cycle day (15, 1, 4, 8 and 11). The results showed that the oral administration of P4 at a dose of 0.22 mg/kg of body weight for 15 days allowed 94.1% of guinea pigs to present vaginal membrane opening (AMV). A mean of 30.1 antral follicles of different sizes available for aspiration was determined, that is, 15.1 follicles/ovary. Collecting 1,249 suitable COC's through the follicular aspiration technique, of which 61.5% come from follicles between (0.5-1 mm), 60% (less than 0.5 mm) and 71.4% (greater than 1 mm). In conclusion, it is confirmed that the follicular dynamics in the guinea pig is biphasic, in addition, the corpus luteum has a growth, static and regression phase and that the preovulatory follicle measures between 0.5-1 mm and that this class of follicles are the ones that provide COC's of the highest quality.
Caracterización morfométrica e índices zoométricos de los grupos raciales bovinos existentes en el cantón Cuenca
(2016) Alvarado Cabrera, Jennifer Marcela; Rodas Balseca, Andrea Cristina; Ayala Guanga, Luis Eduardo
The objective of this study was to evaluate the morphometric characteristics and zoometric rates of existing cattle racial groups in the area. 1,118 cows were evaluated in the rural area in Cuenca Ecuador, with an average of 5.1years, body condition 3.4 and 2.9 parity. 23 linear measurements, 23 Faneroptics features, 4 characters udder, 13 zoometric indices were analyzed. Statistical analysis was based on the determination of frequencies, kruskal Wallis test, Chi cuadrado test, Spearman correlation. Principal component analysis and cluster analysis. An average value of chest circumference to the Holstein breed of 178.9 ± 0.46 cm was determined, Brown Swiss 179.9 ± 2.48 cm, 2.08 cm ± Jersey 168.9, and 170.9 ± 1 Creole 50 cm, an average weight of 425.5 ± 2.97 kg, 444.6 ± 15.03 kg, 355.7 kg and 374.9 ± 12.76 ± 9.31 kg respectively a height at the withers of 129.5 ± 0.26 cm, 1.25 cm ± 133.8, 121.8 ± 1.25 cm, 123.3 ± 0.89 cm. It was established that the Holstein breed in the area has three layer colors like Brown Swiss, two in the Jersey and four in Creole. The thoracic perimeter had correlation with body weight (r = 0.91). The principal component analysis allowed us to establish three groups (weight, height and support) which accounted for 74.52% of one cumulative variance. According to the cluster analysis subgroups of 17 animals it was determined. The existence of four racial groups zootechnical interest in Cuenca was found, with the Holstein breed predominates with 89%. Four breeds were identified in the area of Cuenca meeting within national and international standards set by their associations , with the pelvic zoometric indices , pelvic and relative thickness longitudinal cane presented statistical difference between racial groups
Caracterización morfométrica de útero, ovarios y ovocitos de cobayas criollas (Cavia porcellus) de la sierra sur de Ecuador
(ALPA, 2018) Fernandez Jara, Adriana Estefania; Encalada Sinche, Tania Alexandra; Guaman Guallpa, Anabel Gabriela; Ayala Guanga, Luis Eduardo; Argudo Garzon, Daniel Ernesto; Rosales Jaramillo, Cornelio Alejandro; Perea Ganchou, Fernando Pedro; Fernandez Jara, Adriana Estefania
Los cuyes o cobayos son animales de gran interés productivo en la sierra ecuatoriana y en otros países andinos, debido a que constituyen una fuente alimenticia de alto valor nutritivo y de consumo tradicional; sin embargo, muchos aspectos morfológicos y fisiológicos de estos animales han sido poco estudiados. Se estableció como objetivo de este estudio caracterizar morfométricamente el útero, ovarios y ovocitos de cobayas (Cavia porcellus) nativas de la Sierra sur del Ecuador. Se utilizaron 18 cobayas primíparas de línea genética Azuay y Cañar, con un peso promedio 1002.7 ± 212.7 gramos, en buen estado de salud, que pertenecían a la Unidad de Producción de Cuyes de la Facultad de Ciencias Agropecuarias de la Universidad de Cuenca. Los animales fueron faenados siguiendo las normas de bioética y bienestar animal consideradas por la Organización Mundial para la Salud Animal. Luego de ser identificado y aislado el aparato reproductor de cada hembra, los ovarios fueron retirados y colocados en solución fisiológica a 37ºC, hasta ser pesados en una balanza analítica y medidos su largo y ancho con un calibrador metálico. Los úteros fueron removidos y separados del tejido circundante, e inmediatamente medidos los cuernos derecho e izquierdo, así como también el cuerpo y cuello uterino. Los ovocitos obtenidos (n=48) mediante la técnica de slicing (cortes múltiples sucesivos de la corteza ovárica) dentro de una placa de Petri con solución fisiológica, fueron identificados y lavados varias veces, y removidas las células de cumulo mediante pipeteo repetido en un medio con hialuronidasa al 0,1%. Luego fueron fotografiados y medidos con un software (AmScope V3.7) calibrado para realizar mediciones microscópicas. Los datos se analizaron con el programa estadístico SAS. El peso de los ovarios fue 77±27 miligramos (derecho 77,7; izquierdo 76,3), y su largo y ancho de 8,05±1,25 (derecho: 8,27; izquierdo: 7,83) y 5,27±1,14 mm (derecho: 5,38; izquierdo: 5,16) respectivamente. El cuerno derecho midió 7,97±1,74 cm y el izquierdo 7,85±1.75 cm; mientras que el cuerpo y el cuello uterino midieron 1,2±0,37 y 1,1±0,22 cm respectivamente. La zona pelucida de los ovocitos midió 12,1±2,5 mμ, mientras que su diámetro (sin zona pelucida) y volumen fueron de 75,6±8,2 μm y 234003,8±76547,1 μm3 respectivamente. Se concluye que el peso y las dimensiones de los ovarios derecho e izquierdo de cobayas nativas es similar. Asimismo, conocer las características morfológicas del aparato reproductivo de esta especie es de gran valor para comprender mejor los aspectos funcionales de la misma.
Caracterización morfométrica e índices zoométricos de los grupos raciales bovinos existentes en los cantones occidentales de la provincia del Azuay
(2017) Ramónez Cárdenas, Marco Alberto; Zhunio Samaniego, Luis Eduardo; Ayala Guanga, Luis Eduardo
The objective of the present investigation is to categorize the racial groups of bovines that exist in the Western towns of the Azuay province, trough phenotypic parameters of 799 cows. For the evaluation of the morphometric characteristics were considered 20 lineal characters, 4 of udder; 19 phaneroptic variables, 11 zoometric indeces. We performed principal component analysis (PCA), correlations were established between morphometric variables, conglomerates test determinated racial groups and subgroups, we used a confidence level of 95%. It was established the existence of 4 racial genotypes of productive importance Holstein (73.2%), Brown Swiss (4.5%), Jersey (2.1%) and Criolla (1.3%), in total 10 clusters were determinated. Five main components (ACP) explained 71.69% of the total variance. Correlations greater than (> 0.566) and significant (P <0.05) were found between the variables weight, thoracic perimeter and length of the animal. The zoomometric indeces showed statistical difference (P <0.05) among the 10 clusters, with the exception of facial indece (IFC) and pelvic indece (IPE). When comparing the Holstein genotypes (7 subgroups), with internationally and nationally established parameters are considered as low and intermediate animals of height, their rump angle (GA) had a desired inclination, and excellent external intersquiatic width ( AIIE), udder characters were scored as intermediate. The Criollo genotype was compared at national level with Criollo Lojano cattle described by Aguirre et al., (10) establishing the presence of similar colors layers; However, they were animals of greater height, body length, length and width of rump; and lower thoracic perimeter.
Centrifugación coloidal como método de selección espermática previo a la crioconservación con glicerol en caninos
(2019) Ayala Guanga, Luis Eduardo; Garay Peña, Gabriela Sofía; Carpio Alemán, Fredy; Rodas Carpio, Ermes Ramiro; Nieto Escandón, Pedro Emilio; Calle Ortiz, Guido Rigoberto
Background: The ejaculate of the dog has three fractions, the first and third containing prostatic fluid that is harmful to cryopreservation, and the second rich in sperm. Obtaining only the second fraction of the ejaculate is complicated; therefore, colloidal centrifugation was evaluated as a sperm selection method, plus the addition of glycerol in three concentrations 4, 6 and 8 % as cryoprotector. Methods: The study was conducted at the University of Cuenca-Ecuador, 72 seminal samples from 6 crossbreed dogs were evaluated. Each sample was divided into 2 aliquots, the first for Group 1 (conven-tional centrifugation) and the other Group 2 (colloidal centrifugation), once centrifuged each aliquot was sub-divided into three and 4, 6 and 8 % of glycerol were added. Three spermatic evaluations were carried out (initial, pre and post thawing). Results: The sperm concentration after centrifugation was similar between the initial sample (MI) and Group 1 (P > 0.05); in Group 2 less sperm was observed (P < 0.05). When assessing the progressive indi-vidual motility (MIP) pre freezing, it was observed that the sperm of the Group 1 reduced 30 % its motili-ty in relation to the sample MI and that of Group 2. Post thawing MIP within the groups with different concentrations of glycerol (4, 6, 8 %), which previously received centrifugation with Percoll (Group 2) presented statistical difference (P < 0.05). However, the HOS test gave similar percentages. Conclusions: It is concluded that colloidal centrifugation, prior to the freezing process, is a technique that allows greater selection and sperm purification
Colloidal centrifugation for dog sperm selection prior cryopreservation with glycerol.
(2019) Ayala Guanga, Luis Eduardo; Garay Peña, Gabriela Sofía; Carpio Alemán, Fredi Marco; Rodas Carpio, Ermes Ramiro; Nieto Escandón, Pedro Emilio; Calle Ortiz, Guido Rigoberto
Background: Dog ejaculates are produced in three fractions: the first and third fractions contain prostatic fluid, which is harmful for cryopreservation. The second fraction is spermatozoa-rich. Collecting the second fraction of the ejaculate is complex; hence, colloidal centrifugation plus the addition of glycerol at three different concentrations (4, 6, and 8%) as cryoprotectant was evaluated as a method for sperm selection. Methods: In this study, 72 seminal samples from 6 crossbred dogs were evaluated at the University of Cuenca-Ecuador. Two aliquots were made from each sample, one for conventional centrifugation (Group 1), the other for colloidal centrifugation (Group 2). After centrifugation, each aliquot was subdivided into three parts, and 4, 6, and 8% glycerol were added, respectively. Three sperm evaluations were made (initial, pre-thawing, and post-thawing). Results: Sperm concentration was similar between the initial sample (IS) and Group 1 (P>0.05) after centrifugation, whereas fewer spermatozoa where observed in Group 2 (P <0.05). Evaluation of pre-thawing individual progressive motility (IPM) revealed that the spermatozoa in Group 1 underwent a 30% motility reduction in comparison to the IS and Group 2. Post-thawing IPM within the groups with different concentrations of glycerol (4, 6, and 8%) which underwent previous centrifugation with Percoll (Group 2), showed statistical differences (P <0.05). However, the HOS test produced similar percentages. Conclusions: Colloidal centrifugation prior freezing ensures better sperm selection and purification.
Competencia del ovocito bovino obtenido por ovum pick-up valorado mediante el azul brillante de cresilo
(2018) Ayala Guanga, Luis Eduardo; Samaniego Campoverde, Jorge Xavier; Nieto Escandón, Pedro Emilio; Rodas Carpio, Ermes Ramiro; Dután Sanango, Jorge Bolívar; Calle Ortiz, Guido Rigoberto; Murillo Apolo, Yury Agapito; Vázquez Mosquera, Juan Mesías; Argudo Garzón, Daniel Ernesto; Perea Ganchou, Fernando Pedro
The objective of the present study was to evaluate the bright blue cresyl (BCB) test as an indirect method to select competent oocytes for the in vitro production of embryos (IVP). The cumulus-oocyte complexes (COC) were obtained from two Creole heifers subjected to two treatments: T1 = COC recovered by OPU (ovum pick-up) previous stimulation with FSH-LH; T2 = COC recovered from non-stimulated animals (control).The two heifers were alternated in the two treatments and five repetitions were done. Recovered COCs were classified into types A, B, C and D. Then the BCB test was applied to each of the COC types to determine if they were BCB+ or BCB-. T1 allowed to recover 5.2 more COC than T2 (p<0.05). When applying the BCB test, it was determined that all type A oocytes of T1 and T2 were BCB+; that is, they finished their growth and were ready to start the process of in vitro maturation; however, about 50% of the type B, C and D COCs of T1 and T2 were BCB+. It is concluded that the selection of COC based on morphological characteristics is a reliable method only for type A and has a 50% error for COC type B, C and D and, therefore, the application of the BCB test allows to improve this selection non-invasively
Competencia ovocitaria en procesos de maduración in vitro y su relación con el tamaño del folículo
(ALPA, 2018) Ayala Guanga, Luis Eduardo; Nieto Escandón, Pedro Emilio; Dután Sanango, Jorge Bolívar; Calle Ortiz, Guido Rigoberto; Ortega Herrera, Vanessa Viviana; Samaniego Campoverde, Jorge Xavier; Estrella Bermeo, Carlos Adrián; Suconota Pizarro, Ana Gabriela; Ayala Guanga, Luis Eduardo
El objetivo fue valorar la competencia post maduración in vitro (MIV) de ovocitos bovinos provenientes de folículos de tres tamaños diferentes. Se realizó en el laboratorio de Biotecnología Animal de la Universidad de Cuenca a 2.650msnm. Previo a la aspiración, los folículos fueron medidos y clasificados en grupo 1 (<4mm); grupo 2 (4-8mm) y grupo 3 (>8mm). La punción folicular se realizó a cada grupo por separado con una aguja 21G conectada a una bomba de vacío, a presión de 65mmHg. Los complejos cumulus ovocitos (COC´s) recuperados de cada grupo fueron clasificados en base a las características del cumulus y citoplasma en aptos y no aptos para la producción de embriones in vitro (PIV). La determinación enzimática se realizó a través de la prueba del azul brillante de Cresilo (BCB). La maduración se realizó en microgotas colocadas en una cámara de CO2 al 5%; a 38,5°C y 90% de humedad, durante 24h, usando como medio TCM 199. La valoración de la progresión meiótica a metafase II (competencia) fue determinada con la prueba de Hoesch en base a la extrusión del primer corpúsculo polar, valorados mediante epifluorescencia bajo un microscopio invertido. Los resultados fueron analizados con el paquete estadístico IBM® SPSS® versión 22. Se realizaron 14 sesiones, aspirando 1.964 folículos en el grupo 1 (G1), grupo 2 (G2=1.073) y grupo 3 (G3=336). Se obtuvo un porcentaje de recuperación del 76,1% en G2, 64,7% en G1 y 63,4% en G3 con diferencia estadística (P<0,05). El grupo G2 presentó un mayor porcentaje de COC´s valorados como aptos (65,7%), seguido de G3 (54,9%) y finalmente de G1 (42,4%), con diferencia entre grupos (P<0,05). De los COC’s clasificados como aptos, en G2 el 59,0% fueron positivos al colorante (BCB+), en G1 (44.6%) y G3 (35.7%); es decir, habían terminado su crecimiento y estaban listos para continuar con el proceso de maduración (P>0,05). Sin embargo, al valorar el porcentaje de COC´s clasificados como aptos que fueron BCB+ y BCB- dentro de un mismo grupo, se estableció que G2 presentó más BCB+ que BCB- (P<0,05). Finalmente, los ovocitos clasificados como aptos de G1 y G2, reanudaron la meiosis y llegaron a metafase II en un 75% a diferencia de G3 (61%), (P<0,05). Se concluye que los COC's provenientes de folículos entre 4-8mm proporcionan mayor porcentaje de maduración; sin embargo, los folículos <4mm son una fuente interesante de ovocitos viables por lo cual deberían ser utilizados para la PIV. Palabras clave: tamaño, COC’s, aptos, meiosis
Concentración de la hormona folículoestimulante y respuesta a un protocolo de superovulación administrado por vía epidural en vacas Holstein
(Universidad de Cuenca, 2024-01-12) Delgado Tello, Paul Danilo; Vásquez Prado, Ashley Nicole; Ayala Guanga, Luis Eduardo
The research was carried out at the Nero Farm of the University of Cuenca, the objective was to determine the plasma concentration of Follicle Stimulating Hormone (FSH) and the ovarian response when applying 200 mg of FSH, in a single dose epidurally, in cows. Holstein crossbreeds. Two routes of FSH administration were compared in a superovulation (SOV) protocol: intramuscular (T1) and epidural (T2). The FSH concentration, superovulatory response, ovulation percentage, quantity and quality of structures collected in each treatment were assessed. The FSH concentration remained high until hour 50, then the hormone decreased until reaching basal levels in both treatments. The number of follicles observed after SOV treatment was similar at T1 (15.5 ± 4.29) and T2 (15.3 ± 1.89). No significant difference will be observed in the diameter of the follicles in T1 (11.9 ± 0.49 mm) and T2 (10.8 ± 1.49 mm) p>0.05. The number of corpora lutea in T1 (2.8 ± 1.03) and T2 (7.5 ± 3.7), as well as their size (T1= 16.80 ± 0.68 mm; T2= 18.1 ± 0.99 mm) were similar (p>0.05). Likewise, a large number of follicles that did not ovulate were observed (T1= 12.8 ± 4.33; T2 = 7.50 ± 2.59); and no statistical difference was found between the number of structures (T1=1.8 ± 0.9; T2=4.8 ± 3.0) and transferable embryos collected (T1=0.5 ± 0.3; T2=3 .8 ± 2.6) at the end of the protocol. In conclusion, FSH administered epidurally maintained similar levels during the first 50 h to those observed when FHS was applied intramuscularly in a conventional protocol; However, at 52 h, the FSH concentration dropped to basal levels in T1, which were maintained until the end of the protocol.
Control of the emergence of the follicular wave by the application of oestradiol benzoate, GnRH and follicular ablation in the late metaoestrous in heifers in the high tropics
(2020) Ayala Guanga, Luis Eduardo; Nieto Escandón, Pedro Emilio; Rodas Carpio, Ermes Ramiro; Sarmiento Quito, Santiago Xavier; Dután Sanango, Jorge Bolívar
The response of the dominant follicle (DF), the profile of the FSH and estradiol and the onset of the follicular wave after the application of estradiol benzoate, GnRH, or follicular ablation in late metestrus were characterized in crossbred Holstein heifers, reared at 2500 meters above sea level and fed to grazing. Nine animals weighing 427.7±23.0 kg, body condition 2.7±0.1, age 26.7±1.4 months were used. Before the experiment, the heifers were synchronized and day 6 of the oestrous cycle was considered day zero (start of the experiment). There were three treatments: T1 = Oestradiol benzoate - BE (n=9), T2 = GnRH (n=9), T3 = Ablation (n=9). The evaluation of the DF was carried out by ultrasound every 24 hours, for 5 consecutive days. FSH and oestradiol levels were analysed every 5 days from day 0 by radioimmunoassay. The onset of the follicular wave and number of follicles recruited were determined retrospectively when assessing the daily ultrasound. The application of BE (T1) caused an initial growth of the DF, then it was maintained and finally went to atresia, the peak of FSH appeared at 48h (0.87±0.21 ng/ml) and the onset of the follicular wave was at 3.2±0.15 d post-treatment. In T2, 55.5% of the heifers ovulated in 24h and 44.5% between 24-48h, the peak of FSH was at 24h post-treatment and the onset of the wave in 2.4±0.18 d. The T3 heifers showed the FSH peak at 24h and wave restarted at 1.8±0.15 days. It is concluded that the application of BE in the heifers of the study favoured then an earlier restart of the follicular wave. Besides, the presence of corpus luteum and DF prior to the application of GnRH and ablation allows a more solid and homogeneous restart of the follicular wave.
Desarrollo agroindustrial: un impulso para la producción animal en industrialización
(Universidad Nacional de Chimborazo. UNACH, 2024) Rosales Jaramillo, Cornelio Alejandro; Taboada Pico, Juan Wualverto; Once Carabajo, Veronica Elizabeth; Ayala Guanga, Luis Eduardo
Dinámica folicular de vaquillas criollas al pastoreo en el altiplano ecuatoriano
(2019) Ayala Guanga, Luis Eduardo; Pesántez Pacheco, José Luis; Rodas Carpio, Ermes Ramiro; Dután Sanango, Jorge Bolívar; Calle Ortiz, Guido Rigoberto; Vázquez Mosquera, Juan Mesías; Nieto Escandón, Pedro Emilio
The aim was to characterize the behavior pattern of follicular dynamics in creoles heifer (CR) to grazing in the high mountains of Ecuador. It was carried out in the Irquis experimental farm at the University of Cuenca, in 2016. The average weight was 243.3±45.0kg. Body condition (CC) 2.5±0.4, scale 1-5 points. Age 19.9±4.8 months. Daily scans were performed during an estrous cycle. Every 48h the levels of Progesterone (P4) were determined. A pattern of two and three follicular waves was established (44.4 and 55.6% respectively). The average duration of the estrous cycle was 20.3±0.03 days (two waves) and 23.6±0.02 days (three waves). The size of the preovulatory follicle (FPO) was 15.3±0.04mm for two-wave animals and for those with three waves, 13.8±1.48mm. The subordinate follicle (FS) reached its maximum size on day 4.0±0.04, with 8.0±0.04mm (two waves) and 4.8±0.03 days with 7.4±0.03mm (three waves). The development of the corpus luteum (CL) presented three phases: growth (until day 6), static (6-18 days) and regression (>18 days). On day 12, the CL reached its largest size 21.7±1.45mm and 23.5±0.61mm for animals of two and three waves respectively. P4 reached levels above 1ng / ml from day 4 (5.8±3.35ng/ml two waves and 5.1±1.15ng / ml three waves). The levels of P4 during the estrous cycle were higher than those reported in other breed. In conclusion, Creole genotype heifers have their own characteristics, which are influenced by the pattern of follicular behavior (two or three waves)