Browsing by Author "Garay Peña, Gabriela Sofía"

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Assessment of different diets in the productive behavior of native guinea pigs (Cavia porcellus) from the Andes of Ecuador
(2023) Jacome Aucay, Andres Santiago; Velesaca Ayala, Pablo Geovanny; Garay Peña, Gabriela Sofía; Murillo Apolo, Yury Agapito; Rosales Jaramillo, Cornelio Alejandro; Nieto Escandón, Pedro Emilio
The objective of this study was to evaluate the productive performance of native guinea pigs fed forage and forage plus concentrate diets. Thirty-six native weaned guinea pigs from the Provinces of Azuay and Cañar were distributed under a completely randomized design consisting of six diets with different levels of inclusion of grass (Lolium multiflorum) and legume (Medicago sativa) with or without the addition of concentrate (D1, D2, D3 and D4, D5, D6, respectively), where productive performance: total feed intake (CTA), total protein intake (CTP), feed conversion (CA), final live weight (PF), total weight gain (GPT), average daily weight gain (GDP) and economic parameters (Production cost, net profit, merit economic) was evaluated in the different treatments. Diets 3 (20 % L. multiflorum; 70 % M. sativa and 10 % commercial feed) and 4 (20 % L. multiflorum; 80 % M. sativa) had the best CA (8.21 and 8.59; P<0.05, respectively); GPT (624.47 and 593.78 g; P<0.05, respectively) and daily GDP compared to the other treatments (5.95 and 5.66 g·d-1; P<0.05, respectively). Therefore, although native guinea pigs have lower productive yields with respect to improved lines, the diets that allow expressing their maximum performance in reference to CA, GPT, GDP, PF and economic merit, are those containing levels greater than 50 % of alfalfa inclusion with or without commercial concentrate.
Caracterización histo-morfológica del ovario, útero y células epiteliales de la vagina en las fases del ciclo estral de la cobaya
(Universidad de Cuenca, 2025-05-03) Borja López, Edisson Mauricio; Cevallos Cabrera, José Enrique; Garay Peña, Gabriela Sofía
The present investigation characterized the histo-morphological changes in ovary, uterus and vaginal epithelial cells during the estrous cycle of guinea pigs, 48 guinea pigs of 5 months of age and average weight of 750 ± 0.38 grams (g) were evaluated, which were synchronized with oral progesterone (0.44 mg / Kg) for 15 days, with the purpose of assessing the opening of vaginal membrane (AMV) to determine the heat and start with the realization of vaginal cytologies (CV), in addition by histology as well as direct visualization we determined: follicular characteristics, characteristics of the corpus luteum (CL), morphology of the ovaries and uterine characteristics determined at 7 moments of the estrous cycle (0, 2, 5, 8, 11, 14 and 16). From the heat we defined the study moments in: estrus (E), metestrus (M), diestrus (D5, D8, D11, D14) and proestrus (P). In ovaries, weight (P=0.036), volume (P=0.05) and diameter (P=0.026) were greater in M and D11, in addition, tertiary follicles were the most abundant structures (P=0.001; D11: 28.3±2.5 n) and with greater diameter in E (294.7±64.21 μm) and D11. (295.6±44.7 μm), the CL reached its largest size in D5 (408.0±95.1 μm), with no significant differences between moments. In the uterus, the endometrium showed significant differences on D8 with the highest thickness in horns (P=0.03; 300.2±39.0 μm), on the other hand, the myometrium in the uterine body differs between moments (P=0.04) with greater thickness in M (145.9±12.9 μm), and the thickness of the perimetrium differs on D11 with the highest value in horns (P=0.03; 152.2±9.8 μm) and body (P=0.02; 11.3±1.8 μm), similar data were observed in the diameter of endometrial glands, where D11 recorded the largest diameter in uterine horns (P=0.002; 10.3±1.1 μm). The posterior width of the horns differed on D8 with the highest measurement (P=0.0002; 3.6±0.2 mm) while, in the body, P recorded higher figures in length (P=0.028; 5.2±0.8 mm) and width (P=0.019; 5.4±0.7 mm). Finally, the CV showed variations between moments for large intermediate cells (P=0.001; M: 36.8±23.8 n), small cells (P<0.01; D5: 48.6±25.1 n), neutrophils (P<0.01; D11: 111.5±45.1 n), parabasal cells (P=0.001; E: 32.4±29.8 n) and basal cells (P=0.026; M: 1.4±3.6 n). It is concluded that the guinea pig presents a biphasic pattern, generating significant histomorphological changes in follicular development, in the uterus and vaginal cytology between the 7 study moments.
Caracterización morfológica del periodo gestacional de cobayas in vivo y post mortem mediante ultrasonografía
(Universidad de Cuenca, 2025-02-06) Gañán Cornejo, Gissela Eugenia; Munzón Guallpa, Fernanda Estefanía; Garay Peña, Gabriela Sofía
The research was conducted at a commercial farm in Santa Ana, Cuenca, Ecuador, involving 35 female guinea pigs and 12 males of the Peruvian line. The study aimed to evaluate the morpho-structural development of the fetus and placenta during the gestational period, both in vivo and post mortem. In the first phase, ultrasonography (US) was used to measure variables in pregnant animals both in vivo and post-mortem. Subsequently, the same variables were evaluated post-mortem using a caliper. In vivo US measurements included biparietal diameter (BPD), abdominal diameter (AD), thoracic diameter (TD), caudal skull length (CCL), heart rate (HR), placental diameter (PD), and gestational sac diameter (GSD), assessed on days 15, 20, 25, 30, 35, 40, 45, 50, 55, and 60 of gestation. On days 15, 20, 25, 30, and 35, after in vivo US evaluation, the guinea pigs were euthanized to analyze the same variables post-mortem using both US and the caliper. Additionally, progesterone (P4) levels were measured. Through oral P4 administration, estrus was successfully induced in 83% of the guinea pigs. The results showed that in vivo US provided reliable measurements of PD and GSD, comparable to those obtained post-mortem using the caliper. Furthermore, BPD was identified as the most consistent variable when comparing the three measurement methods. However, AD, TD, and CCL showed statistically significant variations (P<0.05) between in vivo and post-mortem measurements, limiting their reliability. HR remained stable and showed no significant differences (P>0.05) during the monitoring periods. Regarding P4 levels, an increase was observed on day 15, followed by a decrease by on day 20. These levels remained steady until day 25, increasing again from day 30 and doubling by day 35 of gestation. It is concluded that in vivo ultrasonography is a highly reliable tool for visualizing the placenta and gestational sac, with BPD being the best measure to estimate gestational age in guinea pigs.
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.
Efecto de la centrifugación coloidal previo al proceso de crio conservación sobre la calidad seminal post descongelación en caninos
(2019) Garay Peña, Gabriela Sofía; Ayala Guanga, Luis Eduardo
The objective of the investigation was to evaluate the colloidal centrifugation as a method of sperm selection plus the addition of glycerol in three concentrations 4%, 6% and 8% as cryoprotectant. We evaluated 72 seminal samples from 6 mestizo dogs, healthy, CC 5 (scale 1 to 9), from 3 to 5 years old, whose ejaculates met the following parameters: minimum volume 1ml, mass motility 3 (scale 1 to 5), Individual progressive motility 60% and less than 30% of abnormalities. Each sample was divided into 2 aliquots, the first for Group 1 (conventional centrifugation) and the other for Group 2 (colloidal centrifugation), after which each aliquot was divided into three, corresponding to the concentration of glycerol. Three sperm evaluations were performed (initial, pre-freezing and post-thawing). The comparative analysis between the initial samples and Groups 1 and 2 pre-freezing presented statistical differences (P <0.05) for the concentration, being lower in Group 2 (183x106), as for the progressive individual motility (MIP) reduced in Group 1 (61.3%); the vitality and the percentage of abnormalities did not show statistical differences (P> 0.05), between groups. It was determined that adding glycerol to 4%, improves cryopreservation expressed in a higher MIP (76.7%), as well as a lower percentage of abnormalities (4.3%) and greater vitality (93.6) post thawing, this when the seminal sample was centrifuged previously in colloidal medium. In conclusion, the use of the colloidal medium contributes to improve the selection of spermatozoa that together with a cryoprotectant based on glycerol to 4% allows to maintain the minimum parameters after thawing of the seminal sample in canines.
Niveles de progesterona en la fase de proestro y su relación con la manifestación de celo en cobayas sincronizadas
(Universidad de Cuenca, 2025-08-06) Dávila Cueva, Janeth Gabriela; Paguay Lliguicota, Franklin Israel; Garay Peña, Gabriela Sofía
The present study quantified serum progesterone concentrations in the induced proestrus phase and its relationship with estrus in synchronized guinea pigs, and also evaluated the characteristics of the vaginal epithelium from the day of the opening of the membrane for 9 consecutive days. For this purpose, 48 guinea pigs of 6 months of age and average weight of 750 grams (g) were synchronized with oral progesterone (0.44 mg/kg) for 15 days; After the last dose, blood samples were taken daily to determine the serum concentration of progesterone (P4; ng/mL) until the guinea pig presented an opening of the vaginal membrane (VMA) of 50% or for 9 consecutive days, after the VMA, vaginal cytology (VC) was performed daily for 9 days and in each cytology 200 cells were counted per plate classified between: large intermediate (IG), small intermediate (IP), superficial (S), neutrophils (N), parabasal (P) and basal (B); for the evaluation of the concentration of P4 and MVA, the results were grouped into three periods; first the record of day 15 considered as basal; Second, from day 16 to 19 and third, from day 20 to 23, the estrus and ovulation time was determined from the end of the protocol until the MVA and until the recording of the highest number of neutrophils in the CV, respectively. The results obtained indicate an estrus time of 8.2±1.9 days and ovulation time of 8.7±1.9 d, the concentration of P4 were different between periods (P<0.05) and did not reveal values higher than 0.6 ng/mL where the second period was the lowest value with 0, 32±0.03 ng/mL, on the other hand, MVA was statistically significant (P=0.016) between periods and presented a higher amount of animals with 50% MVA between days 20 to 23, the correlation analysis between serum P4 and MVA was not significant (P=0.575); in the CV analysis, significant morphological changes were observed in IG (P<0.01), IP (P=0.04), N (P<0.01), P (P<0.01) and B (P<0.01) cells. During estrus, a predominance of P cells was evidenced, followed by N, IP, IG, S and B cells. From metaestrus to diestrous 6, there was a significant increase in the proportion of N cells, together with a numerical decrease in S cells. In conclusion, it was determined that there is no correlation between serum P4 levels and 50% MVA during the induced proestrus phase in synchronized guinea pigs and that after MVA there were significant changes in the VC, the most relevant change being the increase in N cells.
Relación de los niveles de estrógenos y progesterona con los cambios histo-morfológicos del ovario durante el ciclo estral de la cobaya
(Universidad de Cuenca, 2025-08-06) Torres Contreras, Aleida Tamara; Garay Peña, Gabriela Sofía
This investigation evaluated serum concentrations of estrogen (E2) and progesterone (P4) at eight moments of the guinea pig estrous cycle (days 0, 2, 5, 8, 11, 14, 17 and 20), relating them to cytological changes in the vaginal epithelium and histo-morphological characteristics of ovaries. For this purpose, 48 females of six months of age and 750 g of average weight were synchronized by oral administration of P4 (0.44 mg / kg) for 15 days. The onset of heat (day 0) was determined with the opening of the vaginal membrane and vaginal cytologies were performed (200 cells / smear) classified into six cell types. In parallel, ovaries were collected for morphological and histological analysis of follicles and corpora lutea. The results showed that P4 reached its highest levels between D3 and D12 (1.65–1.50 ng/mL), correlating with a significant increase in neutrophils and a lower number of tertiary follicles, except on D9, when these increased. The corpora lutea remained stable during diestrus, reaching their largest diameter on D6 (408 μm). In contrast, E2 peaked in estrus (60.26 pg/mL) and proestrus (42.10 pg/mL), associated with increases in large intermediate and superficial cells, respectively. Likewise, E2 levels were related to larger follicular size in estrus (357 μm) and proestrus (220 μm), along with the progressive reduction and subsequent absence of corpora lutea. In conclusion, the guinea pig estrous cycle is characterized as biphasic, with a predominance of tertiary follicles in estrus and proestrus, a high presence of neutrophils in diestrus, and an absence of corpora lutea in proestrus.