Tesis Medicina Veterinaria
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Item Evaluación de extracto etanólico microencapsulado de semillas de (Carica papaya) en comparación con Zinaprim sobre la excreción de ooquistes de Eimeria spp., digestibilidad aparente, signos clínicos digestivos y parámetros bio-productivos en conejos de ceba (Oryctolagus cuniculus)(Universidad Técnica de Ambato Carrera de Medicina Veterinaria, 2026-07) López Enríquez, Damaris Micaela; Díaz Sjostrom, PedroCoccidiosis in fattening rabbits is one of the main digestive diseases that limits rabbit production, as it affects nutrient absorption, reduces growth, and promotes diarrhea and other intestinal disorders. Given the conventional use of chemical anticoccidials, there is a need to evaluate natural alternatives that contribute to disease control and reduce dependence on pharmaceuticals. In this context, the present research aimed to evaluate the effect of microencapsulated ethanolic extract of Carica papaya seed, compared to Zinaprim, on the excretion of Eimeria spp. oocysts, apparent digestibility, digestive clinical signs, and bio-productive parameters in fattening rabbits. The study was conducted using a completely randomized design, with 40 rabbits distributed into four treatments: Control, Zinaprim, Carica papaya 50 mg, and Carica papaya 100 mg. Oocyst counts per gram of feces, presence of diarrhea, cecotrophy alterations, apparent digestibility, feed intake, feed conversion ratio, final weight, and average daily gain were evaluated. The results suggested that the treatment with Carica papaya 50 mg resulted in lower oocyst excretion on day 21 and a lower frequency of diarrhea, demonstrating a favorable effect against Eimeria spp. Apparent digestibility showed a higher trend in the group treated with Zinaprim, while the bio-productive parameters did not show statistically significant differences; however, the 50 mg treatment showed the best numerical values for final weight, weight gain, and average daily gain. These findings suggest that the microencapsulated ethanolic extract of Carica papaya seeds, especially at 50 mg, constitutes a promising natural alternative to reduce parasite load and improve digestive stability without negatively affecting the productive performance of rabbits.Item Prevalencia y susceptibilidad de Staphylococcus aureus en mastitis subclínica bovina en Tungurahua, ecuador(Universidad Técnica de Ambato Carrera de Medicina Veterinaria, 2026-07) Araque Carvajal, Angeles Galilea; Villavicencio Villavicencio, Blanca JeanethThe fragmentation of epidemiological information on bovine mammary health in the Ecuadorian highlands limits the design of effective control strategies against pathogens such as Staphylococcus aureus. Objective: to evaluate the prevalence of subclinical mastitis and the susceptibility profiles of Staphylococcus aureus in five cantons of Tungurahua, Ecuador. Method: a descriptive and cross- sectional study was conducted on 1343 cattle using the California Mastitis Test. Microbiological analysis was performed on 892 milk samples through hemolysis tests, Gram staining, mannitol salt agar, and coagulase activity; antimicrobial susceptibility was evaluated by disk diffusion, and data were processed using Chi-squared tests and 95 % confidence intervals in InfoStat. Results: the global prevalence of subclinical mastitis was 39.8 %, with 12.2 % positivity for S. aureus, highlighting a critical resistance to penicillin G (99.0 %) and the presence of multidrug-resistant strains with decreased sensitivity to ciprofloxacin and trimethoprim-sulfamethoxazole. Conclusion: subclinical mastitis in the region represents a persistent sanitary challenge with unusually high selective resistance pressure, making it imperative to replace empirical therapies with treatments based on local susceptibility profiles to mitigate economic and sanitary impacts.Item Detección y cuantificación de partículas plásticas en sangre y huevos en aves de traspatio (Gallus gallus domesticus) en la comunidad Huambula.(Universidad Técnica de Ambato Carrera de Medicina Veterinaria, 2026-07) Yépez Amores, Delimar Mayeli; Becerra Becerra, Verónica AlexandraThis research aimed to evaluate the presence, bioavailability, and physiological effects of plastic particles (microplastics and nanoplastics) in the blood and eggs of Creole chickens (Gallus gallus domesticus) raised in backyard systems in the community of Huambula, Cotundo parish, Archidona canton, Napo province, Ecuadorian Amazon. The study was conducted using an observational, quantitative, and correlational approach. Twenty-four birds and eleven fresh eggs were sampled with voluntary consent. Blood samples were processed using scanning electron microscopy (SEM), and serum biochemistry was analyzed using colorimetric methods. Eggs were analyzed by Fenton chemical digestion and optical microscopy. The results revealed the ubiquitous presence of polymers in 100% of the blood samples, registering an average of 20.67 total particles with a marked predominance of the nanometric fraction (X = 13.83 PP; 753.4 nm). The correlation and significance analysis showed a causal link between the microplastic load and impaired renal function, manifested in a significant retention of serum urea (r = 0.52); (p = 0.026). In the hepatobiliary component, the nano size directly influenced the alteration of gamma-glutamyl transferase (p = 0.021), reflecting localized chronic metabolic stress. Finally, massive vertical transfer to the reproductive matrices was demonstrated, accumulating an alarming average of 2535.75 transparent plastic particles per egg. In conclusion, backyard chickens serve as relevant bioindicators of environmental microplastic pollution. The presence of these particles in products intended for human consumption poses an emerging risk to public health and food safety, underscoring the need to strengthen environmental monitoring strategies and comprehensive approaches based on the One Health paradigm.Item Determinación de la prevalencia de Staphylococcus aureus resistente a meticilina a partir de muestras de leche en vacas con mastitis subclínica en las haciendas del cantón Baños(Universidad Técnica de Ambato Carrera de Medicina Veterinaria, 2026-07) Lozada Pico, Juan Carlos; Lozada Ortíz, Jenny PiedadSubclinical mastitis is one of the main diseases affecting dairy cattle production due to the associated economic losses and its repercussions on milk quality and safety. The aim of the present study was to determine the prevalence of methicillin-resistant Staphylococcus aureus from milk samples obtained from cows with subclinical mastitis belonging to farms located in Baños canton. A descriptive cross-sectional study was conducted on a sample of 165 cattle selected from a population of 474 animals. Subclinical mastitis was detected using the California Mastitis Test, identifying 82 positive cows and a prevalence of 17.3%, with a total of 128 affected mammary quarters. Samples were processed by microbiological isolation on blood agar, Gram staining, and biochemical tests including mannitol fermentation, catalase, and coagulase, confirming 49 Staphylococcus aureus isolates, corresponding to 59.75% of the evaluated isolates. Antimicrobial susceptibility was determined using the Kirby-Bauer disk diffusion method against ten antibiotics, revealing high resistance rates to penicillin (93.2%) and oxacillin (89.8%), whereas chloramphenicol showed the highest susceptibility. The findings demonstrated the presence of strains compatible with methicillin-resistant Staphylococcus aureus, representing a potential risk to animal and public health. Consequently, the importance of strengthening microbiological surveillance, promoting the rational use of antimicrobials, and improving biosecurity measures in dairy production systems is emphasizedItem Efecto de la alholva (Trigonella foenum-graecum) en dieta sobre producción, calidad de leche, reproducción posparto y perfiles sanguíneos en conejas (Oryctolagus cuniculus).(Universidad Técnica de Ambato Carrera de Medicina Veterinaria, 2026-07) Paspuel Martínez, Diana Estefanía; Díaz Sjostrom, PedroThis research aimed to determine the effect of including fenugreek (Trigonella foenum-graecum) in the diet of breeding does on milk production and quality, reproductive parameters, and blood profiles during gestation and lactation. New Zealand White rabbits were used, divided into three treatments: a control group (G1) and two groups supplemented with 1.5 g (G2) and 2.0 g (G3) of animal fenugreek meal per day. Milk production was evaluated using the indirect weighing method of the kits before and after lactation, as well as the chemical composition of the milk, litter performance parameters, reproductive indicators, and hematological and biochemical variables. The results showed a favorable trend in milk production in the does supplemented with fenugreek; group G3 reached an average production of 323.05 g on day 18 of lactation, surpassing groups G1 and G2. Milk quality showed increases in the percentages of fat, protein, lactose, ash, and total solids. Overall, fenugreek supplementation produced an average improvement of 9.66% compared to the control group. Productive and reproductive parameters showed positive biological trends, reflected in higher weaning weights, better average daily gain, greater receptivity to bucks, fertility, and prolificacy. In blood profiles, glucose remained within physiological ranges with no significant differences between treatments, while cholesterol and triglycerides decreased significantly in the supplemented groups, especially in G3. Hematological parameters remained within normal values for the species. Fenugreek supplementation constitutes a promising phytobiotic alternative for feeding breeding rabbits, as it promotes milk quality and improves the metabolic profile without compromising the animals' health.Item Evaluación del ácido hipocloroso en el tratamiento de enfermedades bacterianas de la superficie ocular en perros(Universidad Técnica de Ambato Carrera de Medicina Veterinaria, 2026-07) Jaramillo Leon, Carlos Andres; Lozada Ortiz, Jenny PiedadIn veterinary medicine, there is a major problem with antibiotic resistance, which has led us to seek treatment options that prevent this resistance in the long term. To test an alternative that reduces antibiotic resistance, the clinical efficacy and economic viability of hypochlorous acid were evaluated in comparison with tobramycin in patients with eye infections. The study involved 20 canine patients, who were divided into two treatment groups: T1, which received 0.01% hypochlorous acid, and T2, which received 0.3% tobramycin. In both groups, ocular swabs were taken before the application of the eye drops and 20 minutes afterwards, thereby measuring the bacterial load in colony-forming units per millilitre (CFU/ml). Cultures and antibiograms demonstrated that Staphylococcus aureus was isolated in all cases as the primary pathogen, whilst Escherichia coli and Streptococcus spp. were isolated in some patients in cases of mixed infections. As a result, it was demonstrated that both treatments significantly reduced the bacterial load. The group treated with HOCl fell from an average of 75.50 CFU/ml to 8.60 CFU/ml, whilst the group treated with tobramycin fell from 74.00 CFU/ml to 9.59 CFU/ml. When a Student’s t-test was performed to compare these two groups, a p-value of 0.4634 was obtained, demonstrating that there were no significant differences between the two treatments. It was concluded that hypochlorous acid is a viable, safe and cost-effective therapeutic alternative for the treatment of bacterial eye infections in dogs, with results similar to those of tobramycinItem Staphylococcus aureus meticilino resistente en bovinos lecheros: situación actual y desafíos en la producción láctea(Universidad Técnica de Ambato Carrera de Medicina Veterinaria, 2026-07) Chisag Chisag, Mayra Lisbeth; Villavicencio Villavicencio, Blanca Jeaneth.Methicillin resistance in Staphylococcus aureus has become a relevant issue in dairy cattle production due to its association with clinical and subclinical mastitis, its persistence within production systems, and its impact on milk quality and economic losses. Objective: to provide information on the current epidemiological situation of methicillin-resistant Staphylococcus aureus in dairy cattle, by describing its resistance mechanisms and evaluating its impact on productivity, the economy, and milk quality, as well as reviewing the main control, prevention, and surveillance strategies. Method: an exhaustive search of recent scientific publications was conducted, focusing on epidemiological aspects, resistance mechanisms, productive impact, and control strategies. Results: the prevalence of methicillin-resistant Staphylococcus aureus in dairy systems varies according to region and production conditions. The predominance of livestock-associated lineages, together with resistance genes and the ability to form biofilms, promotes chronic and subclinical infections, which increase antibiotic use and generates productive impacts. Conclusion: the presence of methicillin-resistant Staphylococcus aureus in dairy cattle represents a sanitary and productive risk that requires strategies centered on strengthening biosecurity measures, promoting responsible antimicrobial use, and maintaining continuous epidemiological surveillanceItem Detección de genes de virulencia pvl-1 y sec en aislados de Staphylococcus aureus meticilino-resistente (SARM) obtenidos de muestras de leche de bovinos con mastitis subclínica(Universidad Técnica de Ambato Carrera de Medicina Veterinaria, 2026-07) Vera Zambrano, Yuli Paulina; Cruz Quintana, Sandra MargaritaBovine mastitis caused by Staphylococcus aureus represents the primary problem in dairy production due to the associated economic losses and the potential risk posed by the circulation of MDR strains. In this context, the presence of virulence genes in isolates of methicillin-resistant Staphylococcus aureus (MRSA) is of epidemiological interest, as the combination of resistance and virulence may promote bacterial persistence and increase its pathogenic potential. The present study aimed to determine the presence of the virulence genes pvl-1 and sec in MRSA isolates obtained from milk samples of cattle with subclinical mastitis from different cantons in the province of Tungurahua, Ecuador. For this purpose, 80 samples of previously stored strains were used, which were reactivated and microbiologically verified using conventional phenotypic tests. Subsequently, DNA extraction was performed, followed by molecular detection of the genes of interest via PCR using specific primers. The results obtained showed no amplification for any of the genes analyzed, indicating the absence of pvl-1 and sec in the isolates evaluated. Additionally, a review was conducted of the scientific evidence related to the molecular mechanisms of action of these genes and the interaction between virulence and antimicrobial resistance in S. aureus, highlighting. These findings provide information on the virulence profile of MRSA strains associated with subclinical bovine mastitis in the region.Item Efecto de la adición de aceite esencial de Eucalyptus globulus sobre los índices productivos y la calidad del huevo en Coturnix japonica(Universidad Técnica de Ambato Carrera de Medicina Veterinaria, 2026-07) Vasquez Lalama, Isaac David; Núñez Torres, Oscar PatricioThe present research work determined the effect of the addition of Eucalyptus globulus essential oil on the productive indices and egg quality in Japanese quail (Coturnix japonica). The study is of great importance due to the current search for phytogenic alternatives which allow us to improve productive efficiency and reduce dependence on conventional growth promoters. The study was developed under the line of research oriented to poultry nutrition and production with emphasis on the use of natural additives in minor species. Four treatments were evaluated, a control group without essential oil and 3 levels of inclusion of eucalyptus oil globulus, which are T1 (0.01%), T2 (0.015%) and T3 (0.02%). The variables analyzed were bird production/day, bird/housed production, feed consumption, feed conversion, mortality, egg quality using Haugh units, albumen height, egg weight and shell thickness. All variables were analyzed in 288 birds which were distributed in 9 repetitions of 8 birds each experimental unit, a completely randomized design (DCA) was used. The data were subjected to parametric statistical tests while mortality was evaluated using Kruskal-Wallis. The results showed that the addition of the essential oil did not have a significant value in production, feed consumption, mortality or egg quality; however, the treatment with 0.02% significantly improved feed conversion, demonstrating greater efficiency in feed use, which determines that Eucalyptus globulus essential oil can be a phytogenic alternative to optimize feed efficiency in Japanese quail, without compromising the other productive parameters or egg quality.Item Terapia de presión negativa como coadyuvante en injertos cutáneos de espesor total en perros (Canis lupus familiaris): Revisión Bibliográfica(Universidad Técnica de Ambato Carrera de Medicina Veterinaria, 2026-07) Salvatierra Cueva Dayana Nicole; Mora Tola Miguel AndrésNegative pressure wound therapy (NPWT) has gained relevance in veterinary reconstructive surgery as a supportive approach for full-thickness skin grafts in dogs. The present study consisted ofa structured literature review conducted according to PRISMA guidelines using the Web of Science and Scopus databases. Risk of bias assessment was independently performed considering parameters such as negative pressure levels, type of device used, graft integration, and postoperative outcomes. Clinical findings were comparatively analyzed based on tissue integration rates, granulation tissue formation, and pressure ranges applied. Studies conducted in humans or other animal species, wounds unrelated to canine skin grafts, and non-scientific documents such as editorials or conference abstracts were excluded. After the selection process, 32 studies were considered eligible for qualitative and bibliometric analysis. The collected evidence demonstrates a progressive evolution of NPWT, from highly cited pioneering investigations to more recent studies focused on technological optimization and cost reduction. Several authors agree that NPWT promotes biological processes such as plasmatic imbibition, vascular inosculation, and neovascularization, while also reducing edema, seroma formation, and graft displacement. Although variability exists among devices and therapeutic protocols, the —100 to —125 mmHg range remains the most frequently applied clinical parameter. Overall, NPWT represents an effective tool for improving survival and integration of full-thickness skin grafts in dogs. These findings support its clinical application in complex veterinary reconstructive procedures.