Tesis Medicina Veterinaria

Permanent URI for this collectionhttp://repositorio.uta.edu.ec/handle/123456789/36415

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    Evaluación de la preferencia de consumo y digestibilidad aparente de forrajes en conejos (Oryctolagus cunículus) de la raza californiana
    (2025-02) Chasi Chango Pamela Lizbeth; Aragadvay Yungan Ramon Gonzalo
    The purpose of this research was to evaluate the consumption preference and digestibility in rabbits with different forages as a food alternative for them, thus employing five treatments through a completely randomized design completing a 32- day study. The treatments Avena sativa (T1), Lolium perenne (T2), Medicago sativa (T3), Zea mays (T4) and Malva sylvestris (T5) presented significant differences in the various parameters studied, thus determining that when assessing consumption preference, T1 (2386g) and T3 (2513g) statistically registered the best values compared to T5 (885g), which was the treatment with a lower total consumption during the experimental period, which would determine a better palatability in the treatments with higher consumption. Likewise, in productive parameters such as weight gain, it was noted that the T3 (1027.33g) and T1 (944.67g) treatments stood out, which presented a better weight gain unlike T2 (555.67g), which registered the lowest productive values of the research. At the same time, it was determined that forages such as T1 and T3 presented a better digestibility in dry matter (63.9%) and (59.7%) respectively, organic matter (63.8%) and (48.8%) as they presented a lower content of non-digestible fiber (FDA), which indicates that being a species that practices cecotrophy presents a better use of nutrients, which did not happen with T5, which presented a lower digestibility of nutrients in DM, MO, NDF and FDA which would be aligned with the limited efficiency of this forage and the presence of secondary compounds that also affect the consumption of these forages. This is how he highlights the importance of the implementation of highly palatable forages that also provide the necessary nutrients in the species in order to obtain positive productive parameters together with good digestibility.
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    Evaluar las técnicas de resuspencion espermática sobre la calidad post descongelado de semen equino de diferentes razas
    (2025-02) Proaño Cruz Miguel Eduardo; Aragadvay Yungan Ramon Gonzalo
    The cryopreservation of equine semen is a key tool in assisted reproduction, as it allows the preservation of genetic material from high-value horses and optimizes artificial insemination programs. However, one of the main challenges of this process is the decrease in sperm viability and functionality post-thaw, due to osmotic, thermal, mechanical, and oxidative stress factors that affect the structural and functional integrity of sperm. The objective of this study was to evaluate the effect of different sperm resuspension techniques on the post-thaw quality of equine semen in three breeds: Arabian, Colombian Criollo, and Spanish. Three treatments were analyzed: 1. Conventional method without centrifugation (control). 2. Sperm resuspension at 1500 rpm for 10 minutes. 3. Sperm resuspension at 1700 rpm for 10 minutes. Key seminal parameters were evaluated, such as sperm concentration, motility, vigor, morphology, and membrane and acrosome integrity, using specialized laboratory tests. The results indicated that the application of sperm resuspension techniques significantly improved the quality of post-thaw equine semen compared to the conventional method. It was found that sperm subjected to resuspension at 1500 rpm maintained significantly higher motility (above 70%) compared to semen treated with the conventional method, where motility decreased to values below 50%. The 1700 rpm technique also improved sperm motility, although to a lesser extent than the 1500 rpm technique, possibly due to an increase in mechanical stress. Regarding sperm morphology, sperm treated with resuspension showed fewer structural alterations compared to those in the conventional method. In particular, the resuspension at 1500 rpm reduced the incidence of abnormalities in the head and tail of sperm, suggesting less damage from the freezing-thawing process. Membrane integrity analysis through the HOST (Hypoosmotic Swelling Test) revealed that sperm subjected to resuspension showed a better osmotic response, indicating greater functionality of the plasma membrane. In the conventional method, membrane integrity decreased to values near 45%, while in the samples subjected to resuspension at 1500 rpm, it remained above 65%, showing greater cellular protection. On the other hand, acrosomal integrity analysis indicated that resuspension treatments reduced the percentage of sperm with damage to this structure, suggesting a higher fertilizing capacity compared to the conventional method. From a comparative approach between breeds, it was observed that Colombian Criollo and Spanish horses showed a better response to resuspension techniques, with greater preservation of motility and sperm viability post-thaw. In contrast, sperm from Arabian horses were more sensitive to centrifugation changes, showing a slight decrease in motility with the 1700 rpm technique, suggesting that the intensity of the procedure should be adjusted according to breed and semen characteristics. Overall, the findings of this study confirm that the implementation of sperm resuspension techniques optimizes the post-thaw quality of equine semen by reducing the negative effects of the cryopreservation process. This represents a significant advance in improving the efficiency of assisted reproduction programs in the equine industry, increasing the success rates of artificial insemination and the preservation of valuable genetic lines.