1. Investigación

Mycobacteriosis is an important disease that affects captive and wild aquatic fish. Syngnathids are susceptible to infection by non-tuberculous mycobacteria. The aim of this study was to describe clinical signs, and macroscopic and histological lesions in 25 syngnathids and the molecular characterization of the causative mycobacteria. Clinical presentation ranged from sudden death to non-specific signs, including anorexia, poor body condition, weight loss and marked dyspnea with increased respiratory effort and rate. Gross lesions were mostly ulcers on the tail and small white nodules in the liver, coelomic cavity and inside the eye. The most affected organs were gills, liver, intestine and coelomic mesentery. Microscopic lesions consisted of areas of multifocal to diffuse granulomatous inflammation and bacterial emboli with numerous intralesional acid-fast bacilli. Epithelioid cells, multinucleated giant cells, lymphocytes and fibrous connective tissue, which are commonly observed in granulomatous inflammation, were not observed here. In the real-time PCR, M. fortuitum, M. chelonae and M. marinum common primers, Mycobacterium spp. were detected in 4, 7 and 14 individuals, respectively. In addition, this is the first description of mycobacteriosis found in Syngnathus acus.

Morphometric studies in Lidia cattle are scarce due to the challenges of handling and approaching this breed of cattle. For this reason, the first morphological characterization of the Lidia breed was carried out using photogrammetry. In the present work, 264 adult individuals (184 males and 80 females), belonging to 21 di erent herds, were studied. A total of 20 morphological measurements and five indexes were determined in every individual. There were many positive correlations between the measures, giving the model great morphostructural harmony. Considerable internal variability of the studied parameters was observed. This breed reflected significant sexually dimorphic features and internal morphological di erences between the di erent genetic lines of the breed. Lidia cattle are small and mostly have a sub-concave profile (58.4% males and 69.7% females). The male proportionality indexes and the relative depth of the thorax indicated great muscular development of the anterior third and high thoracic capacity. The phaneroptic information describes a mostly black animal with black mucous and hooves and an outstanding development of the dewlaps and the tail in the males.

Caecal microbiota and its modulation play an important role in poultry health, productivity and disease control. Moreover, due to the emergence of antimicrobial-resistant bacteria, society is pressing for a reduction in antibiotic administration by finding e ective alternatives at farm level, such as less intensified production systems. Hence, the aim of this study was to characterise the caecal microbiota in two di erent broiler management systems, fast and slow-growing, using 16S rRNA sequencing analysis. To this end 576 broilers were reared in two di erent management systems (fast and slow-growing). Results showed that Firmicutes represented the dominant phylum for both systems. At the onset, Proteobacteria was the second prevalent phylum for fast and slow-growing breeds, outnumbering the Bacteroidetes. However, during the rest of the production cycle, Bacteroidetes was more abundant than Proteobacteria in both groups. Finally, regardless of the management system, the most predominant genera identified were Oscillospira spp., Ruminococcus spp., Coprococcus spp., Lactobacillus spp. and Bacteroides spp. In conclusion, fast and slow-growing broiler microbiota are in constant development throughout rearing, being relatively stable at 21 days of age. Regarding the genus, it should be noted that the three most abundant groups for both systems, Ruminococcus spp., Lactobacillus spp. and Bacteroides spp., are related to better productive performance and intestinal health.

La importancia del estudio de la fisiología reproductiva del conejo (Oryctolagus cuniculus) viene dada por un lado, por su carácter como animal de laboratorio de interés en biomedicina y, por otro como especie de interés zootécnico. En este trabajo se han tratado de caracterizar a nivel reproductivo dos líneas de conejo seleccionadas por diferente criterio, estudiando diferentes parámetros. Los resultados obtenidos han mostrado diferencias en varios de estos parámetros entre las dos líneas, entre los que se encuentran la inducción de la ovulación, el número de embriones implantados a los 12 días de gestación y el tamaño de camada. Con el fin de estudiar algunas de las posibles causas de estas diferencias en el número de embriones implantados, en la segunda parte del trabajo se ha analizado la expresión génica de algunos genes relacionados con el fenómeno de implantación embrionaria en blastocistos de 5 y 6 días, como son el Oct4, la Integrina, los Interferones γ y ω, el Factor de Crecimiento del Endotelio Vascular (VEGF), el receptor 3 del Factor de Crecimiento Epidérmico (erbB3) y el Factor β de Crecimiento Transformante (TGF-β).