Characterization of the vertebral anomalies in different phases of the production of Senegalese sole (Solea Senegalensis)Stereoscopic, radiographic and histological approach

  1. Ana Manuela De Azevedo Gomes
Supervised by:
  1. María Isabel Quiroga Berdeal, Director
  2. Andrés Barreiro Lois Director
  3. Sonia Vázquez Rodríguez Director

Defence university: Universidade de Santiago de Compostela

Year of defence: 2017

  1. Paulo Gavaia non Chair
  2. Carmen Bouza Fernández Secretary
  3. Francesc Padrós Bover Committee member
  1. Department of Anatomy, Animal Production and Clinical Veterinary Science

Type: Thesis


Senegalese sole (Solea senegalensis) is one of the most promising species in the Spanish aquaculture. This Doctoral Thesis arises from the need to find solutions to prevent the high frequency of skeletal abnormalities detected in this species, coming up to 100% of deformed individuals, in some experimental studies. This supposes a major limitation for its aquaculture because they are often diagnosed using macroscopic techniques when they already have repercussions on the morphology of the fish. In consequence, besides welfare and productive inconveniences there could be rejection by consumers of a downgraded product. Currently, there is still scarce information on the anomaly profile affecting reared Senegalese sole in industrial facilities, especially, at later stages of the productive cycle. This Doctoral Thesis underlines the importance of an interdisciplinary approach to cope a multi-factorial issue in the aquaculture sector. The magnitude of the problem impelled to look for diagnostic tools to provide a detailed scan of the most common deformities at distinct farming phases in Senegalese sole. The employment of stereomicroscopy in larvae, and radiographic techniques in juveniles, allowed the comprehensive characterization of skeletal anomalies for each developmental stage. The results showed a frequency of skeletal anomalies higher than 75% in reared larvae, early juvenile and juvenile Senegalese sole. The main differences detected in the anomaly profiles among ages lied in the incidence of deformations in the caudal complex plates or neural/haemal spines, which clearly diminished in later phases. Vertebral body anomalies and vertebral column deviations were similarly frequent at the three studied ages. Once this was elucidated, the same systematic was used to evaluate the influence of a nutritional strategy on the skeletogenesis of reared larvae and early juveniles. In this sense, a multivariate approach was applied, revealing differences in the anomaly profile between ages rather than a clear effect of commercial enrichment products for live prey on the development of vertebral abnormalities. The histological techniques complemented considerably the radiographic studies and allowed to deepen into the knowledge of Senegalese sole anosteocytic bone reaction during anomaly development. The presence of ectopic chondrocytes in the endplates and within the intervertebral space (IVS) was notable and it seems to be a common mechanism in different types of anomalies affecting diverse teleost species with either osteocytic or anosteocytic bone. Moreover, some histopathological changes in deformed vertebrae as flattened endplates, narrow IVS and/or abundant cartilaginous tissue in such space could be consistent with initial stages of fusion, and in one case, with the aggravation of a primary fusion process.