RT Dissertation/Thesis
T1 Ontogenetic development and digestive functions in the long snouted seahorse "Hippocampus guttulatus"
T2 Desarrollo ontogénico y funciones digestivas en el caballito de mar narizón "Hippocampus guttulatus"
A1 Ofelio, Claudia
K1 2401.05 desarrollo Animal
K1 2510 Oceanografía
K1 3104.06 Nutrición
AB The high demand of seahorses for aquarium trade, traditional Chinese medicine (TCM) and as souvenirs, along with the destruction and degradation of coastal habitats (seagrass beds, coral reefs and mangroves), and accidental captures, has raised many concerns about the medium-term viability of seahorse’s natural populations (Hippocampus spp.) (Lourie et al. 1999; Vincent 1996; Vincent et al. 2011; Kumaravel et al. 2012). Currently, all seahorse species are included in Appendix II of CITES (Convention on International Trade in Endangered Species) (CITES 2002), which regulates the legal import and export of seahorses, both alive and dry. The ex-situ production of seahorses has the potential to represent a valid partial alternative to individuals captured in the wild, although, for most species such activity is still a relatively new field of knowledge, which needs to implement the appropriate methodological techniques.  The knowledge of morphological development and growth patterns of cultivated fishes is of fundamental importance for the optimization of the production in captivity and for the determination of the offspring quality in controlled restocking or population reinforcement programs. The initial ontogenetic development includes complex processes of cell growth and differentiation that develop on different time-scales for each species.The high mortality of newborn at early developmental stages (from 6 to 15 days after birth), mainly due to the low digestion efficiency and absorption of nutrients from the diet (Celino et al. 2012; Willardino et al. 2012; Blanco et al. 2015), represents a major bottleneck in the rearing of seahorses.  The European long snouted seahorse Hippocampus guttulatus Cuvier 1829 is a recent candidate in the ornamental trade and its rearing will help in both the experimental assessment of ecological hypotheses and further development of conservational plans. Many aspects such as the effect of temperature, diet and enzymatic activities have been recently investigated; allowing to successfully breeding H. guttulatus in captivity. In spite of these studies, there is still a general lack of information on many important morphological and physiological aspects of the early development of these animals. Seahorses are species of agastric teleosts, which lack of a functional stomach (Wilson and Castro 2010). In such species, digestion takes place mainly in the intestine (Rønnestad et al. 2013), which develops during the ontogeny from a short and straight tube into a long and segmented duct. The exocrine pancreas synthesizes and secretes digestive enzymes such as proteases, glucosidases and lipases into the intestine, facilitating the process of decomposition of nutrients from the diet into easily absorbed molecules (Zambonino and Cahu 2001). The production of digestive mucosubstances in many marine teleost species is mainly related to glycoconjugates (GCs), molecular components secreted by mucins (goblet cells) throughout the digestive tract. As reported in other agastric species, the numerous goblet cells present in the oesophagus, secreting neutral, sulphated and sialylated GCs, could be considered as a morphological adaptation that replaces a functional stomach (Jaroszewska et al. 2008). Consequently, neutral GCs are probably involved in the enzymatic digestion and absorptive processes (Domeneghini 1998; Radaelli et al. 2000). Otherwise, sulphated GCs and sialic acid residues might be involved in the regulation of protein and peptide transfer.
YR 2018
FD 2018-06-27
LK http://hdl.handle.net/11093/1019
UL http://hdl.handle.net/11093/1019
LA eng
NO Unión Europea | Erasmus+ trainesship
DS Investigo
RD 06-dic-2024