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Identifier

000454149

Title

Μοριακή και ενδοκρινική ρύθμιση της αύξησης στα πρώτα αναπτυξιακά στάδια του μαγιάτικου, Seriola dumerili

Alternative Title

Molecular and endocrinal regulation of growth in the early developmental stages of greater amberjack, Seriola dumerili

Author

Λιαμάκη, Άννα Χ.

Thesis advisor

Παυλίδης, Μιχαήλ

Reviewer

Πουλακάκης, Νικόλαος
Παπανδρουλάκης, Νικόλαος

Abstract

The greater amberjack (Seriola dumerili) shows great size diversity (variability), which starts from the first developmental stages and can reach a percentage (CV%) of 200 to 300% during pre - fattening and fattening respectively, creating management problems. In the present study, the molecular and endocrinal basis of variability in the greater amberjack were investigated by studying the pathways of appetite, metabolism and growth. Specifically the expression of the genes of the GH-IGF axis and HPT (Hypothalamic – Pituitary – Thyroid) axis as well as regulatory hormones of appetite and metabolism (leptin, ghrelin, neuropeptide NPY) were studied in the bodies of pre larvae and larvae. Different water temperature conditions (20^oC and 24^oC) during the first developmental stages (embryo – first feeding) were examined and temperature was regulated at 24^oC in all the tanks after the first feeding. Additionally two different feeding protocols which consisted of a) rotifers and b) a combination of rotifers and copepods where the food was alive were compared. Samples from each condition were collected during the following stages/phases of the first developmental stages: first feeding (3 – 3,5 mm), flexion of notochord (5 – 6 mm), end larvae rearing (10 – 14 mm) and mid-metamorphosis (15 – 20 mm). The results showed that the regulation of the temperature at 20^oC during the early developmental in the autotrophic stage (embryo – first feeding), was more ideal for the expression of most of the genes that examined, without observing differences between the two temperatures in the expression of genes that included in the GH – IGF-1 axis. In the next developmental stages where exogenous food was introduced, the consisted of rotifers & copepods gave better results. Therefore, the conclusion reached at the end of the larvae rearing was that the reduced temperature during the autotrophic stage and the addition of copepods in the diet of the fish larvae improved their growth and development, as well as minimized the phenomenon of variability.

Language

Greek

Subject

Genes

Hormones

Variability

Γονίδια

Ορμόνες

Παραλλακτικότητα

Issue date

2023-03-24

Collection