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Identifier 000397282
Title Εντατικές συνθήκες εκτροφής και εκτίμηση καταπόνησης στον κρανιό Argyrosomus regius
Alternative Title Husbandry and stress response in meagre Argyrosomus regius
Author Κωσταρή, Μαριλένα Μ.
Thesis advisor Παυλίδης, Μιχάλης
Reviewer Παπανδρουλάκης, Νικόλαος
Καρακάσης, Ιωάννης
Abstract The meagre (Argyrosomus regius- family Sciaenidae) is relatively new species in aquaculture, with fast growth and high meat quality, features that make it important economically. The present thesis deals with the study, for the first time, of the stress response in meagre, and in particular with the effect of acute stress and simulated transportation stress, as well as with the performance of meagre under different intensive rearing conditions. The purpose of the first experiment was to determine the response to acute stress by determining various hematological, biochemical and hormonal indicators at specific time intervals post-stress. The results indicate that the glucose showed the highest concentrations at 2 hours post-stress, lactate at 1 hour post-stress, cortisol in 2 hours post-stress and the osmotic pressure to 0.5 hours post-stress, while the other parameters showed no differences. It was also shown that meagre is a fish with very low concentrations of cortisol, for both baseline and post-stress values. The purpose of the second experiment was to find the optimal conditions for transportation, through the determination of various stress indicators under three different stocking densities (small-medium-high) at two different time points following simulated transportation. The results showed that dead individuals was found only at the high stocking density, while as regards the various parameters studied appeared that the stocking density only affected by hematocrit and cortisol. The lactate and liver glycogen were affected only by the sampling time, and hemoglobin and glucose showed no differences. The third experiment was about the ongrowing phase of intensive rearing system (net-pen sea cages). The purpose of the experiment was to find the best feeding conditions according to two different depths (8 m deep net and shallow net 6 m) for a period of about one year by recording mortality and determining the growth and various physiological and biochemical indicator. The results showed that the growth performance of the fish in deep net was better, based on the mortality and the Food Conversion Ratio (FCR), even if in most of the other parameters tested, no significant difference between the depths was shown statistically, while seasonal differences were presented. Specifically, both the Feed Conversion Ratio (FCR) and mortality had better values in cages with deep net. Hematocrit, hemoglobin and osmotic pressure only showed seasonal differences and showed the highest concentrations in November. Cholesterol also showed only seasonal differences, as the total protein, while free fatty acids are influenced by both factors examined, but appear to have lower concentrations at lower temperatures. Lactate, glucose and lysozyme appeared to be affected by both factors examined, while for the latter, difference were shown between the depths only in warm months. The thyroid hormone triiodothyronine (T3) did not show neither seasonal nor differences between the two depths, while the thyroxine (T4) showed seasonal differences probably related with photoperiod. Finally, cortisol showed only seasonal differences with highest concentrations in March, the month with the lowest temperature.
Language Greek
Subject Net depth
Βάθος δικτύου
Issue date 2015-11-20
Collection   Faculty/Department--Faculty of Sciences and Engineering--Department of Biology--Post-graduate theses
  Type of Work--Post-graduate theses
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