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| Politis, Sebastian Nikitas. |
| The research conducted within this PhD project contributes to filling gaps in knowledge about the enigmatic life cycle of European eel (Anguilla anguilla) by addressing biotic and abiotic factors influencing early larval stages. This involves experimental studies and utilization of state-of-the-art molecular tools elucidating links between morphology and molecular mechanisms in the quest to identify suitable rearing and feeding conditions for larviculture. As such, this thesis comprises six studies within three main topics: i) temperature, ii) salinity and iii) nutrition, influencing larval development and survival. The first three studies address the influence of temperature on early larval ontogeny. Here, Study 1 determined the thermal tolerance limits... |
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| Ano: 2018 |
URL: https://archimer.ifremer.fr/doc/00499/61083/64543.pdf |
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| Politis, Sebastian Nikitas; Sorensen, Sune R.; Mazurais, David; Servili, Arianna; Zambonino-infante, Jose-luis; Miest, Joanna J.; Clemmesen, Catriona M.; Tomkiewicz, Jonna; Butts, Ian A. E.. |
| Digestive system functionality of fish larvae relies on the onset of genetically pre-programmed and extrinsically influenced digestive functions. This study explored how algal supplementation (green-water) until 14 days post hatch (dph) and the ingestion of food [enriched rotifer (Brachionus plicatilis) paste] from 15 dph onward affects molecular maturation and functionality of European eel larval ingestion and digestion mechanisms. For this, we linked larval biometrics to expression of genes relating to appetite [ghrelin (ghrl), cholecystokinin (cck)], food intake [proopiomelanocortin (pomc)], digestion [trypsin (try), triglyceride lipase (tgl), amylase (amyl)], energy metabolism [ATP synthase F0 subunit 6 (atp6), cytochrome-c-oxidase 1 (cox1)], growth... |
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Palavras-chave: Anguilla anguilla; Ingestion; Digestion; Gene expression; RNA/DNA; Aquaculture. |
| Ano: 2018 |
URL: https://archimer.ifremer.fr/doc/00463/57445/59550.pdf |
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| Politis, Sebastian Nikitas; Mazurais, David; Servili, Arianna; Zambonino-infante, Jose-luis; Miest, Joanna J.; Tomkiewicz, Jonna; Butts, Ian A. E.. |
| European eel (Anguilla anguilla) is a euryhaline species, that has adapted to cope with both, hyper- and hypo-osmotic environments. This study investigates the effect of salinity, from a morphological and molecular point of view on European eel larvae reared from 0 to 12 days post hatch (dph). Offspring reared in 36 practical salinity units (psu; control), were compared with larvae reared in six scenarios, where salinity was decreased on 0 or 3 dph and in rates of 1, 2 or 4 psu/day, towards iso-osmotic conditions. Results showed that several genes relating to osmoregulation (nkcc2 alpha, nkcc2 beta, aqp1dup, aqpe), stress response (hsp70, hsp90), and thyroid metabolism (thr alpha A, thr alpha B, thr beta B, diol, dio2, dio3) were differentially expressed... |
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| Ano: 2018 |
URL: https://archimer.ifremer.fr/doc/00448/55982/57456.pdf |
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| Politis, Sebastian Nikitas; Mazurais, David; Servili, Arianna; Zambonino, Jose-luis; Miest, Joanna J.; Sorensen, Sune R.; Tomkiewicz, Jonna; Butts, Ian A. E.. |
| Temperature is important for optimization of rearing conditions in aquaculture, especially during the critical early life history stages of fish. Here, we experimentally investigated the impact of temperature (16, 18, 20, 22 and 24°C) on thermally induced phenotypic variability, from larval hatch to first-feeding, and the linked expression of targeted genes [heat shock proteins (hsp), growth hormone (gh) and insulin-like growth factors (igf)] associated to larval performance of European eel, Anguilla anguilla. Temperature effects on larval morphology and gene expression were investigated throughout early larval development (in real time from 0 to 18 days post hatch) and at specific developmental stages (hatch, jaw/teeth formation, and first-feeding).... |
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| Ano: 2017 |
URL: http://archimer.ifremer.fr/doc/00395/50616/51328.pdf |
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| Politis, Sebastian Nikitas; Servili, Arianna; Mazurais, David; Zambonino-infante, Jose-luis; Miest, J. J.; Tomkiewicz, J.; Butts, I. A. E.. |
| Thyroid hormones (THs) are key regulators of growth, development, and metabolism in vertebrates and influence early life development of fish. TH is produced in the thyroid gland (or thyroid follicles) mainly as T4 (thyroxine), which is metabolized to T3 (3,5,3’-triiodothyronine) and T2 (3,5-diiodothyronine) by deiodinase (DIO) enzymes in peripheral tissues. The action of these hormones is mostly exerted by binding to a specific nuclear thyroid hormone receptor (THR). In this study, we i) cloned and characterized thr sequences, ii) investigated the expression pattern of the different subtypes of thrs and dios, and iii) studied how temperature affects the expression of those genes in artificially produced early life history stages of European eel (Anguilla... |
| Tipo: Text |
Palavras-chave: Aquaculture; Fish; Early life history. |
| Ano: 2018 |
URL: https://archimer.ifremer.fr/doc/00409/52020/52678.pdf |
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