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Identifier

000448883

Title

Επιδράσεις της έκθεσης των εμβρύων και λεκιθοφόρων νυμφών zebrafish σε υποθνησιγόνα επίπεδα εκχυλίσματος του κυανοβακτηρίου Microcystis aeruginosa. Αερόβια κολυμβητική ικανότητα και γονιμότητα

Alternative Title

Sublethal exposure to Microcystis aeruginosa extracts during yolk-sac larvae and embryonic stage has long-lasting effects on zebrafish. Aerobic swimming capacity and relative fecundity

Author

Κέκελου, Αθηνά-Νικολίτσα Σ.

Thesis advisor

Κουμουνδούρος, Γεώργιος

Reviewer

Πήττα, Παρασκευή
Σωμαράκης, Στυλιανός

Abstract

Cyanobacterial blooms are intensifying in parallel with climate change and eutrophication. Microcystis aeruginosa comprises a species of freshwater cyanobacteria which can form a plethora of bioactive compounds, some of which have toxic effects. The toxicity of cyanobacteria is mainly attributed to the endotoxin microcystin-LR (MCLR), which bioaccumulates in fish tissues and affects many systems and functions. MCLR action has been shown to be enhanced by other substances which are produced by the cyanobacteria. The aim of the present study was to examine whether the sublethal embryonic exposure to Microcystis aeruginosa extract (200 mg d.m. L^-1) affects the fecundity of female zebrafish. Moreover, following the recent publication of Sergi et al. (2022), this study examined whether the sublethal yolk-sac larval exposure to Microcystis aeruginosa extract (200 mg d.m. ^-1) affects the swimming performance of metamorphosing zebrafish. For both scientific questions, trials were performed in two independent replicates. Embryonic exposure trials revealed a significant decrease of the relative fecundity of fish in response to the early exposure to M. aeruginosa (536.9±46.5 vs 701.9±46.54 eggs per g of female weight in the control group) (p<0.05, ANOVA). This result was associated with a significant increase in the gene expression levels of the ovarian fshr and bmp15 (p<0.05, ANOVA). In contrary, the expression levels of the liver vtg1, vtg2 and cyp1a were not affected by fish pre-exposure to M. aeruginosa extracts (p>0.05, ANOVA). Concerning the yolk-sac larval exposure trials, they revealed a significant decrease of the aerobic swimming performance (RU_crit) of the metamorphosing zebrafish in response to the early exposure to M. aeruginosa (9.24±1 vs11.25±1.3 TL s^-1 in the control group) (p<0.05, ANOVA). In contrary to the effect on RU_crit, heart morphology and skeleton development were unaffected by the initial exposure of the fish. The results of the present study are discussed with respect to the effects of harmful algal blooms on aquatic organisms, as well as to the underlying mechanisms of the M. aeruginosa effects on zebrafish fecundity and swimming performance.

Language

Greek

Subject

Cyanohabs

First developmental stage of fish

Sublethal

Μακρόχρονη επίπτωση

Πρώιμα αναπτυξιακά στάδια ιχθύων

Τοξικές ανθίσεις

Υποθνυσιγώνος

Issue date

2022-07-29