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Environmental salinity modifies mucus exudation and energy use in European Sea Bass Juveniles
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Orientador(es)
Resumo(s)
The European sea bass (Dicentrarchus labrax) is a euryhaline marine teleost that can often
be found in brackish and freshwater or even in hypersaline environments. Here, we exposed
sea bass juveniles to sustained salinity challenges for 15 days, simulating one hypoosmotic (3‰),
one isosmotic (12‰) and one hyperosmotic (50‰) environment, in addition to control (35‰). We
analyzed parameters of skin mucus exudation and mucus biomarkers, as a minimally invasive tool,
and plasma biomarkers. Additionally, Na+/K+
-ATPase activity was measured, as well as the gill
mucous cell distribution, type and shape. The volume of exuded mucus increased significantly under
all the salinity challenges, increasing by 130% at 50‰ condition. Significantly greater amounts of
soluble protein (3.9 ± 0.6 mg at 50‰ vs. 1.1 ± 0.2 mg at 35‰, p < 0.05) and lactate (4.0 ± 1.0 µg at
50‰ vs. 1.2 ± 0.3 µg at 35‰, p < 0.05) were released, with clear energy expenditure. Gill ATPase
activity was significantly higher at the extreme salinities, and the gill mucous cell distribution
was rearranged, with more acid and neutral mucin mucous cells at 50‰. Skin mucus osmolality
suggested an osmoregulatory function as an ion-trap layer in hypoosmotic conditions, retaining
osmosis-related ions. Overall, when sea bass cope with different salinities, the hyperosmotic condition
(50‰) demanded more energy than the extreme hypoosmotic condition.
Descrição
Palavras-chave
Dicentrarchus labrax Mucus exudation Salinity adaptation Osmoregulation Gill Na+/K+ - ATPase
Contexto Educativo
Citação
Animals 11 (6): 1580 (2021)
Editora
MDPI