Water mould exposure induces enzymatic antioxidant defences in embryos of the Two-colored Oval Frog (Elachistocleis bicolor) (Anura: Microhylidae)

GHIRARDI, ROMINA; JIMENA CAZENAVE; LÓPEZ, JAVIER ALEJANDRO; ANTONIAZZI, CAROLINA ELIZABET; PEROTTI, MARÍA GABRIELA

CANADIAN JOURNAL OF ZOOLOGY

NATL RESEARCH COUNCIL CANADA-N R C RESEARCH PRESS

Lugar: Otawa; Año: 2020 vol. 98 p. 411 - 416

0008-4301

Water moulds are pathogens of amphibian eggs and embryos. However, little is known about oxidant or antioxidant status of amphibians in response to stress caused by water moulds. We exposed embryo stages of two-coloured oval frogs Elachistocleis bicolor (Guérin-Méneville, 1838) to Saprolegnia-like sp. water mould in order to explore homeostatic adjustments by the shifting of oxidative stress markers. We also tested whether water mould infection affected survivorship and hatching time and morphology of hatching embryos. We found that Saprolegnia-like sp. is a genuine stressor and substantially altered the physiological state of E. bicolor embryos. Among antioxidant defences, superoxide dismutase (SOD) and glutathione S-transferase (GST) activity increased in embryos exposed to Saprolegnia-like sp. However, no difference in lipid peroxidation levels was found between treatments, which might indicate that SOD and GST activation could be enough to prevent oxidative damage. Finally, we found higher mortality and number of malformations in the water mould treatment. We showed the stressful effect of water moulds on amphibian embryos, evidenced by the activation of their antioxidant system, and reveal the importance of considering physiological stress markers as key information when studying the potential consequences of disease outbreaks in the ecology and conservation of amphibians