DAO prepress abstract  -  DOI: https://doi.org/10.3354/dao03199

Stress effects of amyloodiniosis in gilthead sea bream (Sparus aurata)

Márcio Moreira, Marcelino Herrera, Pedro Pousão-Ferreira, Jose Ignacio Navas Triano, Florbela Soares*

*Email: fsoares@ipma.pt

ABSTRACT: Amyloodiniosis is a parasitological disease caused by one of the most common and important parasitic dinoflagellate in fish, Amyloodinium ocellatum (Brown), that represents a major bottleneck for gilthead seabream semi-intensive aquaculture in Southern Europe. Therefore, in this experiment we analyzed some metabolic, osmoregulatory and stress indicators to enlighten some of the physiological responses of gilthead sea bream when exposed to an A. ocellatum outbreak. We observed that there were significant differences in the cortisol, lactate and gill Na+/K+-ATPase (NKA) activity levels and that glucose, osmolarity, pH and total protein did not present significant differences between Control and Infection groups. This could indicate that the presence of the parasite induced a stress response, possibly enhancing the metabolization of glucose and subsequently lactate to cope with the higher energy requirements of the organism. There was also a decrease in gill NKA activity possibly due to severe epithelial damage and increased mucus production caused by the parasite A. ocellatum, which could induce anoxia and osmoregulatory impairment in the organism. However, further works must be performed to fully understand the physiological reactions of fish for A. ocellatum outbreaks.