engleski

Extraintestinal gamogony of Aggregata octopiana in the reared common octopus (Octopus vulgaris) (Linnaeus, 1758) (Cephalopoda: Octopodidae)

Aggregata octopiana (Apixomplexa, Aggregatidae) is the most prevalent coccidian in the wild common octopus (Octopus vulgaris), with a heteroxenous life cycle where gamogony and sporogony were described undergoing in octopus digestive tract. Along with a new trend of introduction of wild octopus for fattening in rearing environment, A. octopiana infections were commonly reported but rarely showed an intensive character that would reflect in mortalities. In experimental flow-through rearing system of Laboratory of Aquaculture, Institute of Oceanography and Fisheries (Split, Croatia), 9% mortalities occurred in animals over two-year rearing period. Histological examination and ultrastructural study revealed numerous A. octopiana oocysts in various tissues. Before mortalities started, octopi displayed changes in behavior and weight loss. The cause was attributed to extensive necrosis and desquamation of spiral caeca epithelium, induced by Aggregata sp. superinfection, probably exacerbated with other factors. Unusual extraintestinal distribution of the coccidian was also observed, and for the first time gamogony and sporogony were demonstrated in gill tissue. From the aquacultural point of view, parasite in the intensive rearing environment could elict great economical losses aside of direct mortalities, also in means of weak weight gain in infected animals.

common octopus (Octopus vulgaris) ; rearing ; coccidia ; Aggregata octopiana

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