Diplomonad flagellates of some ornamental fish cultured in Thailand
Vol. 34 No. 5
The study on diplomonad flagellates infection in some ornamental fishes in the family c ichlidae i.e., angelfish ( Pterophyllum scalare ), oscar ( Astronotus ocellatus ), blue mbuna ( Labeotropheus fuelleborni ) and the family osphrone- midae i.e., Siamese fighting fish ( Betta splendens ) revealed that this parasite infected three out of four ornamental fish species, angelfish, oscar and blue mbuna. The highest infection was recorded in angelfish (90%) followed by o scar (75.4%) and blue mbuna (61%), respectively. Identification of diplomonad flagellates from angelfish by means of morph ological studies under light and electron microscopes indicated that the parasite was Spironucleus vortens. The 14?days LD 50 of S. vortens in angelfish was 2.99x10 3 cells. Histopathological changes of infected angelfish revealed granulomatous liver, nume rous numbers of melanomacrophage in the spleen and inflammation of the intestine. Susceptibility study of S. vortens to goldfish ( Carassius auratus ), guppy ( Poecilia reticulata ) and platy ( Xiphophorus maculatus ) indicated that they were resistant to artificial infection. In vitro examination of the growth inhibition assay of S. vortens indicated that dimetridazole and metro- nidazole were effective in inhibiting parasite growth after 48 hrs exposure at concentrations of > 4.0 ?g/ml and > 6.0 ?g/ml, respectively. Magnesium sulfate at a concentration of > 60 mg/ml inhibited the parasite growth after 72 hrs exposure. In vivo examination of the dimetridazole efficiency on S. vortens infection indicated that dimetridazole at 4.0 ?g/ml provided the highest efficiency which could be used for treatment of spironucleosis in angelfish.
Songklanakarin Journal of Science and Technology