Abstract:
Protozoan ciliate, Ichthyophthirius multifiliis and monogenean flukes,
Gyrodactylus spp. and Dactylogyrus spp. are common external parasites of
goldfish, Carassius auratus. At high densities of fish, those infestations lead to
death and therefore various chemicals with different efficacies are used by
farmers as bath treatments. The present study investigated the efficacy of row
turmeric (Curcuma longa) extract in controlling I. multifiliis, Gyrodactylus spp. and
Dactylogyrus spp. on goldfish.
Effective minimum concentration that required to kill I. multifiliis in vitro
was found out by exposing the parasite to different concentrations of row
turmeric extract; toxicity of the turmeric extract on healthy goldfish was tested at
a range of concentrations closer to this effective minimum concentration. In vivo
effective concentration was found out by exposing infested fish to the same
range of concentrations used for the toxicity test; random samples of fish were
observed for the presence of parasites two times a day. Anti-parasitic efficacy of
the turmeric extract on I. multifiliis and both flukes were calculated. Formalin
(200 mgr') at 4 hours of exposure was used as the positive control while
untreated, infested fish were maintained as the negative control.
In vitro effective minimum concentration of turmeric extract on I.
multifiliis was 250 mgr' at 4.5 hours of exposure. Hundred percent removal of I.
multifiliis and both flukes from the body surface and gills of goldfish was
recorded at 270 mgr' of row turmeric extract in 3 days of exposure at 24°C-27°C;
mean anti-parasitic efficacy (1.571:1:0.000) on I. multifiliis and both monogenean
flukes at the end of third day of exposure was not significantly different from the
mean anti-parasitic efficacy of formalin at 200 mgr' (P>0.05). Severe histological
alterations of gill tissue were observed in fish treated with formalin while fewer
alterations were seen in fish treated with turmeric extract.
