Cynatratoside-C efficacy against theronts of Ichthyophthirius multifiliis, and toxicity tests on grass carp and mammal blood cells

Abstract

Infection by Ichthyophthirius multifiliis, a ciliated protozoan parasite, results in high fish mortality and causes severe economic losses in aquaculture. To find new, efficient anti-I. multifiliis agents, cynatratoside-C was isolated from Cynanchum atratum by bioassay-guided fractionation in a previous study. The present study investigated the anti-theront activity, determined the toxicity of cynatratoside-C to grass carp Ctenopharyngodon idellus and mammalian blood cells, and evaluated the protection of cynatratoside-C against I. multifiliis theront infection in grass carp. Results showed that all theronts were killed by 0.25 mg l −1 of cynatratoside-C in 186.7 ± 5.8 min. Cynatratoside-C at 0.25 mg l −1 was effective in treating infected grass carp and protecting naive fish from I. multifiliis infestation. The 96 h median lethal concentration (LC 50 ) of cynatratoside-C to grass carp and 4 h median effective concentration (EC 50 ) of cynatratoside-C to theront were 46.8 and 0.088 mg l −1 , respectively. In addition, the hemolysis assay demonstrated that cynatratoside-C had no cytotoxicity to rabbit red blood cells. Therefore, cynatratoside-C could be a safe and effective potential parasiticide for controlling I. multifiliis.

The fish parasite Ichthyophthirius multifiliis – Host immunology, vaccines and novel treatments

“…The same concentration was used for in vivo infections and showed significant treatment efficacy and protection. Furthermore, the substance was tested for toxicity to grass carp and the median lethal concentration (LC50) was found to be 46.8 mg/L and thus safe for treatment against I. multifiliis [110].…”

In vivo antiviral efficacy of moroxydine hydrochloride against grass carp reovirus and the drug safety assessment

“…Chlorella vulgaris, as a beneficial algae strain with abundant nutrients which can be used by omnivorous or herbivorous animals in aquaculture, was frequently chosen as the toxicity test materials (Geiger, Hornek‐Gausterer, & Saçan, ; Najafabadi, Malekzadeh, Jalilian, Vossoughi, & Pazuki, ). Moreover, fish as a consumer of aquatic ecosystems and an important source of food is one of the closest relationships with human beings and also was used as a subject of aquatic biological toxicity test (Folmar, Sanders, & Julin, ; Fu et al, ). Bacillus subtilis has the ability to produce protease, lipase and amylase which enhances the water quality, growth performance, immune response and disease resistance in feed (Fisher, ; Zokaeifar et al, ).…”

Antiparasitic activity of medicinal plants against protozoan fish parasite Ichthyophthirius multifiliis

“…Therefore, these protective properties of trophonts make fighting and killing them more brutal than theront and nonencysted tomonts. 12,20 The results showed that essential oils of sage at a concentration of 0.50 ml L -1 , lavender at a concentration of 0.25-and 0.50-ml L -1 , and oregano at a concentration of 0.1, 0.25-, and 0.50-ml L -1 can kill about 100% of I. multifiliis trophonts after 60 min of exposure. Further-Antiparasitic activity of medicinal plants against protozoan fish parasite Ichthyophthirius multifiliis Israeli Journal of Aquaculture -Bamidgeh more, antiparasitic efficacy correlated positively with the high concentrations of the essential oils and prolonged exposure (p<0.05).…”