Antiparasitic effect of garlic ( Allium sativum) and thyme (Thymus vulgaris) on Ichthyophthirius multifiliis, the cause of white spot disease

In this study, the effect of two plant extracts, garlic and thyme, on the theront and tomont stages of the parasitic protozoa Ichthyophthirius multifiliis was evaluated. For this purpose, first, hydroalcoholic extracts of these plants were prepared. In the next step, both stages of the parasite were exposed. The parasite survival rate at each concentration, every 3 hours and for 12 hours were recorded and LD50 of each extract in this time period was calculated using Probite method. Malachite green was used as a positive control. The results showed that the LD50 of garlic and thyme on tomont were 1 and 2.5 mg/L, respectively. While this amount was 0.24 mg/L for malachite green. LD50 of garlic and thyme extracts on theront were 1.66 and 0.57 mg/L, respectively, and in the case of malachite green was 0.121 mg/L. According to the results, the antiparasitic effect of garlic and thyme extracts is insignificant compared to the effects of malachite green and it is not possible to replace malachite green with these extracts. Although these extracts can be used as adjunctive therapy along with chemical treatments.