Garlic Extract as a Bath Treatment against Gyroductylus sp. in Guppy Fish (Poecilia reticulata)

Parasitic infection is considered one of the major constraints in commercial fish farms owing to huge economic losses. Although there are plenty of commercial drugs available for treatments, those synthetic chemicals are more hazardous to the host and the environment than the parasite. Therefore, a special trend can be seen towards herbal medications. The present study is utmost significance as it focused on a well-known spice, Garlic (Allium sativum) as a bath treatment against gyrodactylosis caused by Gyrodactylus sp. The soxhlet extraction method was used to haul out the water-soluble compounds and the major components were identified using Thin-Layer Chromatography (TLC) techniques. During the phytochemical analysis, flavonoids, glycosides, quinones, and diterpenes were identified where the alkaloids, tannins, and phenols were absent in garlic extract. To find out the LC50, values acute toxicity test was performed in 72 hours with triplicates and 802.2ppm value was resulted. 216 of infected adult guppies (2.9 ± 0.1cm, 0.32 ± 0.05 g) were used for a three-hour in vitro bath treatment with different concentrations of garlic extract including 50, 100, 150, 200, and 250 mg/L. Complete recovery from gyrodactylosis is observed by the means of microscopic observations at 3, 2.5, 2, and 1.5 h with 50, 100, 150, and 200mg/L of concentrations, respectively. According to the observations, it can be concluded that exposure to garlic extract caused the parasite to first detach from the host, then restrict its movements, and finally die. A significant negative correlation (p<0.01) can be observed between the garlic concentration and the eradication time. 250 ppm garlic extract bath for 0.5 hours was identified as the optimal and most effective treatment against gyrodactylosis. Therefore, garlic extract can be suggested as a herbal bath treatment against agent Gyrodactylosis infection in guppy fish.  Keywords: Bath treatment, LC50, Gyrodactylus sp, Poecilia reticulata