Efficacy of Some Aromatic Plant Extracts on Treating the Eggs of the Common Carp (Cyprinus carpio L.) Against Fungal Infection in Comparison with Traditional Fungicide Malachite Green

Abstract

The current study was carried out in Basrah Prawn Hatchery during the period from 23 March 2016 till 15 April 2016. Water extracts of four species of aromatic plants: garlic Allium sativum L., eucalyptus Eucalyptus camaldulensis Deh., mint Mentha spicata L. and ginger Zingiber officinale Roscoe were used as alternative materials instead of malachite green to control the pathogenic fungus Saprolegnia parasitica on eggs of the common carp Cyprinus carpio. The reason of using these substituted materials used here is to avoid the carcinogenic effect of malachite green for producers, consumers and abnormalities malformations of fish fries, contamination of the aquatic environment and economic losses resulted from malformation of fish larvae. The results showed significant differences in the sterilization ratio with the studied plants according to species and concentration of the extract in comparison with that of malachite green. The results showed that with application of 100% of the stock solution (full strength of garlic extract), the activity of treatment reached 96%, while lowest activity of sterilization reached 90% with using 100% ginger extract as compared to malachite green (99%). The number of alive fish larvae differs according to the species of the plant; the highest number of alive fish larvae (18694 larvae) was achieved with ginger, while the lower number (12320) was with eucalyptus in comparison with malachite green (13878). No such malformation in the larvae was occurred when treated with garlic, ginger and mint, while just 1% (non-significant) of malformation occurred with eucalyptus in comparison with malachite green (7%).