In Vitro Effect of Three Medicinal Herb Including Tan Bark , GreenTea and Chamomile Extracts on Pathogenesis of Aspergillus sp. inShrimp

Introduction: Today, proliferation and breeding of aquatics, particularly shrimp,is of great importance due to the presence of proteins and mineral rich materialsas well as short duration of its proliferation and breeding. Unfortunately, in someconditions due to the presence of some fungi such as Aspergillus, irreparablelosses are imposed to shrimp farming industry. Today, the desire to usemedicinal herb to improve diseases led this study to investigate the effect ofthree medicinal herb extracts including tan bark, green tea and chamomile onpathogenesis of Aspergillus in shrimp.Methods:The Aspergillus samples were prepared from Scientific and Industrial ResearchOrganization of Iran and Pasteur Institute of Iran. They were maintained inPotato Dextrose Agar (PDA) gradient culture for ۵-۷ days at ۲۵ ˚C. Myceliumcauses disruption in the culture and reduces the impact of the extracts. Toremove them from fungal suspension, the suspension was filtered using glass wool. Then, light transmittance from the suspension was measured using aspectrophotometer device at a wavelength of ۵۳۰ nm. The light transmittance of۹۰% is required to obtain a suspension with approximately ۱۰۶ fungal spores perml. Five test tubes including yeast extract (YES) were prepared for each extractand totally ۱۵ medium cultures were obtained. The extracts with concentrationsof ۲۰۰, ۴۰۰, ۶۰۰, ۸۰۰, ۱۰۰۰ ppm with Tween were added to yeast extract (YES)medium. The tubes were vortexed to maintain the suspension and the extracts for۶۰ seconds and they were visually assessed up to ۴ days in terms of degree ofgrowth or lack of growth. The contents of the tubes were then filtered usingWhatman Grade ۴۲ filter paper and mycelial dry weight was obtained by aspecial scale.Results :Among ۳ studied extracts, chamomile extract had the best inhibitory effect onAspergillus and tea extract had the weakest inhibitory effect. The inhibitoryeffect of tan bark extract was near to the effect of chamomile extract so that theyboth had approximately similar effect on fungal growth at concentrations of ۶۰۰and ۱۰۰۰ ppm. The impact of tan bark extract at the concentration of ۲۰۰ ppmon inhabitation of fungal growth had better, with a little difference, fromchamomile extract.