Isolation and Identification of Saprolegnia Sp from Fresh Water Aquarium Fishes and the Hemolymph Immune Response of Dactylopus coccus Costa de 1835 (Homoptera: Coccoidea: Dactylopidae) against this Oomycete

Abstract

Saprolegnia sp. is an oomycete responsible for fresh water fish diseases causing great economical losses. There are a few effective treatments to combat saprolegniasis, being of great importance to have available tools to detect and prevent it. In some studies made with the homopteran Dactylopius coccus it was observed that its immune system reacted when it came into contact with some of the components of the fungi cell wall as n-acetylglucosamine and 1-3 glucans; with melanin formation by this can be used as a tool for the detection of water pathogens. To detect Saprolegnia sp. A preparation of hemolymph (HL) from adult female of D. coccus, was used. The hemolymph response, against the presence of the oomycete in vitro, was measured spectrophotometrically at 495 nm. The isolation strain of Saprolegnia sp. induced a reaction leading to the consumption of the pigment carminic acid, and was made from water and epidermic scrape of commercial fresh water fish tanks, obtaining a strain of Saprolegnia sp. identify by its´ reproductive structures and morphological characteristics. The strain of Saprolegnia sp. isolate induced reaction that leads the consumption of the pigment carminic acid, and as a consequence the formation of melanin, having the capacity to identify the presence of Saprolegnia from the amount of 5 to 282 zoospores. There is important to have quick methods to detect and prevent infections avoiding massive loses of fish production. In this work we propose a tool for its detection that does not require expensive material for the application.