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Gill amoebae from freshwater rainbow trout ( Oncorhynchus mykiss ): In vitro evaluation of antiparasitic compounds against Vannella sp.
Author(s) -
Jensen Hannah Malene,
Karami Asma Mohammad,
Mathiessen Heidi,
AlJubury Azmi,
Kania Per Walter,
Buchmann Kurt
Publication year - 2020
Publication title -
journal of fish diseases
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.819
H-Index - 85
eISSN - 1365-2761
pISSN - 0140-7775
DOI - 10.1111/jfd.13162
Subject(s) - rainbow trout , biology , gill , peracetic acid , ichthyophthirius multifiliis , microbiology and biotechnology , saprolegnia , hydrogen peroxide , fishery , fish <actinopterygii> , biochemistry
Abstract Gill parasitic infections challenge farming of rainbow trout ( Oncorhynchus mykiss, Walbaum) in freshwater facilities. Apart from flagellates ( Ichthyobodo, (Pinto) and ciliates ( Ichthyophthirius (Fouquet) , Ambiphrya (Raabe), Apiosoma (Blanchard), Trichodinella (Sramek‐Husek) and Trichodina (Ehrenberg)), we have shown that amoebae are prevalent in Danish trout farms. Gills were isolated from farmed rainbow trout in six fish farms (conventional and organic earth pond and recirculated systems) and placed on non‐nutrient agar (NNA) moistened with modified Neff's amoeba saline (AS) (15°C). Gill amoebae from all examined fish colonized the agar and were identified based on morphological criteria showing species within the genera Trinema (Dujardin) (family Trinematidae), Vannella (Bovee) (family Vannellidae). In addition, hartmannellid amoebae were recorded. We established a monoculture of Vannella sp., confirmed the genus identity by PCR and sequencing and performed an in vitro determination of antiparasitic effects (dose–response studies) of various compounds including sodium chloride (NaCl), hydrogen peroxide, peracetic acid, formalin, aqueous garlic and oregano extracts and a Pseudomonas H6 surfactant. All amoebae were killed in concentrations of 16.90 mg/ml (garlic), 17.90 mg/ml (oregano), NaCl (7.5 mg/ml), hydrogen peroxide (100 µg/ml), peracetic acid (0.03 µg/ml), formaldehyde (25 µg/ml) and the Pseudomonas H6 surfactant (250 µg/ml).