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Controlled infection of P oecilia reticulata P eters (guppy) with T etrahymena by immersion and intraperitoneal injection
Author(s) -
Sharon G,
PimentaLeibowitz M,
Vilchis M C L,
Isakov N,
Zilberg D
Publication year - 2015
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.12204
Subject(s) - guppy , poecilia , tetrahymena , biology , ichthyophthirius multifiliis , intraperitoneal injection , parasite hosting , microbiology and biotechnology , zoology , pharmacology , fish <actinopterygii> , fishery , biochemistry , world wide web , computer science
Tetrahymena is a protozoan parasite, which infects guppy, P oecilia reticulata P eters, and causes substantial economical losses in commercial farms worldwide. Studies of guppy infected by T etrahymena require standardized infection protocols. The LD 50 for T etrahymena infection of guppies by intraperitoneal ( IP ) injection was calibrated, and the level obtained was 946 parasites per fish. Guppy infection with T etrahymena by immersion, imitating the natural route of infection via the integument, was studied under normal or stress conditions. Exposure to cold and netting ( CNI ) and to cold only ( CI ) followed by immersion exposure to 10 000 T etrahymena per mL resulted in 22.5% and 19.2% mortality, respectively, as compared to 14.2% and 10% in groups that were netted only ( NI ) or non‐stressed ( I ). Histopathology revealed that immersion infection resulted in a systemic infection. Lysozyme levels, measured 3 weeks after infection, were significantly higher in the CNI group (288 μg per mg protein) compared with CI ‐, NI ‐ and I ‐treated groups (94.5, 64 and 62.3 μg mg −1 , respectively). There was no evident parasite immobilization activity in body homogenates, suggesting no development of acquired immunity. Re‐infection by IP injection revealed no increase in protection in any of the treatment groups, mortality range of 56.3–75%, higher than in the non‐exposed control (40.6% mortality).