| Tropical fishes like Leporinus macrocephalus Garavello & Britski, 1988 ("piauçu") and the hybrid "tambacu" (Piaractus mesopotamicus Holmberg, 1887 "pacu" male x Colossoma macropomum Cuvier, 1818 "tambaqui" female) were experimentally infected with four inocula of trophonts of Ichthyophthirius multifiliis Fouquet, 1876 (Protozoa, Ciliophora) and the infection level was evaluated. Each one of twelve experimental units consisted of a tank with 200 liters of water and two specimens of each kind of fish. The following treatments were designed to each tank, in triplicate: 8, 16,32 and 64 trophonts. After 8 days of exposure the fishes were killed and the number of trophonts was counted at a stereoscopic microscope. This assay showed to be feasible at... |
