کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
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5805331 | 1555717 | 2012 | 7 صفحه PDF | دانلود رایگان |

Protozoan Ichthyophthirius multifiliis Fouquet (Ich) and bacterium Aeromonas hydrophila are two common pathogens of cultured fish, which cause high fish mortality. Currently there is no information available for the effect of parasitism by Ich on survival of channel catfish and invasion of A. hydrophila in fish tissues following exposure to A. hydrophila. A trial was conducted in this study to: (1) determine whether A. hydrophila increased fish mortality in Ich-parasitized channel catfish; and (2) compare the bacterial quantity in different tissues between non-parasitized and Ich-parasitized catfish by real-time polymerase chain reaction (qPCR). The results demonstrated that the Ich-parasitized catfish showed significantly (PÂ <Â 0.05) higher mortality (80%) when exposed to A. hydrophila by immersion than non-parasitized fish (22%). Low mortality was observed in catfish exposed to Ich alone (35%) or A. hydrophila alone (22%). A. hydrophila in fish tissues were quantified by qPCR using a pair of gene-specific primers and reported as genome equivalents per mg of tissue (GEs/mg). Skin, gill, kidney, liver and spleen in Ich-parasitized fish showed significantly higher load of A. hydrophila (9400-188,300Â GEs/mg) than non-parasitized fish (4700-42,100Â GEs/mg) after exposure to A. hydrophila. This study provides evidence that parasite infections enhance bacterial invasion and cause high fish mortality.
Journal: Veterinary Parasitology - Volume 184, Issues 2â4, 23 March 2012, Pages 101-107