The Effects of Iron Compounds on the Virulence of Vibrio anguillarum in Japanese Eels and Ayu

Vibrio anguillarumの病原性に及ぼす鉄化合物接種の影響

Nakai Toshihiro

Kanno Tsuyoshi

Cruz Erlinda R.

Muroga Kiyokuni

魚病研究

When Japanese eels (Anguilla japonica) were injected intramuscularly (IM) with ferric ammonium citrate (FAC) at a sublethal dose of 10 μg/g and followed by IM-injection with various doses of Vibrio anguillarum, FAC injection enhanced greatly the virulence of the pathogen to eels, lowering the LD50 value from 10^7.9 to 10^4.2 CFU/100 g. Similar effects were obtained with ferrous sulfate and ferric chloride in eels. However, such a virulence-enhancing effect of FAC was scarcely observed in ayu (Plecoglossus altivelis), which has high susceptibility to the pathogen by nature. It was also found that addition of FAC (10 μg/ml) in fish sera accelerated the bacterial growth in vitro but the effect was much greater in eel serum than in ayu serum. The results of these in vivo and in vitro experiments demonstrated that the availability of free iron in host fish would have a significant influence on the pathogenesis of V. anguillarum infection.

ウナギにクエン酸鉄アンモニウムを筋注し(10μg/g), その後 V.anguillarum 感染を図ると, 菌の LD50 値は10 7.9から10 4.2CFU/100gにまで低下した。同様の現象は FeSO4 およびクエン酸を加えた FeCl3 の接種によっても認められ, 体内における過剰な鉄の存在は V.auguillarum の病原性を著しく高めることが確かめられた。しかし, V.auguillarum に対するアユの感受性は鉄化合物を接種されても殆んど変化しなかった。ウナギ血清における菌の増殖は鉄化合物の添加により著しく促進されたのに対し, アユ血清では鉄の添加に関係なく十分な増殖が認められた。

Zoology [ 480 ]

eng

日本魚病学会

Copyright (c) 1987 The Japanese Society of Fish Pathology

[ISSN] 0388-788X

[ISSN] 1881-7335

[NCID] AN00063165