養魚用水の紫外線殺菌について. I, 魚病原因菌ならびに養魚水中生存菌の紫外線感受性について

• Main Authors: 木村, 喬久, 吉水, 守, 田島, 研一, 絵面, 良男, 坂井, 稔
• Format: Journal Article
• Language: Japanese
• Published: 日本水産学会 = The Japanese Society of Scientific Fisheries 01.02.1976

Basic experiments were carried out preliminarily to determine the usefulness of a double-tubular U.V.-water treatment unit (Seibu Kagaku Co., Model Cs-50 U) for the disinfection of hatchery water. The results obtained are summarized as follows. 1. The disinfectant effect of U.V. was examined on cell suspensions (10^[5~7] cells/ml) of 5 species of fish pathogen and one strain of Escherichia coli. A 99.99%or more reduction of their viable cells was effected by U.V. treatment of less than 8.5 l/min. flow rate that is equivalent to more than 22,100 μW・sec/cm2 U.V. dosages. 2. The experiments on 4 specimens of fish-rearing pond waters containing 10^[4~6] viable cells/ml indicated that U.V. radiation is an effective means of destroying microorganisms in the hatchery water supply. However, a tendency towards U.V. resistance was shown by some groups of water microflora, e.g. Coryneforms, or yeastlike organisms. 2重管式紫外線流水殺菌装置（西武化学・CS-50-U型）に2台の渦流ポンプ，流量計などを組合せ，流水量を最大14l/minまで可変な装置を用い，養魚用水の殺菌についての基礎的実験を行ない，次のような結果を得た。1. Aeromonas salmonicidaなど5種の魚病原因菌ならびに対照のEscherichia coilの10^[5～7]cells/ml懸濁液を用いた実験では，流量8.5l/minまたはそれ以下，紫外線照射量約22,100μW・sec/cm2以上の場合，いずれの供試菌においても99.99%以上の殺菌効果が認められた。2. 生菌数10^[4～6]/mlを含む養魚池の水を用いた実験でも同様にきわめて良好な殺菌効果が認められたが，試水菌叢中CoryneformsやYeastなど一部のものに若干紫外線に対する感受性の低い傾向が認められた。