IPNVウイルス接種時水温と飼育水温がニジマス稚魚のへい死に及ぼす影響

概要

論文の詳細を見る
The influence of immersing temperature for inoculation with IPNV and/or rearing temperatureon mortality of rainbow trout fry Salmo gairdneri postinfection was studied. An IPNV-Buhl strain which is the most dominant IPNV-serotype in Japan was used as a challenge virus and a highlysensitive strain to IPNV (RT-101 strain, 0.13g in B. W.) was used as an experimental fish in this study. The fry was immersed in 105.0 TCID50/ml of IPNV at 5, 10, 15 and 20°C for 1h and each group was shifted up or down to 5, 10, 15 and 20 and incubated for 28 days. As the results ob-tamed, rearing temperature influenced the cumulative mortality of rainbokw trout fry postinfection and the mortality pattern but immersing temperature for inoculation with IPNV did not. The IPNV-Buhl strain shows low or no cumulative mortaility at 5°C and as high a mortality as≥70% cumulative mortality at 10-20°C for the fish. At 20°C the death of fry started 3 days after inocula-tion in spite of the different immersing temperature and the mortality pattern was the acutest, namely 50% daily mortality appeared on the first or second day after the first death. Although the cumulative mortality at 10 and 15°C was about the same as at 20°C the daily mortality tended to become lower and the death of fry appeared until later, e. g. until 2 weeks after inoculation at 15°C and 3 weeks at 10°C.