实验研究了离体条件下温度对坏鳃指环虫(Dactylogyrus vastator)产卵和孵化的影响,以及在20℃、在体条件下坏鳃指环虫的产卵和发育过程。在离体条件下,坏鳃指环虫的平均产卵量随着温度的升高而增加,在4、10、20、30和35℃时,其平均产卵量分别为0.25、5.9、9.1、9.2和13.4枚/虫;除4℃外,绝大多数虫卵是在离体后的前5h内产出;然而,在体条件下虫体的产卵是连续且稳定的,在20℃条件下平均产卵量为6.5枚/(虫·d)。虫卵的孵化时间和孵化持续的时间随着温度的升高而减少,在10、20、30和35℃条件下,孵化时间和孵化持续时间分别为19d、3d、2d、36h和24d、5d、5d、3d,而最高的孵化率(65.5%)却出现在30℃。在20℃条件下,纤毛幼虫在感染7d后90%的虫体都已成熟,因此,在此温度条件下坏鳃指环虫由虫卵发育到成虫大约需要8—10d。为了有效控制指环虫病的暴发,在第一次用药1周后要进行第二次用药。
The effects of water temperature on egg laying and hatching in vitro were investigated, and egg laying and development in vivo at 20℃ were also characterised. The results indicated a positive correlation between mean egg production and temperature in vitro, and the mean egg production was 5.9, 9.1, 9.2 and 13.4 eggs/worm at 10, 20, 30 and 35℃, respectively. Except 4℃, majority of the eggs were laid during the first 5h. However, egg laying of the mature worms was continuous and uniform, with a mean 6.5 eggs/worm at 20℃ per day. Although the hatching time and the duration of hatching declined with increasing temperature, with 19 d, 3d, 2d, 36 h and 24 d, 5d, 5d, 3d at 10℃, 20℃, 30℃ and 35℃, respectively, the highest hatching success was observed at 30℃. Ninety percent of worms reached maturity within 7 days post-infection when exposed to 20℃. The life-cycle of D. vastator from egg to sexual maturity lasted for 8 to 11 days which indicated that a second treatment should be administered a week later at 20℃.