Comparative efficacy of PycezeReg. (bronopol) in controlling mortality of brown trout Salmo trutta eggs.

摘要

The efficacy of PycezeReg. (Novartis Animal Vaccines) and ProxitaneReg. 0510 (Solvay Interox) in controlling the mortality of eggs was studied in brown trout Salmo trutta eggs under the usual incubation conditions in a hatchery affected by saprolegniosis. Eggs from eight spawnings and from two lines of brown trout were used. The cumulative mortality of eggs at the start of the eyed stage (M1) and at hatching (M2) was measured, as was the percentage of eggs with fungal infection at weekly intervals during the green stage. Mortality at M2 with PycezeReg. ranged between 2.38% and 12.61% depending on the batch, with a mean of 6.10%. Mortality at M2 with ProxitaneReg. varied between 5.83% and 43.86%, with a mean of 22.36%. Fungal colonization at the start of the eyed stage ranged between 0% and 0.15% when PycezeReg. was used and between 0.82% and 12.50% with ProxitaneReg.. Mortality rates were higher among those eggs left untreated. The results indicate that PycezeReg. (bronopol) is efficacious in controlling mortality caused by Saprolegnia spp. and other biological factors in fertilized brown trout eggs, as has been demonstrated previously in other salmonid species..