A Saprolegnia parasitica challenge system for rainbow trout: assessment of Pyceze as an anti-fungal agent for both fish and ova.
A reproducible Saprolegnia parasitica spore delivery system was developed and demonstrated to be effective in providing a sustained spore challenge for up to 10 d. Treatment of rainbow trout with slow-release intraperitoneal implants containing cortisol resulted in chronically elevated blood cortisol levels and rendered the fish susceptible to infection by S. parasitica when exposed to the spore challenge. Sham-implanted fish were not susceptible to infection. Bronopol (2-bromo-2-nitro-propane-1,3-diol), formulated as Pyceze, was effective in protecting predisposed fish from infection by S. parasitica when administered as a daily bath/flush treatment at concentrations of 15 mg l-1 and greater. Pyceze was also demonstrated to protect fertilised rainbow trout ova from S. parasitica challenge when administered as a daily bath/flush treatment at concentrations of between 30 and 100 mg l-1. Pyceze appears to qualify as a safe and effective replacement for malachite green and formalin in the prevention of fungal infections in the aquaculture environment.
NERC Institute of Freshwater Ecology, Windermere Laboratory, Cumbria, United Kingdom. t.pottinger@ife.ac.uk
T G
TG
Pottinger
J G
JG
Day
D000818:Animals; D000900:Anti-Bacterial Agents / Q000032:analysis / Q000494:pharmacology / Q000627:therapeutic use*; D004305:Dose-Response Relationship, Drug; D004343:Drug Implants; D005393:Fish Diseases / Q000188:drug therapy* / Q000382:microbiology; D006854:Hydrocortisone / Q000008:administration & dosage / Q000097:blood / Q000627:therapeutic use; D007166:Immunosuppressive Agents / Q000008:administration & dosage / Q000627:therapeutic use; D007239:Infections / Q000188:drug therapy / Q000382:microbiology / Q000662:veterinary*; D017686:Oncorhynchus mykiss; D009868:Oomycetes / Q000187:drug effects / Q000502:physiology; D011409:Propylene Glycols / Q000032:analysis / Q000494:pharmacology / Q000627:therapeutic use*; D013170:Spores / Q000187:drug effects; D013739:Testosterone / Q000008:administration & dosage / Q000627:therapeutic use; D014867:Water / Q000032:analysis
D000900:Anti-Bacterial Agents; D004343:Drug Implants; D007166:Immunosuppressive Agents; D011409:Propylene Glycols; D014867:Water; D013739:Testosterone; C006827:bronopol; D006854:Hydrocortisone