Gaikowski, M.P., J.J. Rach, W.H. Gingerich, and G.R. Stehly.  1998.  Hydrogen peroxide 
treatment toxicity to rainbow trout eggs.  Part 1: Safety. Final report submitted to Division of 
Therapeutic Drugs for Food Animals, Center for Veterinary Medicine (FDA).  April 24, 1998.  
289 pp.



The data collected for this report was initially collected as described by the protocol 
“Toxicity of hydrogen peroxide to salmonid eggs and fry”, study number TOX-94-
00048-4.  After initial data collection, it became apparent to the study director that 
changes were required to collect data that would more accurately describe the toxicity of 
numerous antifungus agents, therefore, the protocol “Toxicity of hydrogen peroxide to 
eggs and fry of cold-, cool-, and warmwater fish species”, study number CAP-96-00048-
2, was drafted.  A memo (Appendix 1) was submitted by the study director to the Quality 
Assurance Officer at the Upper Mississippi Science Center on 06 February, 1997, 
combining the data from both studies under one encompassing study number, CAP-96-
00048-2.  The margin of safety existing for standard hydrogen peroxide egg treatments 
was determined; the common egg treatment regime used by hatcheries is a fifteen minute 
treatment at 500 ?L/L hydrogen peroxide every weekday (Mon.-Fri.) from fertilization 
through hatch.  Fifteen minute hydrogen peroxide treatments (0, 500, 1000, and 3000 
?L/L) were administered every weekday (Monday-Friday) to eggs from three lots of 
rainbow trout (Oncorhynchus mykiss) and two strains of steelhead trout.  The treatment 
concentrations used were multiples of the Low Regulatory Priority limit of 500 ?L/L and 
were administered to rainbow trout and steelhead trout eggs incubated and exposed to 
hydrogen peroxide in miniature egg jars (one week after hatch) to assess treatment 
toxicity.  Treatment toxicity was evaluated based on the proportion of hatched fry (live 
and dead) to the total number of exposed eggs.  The proportion of hatched fry to the total 
number of exposed eggs was inversely related to treatment concentration.  Control and 
treated eggs from all lots tested remained free of fungal infection throughout incubation. 
The results of toxicity testing indicate that hydrogen peroxide significantly reduced the 
probability of hatch in a dose-dependent manner.  Mean percent hatch of the control eggs 
from the three rainbow trout lots was 78.4 to 94.1%.  Hydrogen peroxide treatment 
reduced the mean percent hatch of the three rainbow trout egg lots to 77.2 to 92.1% when 
treated at 500 ?L/L, 67.7 to 86.7% when treated at 1000 ?L/L, and 57.8 to 79.0% when 
treated at 3000 ?L/L.  Mean percent hatch of Skamania steelhead was significantly 
reduced by hydrogen peroxide treatment, whereas no other strains tested had similar 
mortality at these concentrations.  Dose-dependent mortality of sac-fry was not observed 
at hydrogen peroxide concentrations <1000 ?L/L.  Increased fry mortality was observed 
when eggs and fry were treated at 3,000 ?L/L hydrogen peroxide.