Submitted to: Book of Abstracts World Aquaculture Society
Publication Type: Abstract Only
Publication Acceptance Date: November 25, 2003
Publication Date: March 1, 2004
Citation: Small, B.C. 2004. Effect of temperature on hydrogen peroxide efficacy as an egg disinfectant for channel catfish. Aquaculture 2004, Honolulu, HI. p. 548. Technical Abstract: Fungal and bacterial egg infections can be a significant problem in channel catfish hatcheries. Dead eggs and other organic matter in hatchery culture systems provide excellent substrates for fungi and bacteria. Without chemotherapeutic treatment, these pathogens can quickly overtake the egg mass and significantly reduce embryo survival. Hydrogen peroxide (H2O2) has been investigated as a potential treatment to control egg diseases for a number of fish species, and is currently designated by the U.S. FDA as a low regulatory priority aquaculture drug when administered as a 250-500 mg/L bath. Hydrogen peroxide is a powerful oxidizing agent, effective against many egg and fish pathogens including fungi, bacteria and ectoparasites. Hydrogen peroxide is also considered to be environmentally friendly since it decomposes to water and oxygen. Discrepancies in the literature regarding hydrogen peroxide efficacy as an egg disinfectant may be due in part to water temperature differences between studies. We examined the effect of temperature on H2O2 efficacy by incubating channel catfish eggs at 28 degrees Celsius and 24 degrees Celsius. Eggs at each temperature were treated with 0, 100, 250, 500, and 1000 mg/L H2O2 as a daily 15-min bath. At 28 degrees Celsius, embryo survival was significantly higher when treated with 100 mg/L H2O2, and at 24 degrees Celsius, embryo survival was highest among the 500 and 1000 mg/L treatments. Previously published data from our laboratory indicated that at 26 degrees Celsius, a daily, 15-min 250 mg/L H2O2 bath was optimal for maximizing catfish embryo survival. This concentration (250 mg/L at 26 degrees Celsius) is intermediary of the results obtained at 28 degrees Celsius and 24 degrees Celsius. Together these data support the hypothesis that efficacy of H2O2 as an egg disinfectant is temperature dependent. The effect of water temperature on hydrogen peroxide activity should be considered when developing treatment protocols for disinfecting channel catfish eggs.