| Hydrogen peroxide and its primary decomposition products, oxygen and water, are considered environmentally compatible. The apparent lack of adverse environmental impacts of hydrogen peroxide combined with its effectiveness as an antimicrobial agent makes this compound an excellent candidate for further evaluation in aquaculture. Hydrogen peroxide is currently being evaluated for its potential as a therapeutic compound for a variety of external disease organisms of fish. Research in our laboratory focused on delineating effective hydrogen peroxide dosing regimes for treating bacterial gill disease in rainbow trout and walleye. The primary goals of these studies were to document the effects of hydrogen peroxide on the pathology, blood chemistry parameters, and indices of antioxidiant defense status of the target species.; The toxicity of hydrogen peroxide to fish seems to be dependent on factors such as species, age, dose water temperature and extent of exposure. Walleyes were more sensitive than rainbow trout to treatments with hydrogen peroxide. Older fish were more susceptible to exposure to hydrogen peroxide than younger fish. Acute toxicity was evident from histopathologic inspection of gills (e.g. extensive epithelial lifting, necrosis) of fish treated with high doses of hydrogen peroxide. A digitalized scoring method was developed to quantify the severity of the gill lesions. The index was a good indicator of the toxicity of hydrogen peroxide as well as of the degree of recovery of the gill epithelium of treated fish.; The value of hydrogen peroxide as a therapeutic compound for use in walleye culture has been questioned due to the high sensitivity of walleyes to this compound at suggested treatment levels. Studies indicated that exposure of walleye to low levels of hydrogen peroxide resulted in increased tolerance to subsequent exposure. One possible mechanism involved in the modification of tolerance of fish to treatment with hydrogen peroxide (e.g. induction of antioxidant enzymes such as catalase, glutathione peroxidase and superoxide dismutase) was investigated. This phenomenon of increased tolerance may be of value in the development of management strategies that will permit the use of hydrogen peroxide with walleyes and other sensitive species. |
