Submitted to: North American Journal of Aquaculture
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/3/2009
Publication Date: N/A
Interpretive Summary: Fungal egg infections are a significant problem for commercial channel catfish hatcheries. Prior to this year, formalin was the only U.S. FDA-approved aquaculture drug for the control of fungi on fish eggs. However, formalin is disliked by many catfish producers because of its smell and perceived carcinogenicity. The recent FDA-approval of 35% PEROX AID® for treating fungi on fish eggs gave catfish producers an alternative to formalin. Unfortunately, it too has not been well received by commercial hatchery staff because, as a strong liquid oxidant, hydrogen peroxide irritates and burns the skin. As a free-flowing granular substance, sodium carbonate peroxyhydrate (SCP) was identified as a potential alternative to liquid hydrogen peroxide. SCP is made by combining two molecules of sodium carbonate with three molecules of hydrogen peroxide, thus yielding a 32% hydrogen peroxide compound. In our studies, catfish egg masses treated with SCP at concentrations yielding optimal hydrogen peroxide concentrations had no visible fungus and significantly improved hatch rates. SCP proved to be an attractive alternative to liquid hydrogen peroxide for use in catfish hatcheries; however, SCP can affect water pH. As such, SCP deserves further research in support of its use in fish hatcheries.
Technical Abstract: Two experiments were conducted to evaluate the efficacy of sodium carbonate peroxyhydrate (SCP) for improving channel catfish Ictalurus punctatus hatching success when used as a prophylactic chemotherapeutant during egg incubation. In the first experiment, efficacy of SCP was evaluated in 379-L, aluminum incubation troughs similar to those used in commercial hatcheries. Egg masses treated daily with 254 mg SCP/L had a significantly (P < 0.05) improved mean hatching success compared to untreated controls. The fungistatic effect of the 254 mg/L concentration was also evident; no fungus was observed on the treated egg masses. In the second experiment, the hatching success of egg masses treated daily with 254 mg SCP/L were compared to those treated daily with hydrogen peroxide (70 mg/L). The effect of both treatments on pH, dissolved oxygen (DO), and hydrogen peroxide concentrations in the trough were also examined. The SCP treatment was statistically (P < 0.05) as good as hydrogen peroxide at improving hatching success. Unlike treatment with hydrogen peroxide, water pH increased during treatment with SCP; however, no negative effects on hatching success were observed. The results of this research show SCP acts similarly to hydrogen peroxide on the improvement of channel catfish hatching success and suggests SCP could be an alternative to hydrogen peroxide for managing fungal egg infections.