EVALUATION OF COMPOUNDS AND STRATEGIES FOR CONTROLLING AQUATIC ANIMAL DISEASE
Location: Harry K. Dupree Stuttgart National Aquaculture Research Center
Title: Comparison of percent hatch and fungal infestation in channel catfish eggs after copper sulfate, diquat bromide, formalin, and hydrogen peroxide treatment
Submitted to: North American Journal of Aquaculture
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: December 3, 2009
Publication Date: June 1, 2010
Citation: Mitchell, A.J., Straus, D.L., Farmer, B.D., Carter, R.R. 2010. Comparison of percent hatch and fungal infestation in channel catfish eggs after copper sulfate, diquat bromide, formalin, and hydrogen peroxide treatment. North American Journal of Aquaculture. 72:201-206.
Interpretive Summary: Fungal infestations on channel catfish eggs lower the hatch rate (survival) and ultimately the number of young catfish available for stocking in production ponds. This paper compares the effect of 4 chemicals used to prevent fungal growth on catfish eggs to help increase egg survival. Hydrogen peroxide (250 mg/L), copper sulfate (10 mg/L), diquat bromide (25 mg/L), and formalin (433 mg/L) were all shown to significantly increase egg survival and all but diquat bromide significantly reduced fungal growth on eggs when compared to eggs not treated with the chemical. Although there was no statistical difference between the 4 chemicals, hydrogen peroxide increased egg survival by 8% above the other chemicals and produced lower fungal growth and occurrence than the other chemicals.
Reduced survival is often a result of fungal (Saprolegnia spp.) infestation of fish eggs. However, timely chemical treatments often limit these infestations and increase survival. The effect of copper sulfate pentahydrate (CSP - 10 mg/L), diquat bromide (25 mg/L diquat cation), formalin (433 mg/L), and hydrogen peroxide (H2O2 - 250 mg/L) on the percent hatch and on fungal infestation of channel catfish eggs was compared in two identical trials (5 replicates for each chemical treatment per trial). The percent hatch in all chemical treatments was significantly better than those of the controls. The amount fungal coverage on egg masses treated with CSP, formalin, and H2O2 was significantly less than that found in the controls. Although not statistically different from the other treatments, H2O2 at 250 mg/L exhibited the highest average percent hatch (64%, control was 34%), the lowest fungal coverage (1.5 cm, control was 7.2 cm), and the lowest occurrence of fungi (50%, control was 100%).