Title: Peracetic acid is effective for controlling fungus on channel catfish eggs Authors
Submitted to: Journal of Fish Diseases
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: November 13, 2011
Publication Date: June 10, 2012
Citation: Straus, D.L., Meinelt, T., Farmer, B.D., Mitchell, A.J. 2012. Peracetic acid is effective for controlling fungus on channel catfish eggs. Journal of Fish Diseases. 35:505-511. Interpretive Summary: Peracetic acid (PAA) is used to disinfect wastewater, and to sterilize items for the food industry and hospitals; in Europe it is also approved for aquaculture. Peracetic acid is basically a mixture of acetic acid (very concentrated vinegar) and hydrogen peroxide (HP). This study was designed to see if PAA can be used in the catfish industry by hatchery managers to prevent fungus from growing on eggs while they are incubated in hatching troughs with flow-through well water. We found a safe treatment rate was 2.5 parts per million PAA. This rate is very low and PAA is flushed out of the troughs quickly. Advantages to using PAA are that it does not produce any residues that would harm fry or the environment and it degrades to harmless residues rapidly. Research like this is important information that is needed by the catfish industry to fight fungus problems on eggs.
Technical Abstract: Peracetic acid (PAA) is a relatively new compound suggested for use to treat pathogens in aquaculture. It is approved for use in Europe, but not in the United States. This study determined the effectiveness of PAA for fungus control on channel catfish Ictalurus punctatus eggs. The study consisted of five PAA concentrations (2.5, 5, 10, 15 and 20 mg/L) and an untreated control in a flow-through system. A single spawn was used for each replication (N=4). Eggs were treated twice daily until the embryos developed eyes. When hatching was complete for all viable eggs, fry were counted to determine the percent survival in each treatment. Fungal growth was severe in the untreated controls resulting in 11% survival. Treatments of 2.5, 5 and 10 mg/L PAA were significantly different from the controls (P < 0.05). The highest percent survival of hatched fry, was 5 mg/L PAA administered twice daily; the 2.5 mg/L PAA treatment had slightly less survival, but gives a higher margin of safety in case of treatment error. Very little fungus was present in treatments receiving 2.5 mg/L PAA or higher, and concentrations of 15 and 20 mg/L PAA were toxic to the eggs. The mean survival in the 0, 2.5, 5, 10, 15 and 20 mg/L PAA treatments were 11, 60, 63, 62, 32 and 0%, respectively. Therefore, PAA may be a novel compound which merits further investigations regarding its use in U.S. aquaculture.