Peracetic acid is effective for controlling fungus on channel catfish eggs

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 (Rafinesque), eggs. The study consisted of five PAA concentrations (2.5, 5, 10, 15 and 20mgL(-1) ) 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 10mgL(-1) PAA were significantly different from the controls (P<0.05). The highest percent survival of hatched fry was with 5mgL(-1) PAA administered twice daily; the 2.5mgL(-1) 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 2.5mgL(-1) PAA or higher, and concentrations of 15 and 20mgL(-1) PAA were toxic to the eggs. The mean survivals in the 0, 2.5, 5, 10, 15 and 20mgL(-1) PAA treatments were 11%, 60%, 63%, 62%, 32% and 0%, respectively. Therefore, PAA may be a compound that merits further investigations regarding its use in U.S. aquaculture.